Does Gore overheat global warming?
Al Gore's documentary, "An Inconvenient Truth," continues to trigger heated discussions about global warming, as well as Mr. Gore's political ambitions, real or imagined.Skip to next paragraph
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But how close to the mark is his representation of the science tying humanity's industrial activity to changing climate aka anthropogenic global warming?
In short, say several climate researchers, he basically gets it right, although one can question some aspects of the presentation.
"I worry that the movie is a little heavy on disaster scenarios," says David Battisti, professor of atmospheric science at the University of Washington in Seattle and director of the university's Earth Initiative. Over the course of the coming century, he says, average conditions are likely to change in ways that should prompt action now; it doesn't require extreme examples to make the point.
After viewing the film, he says, his impression is that nothing in it "misstated the science in a qualitative way."
Indeed, his colleague Eric Stieg, also with the University of Washington, has noted that the film includes research that is only a few months old and clearly relevant to the discussion - research that won't appear in the next UN summary of climate science, slated for release early next year. The newest studies were too late to be included in the next UN summary, which is published about every six years and widely cited in public debates.
Among the nits and notes from the cognoscenti:
In the film, Gore points to Mt. Kilimanjaro as an example of global warming's impact on alpine glaciers. Robert Balling, a climatologist at Arizona State University writes, however, that the shrinking glaciers atop Africa's famed volcano have been disappearing for more than a century. Two studies published in 2004 suggest the retreat was triggered by declining rainfall since the end of the 1800s.
But other researchers note that the glacier has survived far more severe and long-term droughts during its 11,000-year history. Regardless of what may have triggered the glacier's shrinkage, researchers say global warming is a plausible, if not fully verified, reason for its accelerating disappearance. The film also points to a range of other large alpine ice fields worldwide that have declined dramatically over the past several decades. If Kilimanjaro ultimately proves to be the wrong global-warming poster child, there are plenty of others to choose from.
As for Greenland and Antarctica, the film shows dramatic footage of calving ice where glaciers meet the sea. Animated maps show the effect of a 20-foot rise in sea levels if larger chunks of Greenland and Antarctica's inventory slides into the sea. Viewers might assume that the 20-foot rise in sea level will take place this century. A pair of studies published in the journal Science in March do suggest that if CO2 emissions continue to rise at a fairly moderate pace, temperatures likely would rise high enough by the end of this century to render such a meltdown unavoidable. But, they add, it would take several centuries for that scenario to play out, giving humans more time to adapt.