From secondhand reports I had long thought that President Bush does not believe that global warming is occurring. I turned out to be wrong; apparently in 2001 he agreed that the earth is getting warmer and called for more research on the causes, saying that to limit emissions from American automobiles and factory smokestacks would devastate the economy.
That got me to wondering: when did the idea that greenhouse gases contribute to global warming move from theory to accepted fact? After a little research I came across the following definitive statement, from Thomas F. Young, a professor of chemistry emeritus at the University of Chicago:
Carbon dioxide in the air reduces the loss of heat by infrared radiation from the earth. The widespread burning of fossil fuels (e.g., coal and oil) increased the carbon dioxide content of the air by about 12% during the first half of the 20th century. This, in turn, caused an increase in the average temperature of the earth of 1.1° C. during the same period. It is estimated that all of the fossil fuels will be consumed in about 1,000 years, if the present rate of consumption is maintained. It has been further estimated that this will cause the temperature of the earth to rise 7° to 14° C. (13° to 25° F.), giving most of the earth a tropical and semitropical climate by the end of the period.
Strong stuff, the more so since Professor Young wrote these words, not for use in the hurly-burly over global warming in the Reagan, Bush 41, and Bush 43 administrations, but for publication in the Encyclopaedia Britannica. I found them in the Encyclopaedia‘s magisterial bicentennial edition — which was published 38 years ago, in 1967. I don’t know how long before 1967 Professor Young (and his sources) came to that conclusion, but I’m willing to believe that global warming from the burning of fossil fuels has been accepted science since before President Bush entered college.