October 2025 Atmospheric CO2 Concentration 424.87 ppm; October 2024 422.38 ppm; October 2023 418.82 ppm
https://gml.noaa.gov/ccgg/trends/https://gml.noaa.gov/webdata/ccgg/trends/co2/co2_mm_mlo.txt
= new reply since forum marked as read
but not much effort is going into reducing it. Makes me wonder how much time we have left. 10 years, 20, 30, 50, 100. No one really knows. 
For example, how long can we keep on emitting greenhouse gases before climate change sets in? We can’t. Climate change started quite some time ago.
OK, how long can we keep on emitting greenhouse gases at the current rate before irreversible effects occur? We can’t. Irreversible effects are already occurring.
If we were to reduce our emissions, that would certainly be a start, but, it is not sufficient, because, CO₂ levels of 350 ppm are likely too high. Despite that, not only are emissions continuing, the rate of emissions is increasing.
If your question is, “How long will humanity survive?” I guess that depends on your definition of “survival.” We believe colonies could survive on the moon and Mars. If they can survive in such harsh environments, they likely could survive on Earth as well (assuming we don’t wipe everybody out in a Nuclear or biological holocaust before climate survival bunkers are built for an extreme minority. — Think the domed city from Logan’s Run.)
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