Andrew Freedman

The amount of carbon dioxide in the Earth’s atmosphere has reached its annual peak, climbing to 419 parts per million (ppm) in May, according to scientists from Scripps Institution of Oceanography and the National Oceanic and Atmospheric Administration (NOAA).

Why it matters: It’s the highest CO2 reading since reliable instrument data began 63 years ago, but evidence shows it’s also a peak since well before the start of human history.

• The rate of increase showed “no discernible impact” from the pandemic-induced economic slowdown, the scientists found.
• Carbon dioxide is a long-lived greenhouse gas emitted through human activities such as fossil-fuel burning, deforestation and agriculture.

Threat level: Not only is CO2 now at its highest levels in human history, but one would have to go all the way back beyond the beginning of human history — to the Pliocene Epoch, between 4.1 to 4.5 million years ago — to find a time when Earth’s atmosphere held a similar amount of carbon. Read more…