Earth Equity News

Increased Arctic Ocean Methane Releases Raises Tipping-Point Concerns. By Susan Q. Stranahan, YaleEnviro360, October 30, 2008. "For the past 15 years, scientists from Russia and other nations have ventured into the ice-bound and little-studied Arctic Ocean above Siberia to monitor the temperature and chemistry of the sea, including levels of methane, a potent greenhouse gas. Their scientific cruises on the shallow continental shelf occurred as sea ice in the Arctic Ocean was rapidly melting and as northern Siberia was earning the distinction -- along with the North American Arctic and the western Antarctic Peninsula -- of warming faster than any place on Earth. Until 2003, concentrations of methane had remained relatively stable in the Arctic Ocean and the atmosphere north of Siberia. But then they began to rise. This summer, scientists taking part in the six-week International Siberian Shelf Study discovered numerous areas, spread over thousands of square miles, where large quantities of methane -- a gas with 20-times the heat-trapping power of carbon dioxide -- rose from the once-frozen seabed floor... Gustafsson of the Department of Applied Environmental Science at Stockholm University and the co-leader of the expedition, said in an interview [that] there was no doubt; the methane was coming from sub-sea permafrost, indicating that the sea bottom might be melting and freeing up this potent greenhouse gas'... The shallow Siberian Shelf alone covers more than 1.5 million square kilometers (580,000 square miles), an area larger than France, Germany, and Spain combined. Should its permafrost layer thaw, an amount of methane equal to 12 times the current level in the atmosphere could be released, according to Natalia Shakhova [a U of Alaska scientist]... What concerns some scientists is evidence from past geological eras that sudden releases of methane have triggered runaway cycles of climate upheaval."