Study On Natural Land Cover Change And Potential Carbon Sequestration In China

Climate change has always been a topic of concern to governments,the public and scientific researchers around the world.It is also a matter of concern to human production and life.Global warming is one of the main problems of climate change,which will directly affect the natural and artificial ecosystems.More than half of the global surface temperature rise during 1951—2010.Thisis caused by an increase in anthropogenic increases in greenhouse gases caused by anthropogenic increases.Fossil fuel combustion results in greenhouse gas emissions due to the rich data source and easy to calculate the induction.In 2010,anthropogenic greenhouse gas emissions reached 49.5 Pg CO₂/yr(1Pg=10¹⁵g),and CO₂ emissions from fossil fuel combustion and industrial processes accounted for 78%of total emissions^[1].However,the greenhouse gas?GHG?emissions data,especially the natural GHG emissions data caused by the spatial and temporal changes of ecosystems are still lacking due to the complexity of data collection and computing.Terrestrial ecosystems are the most visible and fragile ecosystems affected by human activities,and unreasonable human activities have an impact on land use and land cover types on land,thus affecting greenhouse gas emissions from terrestrial ecosystems.China is mainly located in the northern Asia-Europe continent,facing the Northwest Pacific.Its complex natural elements formed the complex variety of terrestrial ecosystems.And our economy has been experiencinga fast development stage;human activities inevitably affect the terrestrial ecosystem.Under the background of climate change,how to evaluate these activities caused by land use and land cover type changes caused by both climate and human effects has a strong theoretical and practical significance.Basedon the literatures of domestic and foreign literature,this paper introduced the GHGV?green-house gas value of ecosystems?model^[2],quantified the GHG volume of each natural ecosystem,and carried out the key parameter localization of the model.After the relevant parameters of the domestic ecosystems were collected and collated,the results were compared with those of the similar ecosystems in the world.The localized parameters were brought into the model to obtain several important simulation results:the potential greenhouse gas emission of the ecosystem Sx,The net greenhouse gas emissions Ix and the greenhouse gas GHGV of the ecosystem and the atmosphere,and the above three parameters were compared with the results of the similar ecosystems in the world.Furthermore,the temporal and spatial changes of Land-Use and Land-Cover Change?LUCC?in China during the corresponding period were analyzed by superimposing the land cover data of China in 2000 and 2010.Finally,the carbon fixation potential of natural ecosystem change from 2000 to 2010 was evaluated by means of model.The main conclusions are as follows:?1?From 2000 to 2010,the types of natural land cover in China changed greatly,and the area of mixed forest,shrub and desert increased,and the area ofmixed forest increased by 7666 km².The area of desert forest and grassland is lower than that of desert grassland,and the area of desert grassland is reduced to8413 km².The main land source of the mixed forest in China is the conversion of grassland and other ecosystem types,evergreen coniferous forest and mixed forest.The conversion between grassland and desert grassland is relatively large.?2?The results of localization of biomass density and gas flux parameters in China were different from those of similar ecosystems in the world.The results of model operation are different from those of the similar ecosystems in the world.The GHGV of the temperate forest land in the world is more than1632Mg CO₂ equivalent/ha,and the GHGV of temperate forest land in China is lower than 848Mg CO₂equivalent/ha.Nevertheless,considering the time span,the results of the changes in the operation is close,GHGV model can be applied to the local situation in China.?3?The total growth of forest carbon fixation potential in China from 2000 to 2010 was about 0.32Pg CO₂equivalent,the growth rate was 0.009Pg C/yr,and the annual variation of GHGV in Chinese shrub and grassland was 0.0018Pg CO₂ equivalent/yr and-0.026Pg CO₂ equivalent/yr.The change of carbon fixation potential caused by land cover change GHG_LUCC is about-0.19Pg CO₂ equivalent,the rate of change is-0.005Pg C equivalent/yr,and the results of this study are in reasonable range after comparison with other scholars'research results.China's GHGV_LUCC value from 2000 to 2010 indicating that the change of land cover in China will increase the carbon fixation potential of terrestrial ecosystem in China,and accordingly,from the point of view of absorption,it means that the ecosystem type represents of the amount of greenhouse gases that can be accommodated also increases,which has a positive effect on the suppression of climate warming.