Report: The heating Arctic now a carbon source
The warming Arctic not only affects local ecosystems and wildlife but also has far-reaching implications for global sea levels and weather patterns.
- The Arctic is undergoing significant environmental changes, including heightened microbial activity, thawing permafrost, and increased wildfire occurrences contribute to a net release of carbon dioxide, rather than its previous role as a carbon sink. This shift raises concerns about the exacerbation of climate change as the region, once a stabilizing factor, now contributes to greenhouse gas emissions.
- An alarming trend of rising temperatures in the Arctic, with the past nine years marking the hottest on record.
- A significant decline of 65% in migratory tundra caribou populations over the last two to three decades underscores the profound impact of environmental changes on the region’s wildlife, likely due to factors such as climate change, habitat loss, and increased human activity, all of which disrupt the caribou’s migratory patterns and access to essential resources.
- Supporting Indigenous leadership, ways of life, and sustained climate action will be crucial for understanding and responding to rapid Arctic change.
The 2024 Arctic Report Card, produced by a team of 97 scientists, indicates a concerning shift in the Arctic region from a carbon sink to a carbon source due to rapid warming, with significant implications for both environmental and human systems, highlighted by declining caribou populations and unprecedented temperature increases.
Mongabay: “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, centered around the Arctic Ocean and bordered by the lands of North America, Europe, and Asia, is characterized by its extensive treeless tundra and permanently frozen permafrost, which plays a crucial role in global carbon storage, encompassing more than half of all carbon in Earth’s soil accumulated over millennia.
This map shows the Arctic’s average carbon balance from 2002-2020. Land areas colored purple were a source of carbon dioxide to the atmosphere. The darkest purple clusters show areas where there were large releases due to wildfires. Green areas had a negative carbon dioxide flux, meaning they were a “sink” that removed and stored atmospheric carbon dioxide. NOAA Climate.gov image based on the 2024 Arctic Report Card – Carbon Cycling
Mongabay: “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.”
The warming temperatures and consequent thawing of permafrost in the Arctic are critically altering the region’s carbon dynamics, transforming it from a carbon sink to a net emitter of CO2. This shift is exacerbated by increased wildfires, with 2024 marking a significant year as fires north of the Arctic Circle emitted 42.3 million metric tons of CO2, ranking as the second-highest emissions record for the area, highlighting the escalating climate challenges in the region.
Tundra erodes into the Beaufort Sea near Pitt Point, exposing permafrost ice, in the National Petroleum Reserve in Alaska. Image courtesy of Craig McCaa/Bureau of Land Management.
Mongabay: “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.”
Similar situation in the Brazilian Amazon, they declared a net carbon source in 2021, mainly due to emissions from wildfires.
The alarming trends in Arctic temperatures highlight a significant impact of climate change, with the past nine years registering unprecedented warmth and 2024 projected as the second-warmest year since 1900. An early August heat wave that shattered daily temperature records in northern Alaska and Canada underscores the urgency of addressing rising global temperatures and their consequences on the environment.
Arctic average air temperature for October 2023–September 2024 compared to the 1991–2020 average. Areas with warmer-than-average temperatures are orange and red, and areas with colder-than-average temperatures are blue. The graph shows how yearly Arctic (red line) and global (gray line) temperatures compared to the long-term average (1991-2020) from 1900–2024. NOAA Climate.gov image based on the 2024 Arctic Report Card – Surface Air Temperature. (NOAA)
Mongabay: 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.
Wildlife
The decline of migratory tundra caribou populations, which have decreased by 65% in the last two to three decades, poses a significant threat to the region’s wildlife, with only some smaller coastal herds showing signs of recovery while the largest inland herds face continued decline. Projections of intensified summer heat over the next 25-75 years further raise concerns about the caribou’s future and the ecological balance of their habitat.
A group of caribou from the Western Arctic Caribou Herd travels along a winter trail between the villages of Selawik and Ambler, Alaska, within the Selawik National Wildlife Refuge. The herd migrates through and sometimes winters on the refuge. Photo by Lisa Hupp (USFWS)
Mongabay: 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.
Ribbon seal (Histriophoca fasciata) in the Chukchi Sea. Photo by Justin Crawford, Alaska Department of Fish and Game
To analyze changes in carbon storage in the Arctic, researchers utilize ground stations for on-the-ground measurements of gas exchanges and satellites for aerial surveillance of environmental shifts, such as wildfires and vegetation growth. By leveraging three decades of CO₂ data from over 200 monitoring sites, scientists can effectively observe and assess the dynamic interactions between the Arctic ecosystem and atmospheric carbon levels from 1990 to 2020.
Mongabay: “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.”
The Angunasuktiit program exemplifies a progressive approach to preserving Indigenous traditions by seamlessly integrating age-old hunting and harvesting practices with cutting-edge technology, enabling new generations to learn and adapt in a rapidly changing world. This synthesis not only honors traditional knowledge but also empowers participants with modern tools, enhancing their ability to engage with their environment and maintain cultural heritage in innovative ways.
Mongabay: “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.
The Angunasuktiit program teach all aspects of hunting, harvesting and living on the land in Kangiqtugaapik (Clyde River), Nunavut, Canada. Photo courtesy of Apiusie Apak / Ittaq Heritage and Research Centre
Mongabay: 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 emphasizes the importance of prioritizing Indigenous leadership and preserving traditional ways of life as integral components in effectively addressing the rapid changes occurring in the Arctic, alongside the necessity for ongoing climate action to foster resilient and adaptive communities in this vulnerable region.
Moon emphasizes the importance of ongoing action despite the sobering findings, highlighting that there is no deadline for striving to improve our responses and reduce risks for the future. It’s essential to remain committed to preparedness and proactive measures to safeguard against potential challenges.
Mongabay: “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.”
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