Scientific American: As the world runs out of oil, the prospect of increased use of coal is bade news for the climate. When will oil production peak and begin to decline? Scientists, engineers and economists have debated the point for years, on the assumption that emissions of carbon dioxide into the atmosphere will decline when less oil is burned. Not so, says Ken Caldeira, a climate scientist with the Carnegie Institution in Stanford, Calif. That assumes society switches to low-carbon fuel. But …