Arctic: Why the Ice is Melting and CO₂ Emissions Are Rising

The Arctic, once a stable reservoir of organic carbon, is now releasing more carbon dioxide (CO₂) than it absorbs. According to the latest NOAA Arctic Report Card 2024, thawing permafrost, increased microbial activity, and more frequent wildfires are driving this development. The Arctic, which long functioned as a carbon sink, is now becoming a major emitter of greenhouse gases. This accelerates global warming and threatens Arctic ecosystems as well as the species living there.

When Permafrost Thaws: Carbon Release with Global Consequences

Permafrost soils, which store more than half of the world’s organic carbon in the ground, are thawing due to rising temperatures. Similar to how thawed food spoils quickly in a freezer, microbial processes become active in thawing permafrost, breaking down stored organic matter and releasing large amounts of carbon dioxide (CO₂) and methane (CH₄).

Additionally, tundra fires north of the Arctic Circle and wildfires in boreal forests near the Arctic significantly contribute to CO₂ emissions. According to the NOAA Arctic Report Card 2024, wildfires in the High Arctic alone released 42.3 million tons of CO₂ in 2024 – the second-highest level ever recorded.

Another crucial factor is the rapid rise in sea temperatures. A study by Merchant et al. (2024) shows that ocean surface temperatures are increasing at an accelerating rate rather than linearly. While the warming trend between 1985 and 1989 was 0.06 degrees Celsius per decade, it had risen to 0.27 degrees Celsius per decade between 2019 and 2023. This has severe impacts on ocean currents and weather patterns, which in turn affect permafrost and ice formation in the Arctic.

Impact on Wildlife

Rapid warming is already having noticeable effects on Arctic wildlife. A prominent example is the migrating caribou (Rangifer tarandus), whose populations have declined by 65 percent over the past two to three decades. Their habitat is changing drastically: As the tundra greens, taller shrubs are displacing the lichens crucial for caribou survival, making it harder for them to find food.

Arctic seal species, such as the ringed seal (Pusa hispida), are also adapting by shifting their diet. They increasingly consume the saffron cod (Eleginus gracilis) instead of the more energy-rich Arctic cod (Arctogadus glacialis). However, the long-term consequences of this dietary change remain uncertain.

One of the most threatened species is the polar bear (Ursus maritimus). Particularly in Hudson Bay, populations are at risk of regional extinction as early as the 2030s if climate change continues unchecked. Scientists predict that warming beyond two degrees Celsius will extend ice-free periods to the point where polar bears can no longer find enough food.

Greenhouse Gases: Why Methane and Carbon Dioxide Are So Harmful

Methane (CH₄) and carbon dioxide (CO₂) are two of the most significant greenhouse gases driving global warming. While CO₂ remains in the atmosphere for centuries, contributing to long-term climate change, methane is even more potent in the short term: It has about 80 times the warming effect of CO₂ over a 20-year period.

Methane is primarily released through the decomposition of organic matter in thawing permafrost, as well as through human activities such as livestock farming and fossil fuel extraction. Although it breaks down in the atmosphere within about twelve years, its high greenhouse effect accelerates warming. This, in turn, speeds up permafrost thawing, releasing even more methane – a dangerous feedback loop that further destabilizes the climate.

Global Consequences and the Need for Action

The Arctic plays a crucial role in regulating the Earth’s climate. The loss of sea ice reduces the reflection of solar radiation, leading to further warming. Additionally, changes in atmospheric circulation contribute to more extreme weather events worldwide.

The accelerating warming of the oceans is a key factor in Arctic destabilization. The study by Merchant et al. (2024) indicates that almost half of the recent temperature increase is attributable to human-caused climate change. This trend intensifies Arctic greenhouse gas emissions, creating a dangerous feedback loop.

The NOAA Arctic Report Card 2024 emphasizes that addressing these challenges requires close collaboration between scientists and Indigenous communities. Indigenous peoples have centuries of experience in adapting to climate changes and can provide valuable insights into mitigation strategies. At the same time, comprehensive measures to reduce greenhouse gas emissions are essential to stabilizing the overheating planet.

A Look at Europe: Potential for Carbon Storage

While the Arctic is increasingly becoming a source of CO₂ and methane, a new report by BirdLife Europe highlights the immense potential of European ecosystems for carbon storage. According to the report, fully restored natural ecosystems in the EU could store around 13 billion tons of carbon – equivalent to the global annual CO₂ emissions. Forests, peatlands, and wetlands, in particular, could sequester significant amounts of CO₂ through targeted restoration efforts, helping to combat climate change. Strengthening rewilding initiatives could mitigate some of the negative feedback effects triggered by Arctic warming and significantly improve Europe’s overall carbon balance.

The Arctic is undergoing rapid, continuous change with far-reaching global consequences. Without decisive action, we risk irreversible disruptions to the climate system.

Sources

• Moon, Twila A. et al. (2024). NOAA Arctic Report Card 2024: Executive Summary.
• Merchant, C. et al. (2025). Accelerated Ocean Surface Warming, Environmental Research Letters.
• BirdLife Europe (2025). Carbon Sequestration on Land through Nature-Based Solutions and Land-Use Trade-Offs.