Man-made reasons: With the development of industry and the massive consumption of fossil energy, the emission of carbon dioxide is increasing year by year, and the greenhouse effect is becoming increasingly obvious.
2. With the increase of population, forests, grasslands and other ecosystems are destroyed, which is the decrease of carbon dioxide consumption, and the balance of oxygen-carbon dioxide circulation in the atmosphere is destroyed, further aggravating the greenhouse effect.
3. With the intensification of the greenhouse effect, glaciers in polar regions and plateaus melt, the reflection effect becomes worse, and more distant energy enters the atmosphere. Since the industrial revolution, human beings have burned a lot of fossil fuels and discharged a lot of carbon dioxide and other greenhouse gases into the atmosphere. In recent years, population explosion is one of the main factors leading to global warming. At the same time, it also seriously threatens the balance between the natural ecological environment. With such a huge population, the annual carbon dioxide emitted by itself will be an amazing number, and the result will directly lead to the continuous increase of carbon dioxide content in the atmosphere, thus directly affecting the climate change on the earth's surface. 2. atmospheric environmental pollution factors at present, the increasingly serious environmental pollution has constituted a major global problem and is also one of the main factors leading to global warming. Now, the research on global climate change has clearly pointed out that the temperature of the earth's surface has started to rise since the end of last century. 3. Deteriorating factors of marine ecological environment At present, sea level changes are on the rise. According to the prediction of relevant experts, the sea level may rise by 50 cm by the middle of the next century. If no measures are taken, it will directly lead to the destruction and pollution of fresh water resources and other adverse consequences. In addition, a large number of toxic chemical wastes and solid wastes produced by land activities are continuously discharged into the sea; Major oil spills in seawater and the destruction of coastal ecological environment by human activities are the main factors leading to the destruction of seawater ecological environment. 4. Improper agricultural production is the main cause of soil erosion and desertification caused by soil erosion, salinization and desertification. As we all know, good vegetation can prevent soil erosion. But so far, it is.
At present, human activities, such as excessive deforestation, land reclamation for agricultural production and overgrazing, are still seriously destroying vegetation. At present, on average, 20 hectares of forests are destroyed, 65,438+00 hectares of land are desertified and 47,000 tons of soil are eroded every minute in the world. Soil erosion reduces soil fertility and water retention, thus reducing soil biological productivity and its ability to maintain productivity; It may also lead to large-scale floods and sandstorms, causing huge economic losses to society and deteriorating the ecological environment. 5. The sharp decline of forest resources is worldwide, and the forest area is decreasing sharply due to natural or man-made factors. 6. The harm of acid rain The impact of acid rain on the ecological environment has attracted more and more attention all over the world. Acid rain will destroy forests, acidify lakes and endanger living things. At present, most of the acid rain in the world is concentrated in Europe and North America, and most of them occur in developed countries and some developing countries. Acid rain is also occurring and developing rapidly. 7. Factors that accelerate the extinction of species Life on the earth is a precious resource for human beings, and the diversity of life is the basis for human survival and development. But at present, the biological species on the earth are disappearing at an unprecedented rate. 8. Water pollution factors According to the water quality monitoring project of the Global Environmental Monitoring System, about 65,438+00% of the monitored rivers in the world are polluted. Since the beginning of this century, the water consumption of human beings is increasing rapidly, and the scale of water pollution is also expanding, forming a contradiction between supply and demand of fresh water. Therefore, the treatment of water pollution will be very urgent and important. 9. Toxic chemicals with increasing toxic waste pollution factors not only pose a serious threat to human survival, but also bring harm to the ecological environment on the earth's surface.
natural cause
1. The world is in a warm period. 2. Periodic orbital changes of the earth. The earth's periodic orbit changes from ellipse to circle, which is closer to the sun. According to a scientist's research, the temperature of the earth has been alternating between high temperature and low temperature, with certain regularity.