Global Science Report is a feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”
Pat Michaels is in San Francisco this week attending the annual meeting of the American Geophysical Union (AGU) and presenting a poster detailing the widening mismatch between observations of the earth’s temperature and climate model projections of its behavior. Since most global warming concern (including that behind regulatory action) stems from the projections of climate models as to how the earth’s temperature will evolve as we emit greenhouse gases into the atmosphere (as a result of burning fossil fuels to produce energy), it is important to keep a tab on how the model projections are faring when compared with reality. That they are faring not very well should be more widely known—Pat will spread the word while there.
We don’t want those of you who are unable to attend the conference to think you are missing out on anything, so we have reformatted our poster presentation to fit this blog format (it is available in its original format here).
Quantifying the Lack of Consistency between Climate Model Projections and Observations of the Evolution of the Earth’s Average Surface Temperature since the Mid-20th Century
Patrick J. Michaels, Center for the Study of Science, Cato Institute, Washington DC
Paul C. Knappenberger, Center for the Study of Science, Cato Institute, Washington DC
Recent climate change literature has been dominated by studies which show that the equilibrium climate sensitivity is better constrained than the latest estimates from the Intergovernmental Panel on Climate Change (IPCC) and the U.S. National Climate Assessment (NCA) and that the best estimate of the climate sensitivity is considerably lower than the climate model ensemble average. From the recent literature, the central estimate of the equilibrium climate sensitivity is ~2°C, while the climate model average is ~3.2°C, or an equilibrium climate sensitivity that is some 40% lower than the model average.
To the extent that the recent literature produces a more accurate estimate of the equilibrium climate sensitivity than does the climate model average, it means that the projections of future climate change given by both the IPCC and NCA are, by default, some 40% too large (too rapid) and the associated (and described) impacts are gross overestimates.