The reason for the obvious global warming, specifically.

The increase of carbon dioxide, which is similar to the function of greenhouse glass, keeps the earth warm, which leads to the "greenhouse effect".

The so-called greenhouse effect means that the short-wave radiation of the sun can penetrate into the ground through the atmosphere, and the long-wave radiation released after the ground warms is absorbed by substances such as carbon dioxide in the atmosphere, resulting in the effect of atmospheric warming.

El Nino indirectly warms the world. El Nino is a periodic natural phenomenon that occurs once every seven years. This is one aspect of global climate anomaly. In normal years, the Pacific coastal area on the west coast of Peru is controlled by a cold ocean current and has a large area of natural fishing grounds. Once the climate anomaly occurs, the cold ocean current in the eastern Pacific Ocean is replaced by a warm ocean current. Warm ocean currents with a thickness of more than 30 meters cover cold ocean currents. A large number of cold water plankton were destroyed and fled or died, which is the El Ni? o phenomenon. The El Nino phenomenon at the end of 1982 led to an abnormal increase in the temperature in the eastern Pacific near the equator, and the range was getting larger and larger.

The increase of freon emissions leads to the destruction of the ozone layer. Methane, ozone, chlorofluorocarbons and water vapor are other gases that play an important role in the greenhouse effect. With the rapid increase of population and the rapid development of industry, the carbon dioxide discharged into the atmosphere has also increased accordingly. Moreover, due to a large number of deforestation, the carbon dioxide that should be absorbed in the atmosphere is not absorbed, and the greenhouse effect is constantly enhanced because of the gradual increase of carbon dioxide. According to analysis, in the past 200 years, if the concentration of carbon dioxide increases by 25%, the average temperature of the earth will rise by 0.5 degrees Celsius. It is predicted that by the middle of this century, the earth's surface temperature will rise by 1.5-4.5 degrees Celsius, especially in the middle and high latitudes.