American Geophysical Union fall 2007 meeting

The fall meeting has begun. Some presentations will be webcast, notably Lonnie Thompson’s talk Wednesday at 6:15 PM, Abrupt Climate Change and Our Future.

Update: Also see the Nature blog on the conference.

RealClimate is blogging on this. Their first dispatch includes the following:

• Greenland experienced an earlier glacier retreat comparable to today’s about 1,000 – 1,200 years ago, so locally temperatures were as warm then as they are today. (This was only locally true.)

• Most glaciers are melting faster. The sea has warmed 4 C over the past 15 year. This change in outlet glaciers increases flow. Melt ponds are now ubiquitous.

melt ponds
melt ponds

Leigh Stearns and collaborators point out that the Greenland Ice Sheet’s contribution to sea level has doubled in the past five years, due largely to factors connected with ice dynamics (and not incorporated in the IPCC estimates). They showed satellite data which indicates that just two glaciers — Helheim and Kangerdlugssuaq — might account for 10% of this increase. Ominously, more glaciers are primed to pop as climate continues to warm. About the increased flow speeds in this region, they suggest the system has entered a new state: “We speculate that these faster flow speeds represent a new long-term state of behavior which, while not as dramatic as the short-lived periods of peak speeds, have important implications for the rate of sea level rise.”

measuring glacier flow
measuring glacier flow

• Bush’s science advisor John Marburger also provoked fear in the audience, because he advocated against greenhouse gas mitigation.

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