In his award-winning film, ‘An Inconvenient Truth’, Al Gore showed the world some satellite images of Lake Chad in Africa – a once giant lake, and a critical water source for millions of people, that has rapidly shrunk. The movie makes it clear that this loss of water is due to global warming, and suggests that the resulting water shortage has had much to do with recent famine and violence in nearby Darfur. The warming, of course, is blamed on the overuse of fossil fuel by energy-obsessed humans.
But actually, Lake Chad has passed through many cycles of fullness and dryness over the millennia, long before human beings began using oil to heat their homes and drive their cars.
Later in the movie, Gore warns us of the likelihood that we will soon be facing an increase in infectious disease, because the insects that carry the germs of fifteen horrible illnesses (including malaria, ebola, SARS, west nile virus, a drug-resistant form of TB, legionnaire’s disease, lyme disease, etc.) will soon be able to expand into new and vaster habitats that are warmer and more hospitable.
But actually, as Mellie Gilder, MD, noted shortly after the film’s release, only four of these diseases are carried by insects. One of them, lyme disease, far from being a tropical illness that will spread northward, is a disease that originated in temperate Connecticut and has been spreading to the south and west. Another, Malaria, is typically seen in certain tropical climates, but this is mostly due to the effects of poverty rather than climate – malaria was once prevalent in the cold regions of northern Europe and Siberia. A third disease, west nile virus, is carried by a mosquito that is found in every temperature zone and on every continent on the planet save Antarctica. There is no evidence that the appearance of west nile virus in the United States was due to global warming that allowed the host mosquito to suddenly thrive here.
Gore’s movie, and the entire global warming movement, is filled with this sort of dramatic but questionable information that gives science a bad name but sways politicians and voters. The public has been convinced that global warming is unquestionably being caused by our irresponsible overuse of fuel oil, which, when burned, releases excessive carbon dioxide into the atmosphere, and this high level of atmospheric carbon causes world-wide warming. We are then treated to vivid and spectacular assertions that the glaciers are going to melt, the oceans are going to rise, our port cities will be deluged, and it’s the end of the world. It is hard to question this frightening scenario since the press assures us that ‘there is scientific consensus’ and ‘no credible scientist disagrees’.
But quite a few credible scientists do disagree, or are at least open-minded enough to question the politicized assumptions and to remember that causality is a complex concept, especially in imprecise sciences like climatology. In any case, science does not run on consensus. Claiming that a consensus already exists, and that debate ought therefore to be stilled, is a cheap maneuver to avoid the continuous questioning that good science demands.
Gore’s movie claims that the presence of excessive amounts of carbon in the atmosphere causes the earth’s temperature to rise. He presents a graph that compares temperature and carbon levels during thousands of years of Earth’s history, and viewers can easily see that these two measurements rise and fall together. It is very tempting to jump quickly to assumptions about causality simply because two events occur together. But the mere correlation of two events does not prove causality. Sure enough, there is plenty of evidence on the very chart that is used in ‘An Inconvenient Truth’ to suggest that increases in temperature cause increases in atmospheric carbon, rather than the reverse. The basic evidence is a simple matter of timing: in the rising-and-falling cycles that the chart depicts, close analysis reveals that on many occasions throughout history the periods of increased levels of atmospheric carbon have been preceded by overall increases in planetary temperature – and this strongly suggests that rising temperature is in fact the driving cause of rising carbon (which is most likely released by warming oceans and land masses).
I am not trying to suggest that there is no possibility that human-mediated carbon release could be leading to dangerous global warming. But there are huge and complex factors involved in climatic events, from oceanic dynamics to solar dynamics to long-term patterns of the earth’s complex movements in space, and we really do not know what is going on. An average rise of about one Fahrenheit degree over the past century or so is not in question, but what still is in question is (1) the cause of this rise, (2) the results that may or may not ensue because of it, and (3) whether anything we do is going to change the future of weather. Exaggerations, personal attacks on opponents, and disingenuous pretensions of knowledge are the bane of science and can only serve to discredit the valid ongoing attempts to impartially and accurately understand and evaluate the effects, if any, of manmade heat-trapping gases. (Both sides of the debate, of course, are guilty of this same blather. Plenty of opponents of the global warming theory spend their time attacking the integrity of its proponents, and insisting that one or another favorite piece of anecdotal evidence about a cooling trend somewhere that day is incontrovertible ‘proof’ that global warming is a hoax.)
It will be objected that, in the meantime, we should err on the side of caution and prevent the release of more carbon by whatever means we can employ. There is value in this precautionary principle, but there is another equally important precautionary principle with which it must be balanced. Limiting the consumption of fossil fuels will be a great nuisance to most Americans, but it will be devastating to the economies of poor and developing nations. Readily available and affordable energy is crucial to these struggling economies and there is a clear connection between thriving national economies and its citizens’ health, life expectancy, happiness and security. Increased wealth brings with it opportunities for better nutrition, better education, better medical care, cleaner environments, and safer more-peaceful societies. Before Americans casually presume to tell the world that we have ever-so-nobly decided that everyone must now limit their energy consumption, we need to err on the side of caution and consider the harmful effects this will have on the lives of others, and not be so surprised and offended when other countries do not fall in line.
Why the ease with which this alleged problem has been accepted? There are several reasons behind this. It provides a wonderful diversion from more pressing matters, including more pressing matters of ecology as well as economic renewal and the improvement of our foreign relations. It allows the far left to challenge the rule of capitalism, since our American economy is very much based on energy. It allows the far right to claim they are ‘green’ and uniquely concerned with saving lives and saving the planet. And in the face of all the propaganda there is the matter of our common ‘suggestibility’, the astonishing ease with which we abdicate all responsibility to think for ourselves. Instead of so quickly jumping on the bandwagon, some healthy skepticism is in order.