Reuters: On the eve of Tuesday's U.N. climate summit, the United Nations chief underscored the urgent need to tackle climate change by moving toward an energy-efficient, low-carbon global economy. Speaking at the opening of Climate Week NYC, a set of more than 140 climate-related events across the city, United Nations Secretary-General Ban Ki-moon said he had noticed much more urgency to address climate change than he had seen in previous U.N. gatherings on the issue in 2007 and in 2009, when governments...