(Yesterday at 8:29 am)Fake Messiah Wrote: This is a rather strange way of gathering data.
Quote:Dinosaur teeth reveal prehistoric air quality was pretty awful, actually
That's from a fascinating study by a team of geochemists and geologists at the University of Göttingen in Germany. The researchers looked at enamel powders off of teeth from several dinosaurs found in North America, Africa, and Europe, in which they found isotopic traces of oxygen molecules they breathed as far back as 150 million years ago.
A strange place to look for an indicator of air quality, I know. But since tooth enamel is extremely stable, it can preserve tiny amounts of the air vertebrates breathe and incorporate into their body water pool through biomineralization. This allowed the scientists to deduce atmospheric composition from all those millions of years ago.
What they discovered was hard to take in, literally. CO2 levels reached roughly 750 parts per million in the late Cretaceous period, and around 1,200 parts per million in the late Jurassic period. The latter figure works out to about four times more CO2 than preindustrial times. The CO2 reading observed in the Cretaceous period is also far greater than the 430 parts per million we see in the atmosphere today.
The team also noticed a strange composition of oxygen isotopes in the teeth of two dinosaurs – a Tyrannosaurus Rex and a long-necked sauropod called Kaatedocus siberi. This indicated some sort of spike in the amount of CO2 in the air, which could be the result of volcanic eruptions. The researchers were also able to determine that the total photosynthesis from plants around the planet in the Mesozoic era was more than twice what we see on Earth today.
https://newatlas.com/environment/dinosau...r-quality/
Urg. Pretty good science, but poor science reporting. We've known for a while that CO2 levels and photosynthesis ran higher at various points in Earth's history. It doesn't mean that there was anything wrong with the air quality. The Sun expands and warms as it ages, which means that earlier in history you needed more greenhouse effect to get liquid water. That excess CO2 gets you more plant growth if other factors are also favorable.
