Economists warn of less sex as climate change heats Earth


Thu, Nov 05, 2015 - Page 7

Climate change has been blamed for many things over the years. Never, until now, has anyone thought it was possible to see it as a kind of contraceptive.

Hot weather leads to diminished “coital frequency,” according to a new working paper put out by the US National Bureau of Economic Research. Three economists studied 80 years of US fertility and temperature data and found that when it is hotter than 26.66oC, a large decline in births follows within 10 months. Would-be parents tend not to make up for lost time in subsequent, cooler months.

An extra “hot day” leads to a 0.4 percent drop in birth rates nine months later, or 1,165 fewer deliveries across the US. A rebound in subsequent months makes up just 32 percent of the gap.

The researchers from Tulane University, the University of California-Santa Barbara and the University of Central Florida believe that their findings give policymakers three major things to think about.

First: Birth rates do not bounce back completely after heatwaves.

That is a problem. As summers heat up, developed countries might see already low birth rates sink even lower. Plunging birth rates can play havoc with an economy. China’s leaders recently acknowledged this by ditching the longtime one-child policy and doubling the number of children couples are allowed to have. A sub-replacement US birthrate means fewer workers to pay social security benefits for retirees, among other consequences.

Second: More autumn conceptions mean more deliveries in summer.

Infants experience a higher rate of poor health with summer births, “though the reasons for worse health in the summer are not well-established,” the authors wrote. One possibility might be “third-trimester exposure to high temperatures.”

Third: Air conditioning might prove to be an aphrodisiac.

Control over the climate at home might make a difference. The researchers suggest that the rise of air conditioning might have helped offset some heat-related fertility losses in the US since the 1970s.

The paper’s title is about as lascivious as the National Bureau of Economic Research gets: Maybe Next Month? Temperature Shocks, Climate Change, and Dynamic Adjustments in Birth Rates.

The researchers assume that climate change will proceed according to the most severe scenarios, with no substantial efforts to reduce emissions. The scenario they use projects that from 2070 to 2099, the US might have 64 more days above 26.66oC than in the baseline period from 1990 to 2002, which had 31.

The result? The US might see a 2.6 percent decline in its birth rate, or 107,000 fewer deliveries per year.

Just when you thought climate change policy could not get any less sexy.