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Climate scientists on reining back hydrocarbon use

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  • Christopher Miller
    Three articles linked to the past couple of days in TreeHugger tell of some client scientists coming to the conclusion that overall warming of the global
    Message 1 of 1 , May 1, 2009
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      Three articles linked to the past couple of days in TreeHugger tell of
      some client scientists coming to the conclusion that overall warming
      of the global climate is reaching such a serious stage of advancement
      that it will be necessary to simply put an absolute cap on total
      allowable emissions and beyond that, simply keep from exploiting any
      of the "dirtiest" hydrocarbon resources (coal, tar sands etc.) once
      conventional current oil and gas resources have been exhausted.

      1. Editorial in the current online edition of Nature:

      http://www.nature.com/nature/journal/v458/n7242/full/4581077a.html

      ---------------------------------------------------------------------------------------------------

      Editorial
      Nature 458, 1077-1078 (30 April 2009) | doi:10.1038/4581077a;
      Published online 29 April 2009


      Time to act
      Topof pageAbstract
      Without a solid commitment from the world's leaders, innovative ways
      to combat climate change are likely to come to nothing.

      It is not too late yet � but we may be very close. The 500 billion
      tonnes of carbon that humans have added to the atmosphere lie heavily
      on the world, and the burden swells by at least 9 billion tonnes a
      year (see page 1117). If present trends continue, humankind will have
      emitted a trillion tonnes of carbon into the atmosphere well before
      2050, and that could be enough to push the planet into the danger
      zone. And there is no reason to think that the pressure will stop
      then. The coal seams and tar sands of the world hold enough carbon for
      humankind to emit another trillion tonnes � and the apocalyptic
      scenarios extend from there (see page 1104).

      Nations urgently need to cut their output of carbon dioxide. The
      difficulty of that task is manifest: emissions have continued to rise
      despite almost two decades of rhetoric, diplomacy and action on the
      matter. But that unhappy fact should not be taken as a licence for
      fatalism. Governments have a wide range of pollution-cutting tools at
      their command, most notably tradable permit regimes, taxes on fuels,
      regulations on power generation and energy efficiency, and subsidies
      for renewable energy and improved technologies. These tools can work
      if applied seriously � so citizens around the world must demand that
      seriousness from their leaders, both within their individual nations
      and in the international framework that will be discussed at the
      United Nations Climate Change Conference in Copenhagen this December.

      As essential as it is, however, simply agreeing to cut emissions will
      not be enough. The fossil fuels burned up so far have already
      committed the world to a serious amount of climate change, even if
      carbon emissions were somehow to cease overnight (see page 1091). And
      given the current economic turmoil, the wherewithal to adapt to these
      changes is in short supply, especially among the world's poor nations.
      Adaptation measures will be needed in rich and poor countries alike �
      but those that have grown wealthy through the past emission of carbon
      have a moral duty to help those now threatened by that legacy (see
      page 1102).

      (Quote box:)
      ----------

      Even a complete halt to carbon pollution would not bring the world's
      temperatures down substantially for several centuries.

      ----------


      The latest scientific research suggests that even a complete halt to
      carbon pollution would not bring the world's temperatures down
      substantially for several centuries. If further research reveals that
      a prolonged period of elevated temperatures would endanger the polar
      ice sheets, or otherwise destabilize the Earth system, nations may
      have to contemplate actively removing CO2 from the atmosphere.

      (...continues at the above link)

      =========================================================

      2. A second freely available article on the Nature site:

      http://www.nature.com/news/2009/090429/full/4581091a.html

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      Published online 29 April 2009 | Nature 458, 1091-1094 (2009) | doi:
      10.1038/4581091a
      News Feature

      Climate crunch: A burden beyond bearing
      The climate situation may be even worse than you think. In the first
      of three features, Richard Monastersky looks at evidence that keeping
      carbon dioxide beneath dangerous levels is tougher than previously
      thought.

      Richard Monastersky

      Download a PDF of this story.
      In 2007, environmental writer Bill McKibben approached climate
      scientist James Hansen and asked him what atmospheric concentration of
      carbon dioxide could be considered safe. Hansen's reaction: "I don't
      know, but I'll get back to you."

      After he had mulled it over, Hansen started to suspect that he and
      many other scientists had underestimated the long-term effects of
      greenhouse warming. Atmospheric concentration of CO2 at the time was
      rising past 382 parts per million (p.p.m.), a full 100 ticks above its
      pre-industrial level. Most researchers, including Hansen, had been
      focusing on 450 p.p.m. as a target that would avoid, in the resonant
      and legally binding formulation of the United Nations Framework
      Convention on Climate Change, "dangerous climate change". McKibben was
      aware of this: he was thinking of forming an organization called
      450.org to call attention to the number, and his question to Hansen
      was by way of due diligence.

      As he thought about McKibben's question, Hansen, who runs NASA's
      Goddard Institute for Space Studies in New York, began to wonder if
      450 p.p.m. was too high. Having spent his career working on climate
      models, he was aware that in some respects the real world was
      outstripping them. Arctic sea ice was reaching record lows; many of
      Greenland's glaciers were retreating; the tropics were expanding.
      "What was clear was that climate models are our weakest tool, in that
      you can't trust their sensitivity in any of these key areas," he says.
      Those warning signs � and his studies of past climate change � led
      Hansen to conclude that only by pulling CO2 concentrations down below
      today's value could humanity avert serious problems. He came back to
      McKibben with not 450 but 350. In 2008, he published a paper spelling
      out his rationale for that target1.

      The difference between 350 and 450 is not just one of degree. It's one
      of direction. A CO2 concentration of 450 p.p.m. awaits the world at
      some point in the future that might conceivably, though with
      difficulty, be averted. But 350 p.p.m. can be seen only in the rear-
      view mirror. Hansen believes that CO2 levels already exceed those that
      would provide long-term safety, and the world needs not just to stop
      but to reverse course. Although his view is far from universal, a
      growing number of scientists agree that the CO2challenge is even
      greater than had previously been thought.

      Several recent studies, for example, indicate that it may be
      exceedingly difficult to cool the climate down from any eventual peak
      or plateau, no matter what CO2 concentration is chosen as a target by
      the international community. And by looking at the problem in a new
      sort of way � by tallying the total amount of carbon injected into the
      atmosphere across human history � two papers in this issue of Nature
      reveal how close the world has come to the danger point (pages 1158
      and 1163). "It's tougher than people have appreciated. We have less
      room to manoeuvre," says Malte Meinshausen, an author of one of the
      papers and a senior researcher at the Potsdam Institute for Climate
      Impact Research in Germany.

      (...more at above link...)

      Also in this issue, Myles Allen of the University of Oxford,
      Meinshausen and their colleagues describe how they ran a series of
      simulations using a simple combination of climate and carbon-cycle
      models (page 1163). They find that if humankind could limit all CO2
      emissions from fossil fuels and changes in land use to 1 trillion tons
      of carbon in total, there would be a good chance that the climate
      would not warm more than 2 �C above its pre-industrial range. Because
      half of that trillion tons has already been spewed into the
      atmosphere, and emissions now average about 9 billion tons a year and
      rising, the trillion-ton limit would allow the world to follow its
      current trend for less than 40 more years before giving up carbon
      emission for good, all at once.

      One way of looking at that challenge is put forward by Hansen. Go
      ahead and burn all the remaining oil and gas in conventional reserves,
      he says, and at the same time concentrate all efforts on quickly
      phasing out coal � or capturing and storing the emissions associated
      with it. If nations can cut off coal use by 2030 and avoid tapping
      unconventional fossil fuels, such as tar sands and methane hydrates,
      the world could limit future CO2 emissions to 400 gigatonnes of carbon.

      (...)

      Although the results of the studies might seem too daunting, they do
      offer a few rays of hope. Andrew Weaver, a modeller at the University
      of Victoria in British Columbia, Canada, says that in the new studies,
      what matters is how much pollution goes into the sky, not when it gets
      emitted. "This allows you some flexibility," he says. From a political
      perspective, the idea of a cap on total emissions "is a lot easier to
      get your head around" than a concentration target or, say, a 20%
      reduction below 1990 emission levels. A cap is like a budget. Once you
      use it up, there's nothing left to spend.

      Unfortunately, the world is behaving as though it expects to be able
      to arrange a large overdraft. And researchers can only come up with so
      many ways of presenting the gravity of the carbon problem to the rest
      of the world. "At some point, you begin to throw your hands up. It's
      very frustrating," says Weaver, who pulls a reference from an ancient
      global crisis. "Climate scientists," he says, "have begun to feel like
      a bunch of Noahs � thousands of Noahs."

      =========================================================

      3. Elsewhere, in Australia, scientists have written a letter to coal
      powered stations asking them to shut down:

      Scientists ask coal plants to shut down : thewest.com.au
      http://www.thewest.com.au/default.aspx?MenuID=28&ContentID=139318

      ---------------------------------------------------------------------------------------------------

      Scientists ask coal plants to shut down
      1st May 2009, 12:30 WST

      A group of scientists have written a letter to the operators of coal-
      fired power stations asking them to shut up shop to save the planet.

      They say real action on climate change will require that existing coal-
      fired power stations �cease to operate in the near future�.

      The seven scientists - three of whom have worked on the
      Intergovernmental Panel on Climate Change - said coal plants should be
      replaced with clean energy.

      No new coal plants should be allowed unless they had zero emissions,
      and this would not be possible for some time.

      �The warming of the atmosphere, driven by human-induced emissions of
      greenhouse gases, is already causing unacceptable damage and suffering
      around the world,� the scientists said in the letter, sent to every
      coal-fired power station in the country.

      �We cannot emphasise enough just how serious the situation has become.�

      Shutting down coal plants would require a social transition for coal
      workers which had to be managed, but the task was unavoidable, they
      said.

      Professor David Karoly, from the University of Melbourne�s School of
      Earth Sciences, headed up the signatories.
      CANBERRA
      AAP

      =========================================================

      Christopher Miller
      Montreal QC Canada



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