World energy consumption may be responsible for extra increases of up to 1 °C in winter surface temperature in northern high latitudes, reports a study in Nature Climate Change this week. Observed twentieth-century surface temperature trends in those regions are higher than corresponding simulations of global warming. By including energy use, this work helps to explain the discrepancy.
Ming Cai and colleagues investigate the effect that heat resulting from energy consumption - an anthropogenic forcing neglected in most model simulations - has on climate. They incorporate energy use in a global climate model, and find that the surface air temperature responses - with winter warming of up to 1 °C in Russia and Northern Asia, and up to 0.8 °C in the Canadian Prairies - are similar to the trends observed in the second half of the twentieth century, that previous studies did not capture. With simulations from the same generation of models used above, they replicate the previous twentieth-century analysis that first found the difference between simulated and observed trends, and confirm the results.
They therefore conclude that energy consumption may have contributed to the unexplained winter warming that is observed in high latitudes of North America and Eurasia.