Drought is universal, extensive and influential in the world. In the late 1960s, the severe drought in some countries around the Sahara Desert in Africa was the most extensive and serious. In the early 1980s, a severe drought swept through 34 countries, and nearly 1 100 million people were threatened by hunger. In addition, China is also one of the countries with severe drought.

According to historical records, there are frequent droughts in China. Historical books, local chronicles, court archives, inscriptions, inscriptions and other cultural relics. From 206 BC to 1949 BC, there were 1056 droughts in China. From16th century to19th century, severe droughts affecting more than 200 counties occurred in 1640, 167 1, 1679,172/kloc-. 1640 (that is, the thirteenth year of Chongzhen in Ming Dynasty), the drought lasted for 4 ~ 6 years in different areas, and in the dry areas, "bark was eaten up and people ate people"; 1785 (that is, 50 years of Qianlong), 13 provinces suffered from drought. According to records, "the grass roots and bark are exhausted, the refugees carry the road, the hungry are wild, and the dead sleep"; 1835 (that is, the 15th year of Qing Daoguang), 15, the drought in the province, there is a record that "people ate Guanyin powder and many people died". Since the 20th century, severe droughts have occurred in Shaanxi, Henan, Hebei, Shandong and Shanxi provinces from 65438 to 0920, affecting 20 million people and killing 500,000 people. 1928, 535 counties in North China, Northwest China and Southwest China 13 provinces suffered from drought; During the drought from 1942 to 1943, millions of people died of hunger and disease in Henan province alone.

From 1950 to 1986, the average annual drought-affected area in China reached 300 million mu, resulting in disasters11million mu. The drought-affected areas of 1959, 1960,19, 1972, 1978, 1986 all exceeded 450 million mu, and the affected area exceeded/. During the period of 1972, there was little rain in the north, and drought occurred in spring and summer, which caused serious disasters. The drought-affected area in some parts of southern China is 460 million mu, causing 200 million mu of disasters. During the period of 1978, the drought in China was extensive, lasting for a long time and serious. In some provinces, the precipitation from June 1 day to June 1 day is 3% ~ 70% less than normal, and the drought in the middle and lower reaches of the Yangtze River is the most serious, with an area of 600 million mu and an area of 270 million mu. From a historical point of view, this is the highest value since statistics.