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.
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:
The snows (and ice) of Kilimanjaro and the poles
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. …