In March 2015, global CO2 levels reached 400ppm (parts per million).
“The concentration of CO₂, widely seen as the most important greenhouse gas, averaged more than 400 parts per million (ppm) for the entire month of April across the Northern Hemisphere, the first time scientists have seen levels that high and that widespread for an entire month.”
Source: National Geographic
350ppm is the considered the safe upper limit of CO2 in our atmosphere so hitting 400ppm consistently is significant news.
“The number 350 means climate safety: to preserve a livable planet, scientists tell us we must reduce the amount of CO2 in the atmosphere from its current level of 400 parts per million to below 350 ppm.”
If you want to learn more about this and the impact it will have, check out some of the links below.
Find out more
- 400ppm.org – find out why the figure of 400ppm is significant
- 350.org ‘The Science‘ – explains the significance of 350ppm (if you only read one of these links, read this one)
- BBC news – Carbon dioxide passes symbolic mark
- Nasa scientists react to 400ppm carbon milestone
- co2now.org – daily atmospheric CO2 readings