Analysis Of Temporal And Spatial Changes Of Global Cultivated Land Under The Background Of Global Warming

In this paper,we analyzed the spatial patterns of cultivated land change between1982 and 2011 using global vector-based land use/land cover data,the British Universi-ty of East Anglia Climate Institute(Climatic Research Unit,referred to as CRU)change between1982 and 2011 global temperature data and global elevation data,the use of geo-graphic information system and Matlab analysis tools,analysis of climate warming since1980s under the background,the basic characteristics and the the spatial pattern of culti-vated land changes in the world and a preliminary study to the expansion of high latitude and high altitude area of cultivated land under the background of global warming.(1)Our analysis showed that the a total global cultivated land area increased by528.768×10~4km~2,with an increase rate of 7.920×10~4km~2,although this increasing trend was not significant,The 90s showed no significant growth trend,but in twenty-first Cen-tury it was not significantly reduced.Since 1980s,the cultivated land area in North Amer-ica,South America and Oceania has increased significantly,and the cultivated land area in Asia,Europe and Africa has been decreasing,while Asia is decreasing linearly.(2)Since the 1980s,the increase in global cultivated lands was mainly due to con-verted grasslands and woodlands,which accounted for 53.536%and 26.148%of the total increase,respectively.The increase was found in southern and central Africa,eastern and northern Australia,southeastern South America,central US and Alaska,central Cana-da,western Russia,northern Finland and northern Mongolia.Among them,Botswana in southern Africa experienced an 80%–90%increase,making it the country with the highest increase worldwide.The total area of cultivated lands converted to other types of land was1071.946×10~4km~2.The reduction was mainly converted to grasslands and woodlands,which accounted for 57.482%and 36.000%,respectively.The reduction occurred mainly in southern Sudan in central Africa,southern and central US,southern Russia,and south-ern European countries including Bulgaria,Romania,Serbia and Hungary.The greatest reduction occurred in southern Africa with a 60%reduction.(3)The global land measured annual average temperature showed increasing trend,the increase rate is 0.346?/10a,showed a significant increasing trend;before 1990s,the average global temperature is 8.288?;after the 90s global measured average temperature of 8.811?,the increasing trend is more obvious,which is consistent with the time back-ground of global warming.Space,global warming is widespread,warming area basically all through the 0.05 probability level test was significantly increased,the temperature rise of high value area mainly distributed in the central and northern Canada,Central America and Alaska;east of South America,is located in eastern Brazil and Northern Argentina;Northeast Russia,Mongolia,Pakistan,Iran,northern Afghanistan,Chinese West;most of Europe;North and Central Africa,is located in Sultan,Libya,Egypt,Chad,Niger and Mali;Australia southern region.(4)Global warming is a global cropland line to high latitude and high altitude areas mobile provides heat condition,land distribution is bounded on the north by moving north latitude 3,Europe land is bounded on the north by moving northward 16 latitudes,Asian land is bounded on the North 2 latitudes;At the same time,the cultivated land boundary expanded to high altitude area,and the cultivated land boundaries in different continents increased in different degrees to high latitudes.