Some say that (Global Warming) is caused by humans, but what they don't tell you is that we had global warming before. some scientists say that this is just a faze that the earth goes through about every 2 million years and it's going trough it now. We dont know forsue what is causing it but we do know how to slow it. We have to stop polluting the air. Still we have to keep studying the earth to find out the ture answer.