Stop pumping C02 into the atmosphere and massive reforestation (not directly for binding C02 but to give moisture into the air which gives other plants a chance to grow for them self's and strengthen the ground)...in short, try to reinstate nature as it was, because we little humans cannot do what nature did for millions of years (washing and binding C02 out the atmosphere and into the ground).

The point is on "millions" of years. We really went too far and there is nothing we can do to "revers" it, for the first time in ~100 years humans will have to adapt to nature and not the other way around.