Children of Men: Will Climate Change Sterilize Males?
November 15, 2018
Movie got it wrong. It’s not women going infertile, it’s males that could be sterilized.
Heat doesn’t just kill. It is also diminishes the vitality of sperm, curtailing the capacity to reproduce, as scientists have documented.
“Heatwaves reduce male fertility and sperm competitiveness, and successive heatwaves almost sterilise males,” wrote the authors of a study published Tuesday in the peer-reviewed Nature Communications.
But the research points newly to an even longer-lasting effect. Ecologists and evolutionary biologists at the University of East Anglia in Norwich, England, found that heat stress appears to be associated with transgenerational fertility problems.
That means that organisms may bear the effects of elevated temperatures long after the initial exposure — in the form of reduced lifespans, reproductive challenges and other types of defects passed to offspring.
The scientists found that heat waves undermine sperm production and viability, and also interfere with movement through the female. They further discovered that extreme heat “reduced reproductive potential and lifespan of offspring when fathered by males, or sperm, that had experienced heatwaves.”
Yes, the scientists used beetles to test their theory. But researchers say the insects can be used as a proxy for people.
Beetles are one of the most common species on Earth, “so these results are very important for understanding how species react to climate change,” said study co-author Matt Gage, an ecologist at the University of East Anglia in the U.K.
Heat waves are predicted to be more frequent and more extreme this century as human-caused climate change continues.
“Research has also shown that heat shock can damage male reproduction in warm-blooded animals too, and past work has shown that this leads to infertility in mammals,” added lead author Kirs Sales, also of the University of East Anglia.
And you may say, “It’s just beetles”.
But a lot of other species reproduce sexually. Extinction is forever.
November 15, 2018 at 10:55 am
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5637027/ Human sperm count numbers are falling dramatically. This article is specifically about Africa, but the trend is world wide particularly in Western Nations.
Here is another article https://www.scientificamerican.com/article/sperm-count-dropping-in-western-world/ “The results, published in the journal Human Reproduction Update, showed a 52.4 percent decline in sperm concentration and a 59.3 percent decline in total sperm count among North American, European, Australian and New Zealand men.”
November 15, 2018 at 6:41 pm
I wouldn’t be surprised if we learn the cause of this is plastic pollution. Plastics often release estrogenic compounds as they decay.
https://www.npr.org/2011/03/02/134196209/study-most-plastics-leach-hormone-like-chemicals
November 17, 2018 at 3:31 am
Plastics, all sorts of other chemicals, the lack of general fitness are all suspects. One study on plastic in humans https://www.news.com.au/technology/science/human-body/plastics-have-entered-human-food-chain-small-poo-study-shows/news-story/81d3383daeae87c6429c92bae2803f2c
November 15, 2018 at 9:13 pm
Sperm count numbers are falling in a worrisome manner, but climate warming and heat waves would seem a small problem, otherwise tropical regions would have dramatically lower sperm and birth counts than temperate regions. For insects and many other species perhaps a serious angle, but warming cannot account for more than a smidgen of the sperm count trends.
November 15, 2018 at 11:13 am
Classic negative feedback
November 15, 2018 at 8:28 pm
Have often heard the argument that Mother Nature will naturally protect the planet from global warming. Sure will, only question is how many of the plague of humans causing it will have to go. MN plays no favorites.
November 15, 2018 at 9:14 pm
Heat is just the icing on the cake. We have been destroying the reproductive capabilities of all sorts of animals since the 1950’s and earlier—-read Rachel Carson.
“Modern” life has filled the environment with many industrial chemicals that are endocrine disruptors, and they may be the cause of autism, lower IQ’s, asthma, lowered fertility, and many other maladies.
A great book was written over 20 years ago about this much-ignored problem.
“Our Stolen Future: Are we threatening our fertility, intelligence, and survival?—-a scientific detective story”, by Theo Colburn, Dianne Dumanosky, and Peterson Myers, Dutton, 1996 (with a foreword by Al Gore)
Here’s a 2-page “20 years later” essay by Myers in 2016 that’s a quick read and update on what they said back then—it hasn’t gotten much better but is at least getting some attention.
https://www.healthandenvironment.org/docs/2016SFMMyersOurStolen.pdf
Anyone interested in thinking about this further should also look into epigenetics and the human microbiome.
November 16, 2018 at 4:10 pm
…and Alex Jones’ gay frogs!
November 16, 2018 at 4:42 am
I remember learning about sperm and heat tolerance from watching the T.V comedy show”Frasier”, repeats of the excellent comedy are still regularly shown down under in New Zealand. That’s why the testicles hang outside the body out, in cooler, airier climes. In my days living in Saudi and the U.A.E the desert folk (Bedouins), who survived (without A/C) in the empty quarter in temperatures that seem much too high to support life, managed to reproduce and looking at the birth rate in Ethiopia (one of the hottest areas of the world), we do not need to get too worried yet about human sperm counts.
November 16, 2018 at 10:51 am
We don’t need to worry too much IF we are happy with the idea that the Bedouins and Ethiopans will outbreed the peoples of the western world. Survival of the fittest and all that crap, and we apparently are not among the fittest (which I blame on how “modern” we are—see “Our Stolen Future”)
(Frazier is still showing as reruns in the U.S. also, and is still one of the highest quality shows ever made).
November 16, 2018 at 8:33 pm
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