CO2 now comparable to levels seen 4 million years ago: NOAA

CO2 Past

CO2 Now

Atmospheric CO2 levels accelerate upwards, smashing records

USA

Climate Milestone: Earth's CO2 Level Passes 400 ppm

Atmospheric carbon dioxide levels at 4-million-year high; El Nino could boost numbers in 2023, WMO says

Atmospheric Carbon Dioxide Growth Rate

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