400 PPM CO2 Milestone
The last time CO2 was this high, humans didn’t exist. For the first time in human history, the concentration of climate-warming carbon dioxide in the atmosphere has passed the milestone level of 400 parts per million (ppm). The last time so much greenhouse gas was in the air was several million years ago, when the Arctic was ice-free, savannah spread across the Sahara desert and sea level was up to 40 metres higher than today.
NASA scientists react to 400 ppm carbon milestone “Passing the 400 mark reminds me that we are on an inexorable march to 450 ppm and much higher levels. These were the targets for ‘stabilization’ suggested not too long ago. The world is quickening the rate of accumulation of CO2, and has shown no signs of slowing this down. It should be a psychological tripwire for everyone.” – Dr. Michael Gunson
About the Author: CLIMATE STATE

POPULAR
RECENT COMMENTS
- Joe on The exponential growth of global sea level rise
- Glenn Rosendahl on Study: U.S. Bitcoin Mining and Energy consumption mostly powered by Fossil Fuels
- Damien Watson on Study: U.S. Bitcoin Mining and Energy consumption mostly powered by Fossil Fuels
- CLIMATE STATE on Study: Earth’s strongest ocean current is slowed by melting Antarctic ice
- Bob Bingham on Study: Earth’s strongest ocean current is slowed by melting Antarctic ice