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Re: Fast Warming ?

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  • F Cote
    I don t know if the science on this will wash in the final analysis but it tends to support the claim that we are playing an unbelievably stupid and dangerous
    Message 1 of 9 , Dec 3, 2002
      I don't know if the science on this will wash in the final analysis
      but it tends to support the claim that we are playing an unbelievably
      stupid and dangerous game with our planet's life support systems. As
      the various conflicting projections (with varying degrees of
      scientific credibility) demonstrate, humankind does not understand
      (to any sufficient degree of certainty) how our planet's life support
      systems work. Yet despite this fatal ignorance, we continually
      disrupt the operation of natural energy and matter transport cycles
      upon which our species' very survival depends. The only image that
      comes to mind is that of a mad woodcutter high in a tree busily
      sawing off the branch upon which he sits. This is folly folks, folly
      of the highest degree! Until we know at least, how the planet's life
      support systems operate we should not be disrupting them in the
      stupidly cavalier manner as we are now doing. Our golden rule should
      be: if it ain't broke, don't fix it.

      If, in fact, this "little ice age" scenario turns out to be
      correct, it merely reinforces my above argument since the rapid
      cooling scenario would most likely be even more catastrophic
      economically, ecologically, demographically, climatologically and
      geopolitically than the moderately rapid warming scenario which at
      present seems to represent the consensus of climatologists.



      --- In globalwarming@y..., "Banzai (Lance Stinson)" <banzai@m...>
      wrote:
      > A perspective on potential climate changes presented by Dr. Robert
      B.
      > Gagosian, President and Director of Woods Hole Oceanographic
      > Institution
      >
      > http://www.whoi.edu/home/about/whatsnew_abruptclimate.html
      >
      > Over the past two decades, we have heard about greenhouse gases and
      > the idea that our planet is gradually warming. I'd like to throw a
      > curveball into that thinking—specifically the "gradually
      warming"
      > part.
      >
      > This new thinking is little known and scarcely appreciated by
      > policymakers and world and business leaders—and even by the
      wider
      > community of natural and social scientists. But evidence from
      several
      > sources has amassed and coalesced over the past 10 to 15 years. It
      > points to a completely different—almost coun
      terintuitive—scenario.
      >
      > Global warming could actually lead to a big chill in some parts of
      > the world. If the atmosphere continues to warm, it could soon
      trigger
      > a dramatic and abrupt cooling throughout the North Atlantic
      region—
      > where, not incidentally, some 60 percent of the world's economy is
      > based.
      >
      > When I say "dramatic," I mean: Average winter temperatures could
      drop
      > by 5 degrees Fahrenheit over much of the United States, and by 10
      > degrees in the northeastern United States and in Europe. That's
      > enough to send mountain glaciers advancing down from the Alps. To
      > freeze rivers and harbors and bind North Atlantic shipping lanes in
      > ice. To disrupt the operation of ground and air transportation. To
      > cause energy needs to soar exponentially. To force wholesale
      changes
      > in agricultural practices and fisheries. To change the way we feed
      > our populations. In short, the world, and the world economy, would
      be
      > drastically different.
      >
      > And when I say "abrupt," I mean: These changes could happen within
      a
      > decade, and they could persist for hundreds of years. You could see
      > the changes in your lifetime, and your grandchildren's
      grandchildren
      > will still be confronting them.
      >
      > And when I say "soon," I mean: In just the past year, we have seen
      > ominous signs that we may be headed toward a potentially dangerous
      > threshold. If we cross it, Earth's climate could switch gears and
      > jump very rapidly—not gradually— into a completely
      different mode
      of
      > operation.
      >
      >
      > A schematic of the ocean circulation system, often called the Great
      > Ocean Conveyor, that transports heat throughout the world oceans.
      Red
      > arrows indicate warm surface currents. Blue arrows indicate deep
      cold
      > currents. (Animation by Jack Cook, WHOI)
      > This is not something new under the Sun. It has happened throughout
      > Earth's history, and it could happen again.
      >
      > The key to these climate shifts is that Earth's climate is created
      > and maintained by a dynamic system of moving, interacting parts.
      > Earth's climate system has two main components. The first one you
      are
      > all familiar with by watching your local TV meteorologist or The
      > Weather Channel. It is the atmosphere, which circulates heat and
      > moisture around the globe. But, in fact, the atmosphere
      redistributes
      > only about half of the energy that the earth receives from the Sun.
      >
      > The other half is transported around our planet by a circulation
      > system that is equally important, but far less understood—the
      ocean.
      > The ocean isn't a stagnant bathtub. It circulates heat around the
      > planet like the heating and cooling system in your house. The
      > atmosphere and oceans are equal partners in creating Earth's
      climate.
      > The atmosphere is a rabbit. It moves fast. Rapid changes in
      > atmospheric circulation cause storms, cold spells, or heat waves
      that
      > play out over several days.
      >
      > The ocean, on the other hand, is a turtle. It may take years or
      > decades or even millennia for similar "disturbances" to circulate
      > through the ocean. But the ocean is a big turtle. It stores about
      > 1,000 times more heat than the atmosphere. So changes in ocean
      > circulation can set the stage for large-scale, long-term climate
      > changes.
      >
      > One example that you may be familiar with is El Niño. Every few
      > years, oceanic conditions shift, and surface water temperatures in
      > the eastern tropical Pacific get warmer. The atmosphere above the
      > ocean shifts, too. El Niño rearranges worldwide wind and
      rainfall
      > patterns, causing destructive droughts, floods, storms, and forest
      > fires. Not to downplay El Niño in the least, because it causes
      grave
      > human suffering and billions of dollars in damage—but El
      Niño is
      > relatively short-lived. It lasts only a year or two.
      >
      > The climate changes I'm concerned about last longer and involve the
      > ocean circulation system that spans the entire globe—which we
      often
      > call the Great Ocean Conveyor.
      >
      > The Great Ocean Conveyor is the ocean's major heat-circulating
      > system. The ocean keeps our planet from overheating by transporting
      > heat north and south, from the equator to the poles, in currents
      > traveling near the ocean surface. In the Atlantic, the Conveyor
      > removes heat from the Southern Hemisphere and releases it to the
      > Northern Hemisphere.
      >
      >
      > The Great Ocean Conveyor is propelled by the sinking of cold, salty
      > (and therefore denser) waters in the North Atlantic Ocean (blue
      > arrows). That creates a void that pulls warm, salty Gulf Stream
      > waters northward (red arrows). The Gulf Stream gives up its heat to
      > the atmosphere above the North Atlantic Ocean, and prevailing winds
      > (large red arrows) carry the heat eastward to warm Europe.
      (Animation
      > by Jack Cook, WHOI)
      > The most famous and most important of these currents is the Gulf
      > Stream. The vast Gulf Stream transports the equivalent volume of 75
      > Amazon Rivers. It carries heat absorbed in the tropics, and moves
      up
      > the East Coast of the United States, then northeastward toward
      > Europe.
      >
      > When the Gulf Stream's warm, salty waters reach colder latitudes,
      > they give up their heat to the atmosphere. The atmosphere in the
      > North Atlantic region warms by as much as 10 degrees Fahrenheit.
      > Prevailing winds carry the heat eastward into Europe. That's one
      > reason London, England—which is located at the same latitude as
      > Calgary and Edmonton—has warmer winters than New York—which
      is
      > hundreds of miles farther south.
      >
      > When the Gulf Stream's waters reach the Labrador, Greenland and
      other
      > northern seas, and lose their heat to the atmosphere, they become
      > colder—and hence denser. The waters are also relatively salty.
      Salty
      > water is denser than fresher water, so the whole salty mass begins
      to
      > sink to great depths.
      >
      > When this sinking mass of cold water reaches the abyss, it then
      flows
      > at deep levels of the ocean, from the North Atlantic southward into
      > the South Atlantic. The plunge of this great volume of cold, salty
      > water propels the Great Ocean Conveyor. And on the back end, it
      > creates a void that actively pulls the Gulf Stream northward to
      > replace the waters that are sinking.
      >
      > It's a pretty neat system. We have been operating under the climate
      > conditions created by this beneficent oceanic heating, ventilation,
      > and cooling system for centuries.
      >
      > But what if this system weren't operating today? What if cold North
      > Atlantic waters didn't sink and warm equatorial waters weren't
      drawn
      > in to replace the sinking waters? Then the North Atlantic region
      > would be a much different, much colder place.
      >
      > The vast majority of us go about our business thinking that Earth's
      > climate system has always been this way, and always will be. But
      that
      > is just not the case. In fact, we know that the Ocean Conveyor has
      > indeed shut down—stopped operating—in the past.
      >
      > We know this by examining truly interesting and valuable natural
      > archives that record past changes in Earth's climate. For example,
      we
      > can see layers within ice sheets in Greenland or in high elevations
      > in the Andes Mountains in South America. This layering is caused by
      > variations in the amount of snow that fell on the top of the ice
      > sheet in the past.
      >
      >
      >
      > Top: Ice sheets reveal annual layers, which scientists can analyze
      to
      > reconstruct the history of precipitation and air temperatures
      100,000
      > years in the past. (Photo by Lonnie Thompson, Ohio State
      University)
      > Bottom: Cores of seafloor sediments reveal the climate history of
      the
      > ocean. (Photo by Ken Buesseler, WHOI)
      > The light and dark bands within the ice sheet show an annual cycle
      of
      > dust in the atmosphere, so each couplet reflects the amount of snow
      > that fell in one year. By analyzing the chemistry of the ice
      itself,
      > scientists can determine the temperature of the atmosphere when the
      > snow was produced.
      >
      > Thus from a single ice sheet record, it is possible to reconstruct
      > the past history of precipitation and air temperature in a region.
      > For very old ice sheets, like the glaciers on Greenland, it is
      > possible to reconstruct this climate history 100,000 years into the
      > past.
      >
      > The ocean has similar archives of past climate. By taking cores
      from
      > the ocean floor, it is possible to reconstruct the history of ocean
      > climate back many thousands of years. We have used our ships to
      > collect samples of sediments from the seafloor. Preserved in the
      > sediments are the fossil remains of microscopic organisms that
      settle
      > to the seafloor. They accumulate over time in layers—similar to
      the
      > ice core—that delineate many important aspects of past climate.
      >
      > For instance, certain organisms are found only in colder, polar
      > waters and never live in warmer waters. They can reveal where and
      > when cold surface waters existed—and didn't exist—in the
      past.
      >
      > From records like these, we know that about 12,800 years ago, North
      > Atlantic waters cooled dramatically—and so did the North
      Atlantic
      > region. This large cooling in Earth's climate occurred in about a
      > decade. And the cold spell lasted for about 1,300 years.
      >
      > This period is called the Younger Dryas, and it is just one of
      > several periods when Earth's climate changed very rapidly from warm
      > to cold conditions, and then back to warm again. So these long-term
      > cold snaps are not unusual.
      >
      > These shifts almost certainly involved changes in the ocean's
      > circulation. There were shutdowns and restartings of the Ocean
      > Conveyor. These warm-to-cold transitions happen in about 3 to 10
      > years. The cold periods lasted for 500 to 1,000 years. Such
      > oscillations in temperature and ocean circulation have occurred on
      a
      > regular basis.
      >
      > About 1,000 years ago, during a period of unusually warm
      temperatures
      > in the North Atlantic, the Norse established settlements and
      > vineyards in Greenland that would not be possible today. Those
      > settlements were abandoned about 500 years ago, when we believe the
      > most recent shutdown of the North Atlantic Ocean circulation system
      > occurred.
      >
      > During that era, called the Little Ice Age, northern Europe was
      much
      > colder than it is today. Glaciers spread outward and downward in
      the
      > Alps. Winters, on average, were more severe. Farming was affected.
      > Famine was frequent.
      >
      > In the 1730s and 1740s, abrupt European cooling caused famine
      across
      > western Europe, especially in Ireland and France, where farmers
      > depended on wheat and potatoes. In Ireland, this is known as
      > the "forgotten famine." As many people died during the forgotten
      > famine as died during the famed potato famine of the 1840s.
      >
      > The 16th-century Flemish artist Bruegel couldn't have painted his
      > famous frozen landscapes today, because now canals in the
      Netherlands
      > rarely freeze, as they regularly did back then. And likewise, the
      > winter in Valley Forge might not have been so cold, and
      Washington's
      > crossing of the ice-bound Delaware River wouldn't have been so
      > dramatic, if he had done it a century later—because our climate
      > conditions have shifted since then, and today, the Delaware River
      > rarely freezes.
      >
      > If you read David McCullough's biography of John Adams, you will
      > remember that the British were about to set Boston on fire when
      > George Washington was able to bring the cannons of Fort Ticonderoga
      > down from upstate New York in record time. He was able to do it
      > because the ground was frozen solid and they could slide the
      cannons
      > to the Dorchester hills of Boston in time to persuade the British
      to
      > retreat from Boston and to change the course of history.
      >
      > So we have solid evidence that the Great Ocean Conveyor has slowed
      > down or shut down in the past. And we have seen dire impacts on our
      > climate. It begs the question: Could something throw a wrench into
      > the Great Ocean Conveyor in the near future? And could that trigger
      > abrupt, dramatic climate changes throughout our planet? The answers
      > to those questions are, indisputably, "Yes and yes."
      >
      >
      > Like most dynamic systems, Earth's climate seeks a stable mode (top
      > tier). If the system is pushed, it will stagger for a while unitl
      it
      > recovers (middle tier). If it is pushed past a threshold, it will
      > shift into another mode of operation (bottom tier). (Illustration
      by
      > Jack Cook, WHOI, adapted from Abrupt Climate Change, Inevitable
      > Suprises National Research Council)
      > Another way to look at Earth's climate system is a simple mode of
      > balances (see diagram, left). Like most dynamic systems, Earth's
      > climate seeks a stable mode. And it will tend to stay in that mode
      if
      > nothing causes it to change. That's the top tier of the diagram.
      The
      > ball remains ensconced in its cup.
      >
      > The middle tier shows what happens if you push on the system. The
      > ball will rattle and roll around in different directions for a
      while
      > until it settles back down in its cup. We humans would definitely
      > notice that rattling until the climate system returned to
      > equilibrium. The balance, forced to move, staggers but recovers.
      >
      > Then there is a third situation— in which a strong enough push
      at
      the
      > right time could shove the system past a threshold and into a
      > completely different mode of operation. In terms of our climate
      > system, that means that a small or temporary forcing could produce
      a
      > sudden, large, and long-lasting change. That begs the next
      question:
      > What could do that to our climate system today?
      >
      > One answer to that is fresh water. If you simply add too much fresh
      > water to the North Atlantic, the waters there will become less
      salty
      > and less dense. They will stop sinking. Then the Gulf Stream slows
      > down or is deflected southward. Winters in the North Atlantic
      region
      > get significantly colder.
      >
      > Now here's the predicament. In the past year, oceanographers
      > monitoring and analyzing water conditions in the North Atlantic,
      have
      > concluded that the North Atlantic has been freshening
      dramatically—
      > especially in the past decade. New data —from Ruth Curry at
      Woods
      > Hole Oceanographic Institution and her colleague Robert Dickson at
      > the British Centre for Environment, Fisheries, and Aquaculture
      > Science—chronicles salinity changes in the western North
      Atlantic
      > since 1960.
      >
      > The Great Ocean Conveyor transports fresh surface water down into
      the
      > depths. The depths can absorb a lot of fresh water like a sponge.
      But
      > since 1970, the equivalent of an extra 20 feet of fresh water
      across
      > the surface of the northern North Atlantic has been transported
      down
      > into the ocean depths, most of that since 1990.
      >
      > A sponge that is three-quarters saturated can still absorb more
      > water. But the moment that sponge is fully saturated, it can absorb
      > no more water.
      >
      >
      > If too much fresh water enters the North Atlantic, its waters could
      > stop sinking. The Great Conveyor would cease. Heat-bearing Gulf
      > Stream waters (red arrows would no longer flow into the North
      > Atlantic, and winters would become more severe. (Animation by Jack
      > Cook, WHOI)
      > At some point, the North Atlantic will no longer absorb any more
      > fresh water. It will begin to pile up on the surface. When that
      > happens, the Great Ocean Conveyor will be clogged. It will back up
      > and cease functioning.
      >
      > The very recent freshening signal in the North Atlantic is arguably
      > the biggest and most dramatic change in ocean property that has
      ever
      > been measured in the global ocean. Already, surface waters in the
      > Greenland Sea are sinking at a rate 20 percent slower than in the
      > 1970s.
      >
      > At what percent will the Ocean Conveyor stop? 25 percent? 40
      percent?
      > 60 percent? This is not like a dimmer switch, but more like a light
      > switch. It probably goes from "on" to "off."
      >
      > We can't yet determine the precise source or sources of this
      > additional fresh water. Global warming may be melting glaciers, or
      > Arctic sea ice. In recent decades, the volume of Arctic sea ice has
      > decreased by 40 percent. And if North Atlantic sinking slows down,
      > less salty Gulf Stream waters flow northward—which exacerbates
      the
      > situation.
      >
      > In February 2002, at a worldwide meeting of oceanographers, new
      data
      > on North Atlantic freshening prompted many scientists to say that
      > salinity levels in the North Atlantic are approaching a density
      very
      > close to the critical point at which the waters will stop sinking.
      >
      > One of my colleagues at Woods Hole, Terry Joyce, put it this
      > way: "I'm in the dark as to how close to an edge or transition to a
      > new ocean and climate regime we might be," he said. "But I know
      which
      > way we are walking. We are walking toward the cliff."
      >
      > To that sentiment, I would add this: We are walking toward the edge
      > of a cliff—blindfolded. Our ability to understand the potential
      for
      > future abrupt changes in climate is limited by our lack of
      > understanding of the processes that control them.
      >
      >
      > New data shows that North Atlantic waters at depths between 1,000
      and
      > 4,000 meters are becoming dramatically less salty, especially in
      the
      > last decade. Red indicates saltier-than-normal waters. Blue
      indicates
      > fresher waters. Oceanographers say we may be approaching a
      threshold
      > that would shut down the Great Ocean Conveyor and cause abrupt
      > climate changes. (Data from Ruth Curry, WHOI, Bob Dickson, Centre
      for
      > Environment, Fisheries, and Aquaculture Science and Igor Yashayaev,
      > Bedford Institute of Oceanography)
      >
      >
      > In the past decades, we have made great strides in understanding
      > Earth's atmospheric circulation system because we established a
      > global network of thousands of meteorological stations to monitor
      > changing atmospheric conditions. No observational network exists to
      > continuously monitor the oceans. If we just had a few more
      > strategically placed modern instruments in the oceans for an
      extended
      > time, we could understand so much more about how the oceans can
      cause
      > abrupt climate changes. At present, there is no national plan for
      > improving our understanding of the issue, and according to a 2002
      > National Research Council report, no policymaking body is
      addressing
      > the many concerns raised by the potential for abrupt climate
      change.
      >
      > So here's the situation: We have unequivocal evidence of repeated,
      > large, widespread, abrupt climate changes on Earth. It is
      reasonable
      > to assume that greenhouse warming can exacerbate the possibility of
      > precipitating large, abrupt, and regional or global climatic
      changes.
      > We even have strong evidence that we may be approaching a dangerous
      > threshold—that we are squeezing a trigger in the North
      Atlantic.
      >
      > We could downplay the relevance of past abrupt events and deny the
      > likelihood of future abrupt climate changes. But that could prove
      > costly. With growing globalization, the adverse impacts of climate
      > changes are likely to spill across national boundaries—through
      > migration, economic shocks, and political aftershocks.
      >
      > Over human history, one of the major ways that humans have adapted
      to
      > changing environmental and economic fortunes has been to migrate
      from
      > unproductive or impacted regions to more productive and hospitable
      > regions. But today, the world's population has grown too large.
      There
      > is less usable, unpopulated territory to absorb migrants. National
      > borders are less open, so it is difficult for people to move to
      other
      > countries when droughts, floods, famines, and wars occur. These
      > boundary effects could be particularly severe for small and poor
      > countries, whose populations are often unwelcome in richer
      countries.
      > In the 1840s, more than 1 million Irish people emigrated because of
      > the potato blight. Can you imagine an equivalent migration of many
      > millions of people today? Keep in mind that there were only about 1
      > billion people on Earth then. There are 6 billion now.
      >
      > As a society, I believe we must face the potential for abrupt
      climate
      > change. Perhaps we can mitigate the changes. If not, at least we
      can
      > still take steps to adapt to them.
      >
      > The best way to improve the effectiveness of our response is to
      have
      > more knowledge of what can happen—and how and when. Research
      into
      the
      > causes, patterns, likelihood, and effects of abrupt climate change
      > can help reduce our vulnerabilities and increase our ability to
      > adapt.
      >
      > If climate changes come abruptly, we will have less time to adjust.
      > In other words, the more knowledge we have—the more reliably we
      can
      > predict changes—the better our chances.
      >
      > Maybe over the edge of the cliff, there's just a three-inch drop-
      off.
      > Or maybe there's a big, fluffy bed full of pillows. My worry is
      that
      > we are indeed approaching this cliff blindfolded.
      >
      > Are you comfortable and secure with this scenario?
    • Womens Right
      Hello there, Please read these two articles when you get a moment, by very well respected scientists/ecologist, on the current extinction rates and what it
      Message 2 of 9 , Dec 3, 2002
        Hello there, Please read these two articles when you get a moment, by very well respected scientists/ecologist, on the current extinction rates and what it means for our survival. This is the best stuff I have read on the subject, so I'm sure anyone who cares about global warming and our future might feel the same way. There's a story from the BBC, and even CNN, and London's "The Independent". http://www.churchofchomsky.org/ecotwo.html and http://www.well.com/user/davidu/extinction.html and http://news.independent.co.uk/world/environment/story.jsp?story=347797 So three stories, but all very worth reading, no B.S.
        good day.! http://www.churchofchomsky.org/coc.htm
        F Cote <dionysios2100@...> wrote: I don't know if the science on this will wash in the final analysis
        but it tends to support the claim that we are playing an unbelievably
        stupid and dangerous game with our planet's life support systems. As
        the various conflicting projections (with varying degrees of
        scientific credibility) demonstrate, humankind does not understand
        (to any sufficient degree of certainty) how our planet's life support
        systems work. Yet despite this fatal ignorance, we continually
        disrupt the operation of natural energy and matter transport cycles
        upon which our species' very survival depends. The only image that
        comes to mind is that of a mad woodcutter high in a tree busily
        sawing off the branch upon which he sits. This is folly folks, folly
        of the highest degree! Until we know at least, how the planet's life
        support systems operate we should not be disrupting them in the
        stupidly cavalier manner as we are now doing. Our golden rule should
        be: if it ain't broke, don't fix it.


        [Non-text portions of this message have been removed]
      • Womens Right
        I ve often thought that they all want the world to end just like the bible, in Armageddon, where only the God-Lovers, bible-worshipping folk (fools) will be
        Message 3 of 9 , Dec 4, 2002
          I've often thought that they all want the world to end
          just like the bible, in Armageddon, where only the
          God-Lovers, bible-worshipping folk (fools) will be
          saved into a paradise earth.
          it certainly makes sense for the wall street bankers,
          and all of the top 1% of the wealthy really, who must
          believe that they are god anyway, since they control
          everyone's life on earth. It seems that that's what
          they want, to use up the whole earth for capitalism,
          with no regards whatsoever to future generations.
          that's how GOD must want it, so it is. People like
          rockefellers, etc., etc., truly must feel that they
          are god, which explains the blatant stupidity, and
          what appears, TO SANE PEOPLE, as insanity.
          later,


          --- F Cote <dionysios2100@...> wrote:
          > I don't know if the science on this will wash in
          > the final analysis
          > but it tends to support the claim that we are
          > playing an unbelievably
          > stupid and dangerous game with our planet's life
          > support systems. As
          > the various conflicting projections (with varying
          > degrees of
          > scientific credibility) demonstrate, humankind does
          > not understand
          > (to any sufficient degree of certainty) how our
          > planet's life support
          > systems work. Yet despite this fatal ignorance, we
          > continually
          > disrupt the operation of natural energy and matter
          > transport cycles
          > upon which our species' very survival depends. The
          > only image that
          > comes to mind is that of a mad woodcutter high in a
          > tree busily
          > sawing off the branch upon which he sits. This is
          > folly folks, folly
          > of the highest degree! Until we know at least, how
          > the planet's life
          > support systems operate we should not be disrupting
          > them in the
          > stupidly cavalier manner as we are now doing. Our
          > golden rule should
          > be: if it ain't broke, don't fix it.
          >
          >
        • F Cote
          Hi! I haven t the visited the sites you mentioned in an earlier post yet but will later this week. Thanks for the references.. Religion is one of those highly
          Message 4 of 9 , Dec 4, 2002
            Hi!

            I haven't the visited the sites you mentioned in an earlier post
            yet but will later this week. Thanks for the references..

            Religion is one of those highly subjective areas where opinions
            are splayed right accross the spectrum on every issue you can think
            of. Some neo-religionists claim we should worship the Earth as a
            divinity; my own personal reaction is go absolutely ballistic when I
            hear the blasphemy of using God's name to justify human stupidity. So
            there you have it in a nutshell: some people find utterly blasphemous
            what the Holy Joes you mention consider God's will. And I know I am
            not alone in this view. To be honest, some atheists are the most
            cynical proponents of the "Live Today for Tomorrow we die! (and to
            hell with future generations)" school of thought, no? I sure have met
            plenty, anyway.
            My own gut-feeling is that environmental problems won't get better
            until the folly of the status quo has generated massive human
            suffering on an unprecedented scale and then - tragically - it may
            simply be too late to do anything with climate and ecosystems
            spiralling out of control. Spiralling out of control, for one thing,
            because of too many positive feedback loops kicking in all at once; a
            lot of the feedbacks in the climate regulation system are, ominously,
            positive. Global warming cause evaporation of sea water increasing
            water vapoer content of the atmosphere. Well, Gee! It just happens
            that water vapor is a whiz-bang greenhouse gas thus AMPLIFYING (!!)
            the original "signal" of temperature increase. Messing around with
            such a hair-trigger, hairy-arsed system the way we are now - and
            without, mind you, much of a clue as to how it really works in
            detail - is utter, utter insanity. As for "massive human suffering on
            an unprecedented scale" being alarmist: who, back in 1960 or 1970,
            would have accepted the idea that the worst plague in human history
            (AIDS) would hit in the late 20th century? I'll tell you who - aside
            from a few nut cases and cult whackos, nobody, N-O-B-O-D-Y, PERSONNE,
            NADIE..
            It may come to pass that such a crisis, if negotiated, will
            necessarily lead to a "new compact" with Nature in which humankind is
            (once again as among the "primitive" religions) seen as a part of
            Nature. Seen from this perspective, the contemporary "neo-pagan"
            movements would be seen as precursor phenomena similar to the "neo-
            christians" who believe that humankind's duty to God is preserve and
            to cultivate the garden (Earth) which He trusted to us.

            --- In globalwarming@y..., Womens Right <wombrights@y...> wrote:
            > I've often thought that they all want the world to end
            > just like the bible, in Armageddon, where only the
            > God-Lovers, bible-worshipping folk (fools) will be
            > saved into a paradise earth.
            > it certainly makes sense for the wall street bankers,
            > and all of the top 1% of the wealthy really, who must
            > believe that they are god anyway, since they control
            > everyone's life on earth. It seems that that's what
            > they want, to use up the whole earth for capitalism,
            > with no regards whatsoever to future generations.
            > that's how GOD must want it, so it is. People like
            > rockefellers, etc., etc., truly must feel that they
            > are god, which explains the blatant stupidity, and
            > what appears, TO SANE PEOPLE, as insanity.
            > later,
            >
            >
            > --- F Cote <dionysios2100@h...> wrote:
            > > I don't know if the science on this will wash in
            > > the final analysis
            > > but it tends to support the claim that we are
            > > playing an unbelievably
            > > stupid and dangerous game with our planet's life
            > > support systems. As
            > > the various conflicting projections (with varying
            > > degrees of
            > > scientific credibility) demonstrate, humankind does
            > > not understand
            > > (to any sufficient degree of certainty) how our
            > > planet's life support
            > > systems work. Yet despite this fatal ignorance, we
            > > continually
            > > disrupt the operation of natural energy and matter
            > > transport cycles
            > > upon which our species' very survival depends. The
            > > only image that
            > > comes to mind is that of a mad woodcutter high in a
            > > tree busily
            > > sawing off the branch upon which he sits. This is
            > > folly folks, folly
            > > of the highest degree! Until we know at least, how
            > > the planet's life
            > > support systems operate we should not be disrupting
            > > them in the
            > > stupidly cavalier manner as we are now doing. Our
            > > golden rule should
            > > be: if it ain't broke, don't fix it.
            > >
            > >
          • Womens Right
            yeah, that s just about what i ve thought as well...that absolute enormous catastrophe must come before the powers that be are no more, and people realize they
            Message 5 of 9 , Dec 4, 2002
              yeah, that's just about what i've thought as
              well...that absolute enormous catastrophe must come
              before the powers that be are no more, and people
              realize they must act. as you say, human suffering on
              a massive scale. it's too bad, but i have a feeling
              that mother nature is starting to vent anger, and it's
              liable to start happening within the next year. not
              total change, but huge environmental disasters.
              peace,


              --- F Cote <dionysios2100@...> wrote:
              > Hi!
              >
              > I haven't the visited the sites you mentioned in
              > an earlier post
              > yet but will later this week. Thanks for the
              > references..
              >
              > Religion is one of those highly subjective areas
              > where opinions
              > are splayed right accross the spectrum on every
              > issue you can think
              > of. Some neo-religionists claim we should worship
              > the Earth as a
              > divinity; my own personal reaction is go absolutely
              > ballistic when I
              > hear the blasphemy of using God's name to justify
              > human stupidity. So
              > there you have it in a nutshell: some people find
              > utterly blasphemous
              > what the Holy Joes you mention consider God's will.
              > And I know I am
              > not alone in this view. To be honest, some atheists
              > are the most
              > cynical proponents of the "Live Today for Tomorrow
              > we die! (and to
              > hell with future generations)" school of thought,
              > no? I sure have met
              > plenty, anyway.
              > My own gut-feeling is that environmental problems
              > won't get better
              > until the folly of the status quo has generated
              > massive human
              > suffering on an unprecedented scale and then -
              > tragically - it may
              > simply be too late to do anything with climate and
              > ecosystems
              > spiralling out of control. Spiralling out of
              > control, for one thing,
              > because of too many positive feedback loops kicking
              > in all at once; a
              > lot of the feedbacks in the climate regulation
              > system are, ominously,
              > positive. Global warming cause evaporation of sea
              > water increasing
              > water vapoer content of the atmosphere. Well, Gee!
              > It just happens
              > that water vapor is a whiz-bang greenhouse gas thus
              > AMPLIFYING (!!)
              > the original "signal" of temperature increase.
              > Messing around with
              > such a hair-trigger, hairy-arsed system the way we
              > are now - and
              > without, mind you, much of a clue as to how it
              > really works in
              > detail - is utter, utter insanity. As for "massive
              > human suffering on
              > an unprecedented scale" being alarmist: who, back in
              > 1960 or 1970,
              > would have accepted the idea that the worst plague
              > in human history
              > (AIDS) would hit in the late 20th century? I'll tell
              > you who - aside
              > from a few nut cases and cult whackos, nobody,
              > N-O-B-O-D-Y, PERSONNE,
              > NADIE..
              > It may come to pass that such a crisis, if
              > negotiated, will
              > necessarily lead to a "new compact" with Nature in
              > which humankind is
              > (once again as among the "primitive" religions) seen
              > as a part of
              > Nature. Seen from this perspective, the contemporary
              > "neo-pagan"
              > movements would be seen as precursor phenomena
              > similar to the "neo-
              > christians" who believe that humankind's duty to God
              > is preserve and
              > to cultivate the garden (Earth) which He trusted to
              > us.
              >
              > --- In globalwarming@y..., Womens Right
              > <wombrights@y...> wrote:
              > > I've often thought that they all want the world to
              > end
              > > just like the bible, in Armageddon, where only the
              > > God-Lovers, bible-worshipping folk (fools) will be
              > > saved into a paradise earth.
              > > it certainly makes sense for the wall street
              > bankers,
              > > and all of the top 1% of the wealthy really, who
              > must
              > > believe that they are god anyway, since they
              > control
              > > everyone's life on earth. It seems that that's
              > what
              > > they want, to use up the whole earth for
              > capitalism,
              > > with no regards whatsoever to future generations.
              > > that's how GOD must want it, so it is. People
              > like
              > > rockefellers, etc., etc., truly must feel that
              > they
              > > are god, which explains the blatant stupidity, and
              > > what appears, TO SANE PEOPLE, as insanity.
              > > later,
              > >
              > >
              > > --- F Cote <dionysios2100@h...> wrote:
              > > > I don't know if the science on this will wash
              > in
              > > > the final analysis
              > > > but it tends to support the claim that we are
              > > > playing an unbelievably
              > > > stupid and dangerous game with our planet's life
              > > > support systems. As
              > > > the various conflicting projections (with
              > varying
              > > > degrees of
              > > > scientific credibility) demonstrate, humankind
              > does
              > > > not understand
              > > > (to any sufficient degree of certainty) how our
              > > > planet's life support
              > > > systems work. Yet despite this fatal ignorance,
              > we
              > > > continually
              > > > disrupt the operation of natural energy and
              > matter
              > > > transport cycles
              > > > upon which our species' very survival depends.
              > The
              > > > only image that
              > > > comes to mind is that of a mad woodcutter high
              > in a
              > > > tree busily
              > > > sawing off the branch upon which he sits. This
              > is
              > > > folly folks, folly
              > > > of the highest degree! Until we know at least,
              > how
              > > > the planet's life
              > > > support systems operate we should not be
              > disrupting
              > > > them in the
              > > > stupidly cavalier manner as we are now doing.
              > Our
              > > > golden rule should
              > > > be: if it ain't broke, don't fix it.
              > > >
              > > >
              >
              >
            • pawnfart
              I am an unabashing liberal BUT I am a Gaia scientist--not a CO2 as a GHG warmer. Our methane hydrate club/group now has 50 members and there are daily reports
              Message 6 of 9 , Dec 5, 2002
                I am an unabashing liberal BUT I am a Gaia scientist--not a CO2 as a
                GHG warmer. Our methane hydrate club/group now has 50 members and
                there are daily reports of space EMF/weather there. It is the
                hottest place on earth for cutting edge climate discussion.

                Here is my thought for the day.

                The super tanker that went down off the coast of Spain had oil in its
                compartments. But the danger from the spill really ended as the ship
                sank two miles into the deep oceans. Why? Because the oceans are so
                cold that the oil turned into a tar like viscosity.

                Where I am interested in the oil is what would be its EMF characters
                as such. My view is that it becomes like rubber or plastic--VERY EMF
                insulating. That makes for good Doran wave activity, good cirrus
                cloud enhancement by low frequancy large area EMFs. This in turn
                caues the greatest forcing, the clouds, to pack even a greater
                punch.

                On larger timescales, when per the Carl Sagan mystery of an ever
                lumenous sun, the feedbacks in the geo past HAD to be much greater.
                The sun was 25% less lumenous then . . .

                For all you chaos idiots out there, it isn't chaos was chaos is, it
                isn't flip flop was flip flop is, it isn't random inputs here random
                there . . . . burn fossil fuels. Rather, it is biological modulation
                was, modulation is. CO2 is critical not as a green house gas, but as
                a key chemistry in a living chemical dynamic. More CO2 means more
                greenery, more rotting, more material in the near shore oceans where
                the electrical processes impact on precip, on hydrology to a region.
                Warmer probably means drier, less hydrology!

                And to the James Watts of the world, the bible itself speaks of
                stewardship of the planet. Whatever the bible says, we need to
                conduct ourselves in a symbiotic way with the microbrial biosphere--
                dominion and control cannot occur in the way we think--because
                without these microbes we would not exist, period. Translating this
                politically will be difficult to what is essentially diesm, where
                there is a hiearchy between king george, white men, people of
                ethnicity and non-anglican and so forth. This matches poorly with
                the Stokes case, with a microbrial biosphere as critical to our
                existance.



                --- In globalwarming@y..., Womens Right <wombrights@y...> wrote:
                > yeah, that's just about what i've thought as
                > well...that absolute enormous catastrophe must come
                > before the powers that be are no more, and people
                > realize they must act. as you say, human suffering on
                > a massive scale. it's too bad, but i have a feeling
                > that mother nature is starting to vent anger, and it's
                > liable to start happening within the next year. not
                > total change, but huge environmental disasters.
                > peace,
                >
                >
                > --- F Cote <dionysios2100@h...> wrote:
                > > Hi!
                > >
                > > I haven't the visited the sites you mentioned in
                > > an earlier post
                > > yet but will later this week. Thanks for the
                > > references..
                > >
                > > Religion is one of those highly subjective areas
                > > where opinions
                > > are splayed right accross the spectrum on every
                > > issue you can think
                > > of. Some neo-religionists claim we should worship
                > > the Earth as a
                > > divinity; my own personal reaction is go absolutely
                > > ballistic when I
                > > hear the blasphemy of using God's name to justify
                > > human stupidity. So
                > > there you have it in a nutshell: some people find
                > > utterly blasphemous
                > > what the Holy Joes you mention consider God's will.
                > > And I know I am
                > > not alone in this view. To be honest, some atheists
                > > are the most
                > > cynical proponents of the "Live Today for Tomorrow
                > > we die! (and to
                > > hell with future generations)" school of thought,
                > > no? I sure have met
                > > plenty, anyway.
                > > My own gut-feeling is that environmental problems
                > > won't get better
                > > until the folly of the status quo has generated
                > > massive human
                > > suffering on an unprecedented scale and then -
                > > tragically - it may
                > > simply be too late to do anything with climate and
                > > ecosystems
                > > spiralling out of control. Spiralling out of
                > > control, for one thing,
                > > because of too many positive feedback loops kicking
                > > in all at once; a
                > > lot of the feedbacks in the climate regulation
                > > system are, ominously,
                > > positive. Global warming cause evaporation of sea
                > > water increasing
                > > water vapoer content of the atmosphere. Well, Gee!
                > > It just happens
                > > that water vapor is a whiz-bang greenhouse gas thus
                > > AMPLIFYING (!!)
                > > the original "signal" of temperature increase.
                > > Messing around with
                > > such a hair-trigger, hairy-arsed system the way we
                > > are now - and
                > > without, mind you, much of a clue as to how it
                > > really works in
                > > detail - is utter, utter insanity. As for "massive
                > > human suffering on
                > > an unprecedented scale" being alarmist: who, back in
                > > 1960 or 1970,
                > > would have accepted the idea that the worst plague
                > > in human history
                > > (AIDS) would hit in the late 20th century? I'll tell
                > > you who - aside
                > > from a few nut cases and cult whackos, nobody,
                > > N-O-B-O-D-Y, PERSONNE,
                > > NADIE..
                > > It may come to pass that such a crisis, if
                > > negotiated, will
                > > necessarily lead to a "new compact" with Nature in
                > > which humankind is
                > > (once again as among the "primitive" religions) seen
                > > as a part of
                > > Nature. Seen from this perspective, the contemporary
                > > "neo-pagan"
                > > movements would be seen as precursor phenomena
                > > similar to the "neo-
                > > christians" who believe that humankind's duty to God
                > > is preserve and
                > > to cultivate the garden (Earth) which He trusted to
                > > us.
                > >
                > > --- In globalwarming@y..., Womens Right
                > > <wombrights@y...> wrote:
                > > > I've often thought that they all want the world to
                > > end
                > > > just like the bible, in Armageddon, where only the
                > > > God-Lovers, bible-worshipping folk (fools) will be
                > > > saved into a paradise earth.
                > > > it certainly makes sense for the wall street
                > > bankers,
                > > > and all of the top 1% of the wealthy really, who
                > > must
                > > > believe that they are god anyway, since they
                > > control
                > > > everyone's life on earth. It seems that that's
                > > what
                > > > they want, to use up the whole earth for
                > > capitalism,
                > > > with no regards whatsoever to future generations.
                > > > that's how GOD must want it, so it is. People
                > > like
                > > > rockefellers, etc., etc., truly must feel that
                > > they
                > > > are god, which explains the blatant stupidity, and
                > > > what appears, TO SANE PEOPLE, as insanity.
                > > > later,
                > > >
                > > >
                > > > --- F Cote <dionysios2100@h...> wrote:
                > > > > I don't know if the science on this will wash
                > > in
                > > > > the final analysis
                > > > > but it tends to support the claim that we are
                > > > > playing an unbelievably
                > > > > stupid and dangerous game with our planet's life
                > > > > support systems. As
                > > > > the various conflicting projections (with
                > > varying
                > > > > degrees of
                > > > > scientific credibility) demonstrate, humankind
                > > does
                > > > > not understand
                > > > > (to any sufficient degree of certainty) how our
                > > > > planet's life support
                > > > > systems work. Yet despite this fatal ignorance,
                > > we
                > > > > continually
                > > > > disrupt the operation of natural energy and
                > > matter
                > > > > transport cycles
                > > > > upon which our species' very survival depends.
                > > The
                > > > > only image that
                > > > > comes to mind is that of a mad woodcutter high
                > > in a
                > > > > tree busily
                > > > > sawing off the branch upon which he sits. This
                > > is
                > > > > folly folks, folly
                > > > > of the highest degree! Until we know at least,
                > > how
                > > > > the planet's life
                > > > > support systems operate we should not be
                > > disrupting
                > > > > them in the
                > > > > stupidly cavalier manner as we are now doing.
                > > Our
                > > > > golden rule should
                > > > > be: if it ain't broke, don't fix it.
                > > > >
                > > > >
                > >
                > >
              • dmgan106
                Aparently this doomsday scenario is proceeding apace. The BBC is reporting record melting in the Arctic. According to scientists, surface melt on Greenland
                Message 7 of 9 , Dec 9, 2002
                  Aparently this doomsday scenario is proceeding apace. The BBC is
                  reporting record melting in the Arctic.

                  "According to scientists, surface melt on Greenland was the highest
                  in recorded history - and extended to elevations previously untouched
                  by melt - while the amount of Arctic sea ice also reached a record
                  low.

                  While some of the accelerated melting appears to be linked to natural
                  atmospheric oscillations, human influence could not be ruled out,
                  said the scientists."

                  ""Polar sea ice has an important function in moderating the global
                  energy balance," he said (University of Alaska, Fairbanks, researcher
                  Larry Hinzman). He explained that sea ice has albedo of 0.8. That is,
                  it reflects 80% of the solar radiation. When the sea ice melts you
                  have water, which has an albedo of 0.2.

                  "The sea ice goes from absorbing 20% of solar radiation to absorbing
                  80%," said Dr Hinzman. This creates positive feedback for further
                  warming.

                  In total, the arctic warming is an unprecedented trend, according to
                  Dr Hinzman.

                  "We're experiencing the most rapid increase in temperature in
                  recorded history," he said."

                  http://news.bbc.co.uk/1/hi/sci/tech/2558319.stm

                  --- In globalwarming@yahoogroups.com, "Banzai (Lance Stinson)"
                  <banzai@m...> wrote:
                  > A perspective on potential climate changes presented by Dr. Robert
                  B.
                  > Gagosian, President and Director of Woods Hole Oceanographic
                  > Institution
                  >
                  > http://www.whoi.edu/home/about/whatsnew_abruptclimate.html
                  >
                  > Over the past two decades, we have heard about greenhouse gases and
                  > the idea that our planet is gradually warming. I'd like to throw a
                  > curveball into that thinking—specifically the "gradually warming"
                  > part.
                  >
                  > This new thinking is little known and scarcely appreciated by
                  > policymakers and world and business leaders—and even by the wider
                  > community of natural and social scientists. But evidence from
                  several
                  > sources has amassed and coalesced over the past 10 to 15 years. It
                  > points to a completely different—almost counterintuitive—scenario.
                  >
                  > Global warming could actually lead to a big chill in some parts of
                  > the world. If the atmosphere continues to warm, it could soon
                  trigger
                  > a dramatic and abrupt cooling throughout the North Atlantic region—
                  > where, not incidentally, some 60 percent of the world's economy is
                  > based.
                  >
                  > When I say "dramatic," I mean: Average winter temperatures could
                  drop
                  > by 5 degrees Fahrenheit over much of the United States, and by 10
                  > degrees in the northeastern United States and in Europe. That's
                  > enough to send mountain glaciers advancing down from the Alps. To
                  > freeze rivers and harbors and bind North Atlantic shipping lanes in
                  > ice. To disrupt the operation of ground and air transportation. To
                  > cause energy needs to soar exponentially. To force wholesale
                  changes
                  > in agricultural practices and fisheries. To change the way we feed
                  > our populations. In short, the world, and the world economy, would
                  be
                  > drastically different.
                  >
                  > And when I say "abrupt," I mean: These changes could happen within
                  a
                  > decade, and they could persist for hundreds of years. You could see
                  > the changes in your lifetime, and your grandchildren's
                  grandchildren
                  > will still be confronting them.
                  >
                  > And when I say "soon," I mean: In just the past year, we have seen
                  > ominous signs that we may be headed toward a potentially dangerous
                  > threshold. If we cross it, Earth's climate could switch gears and
                  > jump very rapidly—not gradually— into a completely different mode
                  of
                  > operation.
                  >
                  >
                  > A schematic of the ocean circulation system, often called the Great
                  > Ocean Conveyor, that transports heat throughout the world oceans.
                  Red
                  > arrows indicate warm surface currents. Blue arrows indicate deep
                  cold
                  > currents. (Animation by Jack Cook, WHOI)
                  > This is not something new under the Sun. It has happened throughout
                  > Earth's history, and it could happen again.
                  >
                  > The key to these climate shifts is that Earth's climate is created
                  > and maintained by a dynamic system of moving, interacting parts.
                  > Earth's climate system has two main components. The first one you
                  are
                  > all familiar with by watching your local TV meteorologist or The
                  > Weather Channel. It is the atmosphere, which circulates heat and
                  > moisture around the globe. But, in fact, the atmosphere
                  redistributes
                  > only about half of the energy that the earth receives from the Sun.
                  >
                  > The other half is transported around our planet by a circulation
                  > system that is equally important, but far less understood—the
                  ocean.
                  > The ocean isn't a stagnant bathtub. It circulates heat around the
                  > planet like the heating and cooling system in your house. The
                  > atmosphere and oceans are equal partners in creating Earth's
                  climate.
                  > The atmosphere is a rabbit. It moves fast. Rapid changes in
                  > atmospheric circulation cause storms, cold spells, or heat waves
                  that
                  > play out over several days.
                  >
                  > The ocean, on the other hand, is a turtle. It may take years or
                  > decades or even millennia for similar "disturbances" to circulate
                  > through the ocean. But the ocean is a big turtle. It stores about
                  > 1,000 times more heat than the atmosphere. So changes in ocean
                  > circulation can set the stage for large-scale, long-term climate
                  > changes.
                  >
                  > One example that you may be familiar with is El Niño. Every few
                  > years, oceanic conditions shift, and surface water temperatures in
                  > the eastern tropical Pacific get warmer. The atmosphere above the
                  > ocean shifts, too. El Niño rearranges worldwide wind and rainfall
                  > patterns, causing destructive droughts, floods, storms, and forest
                  > fires. Not to downplay El Niño in the least, because it causes
                  grave
                  > human suffering and billions of dollars in damage—but El Niño is
                  > relatively short-lived. It lasts only a year or two.
                  >
                  > The climate changes I'm concerned about last longer and involve the
                  > ocean circulation system that spans the entire globe—which we often
                  > call the Great Ocean Conveyor.
                  >
                  > The Great Ocean Conveyor is the ocean's major heat-circulating
                  > system. The ocean keeps our planet from overheating by transporting
                  > heat north and south, from the equator to the poles, in currents
                  > traveling near the ocean surface. In the Atlantic, the Conveyor
                  > removes heat from the Southern Hemisphere and releases it to the
                  > Northern Hemisphere.
                  >
                  >
                  > The Great Ocean Conveyor is propelled by the sinking of cold, salty
                  > (and therefore denser) waters in the North Atlantic Ocean (blue
                  > arrows). That creates a void that pulls warm, salty Gulf Stream
                  > waters northward (red arrows). The Gulf Stream gives up its heat to
                  > the atmosphere above the North Atlantic Ocean, and prevailing winds
                  > (large red arrows) carry the heat eastward to warm Europe.
                  (Animation
                  > by Jack Cook, WHOI)
                  > The most famous and most important of these currents is the Gulf
                  > Stream. The vast Gulf Stream transports the equivalent volume of 75
                  > Amazon Rivers. It carries heat absorbed in the tropics, and moves
                  up
                  > the East Coast of the United States, then northeastward toward
                  > Europe.
                  >
                  > When the Gulf Stream's warm, salty waters reach colder latitudes,
                  > they give up their heat to the atmosphere. The atmosphere in the
                  > North Atlantic region warms by as much as 10 degrees Fahrenheit.
                  > Prevailing winds carry the heat eastward into Europe. That's one
                  > reason London, England—which is located at the same latitude as
                  > Calgary and Edmonton—has warmer winters than New York—which is
                  > hundreds of miles farther south.
                  >
                  > When the Gulf Stream's waters reach the Labrador, Greenland and
                  other
                  > northern seas, and lose their heat to the atmosphere, they become
                  > colder—and hence denser. The waters are also relatively salty.
                  Salty
                  > water is denser than fresher water, so the whole salty mass begins
                  to
                  > sink to great depths.
                  >
                  > When this sinking mass of cold water reaches the abyss, it then
                  flows
                  > at deep levels of the ocean, from the North Atlantic southward into
                  > the South Atlantic. The plunge of this great volume of cold, salty
                  > water propels the Great Ocean Conveyor. And on the back end, it
                  > creates a void that actively pulls the Gulf Stream northward to
                  > replace the waters that are sinking.
                  >
                  > It's a pretty neat system. We have been operating under the climate
                  > conditions created by this beneficent oceanic heating, ventilation,
                  > and cooling system for centuries.
                  >
                  > But what if this system weren't operating today? What if cold North
                  > Atlantic waters didn't sink and warm equatorial waters weren't
                  drawn
                  > in to replace the sinking waters? Then the North Atlantic region
                  > would be a much different, much colder place.
                  >
                  > The vast majority of us go about our business thinking that Earth's
                  > climate system has always been this way, and always will be. But
                  that
                  > is just not the case. In fact, we know that the Ocean Conveyor has
                  > indeed shut down—stopped operating—in the past.
                  >
                  > We know this by examining truly interesting and valuable natural
                  > archives that record past changes in Earth's climate. For example,
                  we
                  > can see layers within ice sheets in Greenland or in high elevations
                  > in the Andes Mountains in South America. This layering is caused by
                  > variations in the amount of snow that fell on the top of the ice
                  > sheet in the past.
                  >
                  >
                  >
                  > Top: Ice sheets reveal annual layers, which scientists can analyze
                  to
                  > reconstruct the history of precipitation and air temperatures
                  100,000
                  > years in the past. (Photo by Lonnie Thompson, Ohio State
                  University)
                  > Bottom: Cores of seafloor sediments reveal the climate history of
                  the
                  > ocean. (Photo by Ken Buesseler, WHOI)
                  > The light and dark bands within the ice sheet show an annual cycle
                  of
                  > dust in the atmosphere, so each couplet reflects the amount of snow
                  > that fell in one year. By analyzing the chemistry of the ice
                  itself,
                  > scientists can determine the temperature of the atmosphere when the
                  > snow was produced.
                  >
                  > Thus from a single ice sheet record, it is possible to reconstruct
                  > the past history of precipitation and air temperature in a region.
                  > For very old ice sheets, like the glaciers on Greenland, it is
                  > possible to reconstruct this climate history 100,000 years into the
                  > past.
                  >
                  > The ocean has similar archives of past climate. By taking cores
                  from
                  > the ocean floor, it is possible to reconstruct the history of ocean
                  > climate back many thousands of years. We have used our ships to
                  > collect samples of sediments from the seafloor. Preserved in the
                  > sediments are the fossil remains of microscopic organisms that
                  settle
                  > to the seafloor. They accumulate over time in layers—similar to the
                  > ice core—that delineate many important aspects of past climate.
                  >
                  > For instance, certain organisms are found only in colder, polar
                  > waters and never live in warmer waters. They can reveal where and
                  > when cold surface waters existed—and didn't exist—in the past.
                  >
                  > From records like these, we know that about 12,800 years ago, North
                  > Atlantic waters cooled dramatically—and so did the North Atlantic
                  > region. This large cooling in Earth's climate occurred in about a
                  > decade. And the cold spell lasted for about 1,300 years.
                  >
                  > This period is called the Younger Dryas, and it is just one of
                  > several periods when Earth's climate changed very rapidly from warm
                  > to cold conditions, and then back to warm again. So these long-term
                  > cold snaps are not unusual.
                  >
                  > These shifts almost certainly involved changes in the ocean's
                  > circulation. There were shutdowns and restartings of the Ocean
                  > Conveyor. These warm-to-cold transitions happen in about 3 to 10
                  > years. The cold periods lasted for 500 to 1,000 years. Such
                  > oscillations in temperature and ocean circulation have occurred on
                  a
                  > regular basis.
                  >
                  > About 1,000 years ago, during a period of unusually warm
                  temperatures
                  > in the North Atlantic, the Norse established settlements and
                  > vineyards in Greenland that would not be possible today. Those
                  > settlements were abandoned about 500 years ago, when we believe the
                  > most recent shutdown of the North Atlantic Ocean circulation system
                  > occurred.
                  >
                  > During that era, called the Little Ice Age, northern Europe was
                  much
                  > colder than it is today. Glaciers spread outward and downward in
                  the
                  > Alps. Winters, on average, were more severe. Farming was affected.
                  > Famine was frequent.
                  >
                  > In the 1730s and 1740s, abrupt European cooling caused famine
                  across
                  > western Europe, especially in Ireland and France, where farmers
                  > depended on wheat and potatoes. In Ireland, this is known as
                  > the "forgotten famine." As many people died during the forgotten
                  > famine as died during the famed potato famine of the 1840s.
                  >
                  > The 16th-century Flemish artist Bruegel couldn't have painted his
                  > famous frozen landscapes today, because now canals in the
                  Netherlands
                  > rarely freeze, as they regularly did back then. And likewise, the
                  > winter in Valley Forge might not have been so cold, and
                  Washington's
                  > crossing of the ice-bound Delaware River wouldn't have been so
                  > dramatic, if he had done it a century later—because our climate
                  > conditions have shifted since then, and today, the Delaware River
                  > rarely freezes.
                  >
                  > If you read David McCullough's biography of John Adams, you will
                  > remember that the British were about to set Boston on fire when
                  > George Washington was able to bring the cannons of Fort Ticonderoga
                  > down from upstate New York in record time. He was able to do it
                  > because the ground was frozen solid and they could slide the
                  cannons
                  > to the Dorchester hills of Boston in time to persuade the British
                  to
                  > retreat from Boston and to change the course of history.
                  >
                  > So we have solid evidence that the Great Ocean Conveyor has slowed
                  > down or shut down in the past. And we have seen dire impacts on our
                  > climate. It begs the question: Could something throw a wrench into
                  > the Great Ocean Conveyor in the near future? And could that trigger
                  > abrupt, dramatic climate changes throughout our planet? The answers
                  > to those questions are, indisputably, "Yes and yes."
                  >
                  >
                  > Like most dynamic systems, Earth's climate seeks a stable mode (top
                  > tier). If the system is pushed, it will stagger for a while unitl
                  it
                  > recovers (middle tier). If it is pushed past a threshold, it will
                  > shift into another mode of operation (bottom tier). (Illustration
                  by
                  > Jack Cook, WHOI, adapted from Abrupt Climate Change, Inevitable
                  > Suprises National Research Council)
                  > Another way to look at Earth's climate system is a simple mode of
                  > balances (see diagram, left). Like most dynamic systems, Earth's
                  > climate seeks a stable mode. And it will tend to stay in that mode
                  if
                  > nothing causes it to change. That's the top tier of the diagram.
                  The
                  > ball remains ensconced in its cup.
                  >
                  > The middle tier shows what happens if you push on the system. The
                  > ball will rattle and roll around in different directions for a
                  while
                  > until it settles back down in its cup. We humans would definitely
                  > notice that rattling until the climate system returned to
                  > equilibrium. The balance, forced to move, staggers but recovers.
                  >
                  > Then there is a third situation— in which a strong enough push at
                  the
                  > right time could shove the system past a threshold and into a
                  > completely different mode of operation. In terms of our climate
                  > system, that means that a small or temporary forcing could produce
                  a
                  > sudden, large, and long-lasting change. That begs the next
                  question:
                  > What could do that to our climate system today?
                  >
                  > One answer to that is fresh water. If you simply add too much fresh
                  > water to the North Atlantic, the waters there will become less
                  salty
                  > and less dense. They will stop sinking. Then the Gulf Stream slows
                  > down or is deflected southward. Winters in the North Atlantic
                  region
                  > get significantly colder.
                  >
                  > Now here's the predicament. In the past year, oceanographers
                  > monitoring and analyzing water conditions in the North Atlantic,
                  have
                  > concluded that the North Atlantic has been freshening dramatically—
                  > especially in the past decade. New data —from Ruth Curry at Woods
                  > Hole Oceanographic Institution and her colleague Robert Dickson at
                  > the British Centre for Environment, Fisheries, and Aquaculture
                  > Science—chronicles salinity changes in the western North Atlantic
                  > since 1960.
                  >
                  > The Great Ocean Conveyor transports fresh surface water down into
                  the
                  > depths. The depths can absorb a lot of fresh water like a sponge.
                  But
                  > since 1970, the equivalent of an extra 20 feet of fresh water
                  across
                  > the surface of the northern North Atlantic has been transported
                  down
                  > into the ocean depths, most of that since 1990.
                  >
                  > A sponge that is three-quarters saturated can still absorb more
                  > water. But the moment that sponge is fully saturated, it can absorb
                  > no more water.
                  >
                  >
                  > If too much fresh water enters the North Atlantic, its waters could
                  > stop sinking. The Great Conveyor would cease. Heat-bearing Gulf
                  > Stream waters (red arrows would no longer flow into the North
                  > Atlantic, and winters would become more severe. (Animation by Jack
                  > Cook, WHOI)
                  > At some point, the North Atlantic will no longer absorb any more
                  > fresh water. It will begin to pile up on the surface. When that
                  > happens, the Great Ocean Conveyor will be clogged. It will back up
                  > and cease functioning.
                  >
                  > The very recent freshening signal in the North Atlantic is arguably
                  > the biggest and most dramatic change in ocean property that has
                  ever
                  > been measured in the global ocean. Already, surface waters in the
                  > Greenland Sea are sinking at a rate 20 percent slower than in the
                  > 1970s.
                  >
                  > At what percent will the Ocean Conveyor stop? 25 percent? 40
                  percent?
                  > 60 percent? This is not like a dimmer switch, but more like a light
                  > switch. It probably goes from "on" to "off."
                  >
                  > We can't yet determine the precise source or sources of this
                  > additional fresh water. Global warming may be melting glaciers, or
                  > Arctic sea ice. In recent decades, the volume of Arctic sea ice has
                  > decreased by 40 percent. And if North Atlantic sinking slows down,
                  > less salty Gulf Stream waters flow northward—which exacerbates the
                  > situation.
                  >
                  > In February 2002, at a worldwide meeting of oceanographers, new
                  data
                  > on North Atlantic freshening prompted many scientists to say that
                  > salinity levels in the North Atlantic are approaching a density
                  very
                  > close to the critical point at which the waters will stop sinking.
                  >
                  > One of my colleagues at Woods Hole, Terry Joyce, put it this
                  > way: "I'm in the dark as to how close to an edge or transition to a
                  > new ocean and climate regime we might be," he said. "But I know
                  which
                  > way we are walking. We are walking toward the cliff."
                  >
                  > To that sentiment, I would add this: We are walking toward the edge
                  > of a cliff—blindfolded. Our ability to understand the potential for
                  > future abrupt changes in climate is limited by our lack of
                  > understanding of the processes that control them.
                  >
                  >
                  > New data shows that North Atlantic waters at depths between 1,000
                  and
                  > 4,000 meters are becoming dramatically less salty, especially in
                  the
                  > last decade. Red indicates saltier-than-normal waters. Blue
                  indicates
                  > fresher waters. Oceanographers say we may be approaching a
                  threshold
                  > that would shut down the Great Ocean Conveyor and cause abrupt
                  > climate changes. (Data from Ruth Curry, WHOI, Bob Dickson, Centre
                  for
                  > Environment, Fisheries, and Aquaculture Science and Igor Yashayaev,
                  > Bedford Institute of Oceanography)
                  >
                  >
                  > In the past decades, we have made great strides in understanding
                  > Earth's atmospheric circulation system because we established a
                  > global network of thousands of meteorological stations to monitor
                  > changing atmospheric conditions. No observational network exists to
                  > continuously monitor the oceans. If we just had a few more
                  > strategically placed modern instruments in the oceans for an
                  extended
                  > time, we could understand so much more about how the oceans can
                  cause
                  > abrupt climate changes. At present, there is no national plan for
                  > improving our understanding of the issue, and according to a 2002
                  > National Research Council report, no policymaking body is
                  addressing
                  > the many concerns raised by the potential for abrupt climate
                  change.
                  >
                  > So here's the situation: We have unequivocal evidence of repeated,
                  > large, widespread, abrupt climate changes on Earth. It is
                  reasonable
                  > to assume that greenhouse warming can exacerbate the possibility of
                  > precipitating large, abrupt, and regional or global climatic
                  changes.
                  > We even have strong evidence that we may be approaching a dangerous
                  > threshold—that we are squeezing a trigger in the North Atlantic.
                  >
                  > We could downplay the relevance of past abrupt events and deny the
                  > likelihood of future abrupt climate changes. But that could prove
                  > costly. With growing globalization, the adverse impacts of climate
                  > changes are likely to spill across national boundaries—through
                  > migration, economic shocks, and political aftershocks.
                  >
                  > Over human history, one of the major ways that humans have adapted
                  to
                  > changing environmental and economic fortunes has been to migrate
                  from
                  > unproductive or impacted regions to more productive and hospitable
                  > regions. But today, the world's population has grown too large.
                  There
                  > is less usable, unpopulated territory to absorb migrants. National
                  > borders are less open, so it is difficult for people to move to
                  other
                  > countries when droughts, floods, famines, and wars occur. These
                  > boundary effects could be particularly severe for small and poor
                  > countries, whose populations are often unwelcome in richer
                  countries.
                  > In the 1840s, more than 1 million Irish people emigrated because of
                  > the potato blight. Can you imagine an equivalent migration of many
                  > millions of people today? Keep in mind that there were only about 1
                  > billion people on Earth then. There are 6 billion now.
                  >
                  > As a society, I believe we must face the potential for abrupt
                  climate
                  > change. Perhaps we can mitigate the changes. If not, at least we
                  can
                  > still take steps to adapt to them.
                  >
                  > The best way to improve the effectiveness of our response is to
                  have
                  > more knowledge of what can happen—and how and when. Research into
                  the
                  > causes, patterns, likelihood, and effects of abrupt climate change
                  > can help reduce our vulnerabilities and increase our ability to
                  > adapt.
                  >
                  > If climate changes come abruptly, we will have less time to adjust.
                  > In other words, the more knowledge we have—the more reliably we can
                  > predict changes—the better our chances.
                  >
                  > Maybe over the edge of the cliff, there's just a three-inch drop-
                  off.
                  > Or maybe there's a big, fluffy bed full of pillows. My worry is
                  that
                  > we are indeed approaching this cliff blindfolded.
                  >
                  > Are you comfortable and secure with this scenario?
                • F Cote <dionysios2100@hotmail.com>
                  It is exactly this type of positive feedback loop that offers the scariest scenarios: GW-- ice cap melting-- lower albedo-- more solar energy absorbed -- more
                  Message 8 of 9 , Dec 10, 2002
                    It is exactly this type of positive feedback loop that offers the
                    scariest scenarios:

                    GW-->ice cap melting-->lower albedo-->more solar energy absorbed
                    -->more GW

                    It's the old "snowballing" effect and could, theoretically, drive
                    the climate system into some kind of uncontrolled spiral what would
                    entrain massive crop failures (from disrupted weather patterns), etc.
                    The fact that we do not really understand how the climate machine
                    functions in detail only underscores the folly of our current
                    cavalier treatment of our world's critical "life support systems"

                    --- In globalwarming@yahoogroups.com, dmgan106 <no_reply@y...> wrote:
                    > Aparently this doomsday scenario is proceeding apace. The BBC is
                    > reporting record melting in the Arctic.
                    >
                    > "According to scientists, surface melt on Greenland was the highest
                    > in recorded history - and extended to elevations previously
                    untouched
                    > by melt - while the amount of Arctic sea ice also reached a record
                    > low.
                    >
                    > While some of the accelerated melting appears to be linked to
                    natural
                    > atmospheric oscillations, human influence could not be ruled out,
                    > said the scientists."
                    >
                    > ""Polar sea ice has an important function in moderating the global
                    > energy balance," he said (University of Alaska, Fairbanks,
                    researcher
                    > Larry Hinzman). He explained that sea ice has albedo of 0.8. That
                    is,
                    > it reflects 80% of the solar radiation. When the sea ice melts you
                    > have water, which has an albedo of 0.2.
                    >
                    > "The sea ice goes from absorbing 20% of solar radiation to
                    absorbing
                    > 80%," said Dr Hinzman. This creates positive feedback for further
                    > warming.
                    >
                    > In total, the arctic warming is an unprecedented trend, according
                    to
                    > Dr Hinzman.
                    >
                    > "We're experiencing the most rapid increase in temperature in
                    > recorded history," he said."
                    >
                    > http://news.bbc.co.uk/1/hi/sci/tech/2558319.stm
                    >
                    > --- In globalwarming@yahoogroups.com, "Banzai (Lance Stinson)"
                    > <banzai@m...> wrote:
                    > > A perspective on potential climate changes presented by Dr.
                    Robert
                    > B.
                    > > Gagosian, President and Director of Woods Hole Oceanographic
                    > > Institution
                    > >
                    > > http://www.whoi.edu/home/about/whatsnew_abruptclimate.html
                    > >
                    > > Over the past two decades, we have heard about greenhouse gases
                    and
                    > > the idea that our planet is gradually warming. I'd like to throw
                    a
                    > > curveball into that thinking—specifically the "gradually warming"
                    > > part.
                    > >
                    > > This new thinking is little known and scarcely appreciated by
                    > > policymakers and world and business leaders—and even by the wider
                    > > community of natural and social scientists. But evidence from
                    > several
                    > > sources has amassed and coalesced over the past 10 to 15 years.
                    It
                    > > points to a completely different—almost counterintuitive—
                    scenario.
                    > >
                    > > Global warming could actually lead to a big chill in some parts
                    of
                    > > the world. If the atmosphere continues to warm, it could soon
                    > trigger
                    > > a dramatic and abrupt cooling throughout the North Atlantic
                    region—
                    > > where, not incidentally, some 60 percent of the world's economy
                    is
                    > > based.
                    > >
                    > > When I say "dramatic," I mean: Average winter temperatures could
                    > drop
                    > > by 5 degrees Fahrenheit over much of the United States, and by 10
                    > > degrees in the northeastern United States and in Europe. That's
                    > > enough to send mountain glaciers advancing down from the Alps. To
                    > > freeze rivers and harbors and bind North Atlantic shipping lanes
                    in
                    > > ice. To disrupt the operation of ground and air transportation.
                    To
                    > > cause energy needs to soar exponentially. To force wholesale
                    > changes
                    > > in agricultural practices and fisheries. To change the way we
                    feed
                    > > our populations. In short, the world, and the world economy,
                    would
                    > be
                    > > drastically different.
                    > >
                    > > And when I say "abrupt," I mean: These changes could happen
                    within
                    > a
                    > > decade, and they could persist for hundreds of years. You could
                    see
                    > > the changes in your lifetime, and your grandchildren's
                    > grandchildren
                    > > will still be confronting them.
                    > >
                    > > And when I say "soon," I mean: In just the past year, we have
                    seen
                    > > ominous signs that we may be headed toward a potentially
                    dangerous
                    > > threshold. If we cross it, Earth's climate could switch gears and
                    > > jump very rapidly—not gradually— into a completely different mode
                    > of
                    > > operation.
                    > >
                    > >
                    > > A schematic of the ocean circulation system, often called the
                    Great
                    > > Ocean Conveyor, that transports heat throughout the world oceans.
                    > Red
                    > > arrows indicate warm surface currents. Blue arrows indicate deep
                    > cold
                    > > currents. (Animation by Jack Cook, WHOI)
                    > > This is not something new under the Sun. It has happened
                    throughout
                    > > Earth's history, and it could happen again.
                    > >
                    > > The key to these climate shifts is that Earth's climate is
                    created
                    > > and maintained by a dynamic system of moving, interacting parts.
                    > > Earth's climate system has two main components. The first one you
                    > are
                    > > all familiar with by watching your local TV meteorologist or The
                    > > Weather Channel. It is the atmosphere, which circulates heat and
                    > > moisture around the globe. But, in fact, the atmosphere
                    > redistributes
                    > > only about half of the energy that the earth receives from the
                    Sun.
                    > >
                    > > The other half is transported around our planet by a circulation
                    > > system that is equally important, but far less understood—the
                    > ocean.
                    > > The ocean isn't a stagnant bathtub. It circulates heat around the
                    > > planet like the heating and cooling system in your house. The
                    > > atmosphere and oceans are equal partners in creating Earth's
                    > climate.
                    > > The atmosphere is a rabbit. It moves fast. Rapid changes in
                    > > atmospheric circulation cause storms, cold spells, or heat waves
                    > that
                    > > play out over several days.
                    > >
                    > > The ocean, on the other hand, is a turtle. It may take years or
                    > > decades or even millennia for similar "disturbances" to circulate
                    > > through the ocean. But the ocean is a big turtle. It stores about
                    > > 1,000 times more heat than the atmosphere. So changes in ocean
                    > > circulation can set the stage for large-scale, long-term climate
                    > > changes.
                    > >
                    > > One example that you may be familiar with is El Niño. Every few
                    > > years, oceanic conditions shift, and surface water temperatures
                    in
                    > > the eastern tropical Pacific get warmer. The atmosphere above the
                    > > ocean shifts, too. El Niño rearranges worldwide wind and rainfall
                    > > patterns, causing destructive droughts, floods, storms, and
                    forest
                    > > fires. Not to downplay El Niño in the least, because it causes
                    > grave
                    > > human suffering and billions of dollars in damage—but El Niño is
                    > > relatively short-lived. It lasts only a year or two.
                    > >
                    > > The climate changes I'm concerned about last longer and involve
                    the
                    > > ocean circulation system that spans the entire globe—which we
                    often
                    > > call the Great Ocean Conveyor.
                    > >
                    > > The Great Ocean Conveyor is the ocean's major heat-circulating
                    > > system. The ocean keeps our planet from overheating by
                    transporting
                    > > heat north and south, from the equator to the poles, in currents
                    > > traveling near the ocean surface. In the Atlantic, the Conveyor
                    > > removes heat from the Southern Hemisphere and releases it to the
                    > > Northern Hemisphere.
                    > >
                    > >
                    > > The Great Ocean Conveyor is propelled by the sinking of cold,
                    salty
                    > > (and therefore denser) waters in the North Atlantic Ocean (blue
                    > > arrows). That creates a void that pulls warm, salty Gulf Stream
                    > > waters northward (red arrows). The Gulf Stream gives up its heat
                    to
                    > > the atmosphere above the North Atlantic Ocean, and prevailing
                    winds
                    > > (large red arrows) carry the heat eastward to warm Europe.
                    > (Animation
                    > > by Jack Cook, WHOI)
                    > > The most famous and most important of these currents is the Gulf
                    > > Stream. The vast Gulf Stream transports the equivalent volume of
                    75
                    > > Amazon Rivers. It carries heat absorbed in the tropics, and moves
                    > up
                    > > the East Coast of the United States, then northeastward toward
                    > > Europe.
                    > >
                    > > When the Gulf Stream's warm, salty waters reach colder latitudes,
                    > > they give up their heat to the atmosphere. The atmosphere in the
                    > > North Atlantic region warms by as much as 10 degrees Fahrenheit.
                    > > Prevailing winds carry the heat eastward into Europe. That's one
                    > > reason London, England—which is located at the same latitude as
                    > > Calgary and Edmonton—has warmer winters than New York—which is
                    > > hundreds of miles farther south.
                    > >
                    > > When the Gulf Stream's waters reach the Labrador, Greenland and
                    > other
                    > > northern seas, and lose their heat to the atmosphere, they become
                    > > colder—and hence denser. The waters are also relatively salty.
                    > Salty
                    > > water is denser than fresher water, so the whole salty mass
                    begins
                    > to
                    > > sink to great depths.
                    > >
                    > > When this sinking mass of cold water reaches the abyss, it then
                    > flows
                    > > at deep levels of the ocean, from the North Atlantic southward
                    into
                    > > the South Atlantic. The plunge of this great volume of cold,
                    salty
                    > > water propels the Great Ocean Conveyor. And on the back end, it
                    > > creates a void that actively pulls the Gulf Stream northward to
                    > > replace the waters that are sinking.
                    > >
                    > > It's a pretty neat system. We have been operating under the
                    climate
                    > > conditions created by this beneficent oceanic heating,
                    ventilation,
                    > > and cooling system for centuries.
                    > >
                    > > But what if this system weren't operating today? What if cold
                    North
                    > > Atlantic waters didn't sink and warm equatorial waters weren't
                    > drawn
                    > > in to replace the sinking waters? Then the North Atlantic region
                    > > would be a much different, much colder place.
                    > >
                    > > The vast majority of us go about our business thinking that
                    Earth's
                    > > climate system has always been this way, and always will be. But
                    > that
                    > > is just not the case. In fact, we know that the Ocean Conveyor
                    has
                    > > indeed shut down—stopped operating—in the past.
                    > >
                    > > We know this by examining truly interesting and valuable natural
                    > > archives that record past changes in Earth's climate. For
                    example,
                    > we
                    > > can see layers within ice sheets in Greenland or in high
                    elevations
                    > > in the Andes Mountains in South America. This layering is caused
                    by
                    > > variations in the amount of snow that fell on the top of the ice
                    > > sheet in the past.
                    > >
                    > >
                    > >
                    > > Top: Ice sheets reveal annual layers, which scientists can
                    analyze
                    > to
                    > > reconstruct the history of precipitation and air temperatures
                    > 100,000
                    > > years in the past. (Photo by Lonnie Thompson, Ohio State
                    > University)
                    > > Bottom: Cores of seafloor sediments reveal the climate history of
                    > the
                    > > ocean. (Photo by Ken Buesseler, WHOI)
                    > > The light and dark bands within the ice sheet show an annual
                    cycle
                    > of
                    > > dust in the atmosphere, so each couplet reflects the amount of
                    snow
                    > > that fell in one year. By analyzing the chemistry of the ice
                    > itself,
                    > > scientists can determine the temperature of the atmosphere when
                    the
                    > > snow was produced.
                    > >
                    > > Thus from a single ice sheet record, it is possible to
                    reconstruct
                    > > the past history of precipitation and air temperature in a
                    region.
                    > > For very old ice sheets, like the glaciers on Greenland, it is
                    > > possible to reconstruct this climate history 100,000 years into
                    the
                    > > past.
                    > >
                    > > The ocean has similar archives of past climate. By taking cores
                    > from
                    > > the ocean floor, it is possible to reconstruct the history of
                    ocean
                    > > climate back many thousands of years. We have used our ships to
                    > > collect samples of sediments from the seafloor. Preserved in the
                    > > sediments are the fossil remains of microscopic organisms that
                    > settle
                    > > to the seafloor. They accumulate over time in layers—similar to
                    the
                    > > ice core—that delineate many important aspects of past climate.
                    > >
                    > > For instance, certain organisms are found only in colder, polar
                    > > waters and never live in warmer waters. They can reveal where and
                    > > when cold surface waters existed—and didn't exist—in the past.
                    > >
                    > > From records like these, we know that about 12,800 years ago,
                    North
                    > > Atlantic waters cooled dramatically—and so did the North Atlantic
                    > > region. This large cooling in Earth's climate occurred in about a
                    > > decade. And the cold spell lasted for about 1,300 years.
                    > >
                    > > This period is called the Younger Dryas, and it is just one of
                    > > several periods when Earth's climate changed very rapidly from
                    warm
                    > > to cold conditions, and then back to warm again. So these long-
                    term
                    > > cold snaps are not unusual.
                    > >
                    > > These shifts almost certainly involved changes in the ocean's
                    > > circulation. There were shutdowns and restartings of the Ocean
                    > > Conveyor. These warm-to-cold transitions happen in about 3 to 10
                    > > years. The cold periods lasted for 500 to 1,000 years. Such
                    > > oscillations in temperature and ocean circulation have occurred
                    on
                    > a
                    > > regular basis.
                    > >
                    > > About 1,000 years ago, during a period of unusually warm
                    > temperatures
                    > > in the North Atlantic, the Norse established settlements and
                    > > vineyards in Greenland that would not be possible today. Those
                    > > settlements were abandoned about 500 years ago, when we believe
                    the
                    > > most recent shutdown of the North Atlantic Ocean circulation
                    system
                    > > occurred.
                    > >
                    > > During that era, called the Little Ice Age, northern Europe was
                    > much
                    > > colder than it is today. Glaciers spread outward and downward in
                    > the
                    > > Alps. Winters, on average, were more severe. Farming was
                    affected.
                    > > Famine was frequent.
                    > >
                    > > In the 1730s and 1740s, abrupt European cooling caused famine
                    > across
                    > > western Europe, especially in Ireland and France, where farmers
                    > > depended on wheat and potatoes. In Ireland, this is known as
                    > > the "forgotten famine." As many people died during the forgotten
                    > > famine as died during the famed potato famine of the 1840s.
                    > >
                    > > The 16th-century Flemish artist Bruegel couldn't have painted his
                    > > famous frozen landscapes today, because now canals in the
                    > Netherlands
                    > > rarely freeze, as they regularly did back then. And likewise, the
                    > > winter in Valley Forge might not have been so cold, and
                    > Washington's
                    > > crossing of the ice-bound Delaware River wouldn't have been so
                    > > dramatic, if he had done it a century later—because our climate
                    > > conditions have shifted since then, and today, the Delaware River
                    > > rarely freezes.
                    > >
                    > > If you read David McCullough's biography of John Adams, you will
                    > > remember that the British were about to set Boston on fire when
                    > > George Washington was able to bring the cannons of Fort
                    Ticonderoga
                    > > down from upstate New York in record time. He was able to do it
                    > > because the ground was frozen solid and they could slide the
                    > cannons
                    > > to the Dorchester hills of Boston in time to persuade the British
                    > to
                    > > retreat from Boston and to change the course of history.
                    > >
                    > > So we have solid evidence that the Great Ocean Conveyor has
                    slowed
                    > > down or shut down in the past. And we have seen dire impacts on
                    our
                    > > climate. It begs the question: Could something throw a wrench
                    into
                    > > the Great Ocean Conveyor in the near future? And could that
                    trigger
                    > > abrupt, dramatic climate changes throughout our planet? The
                    answers
                    > > to those questions are, indisputably, "Yes and yes."
                    > >
                    > >
                    > > Like most dynamic systems, Earth's climate seeks a stable mode
                    (top
                    > > tier). If the system is pushed, it will stagger for a while unitl
                    > it
                    > > recovers (middle tier). If it is pushed past a threshold, it will
                    > > shift into another mode of operation (bottom tier). (Illustration
                    > by
                    > > Jack Cook, WHOI, adapted from Abrupt Climate Change, Inevitable
                    > > Suprises National Research Council)
                    > > Another way to look at Earth's climate system is a simple mode of
                    > > balances (see diagram, left). Like most dynamic systems, Earth's
                    > > climate seeks a stable mode. And it will tend to stay in that
                    mode
                    > if
                    > > nothing causes it to change. That's the top tier of the diagram.
                    > The
                    > > ball remains ensconced in its cup.
                    > >
                    > > The middle tier shows what happens if you push on the system. The
                    > > ball will rattle and roll around in different directions for a
                    > while
                    > > until it settles back down in its cup. We humans would definitely
                    > > notice that rattling until the climate system returned to
                    > > equilibrium. The balance, forced to move, staggers but recovers.
                    > >
                    > > Then there is a third situation— in which a strong enough push at
                    > the
                    > > right time could shove the system past a threshold and into a
                    > > completely different mode of operation. In terms of our climate
                    > > system, that means that a small or temporary forcing could
                    produce
                    > a
                    > > sudden, large, and long-lasting change. That begs the next
                    > question:
                    > > What could do that to our climate system today?
                    > >
                    > > One answer to that is fresh water. If you simply add too much
                    fresh
                    > > water to the North Atlantic, the waters there will become less
                    > salty
                    > > and less dense. They will stop sinking. Then the Gulf Stream
                    slows
                    > > down or is deflected southward. Winters in the North Atlantic
                    > region
                    > > get significantly colder.
                    > >
                    > > Now here's the predicament. In the past year, oceanographers
                    > > monitoring and analyzing water conditions in the North Atlantic,
                    > have
                    > > concluded that the North Atlantic has been freshening
                    dramatically—
                    > > especially in the past decade. New data —from Ruth Curry at Woods
                    > > Hole Oceanographic Institution and her colleague Robert Dickson
                    at
                    > > the British Centre for Environment, Fisheries, and Aquaculture
                    > > Science—chronicles salinity changes in the western North Atlantic
                    > > since 1960.
                    > >
                    > > The Great Ocean Conveyor transports fresh surface water down into
                    > the
                    > > depths. The depths can absorb a lot of fresh water like a sponge.
                    > But
                    > > since 1970, the equivalent of an extra 20 feet of fresh water
                    > across
                    > > the surface of the northern North Atlantic has been transported
                    > down
                    > > into the ocean depths, most of that since 1990.
                    > >
                    > > A sponge that is three-quarters saturated can still absorb more
                    > > water. But the moment that sponge is fully saturated, it can
                    absorb
                    > > no more water.
                    > >
                    > >
                    > > If too much fresh water enters the North Atlantic, its waters
                    could
                    > > stop sinking. The Great Conveyor would cease. Heat-bearing Gulf
                    > > Stream waters (red arrows would no longer flow into the North
                    > > Atlantic, and winters would become more severe. (Animation by
                    Jack
                    > > Cook, WHOI)
                    > > At some point, the North Atlantic will no longer absorb any more
                    > > fresh water. It will begin to pile up on the surface. When that
                    > > happens, the Great Ocean Conveyor will be clogged. It will back
                    up
                    > > and cease functioning.
                    > >
                    > > The very recent freshening signal in the North Atlantic is
                    arguably
                    > > the biggest and most dramatic change in ocean property that has
                    > ever
                    > > been measured in the global ocean. Already, surface waters in the
                    > > Greenland Sea are sinking at a rate 20 percent slower than in the
                    > > 1970s.
                    > >
                    > > At what percent will the Ocean Conveyor stop? 25 percent? 40
                    > percent?
                    > > 60 percent? This is not like a dimmer switch, but more like a
                    light
                    > > switch. It probably goes from "on" to "off."
                    > >
                    > > We can't yet determine the precise source or sources of this
                    > > additional fresh water. Global warming may be melting glaciers,
                    or
                    > > Arctic sea ice. In recent decades, the volume of Arctic sea ice
                    has
                    > > decreased by 40 percent. And if North Atlantic sinking slows
                    down,
                    > > less salty Gulf Stream waters flow northward—which exacerbates
                    the
                    > > situation.
                    > >
                    > > In February 2002, at a worldwide meeting of oceanographers, new
                    > data
                    > > on North Atlantic freshening prompted many scientists to say that
                    > > salinity levels in the North Atlantic are approaching a density
                    > very
                    > > close to the critical point at which the waters will stop
                    sinking.
                    > >
                    > > One of my colleagues at Woods Hole, Terry Joyce, put it this
                    > > way: "I'm in the dark as to how close to an edge or transition to
                    a
                    > > new ocean and climate regime we might be," he said. "But I know
                    > which
                    > > way we are walking. We are walking toward the cliff."
                    > >
                    > > To that sentiment, I would add this: We are walking toward the
                    edge
                    > > of a cliff—blindfolded. Our ability to understand the potential
                    for
                    > > future abrupt changes in climate is limited by our lack of
                    > > understanding of the processes that control them.
                    > >
                    > >
                    > > New data shows that North Atlantic waters at depths between 1,000
                    > and
                    > > 4,000 meters are becoming dramatically less salty, especially in
                    > the
                    > > last decade. Red indicates saltier-than-normal waters. Blue
                    > indicates
                    > > fresher waters. Oceanographers say we may be approaching a
                    > threshold
                    > > that would shut down the Great Ocean Conveyor and cause abrupt
                    > > climate changes. (Data from Ruth Curry, WHOI, Bob Dickson, Centre
                    > for
                    > > Environment, Fisheries, and Aquaculture Science and Igor
                    Yashayaev,
                    > > Bedford Institute of Oceanography)
                    > >
                    > >
                    > > In the past decades, we have made great strides in understanding
                    > > Earth's atmospheric circulation system because we established a
                    > > global network of thousands of meteorological stations to monitor
                    > > changing atmospheric conditions. No observational network exists
                    to
                    > > continuously monitor the oceans. If we just had a few more
                    > > strategically placed modern instruments in the oceans for an
                    > extended
                    > > time, we could understand so much more about how the oceans can
                    > cause
                    > > abrupt climate changes. At present, there is no national plan for
                    > > improving our understanding of the issue, and according to a 2002
                    > > National Research Council report, no policymaking body is
                    > addressing
                    > > the many concerns raised by the potential for abrupt climate
                    > change.
                    > >
                    > > So here's the situation: We have unequivocal evidence of
                    repeated,
                    > > large, widespread, abrupt climate changes on Earth. It is
                    > reasonable
                    > > to assume that greenhouse warming can exacerbate the possibility
                    of
                    > > precipitating large, abrupt, and regional or global climatic
                    > changes.
                    > > We even have strong evidence that we may be approaching a
                    dangerous
                    > > threshold—that we are squeezing a trigger in the North Atlantic.
                    > >
                    > > We could downplay the relevance of past abrupt events and deny
                    the
                    > > likelihood of future abrupt climate changes. But that could prove
                    > > costly. With growing globalization, the adverse impacts of
                    climate
                    > > changes are likely to spill across national boundaries—through
                    > > migration, economic shocks, and political aftershocks.
                    > >
                    > > Over human history, one of the major ways that humans have
                    adapted
                    > to
                    > > changing environmental and economic fortunes has been to migrate
                    > from
                    > > unproductive or impacted regions to more productive and
                    hospitable
                    > > regions. But today, the world's population has grown too large.
                    > There
                    > > is less usable, unpopulated territory to absorb migrants.
                    National
                    > > borders are less open, so it is difficult for people to move to
                    > other
                    > > countries when droughts, floods, famines, and wars occur. These
                    > > boundary effects could be particularly severe for small and poor
                    > > countries, whose populations are often unwelcome in richer
                    > countries.
                    > > In the 1840s, more than 1 million Irish people emigrated because
                    of
                    > > the potato blight. Can you imagine an equivalent migration of
                    many
                    > > millions of people today? Keep in mind that there were only about
                    1
                    > > billion people on Earth then. There are 6 billion now.
                    > >
                    > > As a society, I believe we must face the potential for abrupt
                    > climate
                    > > change. Perhaps we can mitigate the changes. If not, at least we
                    > can
                    > > still take steps to adapt to them.
                    > >
                    > > The best way to improve the effectiveness of our response is to
                    > have
                    > > more knowledge of what can happen—and how and when. Research into
                    > the
                    > > causes, patterns, likelihood, and effects of abrupt climate
                    change
                    > > can help reduce our vulnerabilities and increase our ability to
                    > > adapt.
                    > >
                    > > If climate changes come abruptly, we will have less time to
                    adjust.
                    > > In other words, the more knowledge we have—the more reliably we
                    can
                    > > predict changes—the better our chances.
                    > >
                    > > Maybe over the edge of the cliff, there's just a three-inch drop-
                    > off.
                    > > Or maybe there's a big, fluffy bed full of pillows. My worry is
                    > that
                    > > we are indeed approaching this cliff blindfolded.
                    > >
                    > > Are you comfortable and secure with this scenario?
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