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In today’s Albany Times Union (March 10, 2017) , my friend Rex Smith writes about the confidence we should place in the scientific pronouncements of athletes or politicians. For an athlete he chooses Kyrie Irving, a basketball player who claims to believe the earth is flat. For a politician, he chooses Scott Pruitt, the Trump appointee now in charge of the Environmental Protection Agency, who does not accept that humans are responsible for global warming. Smith points out that the authority of these two worthies is questionable, at least when it comes to science. We humans know that the earth is more or less spherical, and that the recent rise in the temperature of the earth is due to the burning of fossil fuels. Any individual not versed in science would be hard-pressed to cite or discuss the evidence, and most simply accept what scientists tell them. To do otherwise is to risk, justifiably, being thought a fool.
The article got me to thinking about a book by Steven Weinberg, To Explain the World – The Discovery of Modern Science (HarperCollins, New York, 2015). UK edition: (Allen Lane, Penguin, London, 2015). Derived from a course he taught on the history of science, this little book explains many of the proofs that people have made for various propositions that we accept today, including the calculation of the circumference of the earth by Eratosthenes in Egypt during the third century B.C. He knew that at Aswan at noontime the sun was directly overhead. At Alexandria, a known distance to the North, a vertical stake at noon casts a shadow. (This alone proves the world is not flat). By measuring the length of this shadow he was able to calculate how many degrees difference there was in the direction toward the sun, and thereby infer the circumference of the earth. It is ironic indeed that Irving, who knows something about the properties of spheres, is unaware of this scientific fact which was discovered over two thousand years ago.
One might be forgiven for being a little slow appreciating the reasons behind global warming, but really it is not so difficult to grasp. Carbon dioxide has been known since the 19th century to absorb infrared radiation, which activates it and, in turn, other molecules with which it collides. The motion of these molecules is what thermometers are really detecting when we use them to measure temperature. The more carbon dioxide in the air, the higher the temperature rises. We know for a fact that the level of carbon dioxide in the atmosphere has been rising since 1900 from 280 ppm to over 400 ppm. We know from the amount of fossil fuel burned, and from its isotopic composition (it is deficient in C-14), that the excess carbon dioxide is derived from this fossil fuel. Quod erat demonstrandum.
Rex did not go into it in his excellent editorial, but the rise in temperature that we are experiencing is actually very perilous to ourselves. All organisms are adapted to a specific combination of temperature and rainfall. These two variables have been shown to determine the character of biomes all over the earth. As they change, the distribution of the biomes will change, and that means that many species will go extinct because they cannot change as fast as the environment in which they live. At current rates of extinction, half the world’s species will go extinct in the next 7000 years. The earth will be a pretty awful place for us to try to survive in under such a circumstance.
It does not matter if Kyrie Irving thinks the world is flat. But one cannot be comfortable with a federal official, in charge of protecting our environment, who fails to accept the facts about something so fundamental to our well-being as our responsibility for environmental change.
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