Greenhouse effect is mainly caused by large amount of carbon dioxide in the atmosphere that is released from tail gas and overmuch burning of coal, petroleum and natural gas in modern industrial society. As carbon dioxide can absorb and insulate heat, its increase in the atmosphere will form an intangible glass shield, which prevents the heat radiated from the sun from spreading to the outer space and reflecting infrared ray. As a result, the earth’s surface becomes warmer and warmer. In this way, carbon dioxide is also called the greenhouse gas.

To reduce the superfluous carbon dioxide in the air, people should, on the one hand, save electrical energy (since electricity generation requires burning fossil fuels) and use public transportation whenever possible, and on the other hand, preserve and protect forests and oceans, such as stopping excessive deforestation, keeping the oceans from pollution and protecting the planktons. In addition, it is of importance to afforest actively, reduce the use of disposable chopsticks and paper (paper is made from timber) and protect green plants by keeping off the grass. Green plants could absorb more carbon dioxide to alleviate the greenhouse effect.