Arctic warming same as whole Earth's in past century

The Arctic has warmed by 0.75 degrees Celsius in the last decade alone, whereas the Earth as a whole has warmed by nearly the same amount over the past 137 years, according to a study which examined the global consequences of continued polar warming.

The study, published in the journal Science Advances, documented the effects of warming in the Arctic and Antarctic on wildlife, traditional human livelihoods, tundra vegetation, methane release, and loss of sea and land ice.

The researchers, including those from the University of California (UC) Davis in the US, also examined consequences for the polar regions as the Earth inches towards a 2 degree Celsius warming - a threshold, crossing which may lead to irreversible impacts on global climate, according to the UN's Paris Climate Accords drafted in 2015.

"Many of the changes over the past decade are so dramatic they make you wonder what the next decade of warming will bring," said study lead author Eric Post who teaches climate change ecology at UC Davis.

"If we haven't already entered the new Arctic, we are certainly on the threshold," Post cautioned.

A business-as-usual approach by policymakers, the researchers said may lead to the 2 degree Celsius threshold in just about 40 years.

"But the Arctic is already there during some months of the year, and it could reach 2 degrees Celsius warming on an annual mean basis as soon as 25 years before the rest of the planet," Post said.

According to the study, a global 2 degree Celsius warming may lead to up to 7 degrees of warming for the Arctic, and a 3 degree heating up of the Antarctic during some months of the year.

Reducing carbon emissions is crucial to slowing high latitude warming, especially in the Arctic, the researchers said.

Post cautioned that heating in the polar regions would cause sea-level rise resulting from the rapid melting of land ice in the Arctic and Antarctic.

He added that this may also lead to an increased risk of extreme weather, deadly heat waves, and wildfires in parts of the Earth's Northern Hemisphere.

"What happens in the Arctic doesn't stay in the Arctic. The dramatic warming and melting of Arctic ice is impacting the jet stream in a way that gives us more persistent and damaging weather extremes," said study co-author Michael Mann from the Pennsylvania State University in the US.