Seminar Abstract

DATE:  FRIDAY, September 8, 2017
TIME:  2:30 P.M. - Room 223 (Refreshments served at 2:15 pm)
PLACE: Environmental & Natural Resource Sciences Bldg.
14 College Farm Road, New Brunswick, New Jersey

Alan Robock and Brian Zambri
Rutgers University

Did Smoke from Burning Japanese Cities in 1945 Cause Global Cooling?

Between February 3 and August 9, 1945, an area of 461 km2 in 69 Japanese cities, including Hiroshima and Nagasaki, was burned in U.S. B-29 Superfortress air raids. In the previous five years, 205 km2 in German cities were destroyed. Global average surface air temperature observations during and following World War II are problematic, because of issues with measuring sea surface temperatures, but 1945 global average land surface air temperatures were 0.2 K lower than the average for 1940-1944, and 1946 temperatures were 0.1 K lower. Here we evaluate whether the cooling effects of the smoke from those city fires could have caused the observed global cooling. Observations of solar irradiance show reductions consistent with the hypothesis that smoke that was injected into the stratosphere by the city fires. Although the amount of smoke generated by the fires is somewhat uncertain, historical simulations from the Coupled Model Intercomparison Project 5, with no smoke in their forcing, showed no post-war cooling, so we conclude that the observed cooling was likely caused by the smoke from the fires. These findings add to previous observations of regional cooling from forest fire smoke, and strengthen observational support for nuclear winter theory.