Wealthy nations, led by the United States, should move to reduce or eliminate all tariffs on imports from developing countries as one way to help offset the extraordinary costs these countries face in confronting climate change. If U.S. tariff policy continues on the current trajectory, the U.S. is likely to collect about $90 billion in import duties on products from developing countries, excluding China, by 2020.1 The combined total collected by the European Union, Japan, and other wealthy countries may exceed that amount. These projected duties constitute a vast pool of funds that can and should be tapped to help mobilize a decisive global response to climate change.