Nowadays , with the development of economies around the world may feel that the climate is becoming more and more warmer. CO2 makes up about 70% of the greenhouse gases. There are many reasons for this problem. For example, more and more people are traveling by private cars, which emit a lot of harmful gases, and many factories have polluted the air into the air. And this problem become more and more serious.What's more ,it has bad effect on our environment and our health.So we must do something to avoid these things from happening. First, we should use more and more clean energy and less oil and coal. Second, we should go to work by bus or on foot instead of driving. Third, we should plant more trees. The most important point is we should make a habit of saving energy in everyday life.