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Monbiot on limiting fossil fuel extraction

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  • Christopher Miller
    Following up on last week s news of a proposal by climate scientists that we should now start considering limiting the total amount of fossil fuels we extract
    Message 1 of 1 , May 8, 2009
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      Following up on last week's news of a proposal by climate scientists
      that we should now start considering limiting the total amount of
      fossil fuels we extract to put an absolute limit on emissions, George
      Monbiot deals with this question in his online column:

      http://www.monbiot.com/archives/2009/05/06/how-much-should-we-leave-in-the-ground/


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

      How Much Should We Leave In The Ground?
      Posted May 6, 2009
      Here are some estimates for how much fossil fuel we can use, and a
      call for a global moratorium on new prospecting.


      By George Monbiot. Published on the Guardian�s website, 6th May 2009.

      The two papers on carbon emissions published in Nature last week were
      ground-breaking: they show us how much carbon dioxide we can produce
      if we�re to have a reasonable chance of preventing two degrees of
      global warming. It�s a completely different approach from the UN�s and
      national governments�. They set targets for reductions by a certain
      date but have nothing to say about the total amount of carbon we can
      release.

      One of the papers, by Myles Allen and others(1), suggests that we can
      burn, at most, another 400-500 billion tonnes of carbon at any time
      between now and the extinction of humanity if we want to avoid two
      degrees of warming. The other, by Malte Meinshausen and others(2),
      suggests that producing 1000 billion tonnes of CO2 between 2000-2050
      would give us a 25% chance of exceeding two degrees. That�s a lot less
      than Allen�s estimate, as one tonne of carbon produces 3.667 tonnes of
      CO2 when it�s burnt: 1000 billion tonnes of CO2 arises from 273
      billion tonnes of carbon.

      But let�s err on the side of valour and use Allen�s figures. Moreover,
      let�s disregard all other greenhouse gases (which, he suggests, should
      reduce the total CO2 budget to under 400 billion tonnes). How does his
      maximum allowance of carbon compare with known reserves of fossil fuel?

      Let me make two things clear before I make this calculation. First,
      reserves are not the same as resources. A resource is the total amount
      of a mineral found in the earth�s crust. A reserve is the part of the
      resource which has been identified, quantified and is cost-effective
      to exploit. In most cases this is likely to be a small percentage of
      the total resource.

      Secondly, there is some controversy over the official figures for
      fossil fuel reserves. This is especially the case for oil, as the
      members of OPEC are extremely secretive about how much they possess.
      But for the sake of argument, let�s take them at face value.

      According to the World Energy Council:

      global reserves of coal amount to 848 billion tonnes(3)

      global reserves of natural gas are 177,000 billion cubic metres(4)

      global reserves of crude oil are 162 billion tonnes(5)

      Because the calculations are much harder and the quantities involved
      less certain, I am ignoring unconventional sources of fossil fuel,
      such as tar sands, oil shales, bitumens and methane hydrates, as well
      as liquid natural gas resources.

      On average, one tonne of coal contains 746 kg carbon(6)

      One cubic metre of natural gas contains 0.49 kg carbon(7)

      The figure for oil is less certain, because not all of its refinery
      products are burnt. But the rough calculation here(8) suggests that
      the use of a barrel of oil releases 317kg of CO2. Depending on the
      density of the oil, there are roughly 7 barrels to the tonne, giving
      an approximation of 2219kg CO2, or 605kg of carbon.

      So the carbon content of official known reserves of coal, gas and oil
      amounts to:

      848 x 0.746 = 633

      +

      177,000 x 0.00049 = 87

      +

      162 x 0.605 = 98

      Total conventional fossil fuel reserves therefore contain 818 billion
      tonnes of carbon.

      Even ignoring all unconventional sources and all other greenhouse
      gases and taking the most optimistic of the figures in the two Nature
      papers, we can afford to burn only 61% of known fossil fuel reserves
      between now and eternity.

      Or, using Meinshausen�s figure, we can burn only 33% between now and
      2050. Sorry - 33% minus however much we have burnt between 2000 and
      today.

      So the question which arises is this: which fossil fuel reserves will
      we decide not to extract and burn? There is, as I have argued
      before(9), no point in seeking to reduce our consumption of fossil
      fuels unless we also seek to reduce their production. Yet, apart from
      the members of OPEC (who do it only to shore up the price), no
      government is attempting to limit the amount of fuel extracted. Far
      from it; they all pursue the same strategy as the United Kingdom: to
      �maximise economic recovery�(10).

      The test of all governments� commitment to stopping climate breakdown
      is this: whether they are prepared to impose a limit on the use of the
      reserves already discovered, and a permanent moratorium on prospecting
      for new reserves. Otherwise it�s all hot air.

      www.monbiot.com

      References:

      1. http://www.nature.com/nature/journal/v458/n7242/full/nature08019.html

      2. http://www.nature.com/nature/journal/v458/n7242/full/nature08017.html

      3. http://www.worldenergy.org/publications/survey_of_energy_resources_2007/coal/627.asp

      4. http://www.worldenergy.org/publications/survey_of_energy_resources_2007/natural_gas/664.asp

      5. http://www.worldenergy.org/publications/survey_of_energy_resources_2007/crude_oil_and_natural_gas_liquids/638.asp

      6. http://bioenergy.ornl.gov/papers/misc/energy_conv.html

      7. http://bioenergy.ornl.gov/papers/misc/energy_conv.html

      8. http://numero57.net/?p=255

      9. http://www.monbiot.com/archives/2007/12/11/rigged/

      10. http://www.berr.gov.uk/files/file39387.pdf

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

      Christopher Miller
      Montreal QC Canada



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