> Concentrations of CO2 in the atmosphere were as high as 4,000 ppm during the Cambrian period about 500 million years ago, and as low as 180 ppm during the Quaternary glaciation of the last two million years.
So a range of 0.018% to 0.4% over the last 500 million years. We’re currently at ~420ppm, and human impact is estimated to have been about +140ppm since the 1700s where we had been at 280ppm for the ~10,000 years prior.
If the planet ever hit 0.4% again it would be due to natural not anthropogenic reasons.
So a range of 0.018% to 0.4% over the last 500 million years. We’re currently at ~420ppm, and human impact is estimated to have been about +140ppm since the 1700s where we had been at 280ppm for the ~10,000 years prior.
If the planet ever hit 0.4% again it would be due to natural not anthropogenic reasons.