《尽头的冰》(PBS NOVA Extreme Ice)[720p]&[HDTV]
TV Program Description
Original PBS Broadcast Date: March 24, 2009
Remarkable time-lapse footage by one of the world's foremost nature photographers reveals massive glaciers and ice sheets splitting apart, collapsing, and disappearing at a rate that has more and more scientists alarmed. This NOVA-National Geographic Television special investigates the latest evidence of a radically warming planet.
"Extreme Ice" follows National Geographic-funded photojournalist James Balog to some of the most dangerous places on Earth as he documents the disappearance of an icy landscape that took thousands of years to form. An artist, scientist, explorer, and former mountain guide, Balog braved treacherous terrain to site his cameras in ideal locations to record the unfolding frozen drama. (Watch an audio slide show with Balog's narration and striking images.)
The program charts the progress of Balog's Extreme Ice Survey (EIS), the largest photographic study ever attempted of the cryosphere, the mantle of ice that covers large portions of the Earth and that plays a critical role in weather. The effort involves deploying 26 time-lapse cameras in alpine and arctic locations across the Northern Hemisphere and programming them to shoot a frame every daylight hour for three years.
As the program shows, the resulting time-lapse movies give breathtaking evidence of geology in action. Ominously, the proverbial glacial pace of large masses of ice is no longer as slow as it once was, due to the warming of the planet that is accelerating the break-up of these titanic structures, including the separation of a Rhode Island-sized piece of the Antarctic ice sheet in 2002. Scientists are overwhelmingly convinced that the temperature increase is tied to the rise in greenhouse-gas emissions caused by burning fossil fuels.
A NOVA-Nat Geo film crew accompanies Balog to EIS locations around the world. In Alaska, Balog records the rapid retreat of the Columbia Glacier, one of the largest ocean-feeding glaciers in North America (see photo at right). Amazingly, the calving of such glaciers is so frequent that wetsuit-clad surfers sometimes paddle nearby, waiting for an avalanche of ice to generate massive waves for a wild ride. Later, in Iceland, Balog photographs exquisitely sculpted icebergs on the beach, the last stop in their natural journey from the interior out to sea.
Most dramatically of all, in Greenland the award-winning photographer explores a landscape as magnificent as the canyon country of Utah—except carved in solid ice. Lowering himself by rope into a giant hole in the ice sheet bored out by a torrent of meltwater, Balog finds himself in a world of surpassing beauty, scientific mystery, and maximum peril.
Among the scientists featured in "Extreme Ice" are Richard Alley of Pennsylvania State University, along with Tad Pfeffer and Jim White, both of the University of Colorado at Boulder. (In Ask the Expert, White answers viewer questions about the big melt and its potential consequences worldwide.)
Richard Alley tells NOVA that the shrinking of glaciers has long been clear to anyone who lives near them. But "the ice sheets surprised us," he says. "We thought the little glaciers would melt when it got warmer and that the big ice sheets wouldn't do much. And all of a sudden the big ice sheets started rumbling faster ... and we said, whoa, that wasn't supposed to happen!"
No one knows what will happen next. The ultimate doomsday scenario—the melting of all the ice on Greenland and Antarctica and the subsequent raising of sea level by some 200 feet—seems out of the question anytime soon. (In our visual thought experiment, see some of the coastal areas around the world that would vanish if they did.)
But even the current consensus estimate of a three-foot sea-level rise in the next century would wreak havoc in coastal regions, displacing millions of people, from Florida to Bangladesh. The lesson is that the big melt-off now under way holds a potential for changes of far-reaching and as yet unknown extent. (Watch a series of video podcasts on the impact that arctic melting is already having on Yupik people living on St. Lawrence Island in the Bering Sea.)
Note: Coinciding with the film's premiere is a companion book by James Balog, Extreme Ice Now: Vanishing Glaciers and Changing Climate: A Progress Report, published by National Geographic and available at the PBS Shop.