The reason for the changes in Earth's temperature is due to human activities. In the process of human use of fossil fuel coal, in certain industrial production processes, during the fermentation of organic waste, gases such as carbon dioxide, methane, and nitrogen oxides are continuously released. These gases have the function of preventing the release of heat from the Earth's surface, and their existence is like forming a huge greenhouse on the Earth's surface. Therefore, these gases are collectively referred to as greenhouse gases. Currently, controlling greenhouse gas emissions has become one of the world's hotspots.

　　The culprit of ozone layer destruction is actually humans. In recent decades, chlorofluorocarbons and halons have been widely used as refrigerants, deodorants, sprays, etc. These chemicals will react with ozone and decompose ozone into oxygen after being released into the atmosphere and diffused into the ozone layer.

　　With the progress of science and technology and the development of industrial construction, human destruction of animals and plants is increasing day by day. Statistics show that 4000 to 6000 species of organisms are currently disappearing from Earth every year, and more species are under threat. The 1996 report of the World Association for the Protection of Animals and Plants pointed out that "one quarter of mammals on the earth are in danger of extinction, and 10 million hectares of Tropical forest are destroyed every year". The rate of biodiversity destruction in China is also very alarming.

　　Gases such as sulfur dioxide and nitrogen oxides are mainly emitted during energy use. The higher the level of human production and consumption, the more energy is consumed, and the greater the harm of acid rain. There are three famous acid rain areas in the world, one is in the Great Lakes region of North America, one is in northern Europe, and the other is in China. In the past decade or so, China's acid rain areas have been continuously expanding, with the current area of acid rain areas approaching one-third of the national territory. Its control has been included in the national green engineering plan.

　　Due to excessive logging and improper cultivation by humans, coupled with forest fires caused by climate change, the world's forest area is constantly decreasing. According to statistics, the forest area has decreased by 30% in the past 50 years, and its sharp decline trend has not diminished to this day. China's forest coverage area is only 9%, about one-third of the world's average forest coverage area, but the momentum of forest sharp decline is not inferior.

　　Excessive grazing and reuse of light farming have led to the gradual degradation of grasslands. Construction activities such as land reclamation, mining, and road construction have a significant destructive effect on the land, coupled with continuous erosion of soil and water loss, causing large areas of land in the world to become deserts every day. China is particularly prominent in this regard. The direct consequence of land desertification is the impoverishment of farmers.

　　At present, about one-third of the global population has been threatened by water scarcity, and in 2000, the number of people lacking water increased to over one-third. The per capita share of water resources in China is only 1/4 of the world's per capita share, and coupled with the uneven distribution of water resources in time and space, the contradiction of water resource shortage is very prominent.

　　The increasing amount of sewage and wastewater produced by population expansion and industrial development has finally exceeded the tolerance limit of natural water bodies. As a result, originally clear water bodies turn black and foul, bacteria breed, fish die, algae grow rapidly, and more seriously, water that is already sufficient to nourish the human body often contains toxic substances that can cause diseases and even death.

　　The most common air pollution is caused by the dust generated during the coal combustion process, where small suspended particles are inhaled into the human body and can easily cause respiratory diseases; There is also Summer smog in modern cities, which is due to a large number of chemical substances, such as hydrocarbons, hydroxides, carbon monoxide, etc., carried in industrial exhaust and automobile exhaust.

　　Solid waste, including urban garbage and industrial solid waste, is increasing with the growth of population and industrial development, and has become a major disaster on Earth, especially in cities. Garbage contains various harmful substances, and arbitrary stacking not only occupies land, but also pollutes the surrounding air, water bodies, and even groundwater. Some industrial waste contains toxic and harmful substances such as flammable, explosive, toxic, pathogenic, and radioactive substances, which pose even more serious hazards.