
The main cause of what scientists call global warming is pollution and precisely the release of carbon dioxide in the air. what happens is that when CO2 and other polluting gasses are released they collect up in the atmosphere to form a blanket traping the sun's heat and causing the planet to warm up. The two main sources of CO2 pollution are the U.S coal-burning power plants which produce 2,5 billion tons of CO2 every year. Second are automobiles which produce annually 1.5 billion tons of CO2. The U.S however is currently a big issue in the global warming matter since it produces 25% of the world's carbon dioxide.
Reducing the release of pollutant gasses is a big step in stopping global warming from happening, other than that we could use the new technologies available such as enviroment friendly cars (electric cars), also the use of alternative energy source which don't require producing harmful gasses such as solar energy. Many things can be done by every one of us but the main problem is not many people take this matter seriously.
It's not only one who's going to suffer... so think about it !

References:
NRDC