"Looking for hard date in very soft ground..."
If there's one thing that can make global warming worse, it's large quantities of methane (a powerful greenhouse gas, many times more potent than CO2), and if there's a place that contains a lot of sequestered methane, it's the permanfrost in Northern Russia. That's why it's such bad news to learn that this permafrost is melting and releasing methane rapidly. The video above from the BBC shows a scientific expedition in Western Siberia, and it's obvious that the "perma" part of "permafrost" can't stand for "permanent" anymore. Via Youtube. See also: Steven Chu: China Giving U.S. a Clean Technology "Sputnik Moment"