Saturday, December 09, 2017

Global warming gets warmer

World temperatures could rise 15 percent more than expected this century, obliging governments to make deeper cuts in greenhouse gas emissions to limit global warming, scientists said.

Average surface temperatures could increase up to 0.5 degree Celsius (0.9 Fahrenheit) more than previously projected by 2100 in the most gloomy scenarios for warming, according to a study based on a review of scientific models of how the climate system works.The extra heat would make it harder to achieve targets set by almost 200 nations in 2015 to limit a rise in temperatures to "well below" 2C (3.6F) above pre-industrial times to restrict droughts, heat waves and more powerful storms.

"Our results suggest that achieving any given global temperature stabilization target will require steeper greenhouse gas emissions reductions than previously calculated," authors Patrick Brown and Ken Caldeira of the Carnegie Institution for Science wrote in the journal Nature. 

William Collins, a professor of meteorology at the University of Reading who was not involved in the study, commented, "We are now more certain about the future climate, but the bad news is that it will be warmer than we thought." 

The models that best represent the recent climate "tend to be the models that project the most global warming over the remainder of the twenty-first century," the scientists wrote. In one pessimistic scenario, under which greenhouse gas emissions continue to rise until 2100, temperatures could rise by 4.8C (8.6F) against 4.3C (7.7F) estimated by a U.N. panel of experts in 2014, they said.

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