Global climate warming is a truth in 20 century. The middle latitude area is sensitive to the climate change. Shaanxi-Gansu-Ningxia border area is in the middle latitude area, including Yulin district and Yan'an district in Shannxi province, Xihaigu district in Ningxia province, Qingyang district in Gansu province. There is 13.8×104 km2 and 1 002×104 population. The density of population there is 73 km2, much more higher than that of the limit in similar area by the United Nations which is 20 km2. Shaanxi-Gansu-Ningxia border area is the hill and gully area in the middle of Loss Plateau where the climate is changeful and the soil erosion is the most serious and the ecological environment is the most fragile.
Based on the atmospheric temperature and precipitation records of the Shaanxi-Gansu-Ningxia border area from 1951 to 2000,made an on-the-spot investigation. Analyzed the temperature, precipitation and surface runoff records, reach the conclusion that the characteristics of climate change in the Shaanxi-Gansu-Ningxia border area is becoming warmer and drier.
The linear tendency of warming is 0.194℃/10a,higher than that of the global(0.05℃/10a) and lower than other place's in China. The maximum linear tendency of warming in Shaanxi-Gansu-Ningxia border area is 0.87℃/10a in Dingbian country, it’s far higher than that of the Sanjiang plain which is the maximum in China. The lowest linear tendency of warming in Shaanxi-Gansu-Ningxia border area is 0.0778℃/10a in Jingyuan country. The average value of linear tendency of warming in Shaanxi-Gansu-Ningxia border area is 0.194℃/10a.
Shaanxi-Gansu-Ningxia border area is warming and drying displayed in two aspect, one is the diminution in precipitation, the other is reduction in surface runoff. The linear tendency of annual rainfall is different with district and the mean linear tendency of annual rainfall is -1.0759mm/a. In 50 years, the annual precipitation reduced 54 mm. The surface runoff reduced at the rate of 0.4844 m3/a from 1956 to 2000.
The ecological environment in Shaanxi-Gansu-Ningxia border area is going aggravating under the change of climate. The main aggravation of ecological environment represented by ecological deficient of water resource, soil erosion intensify and extension of desertification.