In 1979, the National Academy of Sciences undertook its first rigorous study of global warming. Climate modeling was a very new and very inexact science at the time, and few groups other than the U.S. National Oceanograpic and Atmospheric Association (NOAA) and the U.S. National Aeronautics and Space Administration (NASA) were even engaged in considering the future consequences of carbon dioxide in the atmosphere (or sequestered in trees and permafrost).

However, a warning issued by the Ad Hoc Study Group on Carbon Dioxide and Climate (or the Charney panel, appointed by former U.S. President Jimmy Carter), stated that: "We may not be given a warning until the CO2 loading is such that an appreciable climate change is inevitable." This, almost three decades ago.

Now, in independent studies, the unthinkable has come to pass. A collaborative effort by scientists from Australia, Russia, the US, the UK, Canada and Europe over a three-year period shows that carbon stored in permafrost is more than double previous estimates.

This 1,500 billion tonnes, according to co-author Dr. Pep Canadell, of The Centre for Australian Weather and Climate Research (CAWCR), is ominous as much by its size as by the fact that climate modeling, specifically permafrost dynamics, can't extrapolate the eventual effects except to say that a mere fraction of this amount released into the atmosphere would "significantly accelerate climate change". And all it would take is a modest rise of eight degrees by the end of the century to trigger this release. 

A study by University of Alaska professor Chien-Lu Ping and colleagues, using data collected over the last decade and based on 100 samples of permafrost from around the state, supports the CAWCR conclusion. His paper, published in the October issue of the journal Nature Geoscience, further suggests that a mere two to three-degree rise in air temperatures could turn the Arctic tundra from a carbon sink to a carbon source capable of tipping the planet into a negative feedback cycle of warming, a scenario supported by Christian Beer of the Max Planck Institute of Biogeochemistry in Germany.

Currently, dead plants in the Arctic tend to freeze faster than they can decompose, which allows them to act as carbon capture mechanisms. This process would be rapidly, and permanently, altered if temperatures continue to rise in the Artic spring, as they have since 1910.

This increase, which has risen from -14 degrees Celsius to more than -8.5, represents an upward arc whose greatest increase has occurred in the last decade. The result, sea ice vanishing at an unexpected rate in 2007, and again in 2008, leaves Artic sea ice at its second lowest extent on record, with ice shelves along Canada's northernmost islands disintegrating at an alarming pace.

In Canada, this melting has closed an Arctic park ironically named Auyuittuq - a word in Inuit that means "land that never melts". Located in the Nunavut territory above Manitoba near Hudson's Bay, this park experienced such extreme melting conditions in early 2009 that hiking trails washed away and 22 visitors had to be airlifted to safety.

As I reported earlier this year, rising densities of atmospheric methane - as reported by the NOAA over the last decade - are another evidence of what melting permafrost may trigger.

"The higher the temperature gets, the more permafrost we melt, the more tendency it is to become a more vicious cycle," notes Chris Field, the director of global ecology at the Carnegie Institution of Washington. "That's the thing that is scary about this whole thing. There are lots of mechanisms that tend to be self-perpetuating and relatively few that tend to shut it off."

Ted Schuur, a professor of ecosystem ecology at the University of Florida, describes these mechanisms as a "slow-motion time bomb".

Time bomb is not a noun we like to hear in association with climate change, standing as we do on the cusp of the century that will either make or break the earth. Unfortunately, it is a term we need to get used to, since British scientists are now suggesting we need to expect the worst.

Related Reading:
Warming Arctic Dooming Earth?
Melting Arctic and Oil

Image Credit: Follidus