Extreme weather is turning the Arctic brown and could contribute to climate change, study warns

Arctic browning has reduced the ability of Arctic heathlands to absorb carbon dioxide by half

Extreme weather is killing off plants in the Arctic and causing the region to appear brown, a new study has claimed. The research also warns that the browning across the Arctic could contribute to climate change in the future.

The research was carried out by scientists at the University of Sheffield, who found that warming in the Arctic has is twice as fast as the global average.

The region has experienced some extreme weather events due to climate change, which caused dieback of the vegetation. Researchers also believe that the impact of extreme weather on plants could drastically reduce the ability of Arctic ecosystems to resist climate change.

"Despite the scale of Arctic browning, until now we knew very little about its impact on ecosystem carbon balance; the balance between carbon uptake by vegetation and its release from vegetation and soils," said Rachael Treharne, a PhD student in Animal and Plant Sciences at the University of Sheffield.

Treharne believes Arctic browning could influence whether climate change will accelerate or slowdown in coming years.

Earlier, some studies had suggested that increasing summer warmth in the Arctic was helping plants to grow and make the area increasingly green.

In the current study, the researchers analysed the impact of two extreme climatic events on the heathland in the Lofoten archipelago of Arctic Norway. The coastal, sub-Arctic plant communities in this area are known to first exhibit the effects of warming in the region.

The researchers found that first event - dubbed 'frost drought' - led to extensive dieback of the dominant evergreen vegetation. Frost drought occurs when the insulating layer of snow, which protects vegetation from the harsh Arctic winter, melts due to high winter temperatures.

The second event - called extreme winter warming - caused a sudden burst of high temperatures during winter. This event also led to melting of snow and fooled evergreen plants into preparing for spring by discarding their cold tolerance.

When these short periods of high temperature end, the return of harsh, cold temperatures usually kills the vegetation. However, researchers observed some unusual results in this case. They found that that heathland plants had managed to survive the second event, but exhibited an extensive 'stress response' that was visible as increased levels of protective anthocyanin (red) pigments in leaves and shoots.

The team also found that Arctic browning due to extreme events has reduced the ability of Arctic heathlands to absorb CO2 by half.

The team now wants to carry out further research across the Arctic to understand the role of extreme weather events in overall Arctic browning trends.

The findings of the study have been published in the journal Global Change Biology.