11 - Concentration of CO2 (ppm)
![](https://memo.climatefresk.org/cards/v9.0/en-GB/default/11-front.jpg)
CO2 measurements have been taken since 1958 in Hawaii, on Big Island, on the flanks of the Mauna Loa volcano. They were initiated by Charles Keeling. In the blue scenario (2°C) they increase until 2040-2050, then they decrease because emissions will have been reduced so much that natural sinks no longer absorb them.
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1Cause
the card n11 represents the concentration in CO2, understood in the atmosphere (it's written behind the card).
1Consequence
You can recognize the molecules of the different GHGs on the card 13 : H2O (red and white), CO2 (grey and red), CH4 (grey and white), nitrious (blue and red).