In recent years, the Arctic tundra’s ability to lower carbon emissions and absorb more carbon has been under fire. A new analysis has confirmed that this ecosystem is now a source of CO2 and methane CH4 emissions.
Arctic Tundra
- The Arctic tundra is a snowy, treeless biome that has existed for thousands of years. It has played a vital role in storing carbon, a key factor in regulating Earth’s climate.
- Scientists estimate that the soil of the Arctic tundra contains more than 1.6 trillion metric tons of carbon, more than twice the amount of carbon currently in Earth’s atmosphere.
Carbon Storage
- Plants normally absorb carbon dioxide (CO2) from the air through photosynthesis, and this carbon can be stored in plants or soils when plants or animals die.
- The cold climate in the Arctic tundra slows down the decomposition process, meaning that dead plants and animals are preserved in the soil for long periods of time.
- Permafrost (a layer of soil that remains frozen for at least two years) traps this organic matter, preventing carbon from being released back into the atmosphere.
Other related information
- According to a NOAA report known as the Arctic Report Card, the Arctic tundra is now emitting more carbon than it absorbs, indicating a decline in its ability to act as a carbon sink.
- This shift is believed to be the first time in several millennia that the Arctic tundra has become a net emitter of greenhouse gases, particularly CO2 and methane (CH4).
- This change will have major global consequences, as it will accelerate climate change, which is already affecting ecosystems around the world.
- Increased incidence of forest fires and warming temperatures are the two main reasons behind the dramatic changes in this Arctic ecosystem.
Key points of the report
In the air:
- According to the report, the Arctic is warming at four times the global rate, and annual surface air temperatures in the Arctic in 2024 will be the second warmest on record since 1900.
- As a result, the Arctic’s permafrost is melting, which means that microorganisms in the soil are becoming active and reacting with organic matter to release CO2 and CH4 into the atmosphere.
- The autumn of 2023 and the summer of 2024 were remarkably warm in the Arctic, with temperatures being the second and third warmest on record, respectively.
- The last nine years have been the warmest years in the Arctic.
- The summer of 2024 in the Arctic was the wettest on record.
At sea
- Arctic sea ice extent in September 2024, which has profound effects on the polar environment, was the sixth lowest in the 45-year satellite record.
- Areas of the Arctic Ocean that were ice-free in August have been warming at a rate of 0.5 degrees Fahrenheit (0.3 degrees Celsius) per decade since 1982.
- The number of plankton, the basis of the marine food chain, has been steadily increasing over the 2003-2024 observational record in all Arctic regions, except the Pacific Arctic.
- In 2024, below-average values will prevail across much of the Arctic.
On land
- When including the effects of increased forest fires, the Arctic tundra region has become a source of carbon from carbon storage in the soil to the atmosphere.
- Smoke from forest fires increases greenhouse gas emissions to the atmosphere, while also accelerating the melting of permafrost.
- 2023 will be the worst wildfire season ever recorded in the Arctic, and 2024 will be the second-highest year for wildfire emissions.
- Alaskan permafrost temperatures were the second-warmest ever recorded.
- Arctic migratory tundra caribou (reindeer) populations have declined by 65% over the past 2-3 decades.
- Snow accumulation during the winter of 2023-2024 was above average in both the Eurasian and North American Arctic.
- Tundra greening, a measure of the expansion of shrub cover due to warming, is the second-highest in the 25-year satellite record.
How the Arctic Tundra Stores Carbon
- Carbon cycle: In a typical ecosystem, plants absorb carbon dioxide (CO₂) from the atmosphere through the process of photosynthesis. When these plants and animals die, microorganisms such as bacteria and fungi decompose the organic matter, releasing CO2 back into the atmosphere. This completes the carbon cycle.
- Slow decomposition: However, in the Arctic tundra, the cold climate slows the decomposition process dramatically.
- Trapped in ice: Organic remains of plants and animals are trapped in permafrost, which refers to any ground that is frozen for at least two consecutive years. Not released: Because of the sub-zero temperatures, the CO₂ stored in organic matter is not released back into the atmosphere.
- Storage: Scientists estimate that 1.6 trillion metric tons of carbon is stored in Arctic soils, which is about twice the amount of carbon present in the atmosphere.