Journal Article

Climate Sensitivity Estimated from Temperature Reconstructions of the Last Glacial Maximum

Shakun, Jeremy D., Bartlein, Patrick J., Urban, Nathan M., Mahowald, Natalie M., Mix, Alan C., Rosell-Melé, Antoni, Schmittner, Andreas, Clark, Peter U.

2011

Overview

Assessing the impact of future anthropogenic carbon emissions is currently impeded by uncertainties in our knowledge of equilibrium climate sensitivity to atmospheric carbon dioxide doubling. Previous studies suggest 3 kelvin (K) as the best estimate, 2 to 4.5 K as the 66% probability range, and nonzero probabilities for much higher values, the latter implying a small chance of high-impact climate changes that would be difficult to avoid. Here, combining extensive sea and land surface temperature reconstructions from the Last Glacial Maximum with climate model simulations, we estimate a lower median (2.3 K) and reduced uncertainty (1.7 to 2.6 K as the 66% probability range, which can be widened using alternate assumptions or data subsets). Assuming that paleoclimatic constraints apply to the future, as predicted by our model, these results imply a lower probability of imminent extreme climatic change than previously thought.

• Publisher: American Association for the Advancement of Science,The American Association for the Advancement of Science
• Subject: Air temperature / Anthropogenic factors / carbon / Carbon dioxide / Climate / Climate change / Climate models / Climate science / Cooling / Earth sciences / Earth, ocean, space / emissions / Environmental impact / Estimating techniques / Exact sciences and technology / Glaciers / Global climate / Greenhouse gases / Land / Land surface temperature / Marine and continental quaternary / Modeling / Oceans / Paleoclimatology / Seas / simulation models / Statistical median / Surface temperature / Surficial geology / uncertainty