The U.N. climate change conference on Wednesday was all about commitments. Of course, the best way the rich country governments can show that they are committed to combating climate change is to hand over wads of cash to poor-country governments. Besides forking over hundreds of billions of dollars, rich countries are also expected to keep their promises to make deep cuts in their greenhouse gas emissions by rapidly phasing out the burning of fossil fuels. Developing countries insist that rich countries are obligated to do that because they are historically responsible for the current climate crisis. Reason Science Correspondent Ronald Bailey delves into the question of just who is responsible for damaging the climate?