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Nuclear Winter Responses to Nuclear War Between the United States and Russia in the Whole Atmosphere Community Climate Model Version 4 and the Goddard Institute for Space Studies ModelE
Author(s) -
Coupe Joshua,
Bardeen Charles G.,
Robock Alan,
Toon Owen B.
Publication year - 2019
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2019jd030509
Subject(s) - stratosphere , climate model , northern hemisphere , climatology , atmospheric sciences , aerosol , environmental science , atmosphere (unit) , troposphere , soot , arctic , sulfate aerosol , ozone layer , climate change , atmospheric model , meteorology , geology , geography , chemistry , oceanography , organic chemistry , combustion
Current nuclear arsenals used in a war between the United States and Russia could inject 150 Tg of soot from fires ignited by nuclear explosions into the upper troposphere and lower stratosphere. We simulate the climate response using the Community Earth System Model‐Whole Atmosphere Community Climate Model version 4 (WACCM4), run at 2° horizontal resolution with 66 layers from the surface to 140 km, with full stratospheric chemistry and with aerosols from the Community Aerosol and Radiation Model for Atmospheres allowing for particle growth. We compare the results to an older simulation conducted in 2007 with the Goddard Institute for Space Studies ModelE run at 4° × 5° horizontal resolution with 23 levels up to 80 km and constant specified aerosol properties and ozone. These are the only two comprehensive climate model simulations of this scenario. Despite having different features and capabilities, both models produce similar results. Nuclear winter, with below freezing temperatures over much of the Northern Hemisphere during summer, occurs because of a reduction of surface solar radiation due to smoke lofted into the stratosphere. WACCM4's more sophisticated aerosol representation removes smoke more quickly, but the magnitude of the climate response is not reduced. In fact, the higher‐resolution WACCM4 simulates larger temperature and precipitation reductions than ModelE in the first few years following a 150‐Tg soot injection. A strengthening of the northern polar vortex occurs during winter in both simulations in the first year, contributing to above normal, but still below freezing, temperatures in the Arctic and northern Eurasia.