The 'Greening' of the Arctic

THE GREENING

OF THE ARCTIC

Author: Katherine Pretorius

The lack of trees is the defining characteristic of the Arctic tundra. In fact, the word tundra is derived from the Finnish' tunturia,' meaning a treeless plain.

However, a recent study in Alaska revealed white spruce trees inching toward the north and rooting in previously too-frigid areas. The cause is non-other than climate change.

White spruce trees are found throughout North America's boreal forest, which spans from Alaska to Newfoundland. The region is populated by vast forests of pines, spruce and fir trees adapted to its cold conditions and short growing seasons.

Known for its forbidding desert-like landscape, the Arctic Tundra reaches temperatures below zero degrees Celsius for ten months of the year, and until now, only specially adapted vegetation like sedges, lichens, and mosses have been able to survive there. But what has changed to make this happen, and what impact will these changes have?

'Arctic greening', the growth of plant biomass and productivity at high latitudes, is one of the most noticeable changes in vegetation in recent decades and brings with it knock-on effects with bad tidings for the Arctic landscape and climate. However, despite considerable research, our understanding of this phenomenon is still incomplete.

A recent study released by NASA revealed that almost a third of the Arctic Tundra throughout Alaska and Canada is warming up. This greening trend is mainly accredited to 'anthropogenic forces' (forcing due to human, rather than natural, factors), specifically rising atmospheric pressure and greenhouse gases. This research forms part of NASA's Arctic Boreal Vulnerability Experiment (ABoVE), which aims to understand the response of ecosystems in these warming environments and their far-reaching social implications.

Another reason suspected of greening is the increase of nitrogen in the atmosphere from the use of fertilisers and fossil fuels. However, scientists feel the real concern is that there is twice as much carbon in permafrost as in the atmosphere.

The thawing of permafrost can have profound effects on our planet.

Permafrost prevents plant matter (organic carbon) from decomposing or rotting in the soil. When thawing occurs, the permafrost melts, allowing microbes to start decomposing plant matter. As a result of this process, greenhouse gases like carbon dioxide and methane are released into the atmosphere. Simultaneously, ancient bacteria and viruses are also released into the soil and ice. These newly unfrozen microbes could pose a health hazard to humans and animals alike.

Some theorise that a greener Arctic may help climate change. The reasoning is that plants absorb carbon dioxide as they grow, so rising temperatures will result in more Arctic vegetation absorbing carbon dioxide from the atmosphere, ultimately reducing greenhouse gases.

Previous field studies to test this hypothesis were limiting; however, recent research has found that despite the greening, carbon dioxide uptake either did not significantly increase or only increased marginally. Plants may only be able to insulate carbon if ecosystems continue to absorb carbon dioxide later in the season.
Without immediate and significant reductions in greenhouse gas (GHG) emissions, reducing global warming will be out of reach.

It may seem strange, but sometimes greener is not always better. This may be one of those times.

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