Causes of drought in Yunnan
1. The abnormal atmospheric circulation and global warming aggravated the El Ni? o phenomenon in the Pacific Ocean, and the atmospheric circulation in the Qinghai-Tibet Plateau began to appear obviously abnormal, resulting in the inability of the ocean monsoon to land and the formation of rainfall. The obvious reduction of precipitation in Yunnan will lead to the long-term sustainable development of meteorological drought, which will lead to drought disasters.
2. Special geographical location and complex geological structure. Yunnan is a plateau terrain, located in the tropic of cancer and subtropical high zone, belonging to monsoon climate, and its peripheral water vapor is difficult to transport to Yunnan. In recent ten years, Yunnan has gradually turned into drought.
3. Human factors. People cut down a large number of virgin forests for their own economic interests, leading to land desertification. At the same time, people also planted eucalyptus forests in a large area, which led to the decline of water level, the destruction of forests and the reduction of water conservation capacity.
4. The foundation of water conservancy facilities is weak. In recent years, the construction of hydropower stations in southwest China has destroyed and changed the ecological environment of some river basins, and hydropower stations have high requirements for water resources. Overexploitation of groundwater leads to drought and desertification on the surface, which is also one of the causes of drought.