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Our Earth is about one degree warmer than it was 100 years ago. A warmer Earth does a lot of harm to our lives and the environment. On December 7~18 this year,there was a meeting about climate (气候) change in Copenhagen (哥本哈根),Denmark (丹麦). People from 192 countries and areas got together to work out a plan to control global warming.
The Earth could be getting warmer on its own. But people do a lot to make it warmer. Factories and cars give off CO2. It is the major gas that creates the greenhouse effect (温室效应). This causes global warming. People are cutting more and more trees. So there are less trees to absorb (吸收) CO2.
