Popular science articles about climate change under increased CO2 often emphasize changes in weather, with a general sense that weather becomes more variable and less predictable. (Thomas Friedman calls this “global weirding”.) But the popular imagination is almost exactly backwards: increasing atmospheric CO2 tends to reduce many kinds of climate variability because it reduces contrasts: nights become more similar to days, winters to summers, polar regions to tropics. We review expected future changes in both precipitation and temperature variability in a variety of model runs, from ultra-high to coarse resolution (12-400 km), and analyze changes at frequencies from days to decades. Variability responses are broadly robust across models and to first order explainable by simple physics. In particular, we see no evidence for increases in low-frequency variability in precipitation, i.e. for increased incidence of multi-year drought.
Past Faculty Workshop•Apr 11, 2017
Elisabeth Moyer, UChicago
Hot, flat, and boring: the climate of the future