Sunday, April 20, 2008

Discovery: Expedition Alaska, and other events tonight highlight global warming


Expedition Alaska (about 100 minutes) aired April 20 on the Discovery Channel. Several teams of scientists and filmmakers traveled to the glacier country in Southeast Alaska, mountains in South Central (Wrengal), and the North Slope.

Scientists compared glaciers today with photos from as early as 1909, with alarming results. On two occasions, they went down into moulons, which are rivers under glaciers that allow them to become loose and slide more rapidly into the sea.

In south central Alaska, around Denali, the spruce bark beetle, with less cold winters to kill them off, are killing off spruce forests, turning them into grasslands, in an area the size of Maryland.

The most alarming findings may be on the North Slope, where a warmer permafrost is allowing methane to escape. Methane is twenty times more effective as a greenhouse gas than carbon dioxide. A recent “Mega Disasters” on the History Channel described hypothetical methane explosions undersea from methane hydrate. (discussion) )

The scientists also observed grizzly bears in their salmon hunting grounds, and polar bears suffering from loss of ice shelf. Grizzly bears and polar bears are starting to interbreed, which could mean the loss of the polar bear as a species by 2050.

PBS (MPT) tonight aired “Global Warming: The Signs and the Science”. Among the topics were the suddenness of big city heat waves (such as Paris in 2003), and the possibility that global climate can flip very suddenly for various reasons, including an ice age caused by the undermining of the jet stream. Global warming was characterized not just as an economic problem but as a moral problem, in which today’s adults are giving away their childrens’ world and where climate change will affect the disadvantaged the most first.

NBC Dateline also covered global warming, with the melting of glaciers in the Andes about Bolivian cities, threatening their water supplies.

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