The Arctic tundra, a frozen and treeless biome that has stored carbon for thousands of years, has recently become a significant source of greenhouse gases (GHGs). These gases, primarily carbon dioxide (CO2) and methane (CH4), are the main drivers of global warming. A new report by the National Oceanic and Atmospheric Administration (NOAA) highlights this alarming transformation, with increased wildfires and unusually high temperatures being the primary factors behind the changes in this delicate ecosystem.
The Arctic Report Card
The analysis, titled Arctic Report Card, is a yearly publication that tracks changes in the polar region. The latest report, published last week, reveals that the Arctic tundra is now emitting more carbon than it is storing, a shift that could have severe global consequences. This change could exacerbate climate change, whose adverse impacts are already being felt worldwide.
The Carbon Cycle in the Arctic Tundra
In a typical ecosystem, plants absorb carbon dioxide (CO2) from the atmosphere through photosynthesis. This carbon is then passed through the food chain as plants and animals grow, die, and decompose. The carbon is eventually returned to the atmosphere by microorganisms such as bacteria and fungi. However, the process is much slower in the Arctic tundra due to its cold climate. Organic matter, such as plant and animal remains, can remain trapped in permafrost for thousands of years, preventing the release of CO2 into the atmosphere.
Scientists estimate that Arctic soils store more than 1.6 trillion metric tonnes of carbon—about double the amount of carbon in the atmosphere. But recent changes in the region’s climate are threatening this carbon sink.
Why the Arctic Tundra Is Now Emitting Carbon
The Arctic tundra’s ability to absorb carbon has been significantly reduced in recent years. Two key factors are contributing to this shift:
- Rising Temperatures: The Arctic is warming at a rate four times faster than the global average. In 2024, the region recorded the second-warmest surface air temperatures since 1900. This warming is causing the permafrost to thaw, allowing microbes in the soil to break down organic matter and release CO2 and CH4 into the atmosphere.
- Increased Wildfires: The frequency and intensity of wildfires in the Arctic have also increased in recent years. 2023 was the worst wildfire season on record, and 2024 was the second-worst. Wildfires not only add GHG emissions to the atmosphere but also accelerate the thawing of permafrost.
Between 2001 and 2020, wildfires and rising temperatures likely caused the Arctic tundra to release more carbon than its plants could absorb, possibly for the first time in millennia.
The Path Forward: Reducing GHG Emissions
While the report suggests that it is still possible to reverse the trend and make the Arctic tundra absorb more carbon than it emits, the key to achieving this is reducing global GHG emissions. Brendan Rogers, a scientist at the Woodwell Climate Research Center, emphasized that lower levels of climate change would result in lower emissions from permafrost. However, with global emissions continuing to rise, this reversal seems increasingly unlikely.
A recent study by the Global Carbon Project found that emissions from burning fossil fuels are expected to increase slightly in 2024 compared to 2023, with total CO2 emissions projected to reach 41.6 billion tonnes, up from 40.6 billion tonnes last year.
Multiple-Choice Questions (MCQs):
1. What is the main reason behind the Arctic tundra becoming a source of greenhouse gases?
A) Rising sea levels
B) Increased wildfires and high temperatures
C) Increased plant growth
D) Overhunting of animals
Answer: B) Increased wildfires and high temperatures
2. How much carbon do Arctic soils store compared to the amount in the atmosphere?
A) Half the amount
B) Double the amount
C) The same amount
D) Four times the amount
Answer: B) Double the amount
3. What is the effect of rising temperatures on permafrost in the Arctic?
A) It causes the permafrost to freeze more
B) It causes permafrost to thaw and release carbon
C) It prevents the thawing of permafrost
D) It has no effect on permafrost
Answer: B) It causes permafrost to thaw and release carbon
4. What role do wildfires play in the Arctic tundra’s carbon emissions?
A) They help the tundra absorb more carbon
B) They add greenhouse gases to the atmosphere and accelerate permafrost thawing
C) They reduce carbon emissions
D) They have no effect on carbon emissions
Answer: B) They add greenhouse gases to the atmosphere and accelerate permafrost thawing
5. What is the primary way to reverse the trend of the Arctic tundra emitting more carbon than it absorbs?
A) Increasing the number of wildfires
B) Reducing global greenhouse gas emissions
C) Planting more trees in the Arctic
D) Increasing the temperature of the region
Answer: B) Reducing global greenhouse gas emissions