For anyone elated by the climate-change accord in Paris, the commodity markets have a reality check for you. World leaders may have vowed to wean the world from fossil fuels, but prices for oil, coal and natural gas are at their lowest in years. Crude, which touched an 11-year low Monday, will probably decline even more with the U.S. ending its 40-year ban on oil exports. So is that bad news for people hoping to switch the world to cleaner fuels? The answer is pretty complicated. The International Energy Agency in May analyzed the impact on greenhouse-gas emissions if global […]