The Truth about An Inconvenient Truth
Former Vice President Al Gore has long argued that human activities - primarily the burning of fossil fuels - are causing the Earth to warm significantly, with potentially catastrophic results. His most recent attempt to persuade the general public of his view is a movie and companion book entitled An Inconvenient Truth.
Most of the material in the movie is not new. It is largely based on a slide show Gore has given more than a thousand times to audiences around the world. Gore has persistently erred in his presentation of climate science for years; unfortunately, he has not taken this opportunity to correct his errors. The movie is filled with misstatements, half-truths and verbal sleights of hand concerning what we can and can't say with some level of certainty regarding the causes and consequences of climate change.
Is Tennessee Warmer? Gore says that since he was a child, he has seen the effects of global warming on his family farm. Inconveniently for Gore, however, any changes on his farm could not have been caused by global warming. According to National Climatic Data Center records, Tennessee has cooled by more than a half degree since Gore was born. Indeed, monthly temperature records show the state's warmest 30-year period since 1895 was 1925 to 1954.
Is Global Warming Causing the Snows of Kilimanjaro to Melt? Early in the film, Al Gore shows some powerful photographs of the diminishing snow-pack on Kenya's Mount Kilimanjaro, implying that human-induced warming is the cause. The snows of Kilimanjaro are retreating, but according to studies in the International Journal of Climatology and the Journal of Geophysical Research, the retreat began in the late 19th century - before most human greenhouse gases were emitted. It is largely due to the decline in precipitation (snowfall) on the mountain as a result of the clearing and burning of the rainforests at its base for agriculture. Precipitation is also declining in parts of the Amazon as the rainforests are cleared. Thus, while humans are to blame for the retreat of Kilimanjaro's glaciers, global warming is not.
Will Melting Polar Ice Sheets Cause Flooding of Coastal Cities? Gore uses stunning computer-generated images to show what would happen to the world's coastal areas if the Greenland and West Antarctica ice sheets melted. Sea levels would rise by as much as 40 feet, radically changing coastlines and creating many refugees.
What Gore doesn't say about the threat to the ice sheets is as important as what he does say, however. Ice and snow is accumulating in the interior of Greenland and Antarctica, but decreasing around the edges. A 2005 study in the Journal of Glaciology by a NASA scientist concludes that there is a net loss of ice that will result in higher sea levels. But the loss is occurring slowly: 0.05 millimeters on average per year. At that rate, it will take a millennium for the oceans to rise 5 centimeters (roughly 2 inches) and 20,000 years to rise a full meter.
More recent research indicates that the pace of melting has increased. But even under the worst case it would take at least several centuries - 1,800 years by one calculation - for the scenario painted in the movie to play out, giving humans a considerable amount of time to adapt.
Do All Scientists Agree? Gore says "the debate is over," "the science is settled," and "scientists agree," humans are causing global warming. The most telling piece of evidence for Gore is a study in the journal Science by Naomi Oreskes, professor at University of California at San Diego. Oreskes searched the Institute for Scientific Information database for 1993 to 2003 studies dealing with global climate change. She analyzed 928 abstracts, 25 percent of which did not mention human influence. According to Oreskes, 100 percent of the studies that addressed human influence on current climate trends either explicitly or implicitly endorse the view that humans are to blame for the current warming.
Researchers who tried to replicate Oreskes findings came up with quite different results. Searching the same database using the same keywords, Benny Peiser, of John Moores University, found 1,117 peer reviewed publications with abstracts. In contrast to Oreskes, he found that:
- Nearly three times as many studies (3 percent) either rejected or doubted that humans are a cause of the current warming as those that explicitly endorsed the "consensus view" that humans are causing warming (1 percent).
- Another 29 percent implicitly accepted the consensus view, but most focused on the projected impacts of climate change rather than its causes.
- Two-thirds of all of the studies either made no mention of human influence or dealt with methodological issues, possible responses to climate change or natural factors that contribute to it.
Scientists Hans von Storch and Dennis Bray - both of whom accept the consensus view - surveyed their fellow climate scientists worldwide in 2003. They asked, "To what extent do you agree or disagree that climate change is mostly the result of anthropogenic [human] causes?" Of the 530 responses, a majority (55.8 percent) indicated moderate to strong support for the consensus view, while 30 percent indicated varying degrees of skepticism. [See the figure.] The number of scientists who strongly disagreed with the consensus view (10 percent) outnumbered those who most strongly supported it (9 percent).
Contrary to Gore's claims, 55.8 percent is hardly as strong a consensus as science ever produces about a theory.
No Inconvenient Solutions. Gore says global warming is the most serious threat ever to face human civilization. So what should we do about it? Surprisingly, Gore's list of remedies is so meek and mild they are unlikely to offend a single significant voter group. He does not call for a higher gasoline tax or any other tax on fossil fuel. He does not endorse gasoline rationing, mandatory no-drive days or banning SUVs and stockcar races. He does pay lip service to the idea that the United States should limit carbon emissions as called for by the Kyoto Protocol, but nowhere does he mention that doing so might lower anyone's (any voter's) wages or cause any inconvenience whatsoever.
Furthermore, according to the National Center for Atmospheric Research, if all of the signatories to the Kyoto Protocol met their greenhouse-gas reduction targets, the Earth would at most be 0.07 degrees Celsius to 0.19 degrees Celsius cooler than without Kyoto. Most analysts argue that it would take multiple Kyotos to substantially reduce future warming. Yet on this "consensus" Gore is amazingly silent.
Conclusion. The Christian Science Monitor coined a new term to describe An Inconvenient Truth and films like it: the "docu-ganda." Docu-gandas differ from documentaries in that the goal of the filmmaker is to influence rather than inform. One media expert interviewed by the Monitor argued that marketing such films as documentaries could be "dangerous if viewers take everything they are saying as the whole truth." A second expert noted that "the danger of the advocacy documentary is that things might be being kept from you...."
H. Sterling Burnett is a senior fellow with the National Center for Policy Analysis.