研究警告：北极“夏季无冰”现象或提前10年出现

随着全球温室污染加剧，气候危机正以快过预期的速度发生。

近日，一项最新研究警告说，北极夏季的海冰全部消失，可能比预计的时间要早大约10年到来。

CNN6日报道：一项新的研究警告称，到本世纪30年代，北极可能会迎来“无冰之夏”

The Arctic could be free of sea ice roughly a decade earlier than projected, scientists warn – another clear sign the climate crisis is happening faster than expected as the world continues to pump out planet-heating pollution.

A new study recently published in the journal Nature Communications found Arctic sea ice could disappear completely during the month of September as early as the 2030s. Even if the world makes significant cuts to planet-heating pollution today, the Arctic could still see summers free of sea ice by the 2050s, scientists reported.

法新社：北极无冰的时间可能比预计的要早十年

The researchers analyzed changes from 1979 to 2019, comparing different satellite data and climate models to assess how Arctic sea ice was changing.

They found that declining sea ice was largely the result of human-caused, planet-heating pollution, and previous models had underestimated Arctic sea ice melting trends.

“We were surprised to find that an ice-free Arctic will be there in summer irrespective of our effort at reducing emissions, which was not expected,” Seung-Ki Min, lead author of the study and professor at Pohang University of Science and Technology in South Korea, told CNN.

Arctic ice builds up during the winter and then melts in the summer, typically reaching its lowest levels in September, before the cycle begins again.

Once Arctic summers become ice-free, the buildup of sea ice in the colder seasons will be much slower, Min said. The warmer it gets, the more likely the Arctic is to stay free of sea ice further into the colder season.

"It is too late to still protect the Arctic summer sea ice as a landscape and as a habitat," co-author Dirk Notz, a professor at the University of Hamburg's Institute of Oceanography, told AFP.

"This will be the first major component of our climate system that we lose because of our emission of greenhouse gases."

"It can accelerate global warming by melting permafrost laden with greenhouse gases, and sea level rise by melting the Greenland ice sheet," a researcher told AFP.

Greenland's kilometres-thick blanket of ice contains enough frozen water to lift oceans six metres.

An Arctic with no summer sea ice would send dire ripple effects around the world. The bright white ice reflects solar energy away from the Earth. When this ice melts, it exposes the darker ocean, which absorbs more heat causing additional warming – a feedback process called “Arctic amplification.”

The decline of sea ice can also have an effect on global weather stretching well beyond the Arctic.

“We need to prepare ourselves for a world with warmer Arctic very soon,” Min said. “Since Arctic warming is suggested to bring weather extremes like heatwaves, wildfires, and floods on Northern mid- and high latitudes, the earlier onset of an ice-free Arctic also implies that we will be experiencing extreme events faster than predicted.”