overview
- This year was the second hottest year on record in the Arctic, according to a new report from NOAA.
- The authors said the tundra has become a carbon source rather than a carbon sink.
- The North Pole is heating much faster than lower altitude locations because melting ice reflects less radiation back into space.
The Arctic just experienced its second warmest year on record. And worryingly, the region's tundra is transitioning from a carbon sink to a carbon emitter as permafrost thaws and methane is released.
This would only increase the amount of heat-trapping gas entering the atmosphere, paving the way for further global warming.
The findings, shared Tuesday in the National Oceanic and Atmospheric Administration's Arctic Report Card, show how climate change is disrupting ecosystems and altering the landscape in regions where global warming is most intense.
The Arctic, considered a leading region for the effects of climate change, is heating much faster than lower-altitude locations, depending on the baseline scientists use for comparisons and which geographies they include in their assessments. But that speed is 2-4 times faster. Each of the last nine years in the Arctic has been the hottest on record since 1900.
This dynamic is the result of a phenomenon called arctic amplification. As snow cover and sea ice are lost in the Arctic, more dark-colored water and rocks are revealed. Their dark surfaces reflect less radiation back into space, instead absorbing heat. In addition, ocean and atmospheric circulation patterns increasingly transport heat toward the Earth's poles.
Taken together, that means the Arctic is a fundamentally different place than it was just a decade ago. Twila Moon said.
“The Arctic is in a kind of new regime, not a new normal, of course, but it's definitely different than it was just a few decades ago,” she says.
Overall, the Arctic is becoming a greener landscape with more extreme precipitation, less snow and ice, the report said. As fires in the Arctic send smoke into populated areas, ice melts and sea levels rise, the effects of those changes are becoming increasingly apparent closer to American homes, scientists said.
“These problems aren't just limited to the Arctic; they affect all of us,” says Brendan Rogers, an associate scientist at the Woodwell Climate Research Center in Woods Hole, Massachusetts. .
This year's report includes a detailed explanation of how the carbon cycle in the Arctic is changing. Scientists have been closely watching what happens when permafrost thaws, releasing powerful greenhouse gases as it thaws and decomposes.
“Permafrost regions contain about twice as much carbon as is currently present in the atmosphere, and about three times as much carbon as is contained in the above-ground biomass of forests around the world. There's a lot of carbon out there,” Rogers said.
He added that permafrost areas “have been carbon sinks for thousands of years on average, primarily due to low temperatures and frozen soil.” Carbon sinks, by definition, absorb and capture more carbon dioxide than they emit. But now such areas are instead sources of greenhouse gas emissions, as they dissolve carbon and methane and release it into the atmosphere, Rogers said.
Wildfires also contribute to Arctic emissions. Last year's wildfires burned more than twice as much area in the region as the year before, and produced more emissions than Canada's economic activity.
Rogers said Canada's total wildfire emissions are “roughly three times the emissions from all other sectors in Canada.” “This is more than the annual emissions of any other country except China, the United States, India and Russia.”
Last year's wildfires forced the evacuation of Yellowknife, the capital of Canada's Northwest Territories. About 19,000 people had to evacuate the cityin Areas with discontinuous permafrost.
Temperature records are organized by Arctic water year, so the most recent records are from October 2023 to September 2024. Every September, scientists measure the extent of Arctic sea ice at its seasonal minimum.
This year's sea ice was the sixth lowest in the 45 years since satellite measurements began. Sea ice extent has decreased by about 50% since the 1980s. Meanwhile, the Arctic tundra is the second greenest since records began in 2000, indicating more shrubs have taken root and spread into new terrain.
Measurements of Arctic permafrost taken from boreholes drilled beneath the earth's surface show that average temperatures were warmer than in all but one year.
“There are many indicators that consistently show extreme or near-extreme conditions,” Moon said.
Source: www.nbcnews.com
