419.3 ppm.

Levels of three primary greenhouse gases — carbon dioxide, methane and nitrous oxide — all continued to rise in 2023, according to annual data from NOAA. Global average CO2 reached 419.3 ppm.

I think it's critical we keep the big picture front and center of all our conversations on climate change: Greenhouse gas emissions, which cause the planet to heat up, are still going up.

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Cat Clifford

Senior Science and Economics Correspondent