By Matt Owens March 12, 2013
A recent study in Nature Climate Change demonstrates that vegetation has been spreading north at a rapid clip over the last 30 years. This is part of the melting permafrost phenomena. And the process takes many decades to stop once it's started. NASA climatologist and long-time outspoken climate change warner, James Hansen points out that the planet is on a slippery slope; this research is just another piece of evidence in a pile that's now high enough to call a mountain that he's right.
If we're going to get off this path - off the slippery slope - we'd better do it fast. ASAP. Perhaps that next vacation you were planning to take would be better spent thinking this issue over, and/or figuring out how to best raise awareness and increase engagement with the people around you.
Only through engagement and awareness can there be real action. And there can only be engagement and awareness if a critical mass is achieved. Keeping this knowledge bottled up doesn't do anyone any good.
Current estimates (by scientists directly studying this issue) of the amount of permafrost thaw by 2100, range from around half of the area, and up. The thaw process can take many years to complete however, because permafrost can be extremely thick, sometimes with dozens or even hundreds of feet deep of frozen soil.
The same scientists believe that between about 200 and 400 gigatonnes of carbon (GtC) could be released from this thawing soil. And that's by 2100. What's more, this carbon release is excluded from climate model baseline assumptions. I've reviewed the literature on this issue, and it is alarming (see "What the models don't show, Part 1 and 2). Based on my personal experience and research with soils, I am inclined to believe the estimates are accurate, although I wouldn't rule out an amount slightly above 400 GtC by 2100. And even with that much release, if the entire permafrost thaws, 100's GtC more will be released over the following centuries.
To put this in perspective, human emissions of CO2 recently reached 10 GtC per year. If 200 to 400 GtC are indeed released by 2100, that would equal 20 to 40 years worth of current human emissions.
The grave implications of this have begun to been examined on this site, from impacts on local cities to sea level rise. But for now, I'd like to just show what this warming would look like from a climate perspective:
While there is a large amount of inertia in the permafrost system, urgent action to reduce emissions could slow the thaw process and probably even halt it by the end of this century, or shortly thereafter. Bringing the process to a halt in such a way would prevent many 100's of GtC from escaping into the atmosphere.
Above, a comparison of two modeled time periods from the end of the 20th and 21st Centuries, and broken down into monthly averages and yearly averages (click for full-sized view).
As discouraging as all this is, inaction would be much, much more discouraging. Restructuring society to deal with this problem will probably mean a radical transformation on par with the changes brought about with the internet revolution. However, this transformation would likely be more visible: a dramatic transition away from single-family housing to high density development, a sharp drop in automobile ownership and use, and a sharp rise in wind, solar, and other non-carbon power sources.