Plants turned atmospheric carbon dioxide into trillions of tons of FOOD!.................
And continue to do so.
And the higher the concentration of CO2 in the atmosphere the more efficient they are at turning CO2 in to food.
The higher the concentration of CO2 in the atmosphere the less water plants need to live and prosper. This means that if there is enough CO2 in the atmosphere that plants can begin to reclaim deserts.
Of course environmental wackos would probably think that is a bad thing because the loss of desert environments would be a change to the ecosystem and stress desert flora and fauna.