Climate Central: The odds that any climate change agreement among the world's biggest greenhouse gas emitters will succeed became a little greater on Tuesday as China and the U.S. committed to slash carbon pollution in the coming decades. It was a critical move because the world's thirst for fossil fuels continues unabated even as wind, solar and other low-carbon energy sources are coming into their prime. The largest transformation in how people use energy across the globe by 2040 will be in the electric power...