Within 35,000 years, the plant cycle removes the last traces of lead left by the Industrial Revolution from Earth's soil, and it may take up to 65,000 years beyond that for CO2 to return pre-human levels.

三万五千年年以内，植物循环将从地球土壤中清除工业革命留下的铅的最后痕迹，而二氧化碳可能需要六万五千年才能恢复到人类出现之前的水平。