Extreme weather occurs frequently. What caused it?

El Nino phenomenon, due to the abnormal rise of seawater temperature, leads to the increase of atmospheric temperature over the ocean, which destroys the dynamic balance of the original normal distribution of heat and water vapor in the atmospheric circulation and causes many disasters. This seasonal increase in seawater temperature is called El Ni? o (El Ni? o is Spanish transliteration, meaning El Ni? o). In addition, with the development of industrial and agricultural production, the degree and scale of human exploitation of natural resources are also developing. When human economic activities violate the laws of nature, it will inevitably lead to nature's revenge. Some mudslides are caused by unreasonable human development. In recent years, there are more and more mudslides induced by human factors. Several aspects of human engineering economic activities may induce mudslides. 1. Unreasonable excavation: unreasonable excavation for the construction of railway, highway, canal and other engineering buildings. Some mudslides are caused by the destruction of hillside surfaces in the construction of roads, canals, railways and other construction activities. For example, in Laogangou of Dongchuan-Kunming Highway in Yunnan Province, the mountain was destroyed due to road construction and canal repair, and the landslide caused by the 1966 rhinoceros mountain earthquake made the debris flow more serious. For example, many large-scale projects and ground buildings have been built in Hong Kong over the years, and almost every project has to be cut off from reclamation or filling in order to obtain a suitable site. 1972 a rainstorm killed 20 people at the excavation site under construction 120. 2. Unreasonable spoil, spoil and quarrying: = There are many examples of debris flow caused by this behavior. For example, in Hanluogou, Lugu Iron Mine, Mianning County, Sichuan Province, due to unreasonable waste of soil and slag, heavy rain occurred at 1972, which washed away loose solid materials about 10000 cubic meters, buried chengdu-kunming railway 300 meters and (Germany)-Xi (Chang) highway 250 meters, interrupted traffic and brought serious losses to transportation. Another example is that near Xishui of Ganchuan Highway, stones were mined in ditches along 1973 winter highway, and in July1974, mudslides occurred, blocking 15 bridges and culverts. 3. Deforestation: Deforestation will make the vegetation disappear, the hillside lose protection, the soil is loose, and gullies develop, which will greatly aggravate the soil erosion, and then destroy the stability of the hillside, resulting in adverse geological phenomena such as collapse and landslide, which is easy to cause mudslides. For example, the middle reaches of Bailong River in Gansu Province is now a famous debris flow-prone area in China. 1000 years ago, there were dense bamboo forests and beautiful scenery here. Later, because of logging and burning charcoal, burning mountains for land reclamation, deforestation and mudslides flooded. Another example is Da 'ertou on Shiaozigou Mountain of Ganchuan Highway, which used to be a forest area. Due to deforestation, a mudslide occurred in 1976, which washed away downstream villages and highways and caused serious losses to people's lives and property. The local people said: "There is a lack of acres on the mountain, and there are lights under the mountain." In addition, the crustal movement of the lithosphere under the action of internal force causes the fracture and displacement of the stratum, which makes the internal energy of the earth strongly released in the form of seismic waves, triggering earthquakes and loosening mountains, which is also an important reason.