It doesn't need to be a lot younger or a lot fewer. The effect will almost certainly be virtually undetectable, especially when compared to many other evolutio

It doesn't need to be a lot younger or a lot fewer. The effect will almost certainly be virtually undetectable, especially when compared to many other evolutionary forces (e.g., diet, particulates in air, lack of exercise, social policies, etc.). If you want to improve global quality of life, CO2 levels are almost certainly not the right place to start.