Cold months in a warming climate

Abstract

The frequency of cold months in the 21st century is studied using the CMIP3 ensemble of climate model simulations, using month-, location-and model-specific threshold temperatures derived from the simulated 20th century climate. Unsurprisingly, cold months are projected to become less common, but not non-existent, under continued global warming. As a multi-model mean over the global land area excluding Antarctica and under the SRES A1B scenario, 14% of the months during the years 2011-2050 are simulated to be colder than the 20th century median for the same month, 1.3% colder than the 10th percentile, and 0.1% record cold. The geographic and seasonal variations in the frequency of cold months are strongly modulated by variations in the magnitude of interannual variability. Thus, for example, cold months are most infrequently simulated over the tropical oceans where the variability is smallest, not over the Arctic where the warming is largest. Copyright 2011 by the American Geophysical Union.