Study reveals greater climate impacts of 2C temperature rise +-

http://www.theguardian.com/environment/2016/apr/21/study-reveals-greater-climate-impacts-of-2c-temperature-rise-heatwaves?CMP=twt_a-science_b-gdnscience

Damian Carrington
April 21, 2016

A difference of half a degree centigrade may be barely noticeable day to day, but the difference between 1.5C 2.7F) and 2C (3.6F) of global warming is a shift into a new, more dangerous climate regime, according to the first comprehensive analysis of the issue.

The scientists found the additional 0.5C (0.9F) would lead to longer heatwaves, greater droughts and, in the tropics, reduced crop yield and all coral reefs being put in grave danger.

The global climate change deal agreed in Paris in December pledged to “hold the increase in the global average temperature to well below 2C above pre-industrial levels and pursue efforts to limit the temperature increase to 1.5C.” Vulnerable countries, such as low-lying islands, have warned that 2C of climate change would wipe their nations from the map.

Understanding the different impacts from 1.5C or 2C of warming has been made more urgent by the recent run of record temperatures, with 2014 and 2015 breaking long-term records and recent months smashing previous highs. In February, the global temperature was 1.34C (2.4F) above the average from 1951-1980, according to Nasa data.

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The researchers found: “For heat-related extremes, the additional 0.5C marks the difference between events at the upper limit of present-day natural variability and a new climate regime, particularly in tropical regions.”

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