By Alister Doyle and Tom Miles OSLO/GENEVA (Reuters) - Greenhouse gases rose to a symbolic milestone in 2015, taking climate change into a new phase which could last generations even if governments act to curb man-made global warming, the U.N. World Meteorological Organization (WMO) said on Monday. Globally averaged concentrations of carbon dioxide, the main man-made greenhouse gas, reached 400.0 parts per million (ppm) in the atmosphere for the first time on record and were 44 percent above levels before the Industrial Revolution, it said. The relentless rise contrasts with accords by almost 200 governments to start reining in emissions, led by the Paris Agreement last year to phase out fossil fuels in favor of renewable energy in the second half of the century.
