The world's largest energy users, starting with the US, Europe, China, Japan, and India, need to agree on collective actions to develop new technologies for carbon capture and storage, and for the affordable development and use of alternative energy supplies. We need to make certain that market prices for energy use reflect the true social costs of using energy, so that energy users and energy suppliers make better choices regarding energy efficiency, the development of alternative energy sources, and the adoption of environmentally safe technologies.