What human industry has done since 1990, pumping a
trillion tons of CO2 into the air, has no precedent. Never before in Earth’s history has so much carbon dioxide been added to the atmosphere over such a short period of time.
It's not smart to mess with Mother Nature. And we're just beginning to see the consequences of our foolishness.
The last time levels of atmospheric carbon dioxide were as high as they are today, Greenland was free of ice and the savanna and grassland ecosystems where humans evolved didn’t exist yet.
That’s the conclusion of a study which researchers say compiles “the most reliable data available to date” on atmospheric carbon dioxide levels over the last 66 million years.
The new study represents the scientific consensus on the carbon dioxide record, and it concludes that the last time carbon dioxide levels were around 419 ppm was 14 million years ago. That’s much earlier than previous estimates of 3 to 5 million years ago.
By burning fossil fuels and clearing natural carbon sinks like forests, industrial capitalism has raised global carbon dioxide levels to 419 parts per million today, from around 280 ppm at the beginning of the industrial revolution.
"Our record shows that we have to go back 14 million years to find levels as high as we have today. At that time not only did humans not exist, but the grassland and savanna environments in which we evolved didn't exist," said University of Utah geologist Gabe Bowen.
“We’ve already pushed the atmosphere way beyond anything we’ve seen as a species,” Bowen added, “and if it stays this way we’re in for big changes in the environment we live in.”
Even today’s concentrations are bound to have lasting consequences. For example, when carbon dioxide levels rapidly increased around 56 million years ago, it significantly altered ecosystems and took around 150,000 years to decrease again.
If policy-makers don’t restrict the burning of fossil fuels, atmospheric carbon dioxide could reach 600 to 800 ppm by the end of the century. The last time levels were that high was 30 to 40 million years ago, when Antarctica was ice-free and the Earth was home to giant insects.
https://countercurrents.org/2023/12/co2-now-at-levels-not-seen-in-14-million-years/#
climatechange
