Suppose future governments of the world discover that a single nation is taking the unprecedented action of spraying sulfur dioxide into the stratosphere to cool Earth's surface temperature by a few degrees celsius? The move is intended to increase the fraction of solar energy that is reflected from Earth back into space—a measure known as modifying Earth's albedo. The nation was prompted by a failed harvest the previous year, the result of greenhouse gas buildup in the atmosphere that boosted average summer temperatures above 32°C. National leaders turn to the science community for answers: What does this action mean for any individual country? Will it make the drought in Saõ Paolo better or worse? If the wheat yield falls in northern Russia, could it be due to the albedo modification? Can science apportion damage caused by such an intervention? Should the United Nations block such action?