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from the couldn't-see-the-wood-for-the-trees^W-ice dept.
https://www.livescience.com/ancient-rainforest-antarctica.html
About 90 million years ago, West Antarctica was home to a thriving temperate rainforest, according to fossil roots, pollen and spores recently discovered there, a new study finds.
The rainforest's remains were discovered under the ice in a sediment core that a team of international researchers collected from a seabed near Pine Island Glacier in West Antarctica in 2017.
As soon as the team saw the core, they knew they had something unusual. The layer that had formed about 90 million years ago was a different color. Back at the lab, the team put the core into a CT (computed tomography) scanner. The resulting digital image showed a dense network of roots throughout the entire soil layer. The dirt also revealed ancient pollen, spores and the remnants of flowering plants from the Cretaceous period.
The sediment core revealed that during the mid-Cretaceous, West Antarctica had a mild climate, with an annual mean air temperature of about 54 F (12 C), similar to that of Seattle. Summer temperatures were warmer, with an average of 66 F (19 C). In rivers and swamps, the water would have reached up to 68 F (20 C).
"Before our study, the general assumption was that the global carbon dioxide concentration in the Cretaceous was roughly 1,000 ppm [parts per million]," study co-researcher Gerrit Lohmann, a climate modeler at Alfred Wegener Institute, said in the statement. "But in our model-based experiments, it took concentration levels of 1,120 to 1,680 ppm to reach the average temperatures back then in the Antarctic."
https://www.nature.com/articles/s41586-020-2148-5
(Score: 3, Interesting) by Anonymous Coward on Friday April 03 2020, @07:38PM
Deserts are not caused by heat, but by a lack of precipitation. So, for instance, Antarctica is a desert. This [deeptimemaps.com] site has a nice series of time-relative biome maps. Suffice to say, deserts were quite rare. For instance this is why you'll often find a desert on one side or another of a mountain. It ends up creating a sort of trap that prevents moisture from getting onto one side or the other so you end up with weird things like a dessert and lush tropics basically side by side.
High temperatures, high humidity, and high CO2 levels are basically a dream scenario for most plant life. Most of the world looked similar, but greener, hotter, and wetter. Keep in mind this period is when beasts like the Argentinosaurus [wikipedia.org] roamed the Earth. At 100 ton, 130 feet - think about the greenery consumed by a single one of these creatures. 'Clear cutting' a forest? Yeah, that's an afternoon snack. And the dinos thrived for tens of millions of years.