What is the difference between chemcal and environmental engineering?

Since I'm very interested in trying to find a solution to resolve global warming (by acting on the pollutants in the atmosphere), but I also wish to preserve the natural environment, I would like to know whether it would be more useful for me to study environmental or chemical engineering.The problem is I don't really understand the difference between these two professional figures when they have to confront with environmental matters and projects.
I wish to thank you for your answer beforehand
posted by Isabel, Bogotà on August 8, 2014