New research into past climates with elevated CO2 concentrations demonstrates the absolute folly of refusing to reduce our greenhouse gas pollution.
A favorite talking point of climate change deniers has been that past CO2 concentrations swung wildly up and down by thousands of ppmV (parts per million by volume). When the concentrations were very high, greenhouse climates were found on Earth. When they were low, ice sheets were able to cover large swaths of the planet.
Like other talking points by the deniers, this one has now been proven to be false. CO2 concentrations did not, in fact, fluctuate by large amounts. It turns out that previously assumed soil CO2 concentrations during carbonate formation (which removes atmospheric CO2, albeit very slowly) were too high. Using more accurate constraints, past greenhouse climates were accompanied by concentrations similar to those projected for the end of this century.
This news is stunning in its implications.