Arctic Carbon Sink Collapsing: A Dangerous Feedback Loop in the Climate Crisis

The Arctic has long been a critical regulator of Earth’s climate. It acts as a massive carbon sink, absorbing more carbon dioxide (CO2) from the atmosphere than it emits. However, new research has revealed a disturbing shift: A large portion of the Arctic releases more carbon than it takes in, speeding up the climate crisis. This alarming trend threatens to destabilise global carbon cycles and undo years of efforts to mitigate climate change.

The Arctic’s Shifting Carbon Balance

A study published in Nature Climate Change provides a comprehensive analysis of carbon fluxes across 200 Arctic sites over the past three decades. The findings reveal that approximately one-third of the Arctic’s landscapes, once known for their carbon-absorbing capabilities, have transitioned into carbon emitters. Rising temperatures, which trigger the melting of permafrost and intensify microbial activity that decomposes organic material, predominantly fuel this transition.

Permafrost, the icy layer of soil that forms the foundation of much of the Arctic, holds vast amounts of organic carbon—estimated at nearly twice the amount currently in the atmosphere. As global temperatures climb, this frozen reservoir begins to thaw, unleashing stored carbon in the form of CO2 and methane (CH4), both potent greenhouse gases. These emissions add to the atmosphere’s greenhouse effect and create a feedback loop where warming accelerates permafrost thaw, perpetuating further emissions. This dynamic jeopardises efforts to stabilise global temperatures and highlights the urgency of addressing permafrost degradation.

Impact of Wildfires on Carbon Emissions

The Arctic is witnessing an unprecedented wildfire surge, exacerbated by rising temperatures and drier conditions. These fires consume vegetation, organic soil layers, and even previously frozen peat, releasing vast quantities of carbon into the atmosphere. In 2024 alone, Arctic wildfires released millions of tons of CO2, marking one of the region’s highest emission years. These fires have turned the Arctic tundra—a historically reliable carbon sink—into a significant net source of emissions.

Beyond their immediate impact, wildfires leave long-lasting scars on the landscape. 

Burned areas lose their insulating vegetation, exposing permafrost to higher temperatures and increasing its vulnerability to thawing. Additionally, these regions often experience a change in albedo or surface reflectivity. Dark, Burned surfaces soak up more sunlight and heat, intensifying local warming and accelerating permafrost degradation. This chain reaction highlights the far-reaching impacts of climate change in the Arctic, which go well beyond the immediate effects of wildfires.

Global Implications and Urgent Actions

The Arctic’s shift from a carbon sink to a source has profound implications for global climate systems. Natural carbon sinks such as forests, oceans, and tundra have absorbed approximately half of the CO2 emitted by human activities for decades. However, these natural systems’ diminishing capacity to sequester carbon means that global efforts to curb emissions must become even more aggressive to achieve the climate targets outlined in the Paris Agreement.

Scientists stress the importance of monitoring and modelling the Arctic carbon cycle to predict its impact on global warming accurately. Improved satellite technologies and ground-based observation networks can provide crucial data on carbon fluxes and permafrost conditions. In parallel, reducing fossil fuel emissions remains an urgent priority. Slowing the pace of global warming can help mitigate the feedback loops driving the Arctic’s transformation. Moreover, preserving other natural carbon sinks, such as rainforests and wetlands, becomes even more critical in offsetting the emissions from the Arctic.

The Arctic’s shift from being a key player in climate stabilisation to a potential danger is a grim reminder of how interconnected the Earth’s systems are. To mitigate this emerging crisis, immediate action to reduce emissions and investments in sustainable practices and carbon removal technologies is vital. As the Arctic warms nearly four times the global average, it sends a clear message: the window for meaningful intervention is rapidly closing, and the stakes could not be higher for the future of our planet.

References:

https://www.nature.com/articles/s41558-024-02234-5

https://www.downtoearth.org.in/climate-change/after-millenia-as-a-carbon-sink-over-a-third-of-arctic-boreal-region-turns-into-carbon-emitter#:~:text=The%20findings%20align%20with%20NOAA’s,in%20the%20Northern%20polar%20region

https://www.theguardian.com/environment/2025/jan/21/third-of-arctic-carbon-sink-now-a-source-of-emissions-study

Banner image:
Photo by Peter Robbins on Unsplash