The 2018 Arctic Report Card also shows sea ice reached its second-lowest extent on record, creating more challenges for coastal people and ecosystems.
By Bob Berwyn, InsideClimate News
On land and at sea, the Arctic is under a relentless global warming siege.
Rising temperatures, melting ice and thawing permafrost threaten ecosystems and communities across the far north with direct impacts like toxic algae outbreaks, harm to fisheries and caribou herds, and coastal erosion.
There are also indirect climate impacts that affect the rest of the world. Emerging research shows the warming Arctic drives changes to the jet stream that can result in extreme weather in North America and Eurasia, and more atmospheric moisture can fuel heavy rain storms.
The National Oceanic and Atmospheric Administration and partnering research organizations explain the impacts in the 2018 Arctic Report Card, highlighting issues like record-low sea ice in the Bering Sea and heat waves across the central Arctic.
Overall, 2018 was the second-warmest year for the Arctic since record-keeping for the region began in 1900, and the Arctic continued to warm at about twice the rate of the global average, to 3.06 degrees Fahrenheit above the 1981-2010 average. Arctic air temperatures for the past five years (2014-2018) exceeded all previous records, and Arctic sea ice extent was the second-lowest overall, with the lowest-recorded winter ice in the Bering Sea.
As they announced the report card findings, the authors also said research has documented a disturbing increase in microplastic pollution in the Arctic Ocean, which isn’t directly related to global warming but may show how warmer ocean currents are spreading farther into the once-frozen region.
“All roads in the global ocean circulation system lead to the Arctic,” said Clark University Arctic climate researcher Karen Frey.
The most visible sign of the vast changes in the Arctic is the continued decline of sea ice, which acts as a global cooling system by reflecting solar radiation back into space. But Earth’s cooling shield is shrinking — the 12 lowest sea ice levels on record have all occurred in the last 12 years.
And the disappearance of older, thicker sea ice leaves the Arctic’s ice cover vulnerable to melting in the summer and prone to unpredictable movement, which threatens shipping. Since scientists started measuring sea ice thickness with satellites in 1985, thick multiyear ice has declined by 95 percent.