Leaders must act, time not on our side: UN chief on climate change

Climate change is happening, it’s almost entirely man’s fault and limiting its impacts may require reducing greenhouse gas emissions to zero this century, the U.N.’s panel on climate science said on Sunday.

The fourth and final volume of the Intergovernmental Panel on Climate Change’s giant climate assessment didn’t offer any surprises, nor was it expected to since it combined the findings of three earlier reports released in the past 13 months.But it underlined the scope of the climate challenge in stark terms. Emissions, mainly from the burning of fossil fuels, may need to drop to zero by the end of this century for the world to have a decent chance of keeping the temperature rise below a level that many consider dangerous. Failure to do so, which could require deployment of technologies that suck greenhouse gases out of the atmosphere, could lock the world on a trajectory with ‘irreversible’ impacts on people and the environment, the report said. Some impacts are already being observed, including rising sea levels, a warmer and more acidic ocean, melting glaciers and Arctic sea ice and more frequent and intense heat waves.‘Science has spoken. There is no ambiguity in their message. Leaders must act. Time is not on our side,’ U.N. Secretary-General Ban Ki-moon said. Amid its grim projections, the report also offered hope. The tools needed to set the world on a low-emissions path are there; it just has to break its addiction to the oil, coal and gas that power the global energy system while polluting the atmosphere with heat-trapping CO2.