A study suggests that the Arctic "may be essentially¹ ice-free during summer within 15 years."

一项研究显示，北极“在15年内可能会在夏季基本无冰”。

The study used statistical² models to predict the future amount of Arctic ice, which suggested that the Arctic could be ice-free in the summer during the decade of the 2030s – most likely in the year 2034.

该研究利用统计模型预测了北极冰层的未来数量，表明在21世纪30年代的十年里，极有可能是在2034年，北极可能会在夏季无冰。

Sea ice is frozen ocean water that melts each summer, then refreezes each winter. The amount of summer sea ice in the Arctic has been steadily³ shrinking over the past few decades because of global warming. It reached its second-smallest level on record in 2019, the National Oceanic and Atmospheric⁴ Administration (NOAA) said.

海冰是冻结的海水，每年夏季融化，然后每年冬季重新冻结。由于全球变暖，过去几十年来，北极夏季海冰的数量一直在稳步减少。美国国家海洋和大气管理局说，2019年北极夏季海冰水平仅次于历史最低记录。

Sea ice affects Arctic communities and wildlife such as polar bears and walruses⁵, and it helps regulate the planet's temperature by influencing the circulation of the atmosphere and ocean.

海冰影响到北极群落以及北极熊和海象等野生动物，并通过影响大气和海洋环流来帮助调节地球温度。

"The extent of Arctic ice is important to Arctic peoples, whose lands are being affected⁶ by increased coastal⁷ erosion," NOAA said in a statement. "Conversely, the disappearance⁸ of ice creates economic opportunities, including the opening of oil fields and new shipping⁹ routes."

美国国家海洋和大气管理局在一份声明中说：“北极冰层的范围对北极地区的居民来说很重要，他们的土地正受到海岸侵蚀加剧的影响。反过来，冰的消失创造了经济机遇，包括开辟油田和新航道。”

It also affects global weather patterns.

北极冰层消失还影响到了全球的天气模式。

The study was conducted by scientists at NOAA, the University of Washington, and the North Carolina Institute for Climate Studies.

这项研究是由国家海洋和大气管理局、华盛顿大学和北卡罗莱纳气候研究所的科学家进行的。

What scientists refer to as the first "ice-free" Arctic summer year will occur when the Arctic has less than 1 million square kilometers of sea ice. The thick ice sheets surrounding Canada's Arctic islands are likely to remain for much longer, even in summer.

科学家所说的首个“无冰”北极夏季的年份将出现在北极海冰不足100万平方公里的时候。加拿大北极岛屿周围的厚冰原很可能会存留更长时间，即便是在夏季。

As the climate changes, the Arctic is warming more than twice as fast as the rest of the planet. Arctic air temperatures were about 3.4 degrees above average in 2019, and were the second-warmest since records began in 1900.

随着气候发生改变，北极的变暖速度是全球其他地区的两倍多。2019年北极的气温比平均水平高出约3.4度，是1900年开始记录以来温度第二高的年份。

Scientists also said the results of the study indicate that there is room for improvement in sea-ice models – and that the ice may disappear even more quickly than current models suggest.

科学家还表示，研究结果表明，海冰模型还有改进余地——海冰消失的速度甚至可能比现有模型显示的还要快。

"Climate models may be collectively underestimating the rate of change,” the authors write in the study.

科学家们在研究报告中写道：“气候模型可能都低估了变化的速度。”

The study was published in the journal Climate.

该研究发表在《气候》期刊上。