February 17, 2011
Permafrost Thaw Could Speed Up Global Warming
Scientists at the National Snow and Ice Data Center (NSIDC) in Colorado estimate that if global warming continues even at a moderate pace, a third of the earth's permafrost will be gone by 2200.
A study released Wednesday, based on UN Intergovernmental Panel on Climate Change (IPCC) scenarios, warns that global warming could cause up to 60 percent of the world's permafrost to thaw by 2200 releasing huge amounts of carbon into the atmosphere increasing the rate of climate change, AFP is reporting.
NSIDC scientists used a computer model to predict how much carbon the thawing permafrost would release and came up with the staggering figure of 190 gigatons by 2200. "That's the equivalent of half the amount of carbon that has been released into the atmosphere since the dawn of the industrial age. That's a lot of carbon," NSIDC scientist Kevin Schaefer, the lead author of the study says.
Predicting the world could see 59 percent of the permanently frozen underground layer of earth thaw out, organic matter, having been trapped in the permafrost for tens of millennia will begin to decay, releasing carbon into the atmosphere.
Escaping carbon from plant material, primarily roots trapped and frozen in soil during the last glacial period that ended roughly 12,000 years ago, he said. Schaefer likened the mechanism to storing broccoli in a home freezer. "As long as it stays frozen, it stays stable for many years," he said. "But if you take it out of the freezer it will thaw out and decay."
Schaefer continued by saying carbon released from melting permafrost has to be accounted for in global warming strategies. "If we don't account for the release of carbon from permafrost, we'll overshoot the C02 concentration we are aiming for and will end up with a warmer climate than we want," he said.
"If we start cutting emissions now, we will slow down the thaw rate and push the start of this carbon release off into the future," Schaefer says, trying to not paint a completely dark future.
University of Florida ecology professor Ted Schuur used a different method to study the effect of thawing permafrost on atmospheric carbon in a 2009 study and arrived at the same annual figure for carbon entering the atmosphere as Schaefer and his co-authors.
The loss of permafrost would not present a significant threat to the planet, some have argued, as plants would start to grow on the warmer earth and suck in carbon dioxide from the atmosphere through photosynthesis, thus negating the issue.
Schuur however, said in his study two years ago that protection from plant growth "doesn't last, because there is so much carbon in the permafrost that eventually the plants can't keep up." Schaefer insisted that a major preventive effort, starting now, could stave off the worst-case scenario of the release of the huge amounts of CO2 into the atmosphere ,further accelerating global warming and permafrost melting.
Image Caption: The image was taken in High Arctic from a helicopter. It shows the crack pattern in permafrost. Credit: Mila Zinkova/Wikipedia (CC BY-SA 3.0)
On the Net:
- National Snow and Ice Data Center (NSIDC)
- University of Colorado Boulder
- UN Intergovernmental Panel on Climate Change (IPCC)
- University of Florida