World could warm by massive 10C if all fossil fuels are burned

http://www.theguardian.com/environment/2016/may/23/world-could-warm-by-massive-10c-if-all-fossil-fuels-are-burned#img-1

Damian Carrington
May 23, 2016

The planet would warm by searing 10C (18F) if all fossil fuels are burned, according to a new study, leaving some regions uninhabitable and wreaking profound damage on human health, food supplies and the global economy.

The Arctic, already warming fast today, would heat up even more – 20C (36F) by 2300 – the new research into the extreme scenario found.

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The carbon already emitted by burning fossil fuels has driven significant global warming, with 2016 near certain to succeed 2015 as the hottest year ever recorded, which itself beat a record year in 2014. Other recent studies have shown that extreme heatwaves could push the climate beyond human endurance in parts of the world such as the Gulf, making them uninhabitable.

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The new work, published in Nature Climate Change, considers the impact of emitting 5tn tonnes of carbon emissions. This is the lower-end estimate of burning all fossil fuels currently known about, though not including future finds or those made available by new extraction technologies.

The researchers used a series of sophisticated climate models and found this rise in CO2 would lead to surface temperatures rising by an average of 8C across the world by 2300. When the effect of other greenhouse gases is added, the rise climbs to 10C.

The heating predicted by the models was not uniform across the globe. In the Arctic, the higher CO2 levels led to 17C of warming, with another 3C from other greenhouse gases, across the year. These rises are higher than indicated by previous, less comprehensive models, which are less accurate at modelling how the oceans takes up heat. In February, parts of the Arctic had already recorded temperatures 16C above normal.

The warming caused by burning all fossil fuels would also have enormous impact on rainfall. The new research shows rainfall falling by two-thirds over parts of central America and north Africa and by half over parts of Australia, the Mediterranean, southern Africa and the Amazon.

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