The Arctic region has shifted from storing carbon dioxide to releasing it into the atmosphere, according to the 2024 Arctic Report Card released by the U.S. National Oceanic and Atmospheric Administration.

The report, authored by 97 scientists from 11 countries, documents widespread changes across the Arctic, from declining caribou populations to record-breaking temperatures. Scientists say this rapid warming is reshaping the region’s environmental and human systems.

“It’s not particularly surprising, although it’s still really sobering,” Twila Moon, deputy lead scientist at the National Snow and Ice Data Center at the University of Colorado Boulder and an editor of this year’s report, told Mongabay.

The Arctic is Earth’s northernmost region, centered around the Arctic Ocean and surrounded by the lands of North America, Europe and Asia. The treeless tundra that rings the Arctic Ocean covers an area nearly twice the size of Alaska.

This region has historically served as Earth’s freezer. Its permanently frozen ground, called permafrost, stores more than half of all the carbon stored in the Earth’s soil, which has accumulated over thousands of years.

“Think of it like a freezer,” Moon said. “While that chicken’s in your freezer, it’s good to go for years, no worries. And as soon as you take it out, it’s thawing, all the microbes are getting to work.”

Warming temperatures thaw the permafrost and stir the microbial communities. As the permafrost thaws, the carbon that is stored gets released. This leads to one of the most significant findings of the new report: the Arctic tundra has transitioned from a carbon sink to a net emitter of CO2.

Add to that an increase in wildfires, and the region is now releasing more CO2 than it stores. In 2024 alone, wildfires north of the Arctic Circle released 42.3 million metric tons of CO2, making it the second-highest fire emissions year on record for the high Arctic.

“This landscape has been storing carbon for us for thousands of years, throughout the Industrial Revolution,” Moon said. “[The Arctic] has done a lot of work of taking carbon up for us, instead of leaving it in the atmosphere … This is one of those places where we’re seeing the landscape no longer able to do that work.”

Another place is the Brazilian Amazon, declared a net carbon source in 2021, primarily due to emissions from fires.

The temperature has also been rising. The past nine years have been the warmest on record in the Arctic, with 2024 marking the second-warmest year since 1900. An early August heat wave in 2024 set an all-time record for daily temperatures across northern Alaska and Canada.

The implications of this change extend far beyond the Arctic. “As we’re heating up the Arctic, we’re changing the way that our air flows around the planet, and we’re actually making it easier for these blasts of Arctic air to come south,” Moon said. She suggested thinking about it “not as global warming, but as global weirding, which is why you can have a cold event that is really unprecedented and surprising.”

While the Arctic region heats up, its role as Earth’s cooling system weakens. Large expanses of white sea ice covering the Arctic Ocean “helped to reflect energy and heat back out to space and act as a cooler system for our planet,” Moon said. But as the ice melts, the surface darkens and absorbs rather than reflects heat.

September 2024 marked the sixth-lowest sea ice extent in the 45-year satellite record. The remaining ice is also younger and thinner, with old, thicker ice reduced by 95% since the 1980s.

The region’s wildlife also faces challenges. Populations of migratory tundra caribou (Rangifer tarandus) have declined by 65% over the past two to three decades. Though some smaller coastal herds in the western Arctic show signs of recovery, the largest inland herds continue declining or remain at historic lows. Scientists project that summer heat will intensify over the next 25-75 years, which could further affect the caribou.

Tundra greenness, measuring expanding vegetation cover and biomass, reached its second-highest level in the 25-year satellite record. “Greening isn’t as positive as it sounds,” Moon said. “For the caribou, these shrubbier plants are crowding out the lichen that are their food source, and so it’s becoming harder for them to get to their food source.”

While Pacific Arctic ice seals — ringed (Pusa hispida), bearded (Erignathus barbatus), spotted (Phoca largha) and ribbon seals (Histriophoca fasciata) — remain healthy overall, their diets are shifting. Ringed seals, for example, are eating more saffron cod (Eleginus gracilis) and less Arctic cod (Arctogadus glacialis) as the waters warm. Scientists aren’t yet sure how this diet change will affect the population.

To understand how the Arctic’s carbon storage is changing, scientists use two main tools: ground stations and satellites. Ground stations across the Arctic directly measure gases moving between the land and air, like taking the region’s temperature. Meanwhile, satellites watch for changes from above, tracking wildfires, melting ice, and growing plants. The team used 30 years of  CO₂ data (1990-2020) from 200 monitoring sites.

“The high resolution of these data means that we can now see how variable the Arctic is when it comes to carbon,” Sue Natali, lead of the Permafrost Pathways initiative at the Woodwell Climate Research Center in the U.S. and a co-author of the study, said in an interview. “The Arctic isn’t one single place — it’s a massive area with diverse ecosystems and climatic conditions. And now we have the capability to track and map carbon processes at a spatial resolution that can reveal what’s happening on the ground.”

The Arctic is also home to about 4 million people, including around half a million Indigenous people. This year’s report touches upon Indigenous knowledge through the work of the Ittaq Heritage and Research Centre in Kangiqtugaapik (Clyde River), Nunavut, Canada.

“Inuit hunters are the original researchers of their homelands,” write Sherry Fox and Mike Jaypoody in their report essay. “Observation, monitoring, and research skills are all integral parts of being a hunter or harvester.”

Their essay highlights how the center’s Angunasuktiit program teaches new generations traditional hunting and harvesting skills, combining Indigenous knowledge with modern technologies like custom-programmed satellite communication devices, digital photos, video, and drones.

“Knowledge is a practice. It cannot be separated from the people, culture, language, and land, and it cannot always be adequately expressed in western scientific terms,” write Fox and Jaypoody.

Moon said that collaboration between scientific and Indigenous communities is essential for addressing challenges. “Being able to collaborate across places about how folks are preparing for disasters, preparing for extreme weather, how they’re then responding to it, there’s a lot of opportunity for collaboration and learning from each other,” she said, adding that such coordination “is going to make us more resilient and help us to reduce risks.”

The report concludes that supporting Indigenous leadership and ways of life, alongside sustained climate action will be crucial for understanding and responding to rapid Arctic change.

While the findings are sobering, action remains vital, Moon said. “There’s not ever an expiration point in us doing our best to show up in an optimal way or create minimized risk or better preparedness into the future.

“This is really a new and different Arctic,” she added. “It’s not a new normal. We haven’t arrived at an end point or something that will stabilize. It’s still continuing to change rapidly … We ignore the Arctic to our peril at this at this point.”

Banner image: of an Arctic fox in Svalbard by Joxean Koret via flickr (CC BY-SA 2.0)

Liz Kimbrough is a staff writer for Mongabay and holds a Ph.D. in ecology and evolutionary biology from Tulane University, where she studied the microbiomes of trees. View more of her reporting here.

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Citation: Moon, T. A., Druckenmiller, M. L., & Thoman, R. L. (2024). NOAA Arctic Report Card 2024. doi: 10.25923/b7c7-6431

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