Study On The Carbon Emission Effect Caused By Change Of Global Land Use

Carbon emissions from land use are considered as an essential part of anthropogenic CO₂ emissions with great significance for clarifying the global carbon cycle process by revealing the temporal and spatial evolution pattern and influencing factors.However,the current research on carbon emissions from land use is mostly concentrated on small and medium scales,and there still are only a little studies on global scale.How much is the global carbon emissions from land use?where is it?How to change?These questions attract people’s eyesight and the underlying driving mechanism remains to be explored for its unclear situation.Based on the global land use data from 1992 to 2015 and clarifying its dynamic changes,the method recommended by the IPCC was employed firstly to estimate the carbon emissions caused by global land use changes during this period to reveal its temporal and spatial evolution.Then,the relationship between indirect carbon emissions from land use change and GDP was studied from regions and countries to analyze the influencing factors by Logarithmic Mean Divisia Index（LMDI）method and the Geographic detector model.The results showed that:（1）From 1992 to 2015,vegetation carbon storage showed a decreasing trend due to the increase in forest carbon while soil carbon storage showed an increasing trend owing to the increase of soil carbon in cultivated land and grassland.（2）The total carbon emission change caused by land use change is26.54Pg C,and the change flux is 1.15Pg C yr^-1,the rate of decrease in carbon reserves was 1.2 times the rate of increase.Although the carbon storage of land use increased during the period of 2005-2010,the total carbon storage is still decreasing overall with a net reduction rate of-0.11Pg C yr^-1.（3）From a spatial perspective,the low-value areas of land-use carbon stock changes are mainly concentrated in the northwest of Brazil,the north of Bolivia,the Democratic Republic of Congo,Indonesia,Malaysia,and the southeast coast of China.The high-value areas are mainly distributed in the northwest and southeast of Canada,the east and southeast of South America,Guinea-C?te d’Ivoire-Nigeria-South Sudan;Myanmar,Thailand,Central China,Russia,etc.also have sporadic distribution;（4）Indirect carbon emissions from land use exhibits an upward trend with the total emission of 146,018.80 million tons(6084.12 million tons yr^-1).89 countries and regions are studied in this paper and 54 of them presents an increase of carbon emissions from energy consumption with GDP growth while only 25 countries and regions’GDP growth and carbon emissions decrease.（5）The economic development effect has the largest positive effect on global indirect carbon emissions with the cumulative contribution rate of189.01%.Energy intensity is the main negative effect factor that affects global carbon emissions,which has inhibited the global carbon emissions growth of 4026.09 million tons.Negative effect factors can offset more than60%of the increase in global carbon emissions caused by positive effect factors.By adjusting energy intensity,North America,Europe and CIS countries can completely offset the increase in carbon emissions caused by economic development,and the remaining regions can also offset more than44%.（6）From 1992 to 2015,the top ten countries with total indirect carbon emissions contributed 64.6%of global carbon emissions,and the per capita carbon emissions of countries and regions with high total carbon emissions are not necessarily high.Except for a few countries such as France and Russia,which reduce indirect carbon emissions,the carbon emissions of most other countries and regions are growing.（7）Energy consumption takes more than 95%of carbon emissions and is the main factor that has the greatest impact on national and regional carbon emissions.With the factor interaction,the carbon emissions can be explained more accurately,manifesting in two effects of dual synergy and nonlinear synergy.In addition to the proportion of trade in GDP,the relationship between carbon emissions and other factors are shown as the proportion of countries and regions in synergistic is more important than that of weighed countries and regions,especially the synergy between carbon emissions and energy consumption.The results highlight the importance of land-use change in the carbon cycle process,and offer a certain reference for formulating related energy conservation and emission reduction measures on keeping carbon imbalance and suppressing global warming.