Research On The Relationship Between The Territory Change Of The Mongol Empire And Climate Change In The 13th Century

The territorial changes of the Mongol Empire in the 13 th century had a significant and far-reaching impact on China and the countries of Asia and Europe at that time.From the establishment of the Mongolian Khanate in 1206 by Genghis Khan to the establishment of the Yuan Dynasty by Kublai Khan in 1271,in less than70 years,its territory has occupied most of the Eurasian continent.With the conquest war,the territory of the Mongolian empire expanded from the Mongolian steppe area where the nation was originally founded to the territory of the four khanates of Mongol Empire.With Kublai Khan established the territory of the Yuan Dynasty added by the Yuan Dynasty,the territory thus covers most of the Eurasian continent.However,from the initial development to the conquering of the Eurasian countries,the Mongol Empire suddenly fell into a huge crisis around 1260 after more than 60 years.After an internal war,it eventually split into the Golden Horde,Wokotai Khanate,and Chagatai Khanate,Ilkhanate and Yuan Dynasty.Most historians analyze the reasons for its expansion and division from the political perspective,but there are other historical climatologists who believe that climate change also plays an important role in it,and this important factor is often ignored by traditional historians.The IPCC Fifth Assessment Report(AR5)believes that the Medieval Warm Period,also known as the Medieval Climate Abnormal Period(MCA,950-1259 A.D.)and the Little Ice Age(1450-1850 A.D),have high credibility,but There are regional and temporal differences across the globe.Due to the low level of productivity in the historical period,the impact of climate change on human civilization at that time was much stronger than that of modern society.It happened that the period of the Mongol Empire was located between the Medieval Warm Period and the Little Ice Age.Various historical records and reconstruction data indicated that the climate change between the Medieval Warm Period and the Little Ice Age was quite variable.Therefore,some scholars inferred that climate change would affect Mongolia.The rapid expansion and division of the empire in a short period of time had an impact.However,different scholars have disagreements on the tendency of temperature change at that time to increase or decrease,and they also have certain disagreements on the change of precipitation at that time.Of course,these views are based on the fact that climate change does have an impact on the changes in the territory of the Mongol Empire.Therefore,to reproduce the climate change during the Mongol Empire period and analyze the relationship between the boundary changes of the Mongol Empire and climate change in the 13 th century is a question worthy of discussion.Based on various historical materials such as " Historical Atlas of China" and "Atlas of Chinese War History",this article uses GIS to draw the space-time distribution of wars in the four periods of the Mongol Empire in the 13 th century,and prepares the territory distribution of the regimes in each period.Figure;Based on the temperature proxy data and instrumental data,the grid weighting method and the unary linear regression method are used to establish the temperature and precipitation changes in the Mongolian Plateau in the 13 th century,as well as the temperature anomaly change curves and the distribution of the cold and warm periods of other regimes in the Chinese region.Figure;Finally,the relationship between warm and humid climate and cold and dry climate and territorial changes is analyzed through correlation analysis method,trend analysis method and other methods.Concluded as follow:(1)This article divides the Mongol Empire into the Genghis Khan period(1206-1226),the Wokuotai period(1227-1241),the Mongko khan period(1251-1259),and the Kublai and the four khanates of Mongol Empire periods.Based on historical atlases and historical records,GIS software was used to correct and draw the maps of the regimes of the Mongolian Empire in 1206,1227,1241,1259 and 1279.(2)During these four periods,the Mongol Empire fought 8 large-scale foreign wars(not counting the Mongol-Song wars),summarizing more than 240 large and medium-sized cities that were attacked and occupied by the Mongol army during the march.The location,use GIS to obtain the coordinates of its current location,and then use Arc GIS software to generate a spatio-temporal distribution map of the Mongolian army marching trajectory in each war.(3)Using the research zoning method,the temperature change is divided into 7regions including the Mongolian Plateau.The grid weighting method is used to obtain the 13 th century temperature change sequence of these 7 regions.The results show that the temperature in these 7 regions was fluctuating and rising in the early and mid-13 th century,and all regions experienced different degrees of cooling around1250 to 1260.Secondly,during this period,the temperature in the Mongolian grasslands in the high latitudes changed greatly,and the average annual temperature in the low latitudes was relatively small.Then,the annual temperature changes in various regions mostly followed the fluctuations,which was in line with the trend of the Middle Ages to the Little Ice Age.Finally,the unitary linear regression equation is used to analyze the temperature change trends of the seven regions by stages,and it is concluded that the regions in each region in this century follow the law of interdecadal cold and warm periods,which is consistent with the change trend of the cold and warm periods on the centennial scale of the historical period.(4)The analysis shows that the warm and humid climate has two influence paths on the changes in the territory of the Mongol Empire.One is the dynamic influence:warm and humid climate-grassland productivity-increase in the number of livestock-dramatic increase in population-increase in military strength-external expansion-changes in territory;It is attraction: warm and humid climate-zonal traction-zonal military strategy-marching direction-occupation of the city-territory change.(5)The analysis shows that the cold and dry climate has two influence paths on the changes in the territory of the Mongolian Empire.The first is the cold and dry climate of the grassland-the decline of grassland productivity-the insufficient supply of the army-the cold and dry climate of the same latitude-the lack of war attractiveness-the change of the direction of entry-the territory The direction of change has changed;the second is the cold and dry climate-internal war supplies to the belligerents-military strength-war victory or defeat-the independence of the four khanates-territorial changes.