This is a re-post from The Guardian's Climate Consensus – the 97%
In an opinion article for the London Times this past Monday, writer Matt Ridley discussed his interpretation of a new paper which suggests that the Earth's climate sensitivity may be a bit lower than current best estimates. Climate sensitivity refers to the average amount of warming that will occur at the Earth's surface in response to an increased greenhouse effect.
This new paper, led by Alexander Otto at the University of Oxford, suggested that the Earth's surface may warm a bit more slowly than climate models generally indicate. I roughly estimate that about 80% of the warming over the past century would be due to human carbon dioxide emissions, if the results of this study are correct. The good news is that Ridley has accepted the consensus amongst 97% of climate experts that humans are causing global warming and has moved on to examine the consequences.
One of the paper's authors, Myles Allen noted in The Guardian that the results of the study would make little difference with respect to long-term climate change.
"...our new findings mean that the changes we had previously expected between now and 2050 might take until 2065 to materialise instead."
If these results are correct, it would give us perhaps an additional decade or two to get our acts together and dramatically reduce our greenhouse gas emissions. From this news, Matt Ridley concludes that our climate policy is "hopelessly misguided." Those two words may indeed be applied to our climate policy, but Ridley has got it backwards. Or policy is misguided because we're not doing nearly enough to solve the problem.
He suggests, based on outdated references from Bjorn Lomborg, that the economic impacts of climate change are nothing to worry about. Cambridge economist Chris Hope tested this claim by running the climate sensitivity estimates from the new Otto paper in his economic assessment model, PAGE09. The model previously estimated the climate damage from greenhouse gas emissions at an average cost of approximately $100 per tonne of carbon dioxide. The revised estimate resulted in an average cost of $80 per tonne. Given that humans emit over 30 billion tonnes of carbon dioxide per year, that amounts to an annual increase in committed climate change damage of $2.4 trillion, or over 3% of the global gross domestic product, quite contrary to Ridley's rosy perspective.
Posted by dana1981 on Thursday, 23 May, 2013
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