Saturday, March 28, 2009

PBS Nova: "Extreme Ice Revealed"

On Tuesday, March 24, PBS aired the Nova segment “Extreme Ice Revealed”, directed by Andrew Gersh, featuring scientific photographer James Balog. The website URL is this.

Imagine a landscape that looks geometrically like the American Southwest, but made up of ice and rivulets rather than sandstone. Other moons in our solar system (Europa and Titan) may look like this to some degree. But so does much of Greenland, Alaska, and Antarctica. Ice with air looks white, but when the air is driven out, it turns sapphire or turquoise. Glacier country is one of the few places in nature (besides sky and ocean) where blue naturally occurs in “the landscape.”

But all of this natural beauty conveys the greatest danger: rapidly rising sea levels by melting ice, at least three feet by 2100, inundating the homes of hundred of millions of people, many in the developing world.

The show provided shocking examples of glacial ice loss since 1980 in many areas, including mountains, Greenland, and coastal Alaska. One glacier in Alaska had lost several hundred feet of ice since 1980.

But the most interesting portion may have been the research explaining the sudden draining of summer glacial lakes on Greenland’s ice cap. The ice caps crack, and the water drains down to bedrock, lubricating and loosening the entire ice cap, causing some of it to slide off. In the meantime, a reflexive cycle then brings even more warm water from the ocean to melt the ice further.

One sixth of the world’s population depends on fresh water from glaciers, including mountain glaciers at more moderate latitudes. This builds up to another “inconvenient truth”.

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