[MCN] Who says we are doing nothing about human population sprawl? We are doing it in two ways, although not intentionally

[Lance Olsen]

Excerpts : When you consider that sperm counts declined by 50 percent in just 40 years, as Shanna's meta-analysis <https://academic.oup.com/humupd/article/23/6/646/4035689> published in a 2017 issue of the journal Human Reproduction Update showed, it’s difficult to deny or discount how alarming this is.

The truth is, these reproductive health effects are interconnected, and they are largely driven by a common cause: the presence of hormone-altering chemicals (a.k.a., endocrine-disrupting chemicals <https://www.niehs.nih.gov/health/topics/agents/endocrine/index.cfm>, or EDCs) in our world. These hormone-hijacking chemicals, which include phthalates, bisphenol A, and flame retardants, among others, have become ubiquitous in modern life. They’re in water bottles and food packaging, electronic devices, personal-care products, cleaning supplies and many other items we use regularly. And they began being produced in increasing numbers after 1950, when sperm counts and fertility began their decline.

https://www.scientificamerican.com/article/reproductive-problems-in-both-men-and-women-are-rising-at-an-alarming-rate/



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Excerpt : But male fertility at high temperatures—compared to the temperature at which they stopped moving or died—was the best indicator of the possibility of warming extinction. Crucially, they revealed that the temperature at which males could no more reproduce was considerably lower compared to temperatures at which they died.

Dr Belinda van Heerwaarden, who recently joined the University of Melbourne, guided the study when she was at the Monash University School of Biological Sciences <https://www.monash.edu/> as part of an Australian Research Council (ARC) Discovery Early Career Researcher Award (DECRA).

The way we currently estimate climate change vulnerability may be underestimating extinction vulnerability. We need to consider fertility if we want to understand the impacts of climate change on biodiversity.

Dr Belinda van Heerwaarden, School of Biological Sciences, Monash University

“Species that we thought could tolerate 7 °C of warming may already be experiencing temperatures that are within 1 °C of their male upper reproductive limit. If males are unable to fertilise females, populations will crash and be unable to replace themselves,” van Heerwaarden added.

Moreover, Dr van Heerwaarden and Professor Carla Sgrò from the Monash University School of Biological Sciences analyzed whether male fertility could change via evolution and adjust to rising temperatures.

The team discovered that irrespective of whether species were from temperate or tropical environments, they had limited ability to react to warming temperatures.

This represents a real risk to biodiversity. We are increasingly finding that many species won’t be able to adapt to projected climate changes.

Carla Sgrò, Professor, School of Biological Sciences, Monash University

https://www.azocleantech.com/news.aspx?newsID=29275 <https://www.azocleantech.com/news.aspx?newsID=29275>

Journal Reference:

van Heerwaarden, B & Sgrò, C M (2021) Male fertility thermal limits predict vulnerability to climate warming. Nature Communications. doi.org/10.1038/s41467-021-22546-w <https://doi.org/10.1038/s41467-021-22546-w>.

OPEN ACCESS pdf
https://www.nature.com/articles/s41467-021-22546-w.pdf <https://www.nature.com/articles/s41467-021-22546-w.pdf>



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"The old saying that 'past performance is no guide to the future' is not a piece of compliance jargon. It is the truth.”

<<https://www.economist.com/news/finance-and-economics/21723845-sheer-luck-good-past-returns-predicting-future-performance-fund>>




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