Permafrost Thawing: Temperate Tantrums

Here Comes the Sun

During this summer of searing heat waves, we don’t need to tell Americans that things are heating up. In a report issued this June by the prestigious National Academy of Sciences, “A panel of top climate scientists told lawmakers that Earth is heating up and that "human activities are responsible for much of the recent warming. Their 155-page report said average global surface temperatures in the Northern Hemisphere rose about 1 degree during the 20th century.-- Earth is the hottest it has been in at least 400 years, maybe more.”

In big brush strokes, the climate of our Earth has changed dramatically since it was formed. Our planet had experienced hotter periods and colder periods. The outcome is determined by the amount of solar energy input vs. the amount of solar energy reflected and heat radiated. See our article on Earth’s Radiation Budget for how this balance is established..

The Heat is On

Global warming is the observed increase in the average temperature of the Earth's atmosphere and oceans in recent decades. The Earth's average near-surface atmospheric temperature rose 0.6 ± 0.2 °Celsius (1.1 ± 0.4 °Fahrenheit) in the 20th century. The prevailing scientific opinion on climate change is that "most of the warming observed over the last 50 years is attributable to human activities." Source

It is widely believed by many scientists that what seems to be a relatively small increase in sea temperature is negatively effecting coral reefs (coral bleaching) and is accentuating the severity of hurricanes. But the impacts on high latitudes are just now starting to get attention.

Polaritis

What may be until now a largely overlooked consequence of global warming is the effect of rising temperatures in the Arctic and Antarctic. As glaciers melt, sea level rises and a darker, more absorbent surface is exposed. Likewise, as sea ice melts, it loses the reflectivity of frozen snow and ice, therefore the darker water surface absorbs more solar energy.

But perhaps of even greater concern is the impact of warming on the high latitude tundras of Siberia, Alaska and Canada. The soil beneath the surface has been mostly frozen for about 10,000 years and over this period it has been accumulating partially decomposed plant and animal matter from the surface. We are not talking about an insignificant area.

Permafrost is found on both land and continental shelves in the Arctic, and it comprises almost 24% of the Northern Hemisphere’s land, covering approximately 22.8 million square kilometers.Source

What is significant is that a half degree change in average global temperature may make us sweat a little (or a lot) more in the temperate climes, at the southern edge of the permafrost regions, there is frozen subsurface permafrost soil that is just barely above freezing. In this case a half a degree means the difference between solid and liquid. And this difference in phases is huge. As the permafrost thaws it allows bacteria and other decomposers to get busy. The outcome is the release of carbon dioxide and methane (10 times more effect than carbon dioxide as a greenhouse gas).

This is what scientists mean when they talk about “tipping points”—a small change can initiate large scale, irreversible changes. What we have here is a positive feedback loop. The end products of the reaction (thawing and the release of carbon dioxide) increase atmospheric warming which stimulates more permafrost thawing. There is reason to believe that this may be an “accelerating” positive feedback loop in which the faster the permafrost melts, the faster the permafrost melts.

Now new research provides an unexpected surprise. Locked beneath the permafrost of northeastern Siberia, there is approximately 75 times the amount of carbon released every year through our burning of fossil fuels.

See the next article for an interview with Dr. Ted. Schurr of the University of Florida, a member of the team who made this startling discovery.

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