It is sad that the title must include the date because it is very likely that we’ll exceed this record of 417.2 ppm, too, and too soon. The good news is a side effect of the pandemic’s bad news: emissions are down about 17%. That at least shows we can still control emissions. Unfortunately,
“If humans were to suddenly stop emitting CO2, it would take thousands of years for our CO2 emissions so far to be absorbed into the deep ocean and atmospheric CO2 to return to pre-industrial levels.” – NOAA
At some point, possibly behind us, we may energize feedback cycles that won’t be stopped by our actions. Nature doesn’t do U-turns very easily. Thawing permafrost, disrupted environments, loss of polar ice, the exposure of previously glaciated land as well as other systems require time to recover. Their cumulative effect may be self-sustaining, or enough to delay the recovery even if we stopped putting more CO2 into the atmosphere. We haven’t stopped putting CO2 into the atmosphere, so the trends are expected to continue. This record is likely to fall.