Regardless of where they come from, greenhouse gas emissions make climate change more dangerous for the whole planet. This characteristic of climate change makes it difficult for individual countries to solve it themselves, because most of the benefits of domestic climate action flow elsewhere. When a country invests in renewable energy sources such as wind, the reduction in emissions is likely to reduce the likelihood of climate catastrophe halfway around the world, as well as prevent it at home. Faced with demands for economic growth and reluctance to spend on clean energy or infrastructure programs, rich and poor countries alike may be tempted to divest themselves of other countries’ mitigation efforts and hope that other countries will solve the problem. (Rachel Glennerster and Seema Jayachandran, more at foreignaffairs.com)