HUMAN IMPACTS ON THE ECOLOGICAL ENVIRONMENT AND MODERN URBAN CLIMATE CHANGE IN THE LOESS PLATEAU

Key words: 
• human activities /
• ecological environment /
• climate change

Abstract: The influence of human activities on environment and climate change is the most conspicuous problem of the Loess Plateau, and it may be divided into two aspects: firstly, the excessive utilization of land by the human race causes the destruction of vegetation, and consequently large expanse of land is under desertification and the characteristics of the ground surface and the water and heat exchange on the ground surface have changed; secondly, the use of coal by industries produces a huge amount of carbon dioxide and trace elements, which enter into the atmosphere to cause air pollution.Data of 1951-1990 are collected from 69 meteorological stations on the Loess Plateau. After analysis, the decadal variations of temperature and rainfall in the last 40 years are obtained as follows: (1) In the arid zone of the north- west of the Loess Plateau, the increase in temperature is the largest. For the past 40 years, the annual mean temperature has increased 0.7-1.0 ℃ . In the semiarid zone of the middle part of the plateau, the annual mean temperature has increased 0.1-0.5℃ , while in the subhumid zone of the southern part, temperature remains almost constant and even has a slight decrease. (2) For the past 40 years, the large and middle-sized cities have the largest temperature increase, especially the new developing cities. (3) For the past 40 years, the rainfall has decreased in the most part of the Loess Plateau.