Climate change double whammy: greatest climate impacts expected to hit region with the most vulnerable permafrost

Falmouth, Mass. – The arctic is warming at twice the rate of the rest of the world, increasing arctic shrub growth and further exacerbating climate change. Research Assistant Kevin Guay and colleagues co-authored a new study, published in Nature Climate Change, which measures, as the title suggests, “Climate sensitivity of shrub growth across the tundra biome.”  The team found that shrub growth is most sensitive to climate in the parts of the tundra biome where the greatest climate change impacts are expected to occur.

Studies of tundra shrubs – which act as a barometer of the Arctic environment – show accelerated growth in warmer temperatures. “While plants help to slow climate change in other parts of the world, in the Arctic, taller shrubs prevent snow from reflecting heat from the sun back into space, thereby warming the Earth’s surface,” said Guay.  Shrubs can also alter soil temperatures and thaw permafrost. More shrubs can change the cycling of nutrients and carbon in soil, affecting its decomposition and the amount of carbon released to the atmosphere. All these factors can contribute to climate warming both in the Arctic and on a global scale.


At sites around the tundra biome, such as this site called Qikiqtaruk-Herschel Island on the Arctic coast of the Yukon Territory, Canada, the tundra is becoming more shrubby with increased growth in willows and other tundra shrubs.  These photos illustrate the difference in shrub cover and canopy height between 1987 and 2013 in the watershed of the same creek.  Photo by Isla Myers-Smith.

Shrub species in wet landscapes, at mid-latitudes of the Arctic, are the most sensitive to climate warming, the study found. These areas are vulnerable to change as they store large amounts of carbon in frozen soil, which could be released by warming and permafrost thaw.

An international team of scientists, led by the University of Edinburgh, studied records of shrub growth at 37 sites in nine countries by analyzing annual growth rings, spanning 60 years, in the plant stems, to explore links between climate and vegetation change.

The findings will help improve models of future changes to tundra ecosystems and the impacts of these changes on the global climate.

Dr. Isla Myers-Smith, of the University of Edinburgh’s School of GeoSciences, who coordinated the study, said: “Arctic shrub growth in the tundra is one of the most significant examples on Earth of the effect that climate change is having on ecosystems. Our findings show there is a lot of variation across this landscape. Understanding this should help improve predictions of climate change impacts across the tundra.”

The International Arctic Science Committee funded the study.

Link to abstract »

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