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Home / Science / The Arctic turns brown because of the strange weather – and could accelerate climate change

The Arctic turns brown because of the strange weather – and could accelerate climate change



In recent years, Arctic scientists have reported a surprising finding: large areas of the Arctic turn brown. This is partly due to extreme events associated with winter weather, such as sudden, short-lived periods of extreme heat. These events occur with the warming of the climate, which in the Arctic is twice as fast as the rest of the planet. Extreme events are therefore increasingly associated with increasingly serious consequences – including widespread damage and death in Arctic plants.

This "tanning" of plant communities has occurred over thousands of square kilometers or more. However, until recently, we knew little about what this could mean for the balance between carbon uptake and release in Arctic ecosystems. Given that the Arctic stores twice as much carbon as the atmosphere, this is an urgent problem.

Now, our study has shown that extreme climatic events can significantly affect the ability of Arctic ecosystems to absorb carbon. The Arctic will help combat or accelerate climate change.

Dead and brown vegetation on a heathland in Norway.
Rachael Treharne The author provided

the carbon cost for extreme weather

] To understand how extreme events affect the Arctic pagans, we traveled to the Lofoten Islands in northern Norway, where the coastal communities of the subarctic Arctic to pioneer future climate change in the far north by first showing the effects of warming in the region

Here we found the effects of two extreme winter weather events. First, the "frost drought" had led to an extensive plant dying. Frost dryness occurs when the insulating layer of snow, which normally protects the plants from the harsh Arctic winter, is typically melted by unusually high winter temperatures. If the plants are exposed to cold, windy conditions for long enough, they constantly lose water and can not replace it from the frozen soil. Eventually, they succumb to the drought.

The second event was the "extreme warming of winter" – a sudden burst of high temperatures during the winter that causes the snow to melt, causing evergreen plants to prepare for spring by refusing their cold tolerance. When the warm period is over, the return of the cold usually kills the plant. In this case, however, we have found something unexpected. Heather trees had survived this extreme warming in winter, but showed signs of severe stress, which is visible in the shoots and leaves as a deep, persistent dark red.

A deep red pigmentation indicates that this plant is under stress due to the unpredictable climate.
Rachael Treharne author provided

We measured how much carbon dioxide was absorbed and released by the plants into three vegetation types: damaged heathland (where the prevalent evergreen species were killed by frost), stressed Heathland and healthy, green heathland that escaped the effects of both extreme events. This was done in three measurement periods during the growing season.

We found that these extreme winter conditions reduce the amount of carbon absorbed in heathland ecosystems by up to 50% over the entire growing season. This is a significant reduction in the ability of a widespread Arctic ecosystem to remove carbon from the atmosphere.

Surprisingly, this was the case both in the damaged heath, where a large part of the vegetation was killed, and in the stressed heathland. Although the processes that led to this change were different in each heather, this clearly shows that we need to consider the role of plant stress in limiting carbon uptake in the plant to fully appreciate the consequences of extreme climatic events.

The Great Brown North [19659007] What does that mean for the Arctic? We now know that extreme climate events can significantly affect the ability of Arctic ecosystems to absorb carbon and combat climate change.

This is particularly worrying as the effects of browning are vastly different from those of a more understandable response from Arctic ecosystems. Climate change: "Arctic green" or the tendency for plants to grow larger and become more productive as summers in the Arctic get warm ,

Instruments for measuring carbon uptake and release at the test site.
Rachael Treharne Author Provided

Many climate models currently anticipate an arbitrary degree of greening throughout the Arctic, so that Arctic ecosystems will absorb more carbon in the future – slowing climate change. The magnitude of the tanning that we have seen in recent years and the negative impact on carbon uptake reported here suggest that the reality could be more complex and question our understanding of the Arctic's role in the Earth's climate.

What does that mean for us? The effects of extreme weather events in the Arctic have global consequences. It is clear that our current efforts to tackle climate change are dangerously inadequate, but ambitious measures could reduce expected Arctic warming by as much as 7 ° C. This is crucial to minimize the effects of climate change in both Arctic ecosystems and globally.


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