The Arctic shattered heat records in the past year as unusually warm air triggered massive melting of ice and snow and a late fall freeze, US government scientists said Tuesday.
The grim assessment came in the Arctic Report Card 2016, a peer-reviewed document by 61 scientists around the globe issued by the US National Oceanic and Atmospheric Administration.
The NOAA report covers from October 2015 to September 2016, a period it said the Arctic's average annual air temperature over land was the highest on record.
"The report card this year clearly shows a stronger and more pronounced signal of persistent warming than any previous year in our observational record" going back to 1900, NOAA Arctic Research Program director Jeremy Mathis told the American Geophysical Union conference in San Francisco, where the report was released.
"Those warming effects in the Arctic have had a cascading effect through the environment."
The environment has steadily declined since scientists started doing the annual report card, now in its 11th year, co-author Donald Perovich said.
"When it started, you kind of had to listen closely because the Arctic was whispering change," said Perovich, who works at Dartmouth College's Thayer School of Engineering in New Hampshire.
"Now it is not whispering anymore. It is speaking change. It is shouting change."