Fourth Observance of the International Day Against Nuclear Tests Andrew S. Kanter, MD MPH FACMI Immediate Past President Physicians for Social Responsibility US Affiliate of The International Physicians for the Prevention of Nuclear War

Animation by Luke Oman. Robock, et. al Animation by Luke Oman. Robock, et. al. Climatic consequences of regional nuclear conflicts. Atmos. Chem. Phys., 7, 2003–2012, 2007

Global climate change unprecedented in recorded human history This slide compares the global warming of the last 120 years with the cooling that would take place in a matter of days. Graph courtesy of Alan Robock 3

Summary of Agricultural Effects Agricultural Crop Studied First 5 years Second 5 Years US Maize (Corn) -20% -10% US Soybeans -15% China Maize (Corn) China Middle Season Rice* China Winter Wheat* -35% -25% * Robock, unpublished data

Effect on Existing Malnourished 870 million people receive 1750 calories per day. 10-35% decrease puts entire group at risk if famine persists for full decade. If market turmoil causes big spike in food prices, the decline in food consumption would be much greater. But the biggest impact is on the 870 million who are already malnourished. At baseline they receive about 1750 calories per day. A10% decline would cut their intake by 175 calories a day, and especially if the famine persisted for a full decade put this entire group at risk.

Surface Air Temperatures 2 years after 150 million tons of smoke enters stratosphere Decrease in Surface Air Temperatures 2 years after full-scale nuclear war Such a conflict would cause the same kind of climate disruption as a limited nuclear war, but on a much larger scale. The South Asian scenario pumps 5 million tons of debris into the atmosphere; a war involving the arsenals on high alert puts 50 million tons, and if the rest of the strategic arsenals that the US and Russia maintain were also drawn into the battle that number rises to 150 million tons. And that drops average global temperatures not 1.3 degrees C., but 8 degrees. In the interior of North America and Eurasia the temperatures drop 20-30 degrees C. We have not seen temperatures on Earth that cold for 18,000 years since the coldest point in the last ice age. In the Northern Hemisphere there would not be a single day free of frost for 3 years. Food production would stop, ecosystems would collapse, the vast majority of the human race would starve, and it is possible that homo sapiens would become extinct. 6