Warmer climates will cause changes in the movement of air, and also mean more lightning strikes - but if I remember my High School biology, isnt lightning strikes the main way nitrates are formed in soil?
Atmospheric nitrogen fixation (lightning) probably contributes some 5– 8% of the total nitrogen fixed.
Fortunately we can add the plant growth benefits of increased CO2.
Add to that the increased benefit of holding off the next ice age and we have a triple winner.