Shrubs are cool! They protect permafrost against climate change

Apr 13, 2010
Shrubs are cool! They protect permafrost against climate change

( -- Tundra shrubs can reduce the thawing of permafrost caused by climate change. This unexpected finding is from research done by Wageningen University in the Siberian tundra. It means that shifts in the plant population of the tundra can slow permafrost thawing.

We speak of “” if a soil is frozen throughout the year, and the upper layer thaws only during the summer. These permafrost soils store gigantic amounts of carbon in the form of dead plant material; according to estimates, amounting to even twice the quantity of carbon that currently exists in the atmosphere. If these carbon-rich soils thaw, the consequences for the climate could be substantial.

In the , substantial warming is now taking place. Although the winter in the Netherlands was cold, in the Arctic regions it was actually much warmer than usual. This considerable warming could have immense consequences for the stability of permafrost and its release of the greenhouse gasses carbon dioxide and methane. With an increase in temperature, however, the plant population changes as well: shrubs such as the dwarf birch (Betula nana) especially profit from rising temperatures and have thus been able to vigorously expand in the Arctic region. Because the vegetation of the relatively darker coloured dwarf birch absorbs more sunlight, the expectation is that its expansion could bring about warmer conditions - thus accelerating permafrost thawing.

However, field research carried out in the pristine tundra of north-east Siberia by Daan Blok, with Monique Heijmans and Frank Berendse, of the and Plant Ecology Group at Wageningen University, showed something else entirely. They demonstrated that a denser covering of shrubs in the tundra vegetation results primarily in an increased shading of the soil, and therefore actually leads to reduced thawing of the underlying permafrost.

Daan Blok: “On test plots measuring ten metres in diameter we removed the dwarf birch, then compared the soils with neighbouring test plots on which we had left the dwarf birch undisturbed. That way we could establish the effect of the dwarf birch on permafrost thawing. Somewhat unexpectedly, we showed that changes in vegetation, caused by an increasing temperature, can in fact slow the thawing of permafrost. This could be an explanation for the stabilisation of permafrost temperatures that has been observed in a number of Arctic regions over the past 10 years.”

Explore further: Pact with devil? California farmers use oil firms' water

More information: This study was published in the scientific journal Global Change Biology: Blok D., Heijmans M.M.P.D., Schaepman-Strub G., Kononov A.V., Maximov T.C. & Berendse F. (2010) Shrub expansion may reduce summer permafrost thaw in Siberian tundra. Global Change Biology, 16, 1296-1305.

Related Stories

Thawing permafrost likely to boost global warming

Sep 01, 2008

The thawing of permafrost in northern latitudes, which greatly increases microbial decomposition of carbon compounds in soil, will dominate other effects of warming in the region and could become a major force promoting the ...

Permafrost may nearly disappear by 2100

Dec 20, 2005

The National Center for Atmospheric Research in Boulder, Colo., says global warming may destroy most permafrost across the Northern Hemisphere.

Arctic soil reveals climate change clues

Oct 08, 2008

Frozen arctic soil contains nearly twice the greenhouse-gas-producing organic material as was previously estimated, according to recently published research by University of Alaska Fairbanks scientists.

Recommended for you

Gimmicks and technology: California learns to save water

Jul 03, 2015

Billboards and TV commercials, living room visits, guess-your-water-use booths, and awards for water stinginess—a wealthy swath of Orange County that once had one of the worst records for water conservation ...

Cities, regions call for 'robust' world climate pact

Jul 03, 2015

Thousands of cities, provinces and states from around the world urged national governments on Thursday to deliver a "robust, binding, equitable and universal" planet-saving climate pact in December.

Will climate change put mussels off the menu?

Jul 03, 2015

Climate change models predict that sea temperatures will rise significantly, including in the tropics. In these areas, rainfall is also predicted to increase, reducing the salt concentration of the surface ...

As nations dither, cities pick up climate slack

Jul 02, 2015

Their national governments hamstrung by domestic politics, stretched budgets and diplomatic inertia, many cities and provinces have taken a leading role—driven by necessity—in efforts to arrest galloping ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (1) Apr 14, 2010
University of Wagen...what?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.