[runarberg]

I see, so we are never going to be able to use trees to capture our current current CO2 emissions. However would it be possible to use trees (and other photosynthetic organisms) to capture our historic emissions in a mass global atmospheric cleanup efforts, after we’ve mostly gone carbon neutral? Or is that also like a 1000 year effort even if we became carbon neutral tomorrow?

[jjk166]

If we stopped emmitting CO2 tomorrow, a realistic increase in number of trees (~1 trillion trees) would take about 900 years to return to pre-industrial co2 levels. The more trees you plant, the faster it goes, but even if you cover the entire planet in forest (including places like Antarctica and the Sahara), you're still looking at centuries.

Other organisms can be used as well, but again you need to sequester the carbon.

[runarberg]

Thanks. I appreciate your answers here. This is why I love HN. Getting answers to questions on niche topics I don’t even know how to begin searching for.

[r_hoods_ghost]

Pretty much. I don't have the numbers but the phrase to always bear in mind is "fossil carbon." All that oil, gas and coal was once living bio matter (to a first approximation). Industrial civilisation has been predicated on us burning fossil carbon laid down over millions of years by earths organisms. It will take more than a few decades to remove the excess that we have pumped in, even if we reforest the earth, reduce the population and all become ascetics.