Natural gas power plants produce substantial amounts of gases that lead to global warming. Replacing old coal-fired power plants with new natural gas plants could cause climate damage to increase over the next decades, unless their methane leakage rates are very low and the new power plants are very efficient.These are the principal findings of new research from Carnegie’s Ken Caldeira and Xiaochun Zhang, and Nathan Myhrvold of Intellectual Ventures that compares the temperature increases caused by different kinds of coal and natural gas power plants. Their work is published in Environmental Research Letters.