During several hours, a panel of three experts from different disciplines discussed the building sector's impact on global warming. Their presentations are available online.

Opening the session was one of the world's leading climate scientists, James Hansen, head climatologist at NASA's Goddard Institute for Space Studies at Columbia University. Hansen began by laying out the current body of information that points toward looming climate change.

Since his appearance before the U.S. Congress in 1988, when his warnings made "greenhouse effect" household words, Hansen has gone from a lone voice to a leading spokesperson in the movement to reduce global warming. At Goddard, he has at his disposal the most advanced climate modeling technology available, with about 10,000 sensors throughout the world.

Though the implications of his studies paint an alarming picture, he remains positive about the prospects of turning the tide on carbon dioxide emissions — but warns that immediate global action is required.   >>>