Researchers at Princeton University and the University of Miami report that the latest generation of climate models with a high “climate sensitivity” — meaning they predict much greater global warming from the same levels of atmospheric carbon dioxide as other models — do not provide a plausible scenario of Earth’s future climate, the researchers reported in the journal Geophysical Research Letters.
Instead, models with lower climate sensitivity are more consistent with observed differences in temperature between the northern and southern hemispheres, and, thus, are more accurate depictions of projected climate change than the newer models.
These findings provide a cautionary tale on interpreting climate simulations that is potentially significant when it comes to climate-change policy. Because models with higher climate sensitivity forecast greater warming from greenhouse gas emissions, they also project more dire — and imminent — consequences.
“A higher climate sensitivity would obviously necessitate much more aggressive carbon mitigation,” said co-author Gabriel Vecchi, a Princeton professor of geosciences and the High Meadows Environmental Institute (HMEI). “Reducing the uncertainty in climate sensitivity helps us make a more reliable and accurate strategy to deal with climate change.
The study was supported by the Carbon Mitigation Initiative (CMI) based in HMEI.