Evidence links volcanoes to Earth's largest mass extinction 252 million years ago
2/07/2018 03:00:00 PM
Pine trees become temporarily sterile when exposed to ultraviolet radiation as intense as some scientists believe Earth experienced 252 million years ago during the planet's largest mass extinction, lending support to the theory that ozone depletion contributed to the crisis.
The effect of high UV on conifers and potentially other trees also suggests caution today in introducing chemicals that deplete Earth's ozone layer, which has yet to recover after a global ban on chlorofluorocarbon refrigerants in the 1980s instituted after ozone holes developed over the poles. Some industrial chemicals also destroy atmospheric ozone, which is the planet's sunscreen, protecting all life from excessive UV rays, in particular UV-B wavelengths, which causes mutations in DNA.
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https://archaeologynewsnetwork.blogspot.com/2018/02/evidence-links-volcanoes-to-earths.html#Eg8wSAyTpOFiXqrQ.99
