Stop in for a cup of coffee

I watched a docomentary regarding global warming. Evaporation tests from locations all over the planet. There is less evaporation than lets say 30 years ago. The only significant change in evaporation was in three days after 9/11. Due to little to no aircraft in the skies.
Imagine all the burned fuel over our heads every day.
Put a drop of gasoline in a pail and what happens? Same thing,millions of tons of toxins deposited in our atmosphere,daily. It has to affect something, no?