We have also filled the global ecosystem with a massive amounts of a plethora of artificial chemicals that have never existed in nature and which we don't know how they will interact long-term with life and other systems...especially the persistent ones that nature does not have a way of breaking down easily.
Not the P-T "Great Dying," but another mass extinction we can gain some insights from for our current catastrophe--Two pieces on the PETM
History suggests impacts of global warming are being underestimated
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Beginning 56 million years ago, during the Palaeocene-Eocene Thermal Maximum — a period between the Palaeocene and Eocene epochs, lasting 10,000 to 20,000 years — temperatures rose between 5 and 8 degrees Celsius.
Using the analysis of ancient sediment cores, scientists analyzed the effects of this dramatic rise in temperature on hydrologic cycles.
Previous studies have charted the rise in temperature during Palaeocene-Eocene Thermal Maximum, or PETM. Castelltort and his colleagues analyzed evidence of shifting river dynamics in the Spanish Pyrenees during the same time period.
The analysis of pebbles in ancient sediment cores allowed researchers to estimate the flow velocity and discharge in the river system. At the beginning the of the PETM, river channels deposited fertile alluvium in the floodplain at the foothills of the Pyrenees. The deposits encouraged the growth of rich vegetation.
As temperature rose during the PETM, the system’s dynamics shifted dramatically. Rising temperatures increased the severity and frequency of flooding by a factor of 14. The sudden change caused fertile alluvium to be carried directly to the ocean, bypassing the floodplain.
As a result of the change in sediment deposition patterns, vegetation disappeared from the Pyrenees foothills. The region was transformed into an arid expanse of gravel.
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“We face effects that we do not understand, which can perhaps be explained by local factors, but also by global factors that are not yet incorporated into current climate models,” Castelltort said.
see:
https://www.upi.com/Science_News/2018/0 ... 536238447/While in the seas:
Shining light on ancient global warming
The impact of global warming on shallow marine life approximately 56 million years ago is the subject of a significant, new article. Researchers have now addressed the effects of the Paleocene-Eocene Thermal Maximum (PETM) — a relatively brief period of global climate change, spanning 200,000 years — on marine invertebrates, including snails, clams and other mollusks.
Which begs the question: What implications do these results hold for the present and future response of shallow marine biota to ongoing global change? Ivany chooses her words carefully, explaining that the carbon dioxide release during the PETM occurred over thousands of years. Compare that to putting the same amount of carbon dioxide into the atmosphere from only a few hundred years of human activity.”
Whatever happened during the PETM was a “best-case scenario” for marine invertebrates, Ivany explains. “With everything happening so much faster now, it is more likely organisms will go extinct,” she adds. “When the environment changes, you must move, evolve or die. If it changes faster than you can move or evolve, you’re toast.”https://www.sciencedaily.com/releases/2 ... 142055.htmThanks to Kassy at rscribbler's sit for these