COPENHAGEN: Governments can keep climate change in check at manageable costs but will have to cut greenhouse gas emissions to zero by 2100 to limit fast-worsening risks, a UN report showed on Sunday. The 40-page synthesis, summing up 5,000 pages of work by 800 scientists already published since September 2013, said global warming was now causing more heat extremes, downpours, acidifying the oceans and pushing up sea levels. "There is still time, but very little time" to act at manageable costs, Rajendra Pachauri, chair of the Intergovernmental Panel on...