The Arctic region is warming twice as fast as any other part of the world, with profound effects on climate, global security, trade and commerce, a new report says.
In 2015, air temperature across the Arctic was significantly above average with many areas over land more than 2 degrees Fahrenheit higher than average, the highest since record keeping began in 1900, the report sponsored by the National Oceanic and Atmospheric Administration says.
"Now in its 10th year, the Arctic Report Card is a key tool to understanding changes in the Arctic and how those changes may affect communities, businesses, and people around the world," said NOAA Chief Scientist Dr. Rick Spinrad.
Among the key findings of the report, introduced in San Francisco at the annual American Geophysical Union Fall Meeting, were increasing air and sea surface temperatures, a reduction in Greenland's ice sheet mass and sea ice extent, and changed behaviors in fish and walrus.
Sea ice coverage at its peak in February was at the lowest maximum ever recorded since records began in 1979, while the September minimum was the fourth-lowest ever recorded, the report showed.
Decline in sea ice represents a threat to many Arctic animal species including walruses, which depend on sea ice for mating and giving birth out of the water.
With less sea ice, walruses have been hauling themselves onto land in Alaska in huge, crowded masses that can expose young walruses to the risk of being trampled to death, experts say.
The effects of dwindling sea ice, along with hunting, have seen walrus numbers in the Pacific fall by half, they say.
Warmer Arctic temperatures have also seen fish such as halibut and cod moving further north in search of colder waters, taking them out of the reach of fishermen and marine animals that depend on them as a food source.
The findings show the important of precise and regular monitoring the Arctic, Spinrad said, noting the Arctic Report Card involved researchers from 10 countries as well as U.S. federal agencies and colleges and universities.
"This year's report shows the importance of international collaboration on sustained, long-term observing programs that provide insights to inform decisions by citizens, policymakers, and industry," he said.
NOAA's Climate Program Office introduced the State of the Arctic Report in 2006, establishing baseline regional conditions at the beginning of the 21st century and updating it annually with the Arctic Report Card to keep pace with conditions that can change quickly.
NOAA maintains a public website for presenting each year's report.