Permafrost is a permanently frozen earth that has remained preserved for anywhere from two to thousands of years, with layered icy soil that contains carbon from deceased animals and plants. Carbon buried in permafrost for millennia releases greenhouse gases (GHGs) such as carbon dioxide (CO₂) and methane (CH₄) when it thaws and decomposes. The northern permafrost region contains twice as much carbon as the Earth’s atmosphere.

Research and Key Findings

NASA scientists co-authored an international research that examined greenhouse gas emissions from Arctic permafrost locations between 2000 and 2020. According to the results, methane emissions have caused the region to become a net contributor to global warming in recent decades.

An illustration shows some of the ways permafrost affects the Arctic landscape. Victor O. Leshyk, from Schuur et al. 2022. Permafrost and Climate Change: Carbon Cycle Feedbacks from the Warming Arctic. Annual Review of Environment and Resources Volume 47 (in press)

Source: The Conversation

Permafrost landscapes, specifically wetlands and lakes, emitted enormous quantities of methane, a greenhouse gas more powerful than CO₂ over short time scales. Methane retains twenty-eight times more heat than CO₂ over a century but has a shorter atmospheric lifetime of 10 years.

The Arctic forests absorbed somewhat more CO₂ than they released, but this was countered by emissions from lakes, rivers, and wildfires. During the 20-year research period, the area contributed to global warming. However, over 100 years, emissions and absorptions might balance out, with the region shifting between a weak carbon source and a weak carbon sink.

Challenges in Measuring Emissions

GHG tracking is made more difficult by the region’s size and environmental diversity, which encompasses tundra, forests, and waterways. NASA’s Arctic-Boreal Vulnerability Experiment (ABoVE) is primarily focused on Canada and Alaska, although gathering data throughout the Arctic is still difficult. The harsh conditions and remote locations make data collection even more difficult, requiring creative approaches and international collaboration to produce accurate results.

Global Carbon Project and RECCAP-2

This research was part of the Global Carbon Project’s RECCAP-2 initiative, which aims to evaluate regional carbon balances every few years. Researchers monitored CO₂, CH₄, and nitrous oxide levels throughout 7 million square miles (18 million square km) of permafrost land, giving crucial data on carbon dynamics in this fragile ecosystem.

Methods for Measuring Emissions

• Bottom-Up Approach: Emissions are estimated using ground and air-based measurements as well as ecosystem models.
• Top-Down Approach: Atmospheric measurements are derived from satellite sensors such as NASA’s Orbiting Carbon Observatory-2 (OCO-2) and Japan’s GOSAT.

It’s interesting to note that although both methods found broad patterns in emissions, they had different conclusions about how much warming had occurred. In contrast to top-down evaluations, the bottom-up estimates indicated more significant warming. This disparity highlights how important it is to keep improving models and measuring methods in order to improve our comprehension of GHG dynamics.

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Implications for Climate Projections

This study has major implications, stressing that thawing permafrost might hasten climate change, especially shortly (the next 20 years). Given the impact of extreme weather events like heatwaves and wildfires, which might intensify warming trends, future climate estimates are still unknown. Permafrost’s contribution to atmospheric GHG concentrations when it thaws might create a feedback loop that worsens global warming and makes climate mitigation methods more difficult.

Permafrost thawing is turning out to be a major cause of global warming, releasing large amounts of greenhouse gases and shifting the balance in favour of a net source of emissions. This study highlights how important it is to combine many data sources to completely understand how the Arctic affects the dynamics of the global climate. Understanding permafrost’s role will be crucial to creating successful mitigation methods as we deal with the effects of climate change. To find answers to the problems caused by permafrost thawing and its effects on the stability of the global climate, scientists and policymakers need to work together.

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