Scientists have found that during ancient warm periods, sea levels vastly increased and rainfall events grew extreme.
https://yaleclimateconnections.org/2019/06/data-from-earths-past-holds-a-warning-for-our-future-under-climate-change/
Our planet’s climate recently achieved a disturbing milestone in history, with atmospheric carbon dioxide levels reaching 415 parts per million (ppm). The last time CO2 levels were so high occurred more than two million years ago during the mid-Pliocene.
Over the years, significant
research has been carried out to reconstruct levels of atmospheric CO2 over geologic time. These reconstructions indicate that during the Miocene (5 – 23.5 million years ago), CO2 levels were around 400 to 500 ppm; during the Oligocene (23.5 – 33.5 million years ago), levels ranged from 500 ppm to 1,000 ppm; and during the mid-to-late Eocene (33.5 – 55 million years ago), levels ranged from 1,000 to 1,600 ppm. CO2 levels declined very slowly from the Eocene to the pre-industrial time period. This slow decline in CO2 is best explained as having occurred because geologic uplifted rock was weathered as a result of increased rainfall, the result of warmer, wetter conditions. That falling rain collected CO2 from the atmosphere and deposited it on rock, where chemical reactions led to the eventual transport of the carbon to the oceans.
Projecting Earth’s future by studying its deep past
Thus, over geologic time, Earth has performed long-term climate experiments with varying levels of atmospheric CO2. By combining geologic, geochemical,
palynological, and paleobotanical data, scientists have created time slices of Earth’s past warm climates. The synthesis of these data clearly indicates a much warmer Earth for past periods – when CO2 concentrations were greater than they were during pre-industrial time.
These past warm climates are radically different from any the human species has experienced. For example, during the
Eocene, crocodiles lived near the Arctic circle and palm trees thrived at high latitudes. The polar regions were much warmer than the mid-latitudes, leading to climate states unable to support large ice sheets. Sea levels were up to 200 feet higher than they are presently, with far fewer large ice sheets. Overall, deep-time geologic
research definitively shows that atmospheric CO2 is a major driver of Earth’s climate.
snip
= new reply since forum marked as read