The greenhouse effect helps keep the Earth warm enough for people and other living things to survive. But right now, some scientists worry that if Earth warms up too much, it could cause serious problems for people, animals, and plants. The Impact on the Earth Last month, the United Nations released a report on global warming. The report predicted that if the release of greenhouse gasses is not controlled, Earth's temperature could increase by over 10 degrees Fahrenheit in the next hundred years. Some scientists disagree with this claim, but most believe that Earth's temperature will increase very quickly in the years ahead.
Scientists list different events as signs of global warming.
One event is that some glaciers are now melting faster than before. A glacier is a large mass of ice formed from snow that has fallen over many years. In addition to melting glaciers, the level of Earth's oceans is rising. In the past century, the overall level of the sea has risen about 7 inches. Melting glaciers and higher ocean levels could mean that low-lying areas might flood, which could kill crops and some animal species.