All Alaskan Tundra Gone by 2100 as Fires and Permafrost Melting Change Vegetation
One day this could well be transformed with trees... photo: Billy Lindblom via flickr.
While recent weird Arctic weather may have more to do with natural variability than upward trends in temperatures, the fact of the matter is the Arctic is warming faster than other places on the planet, with dire consequences for tundra. As a new piece in Yale Environment 360 shows though, it well may not be incremental changes that do in tundra, but dramatic events like fires that push the vegetation in the in the region over the edge:As things are heading the tundra landscape is heading towards oblivion. Some estimates say that by 2100 Alaska will be largely free of tundra--with woody plants and even boreal forest eventually taking over--and all tundra gone sometime in the next century. That much is not new.
Fires & Thermokarst Events Create Positive Feedback Loop
The new wrinkle in the story is that evidence is mounting that major events like fires and the collapse of slopes as permafrost melts will be the driving factor in tundra loss. And these things will in turn act to accelerate melting, as both lead to increases of stored greenhouse gases.
Consider the role of fires in transforming tundra. The original article points out that in areas burned as long as 35 years ago by fire, areas which normally had large amounts of moss and lichen have nearly none, with shrubby trees increasing from about 5% to 40% of the landscape mix.
Warming soils favor the shrubby plants, allowing them to take root in areas which were previously difficult, and shading lower growing plants in the process.
Collapse of slopes due to melting permafrost--thermokarst events--also clear the slate and allow new species to take hold. They also though mean more greenhouse gas emissions, as CO2 and methane stored in soil get released.
Both of these contribute to the decline of tundra--each playing off one another--and with it the animals and communities that have adapted to live in these conditions.
1°C Warming Each Decade Since 1970s
Want a stat to remember? Greg Henry of the University of British Columbia reports that in the area of Nunavut he's studied, the tundra has warmed about 1°C each decade since the 1970s--something which he attributes to the growth of more weedy plants in the region.
Read more: Arctic Tundra is Being Lost As Far North Quickly Warms
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