Goal of limiting rise in average global temperatures to below 2C may not prevent ice-free Arctic, scientists warn
Arctic sea ice could vanish in summers this century even if governments achieve a core target for limiting global warming set by almost 200 countries, scientists have said.
The ice has been shrinking steadily in recent decades, damaging the livelihoods of indigenous people and wildlife, such as polar bears, while opening the region to more shipping and oil and gas exploration.
Under the 2015 Paris agreement, governments set a goal of limiting the rise in average world temperatures to well below 2C (3.6F) above pre-industrial times, with an aspiration of just 1.5C.
“The 2C target may be insufficient to prevent an ice-free Arctic,” James Screen and Daniel Williamson of Exeter University wrote in the Nature Climate Change journal after a review of ice projections.
A 2C rise would still mean a 39% risk that ice would disappear in the Arctic Ocean in summers, they said. Ice was virtually certain to survive, however, with just 1.5C of warming.
They estimated a 73% probability that the ice would disappear in summers unless governments made deeper cuts in emissions. The scientists estimated temperatures would rise 3C on current trends.
This month the extent of Arctic sea ice is rivalling 2016 and 2015 as the smallest for the time of year since satellite records began in the late 1970s. The ice reaches a winter maximum in March and a summer minimum in September.
“In less than 40 years, we have almost halved the summer sea ice cover,” said Tor Eldevik a professor at the Bjerknes Centre for Climate Research at the University of Bergen in Norway, who was not involved in the study.
He predicted sea ice would vanish in the Arctic Ocean in about 40 years on current trends.
Scientists define an ice-free Arctic Ocean as one with less than 386,000 sq miles (1m sq km) of ice because they say some will linger in bays, such as off northern Greenland, even after the ocean is ice-free.
Donald Trump said during the 2016 presidential election campaign that he would cancel the Paris agreement and instead promote the domestic fossil-fuel industry. He has since said he has an “open mind” on the subject.
- This article was amended on 7 March 2017 to correct a temperature conversion.