Some people think that the global warming isn't a big problem for the humanity, but it's not true. If we don't mind about that problem, we will have a lot of problems more soon.
-The poles will thaw and some coastal towns will be inundated.
-Some animals that aren't accustomed to the high temperatures will die, leaving his depredators without food. - The rainforests will dissapear and all of its plants will die with them, so we won't have the oxygen that we need to breath.
Moreover, we should use more rewable energy, because we are wasting natural resources. Probably in 50 years we won't have energy, so we won't have electricity and other things.
The atmosphere will be too contaminated, so we won't be able to breathe, so the humanity will die. Moreover, the gamma rays that come from the sun will cross the atmosphere because we are destroying it. If we want to live thousands and thousands of years more, we must look after to the environment.