Climate Change the Ultimate Mood Killer: Less Sex in a Warmer World

November 3, 2015

Why do climate deniers hate sex?

Bloomberg:

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 National Bureau of Economic Research. Three economists studied 80 years of U.S. fertility and temperature data and found that when it’s hotter than 80 degrees F, 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” (the economists use quotation marks with the phrase) leads to a 0.4 percent drop in birth rates nine months later, or  1,165 fewer deliveries across the U.S. A rebound in subsequent months makes up just 32 percent of the gap.

The researchers, who hail 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.

1. Birth rates do not bounce back completely after heat waves.

That’s a problem. As summers heat up, developed countries may 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 U.S. birthrate means fewer workers to pay Social Security benefits for retirees, among other consequences.

2. More autumn conceptions means more 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 write. One possibility may be “third-trimester exposure to high temperatures.”

National Bureau of Economic Research:

Dynamic adjustments could be a useful strategy for mitigating the costs of acute environmental shocks when timing is not a strictly binding constraint. To investigate whether such adjustments could apply to fertility, we estimate the effects of temperature shocks on birth rates in the United States between 1931 and 2010. Our innovative approach allows for presumably random variation in the distribution of daily temperatures to affect birth rates up to 24 months into the future. We find that additional days above 80 °F cause a large decline in birth rates approximately 8 to 10 months later. The initial decline is followed by a partial rebound in births over the next few months implying that populations can mitigate the fertility cost of temperature shocks by shifting conception month. This dynamic adjustment helps explain the observed decline in birth rates during the spring and subsequent increase during the summer. The lack of a full rebound suggests that increased temperatures due to climate change may reduce population growth rates in the coming century. As an added cost, climate change will shift even more births to the summer months when third trimester exposure to dangerously high temperatures increases. Based on our analysis of historical changes in the temperature-fertility relationship, we conclude air conditioning could be used to substantially offset the fertility costs of climate change.

4 Responses to “Climate Change the Ultimate Mood Killer: Less Sex in a Warmer World”


  1. On the other hand, given that it is generally agreed that the global population has exceeded ecological limits, in the long term, this could be one of a few welcome negative feedbacks.

  2. rabiddoomsayer Says:

    Would it not be the night time temperatures that matter most? I get that heat exhaustion from the day would carry on for a few hours but night temperatures are probably more significant. When it is too hot to sleep you want warmth away from you.

  3. andrewfez Says:

    =1. Birth rates do not bounce back completely after heat waves. That’s a problem.=

    Sound more like a solution. At the heart of climate and environmental maldies, is overpopulation.

    ” At current rates, one third of the Amazon and 40 percent of the Congo Basin rainforests will be gone by 2050, intensifying global warming, shifting weather patterns in North and South America and making life harder for the 1.6 billion people who depend on forests for food, fuel, shelter, medicine and a livelihood.”
    – CQ Researcher, January 18, 2011 • Volume 5, Issue 2, Doug Struck

    We are in a paradoxical system where as the ratio of natural capital and resources per capita declines, secondary to population growth, this somehow creates wealth. More than likely the paradox can be adjudicated by the notions that (discounting the acquisition of knowledge) the first world is just sweeping up the world’s wealth and concentrating it inside their societies, and that short term wealth creation, at the expense of the natural world, is balanced by long term impoverishment (especially in the absence of a material recycling rate less than 100%). It’s almost similar to the law of conservation of mass/energy, save that wealth can be destroyed.

    But what happens when every single human on earth wants to live like a first world citizen and third world societies/emerging markets create capitalist mechanisms that allow wealth to gravitate towards them? The demand for the concentration of natural capital and resources grows and their distribution in the earth system becomes more homogeneous. And on a resource constrained planet, that means the first world has to make concessions: Even at zero interest rates, the US is still just sputtering along, China has to lie about their growth and participate in artificial tasks like building ghost cities, and politicians have to lie about ‘Making America Great Again’.

    It’s structured population and economic deflation that will Make America Great Again.

  4. dumboldguy Says:

    Are we sure this whole thing isn’t satire lifted from The Onion? There are many factors influencing “coital frequency” and birth rates besides temperature.

    Some freakin’ economists play with some numbers and conclude—–“…air conditioning could be used to substantially offset the fertility costs of climate change”. The AGW mortality “costs” from generating the electricity for that air conditioning would likely exceed the so-called “fertility costs”.

    These clowns should leave the science of population dynamics to the scientists, and confine their crystal ball gazing to their supposed area of “expertise”—economic matters (where they have not been very successful).


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