历史时期中国热带的气候波动与自然灾害

根据沉积、考古、热带动物分布及相关史料得出,中国热带地区历史时期(周代至清代)的气候波动有5个冷期及其间的4个暖期.唐宋以后,自然灾害加剧,其中尤以冷期为甚.中国北方晋至南北朝、南宋、明末的3次人口南迁,对热带地区的人口增长和资源开发有深刻影响.热带地区自然条件相对优越而稳定,自然灾害比北方轻,而且国土开发较晚,经济发展滞后,因而环境状况的变化不如北方剧烈.秦汉时期环境好,唐宋时期环境尚好,明清时期则环境渐趋恶化.

Climate fluctuation and natural disasters during historical periods in tropics of China

Deposit,archeology and distribution of tropical faunae show that there were five cooling stages and four warming stages during the past 3000 years from Zhou Dynasty to Qing Dynasty in the tropical zone of China.The natural disasters were aggravated especially in cooling stages since Tang-Song Dynasty.However the disasters in southern China were slighter than those in northern China during the historical period.The three times of cooling event and disaster of war at that time in northern China led to three times of removal of population southward during Jin-Northern and Southern Dynasties,Southern Song Dynasty and the end of Ming Dynasty.It is an important factor resulting in the increase of population in China's tropical zone.Therefore the land is exploited mainly since Song Dynasty especially during Ming-Qing Dynasties in southern China.It is reported that there were three worsened periods of environmental changes in northern China,the Qin-Han,Tang-Song and Ming-Qing Dynasties.However in the tropical zone of southern China because of the relatively superior and stable natural conditions and the stagnation of resources exploitation and economy devalopment,the environment change was not so obvious and it may be divided into three stages.The first stage was of the best environment in Qin-Han Dynasties when the land was exploited only in the northern mountain area.The second stage is Tang-Song Dynasties with better environment,along with the removal of population the economy centres transferred southward and the constructions of water conservancy devaloped by large numbers.The third stage is Ming-Qing Dynasties,owing to the increase of cultivated land and to destroy forest resulting in aggravation of natural disasters and thus it is the worsened stage of environment in China's tropics.