July was the hottest month on record for the lower 48 states. It broke the old record of July 1936 by 0.2 degrees. The weather around 1936 was also very hot and dry (years of the dust bowl). These temperature measurements have only been recorded since 1895 (117 years ago). So what happened to global warming during the intervening 76 years since 1936? If the anthropogenic production of carbon dioxide is driving global warming, then the massive increase in carbon dioxide for the past 76 years seems only now to be having an effect.

After the peak in the ’30s, the temperature actually declined for decades (remember the predictions of the coming ice age in the ’70s). There may be a natural fluctuation in temperatures with a cycle of around every 75 years. Assuming these cycles of temperature fluctuations are symmetric, the trough of the previous cycle would have occurred in 1898 =1936 – (76/2); just a few years after they started keeping records. Temperatures rose from this nadir to a peak in the ’30s and then declined. So it was natural for people to be concerned with declining temperatures from the ’40s to the ’70s, as it is natural for people to be concerned with the rise in temperatures since the trough in the ’70s.

But concern about temperature fluctuations should not be inflamed into hysteria about the impending end of the world. Mankind has flourished by adapting to natural fluctuations in our environment, not by imposing draconian solutions to problems that may only be apparent to people with a limited grasp of past climate fluctuations.

Mikal Saltveit

Davis

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