Projected land use changes in the Qinghai-Tibet Plateau at the carbon peak and carbon neutrality targets

Based on historical land use for eight periods from 1980 to 2020 and the projected land use under seven Shared Socioeconomic Pathways(SSPs:SSP1-1.9,SSP1-2.6,SSP2-4.5,SSP3-7.0,SSP4-3.4,SSP4-6.0,and SSP5-8.5)from 2021 to 2100,we conducted a study on past and future land use changes in the Qinghai-Tibet Plateau(QTP).This work aims to reveal the land use changes during the carbon peak(2021-2040)and carbon neutrality(2051-2070)periods and at the end of the 21st century(2081-2100).The results show that:(1)in the historical period(1980-2020),the land use types in the QTP were grassland(1475×10^(3)km^(2),58.2%),barren land(685×10^(3)km^(2),27.0%),forest land(243×10^(3)km^(2),9.6%),water(114×10^(3)km^(2),4.5%),cropland(18.6×10^(3)km^(2),0.7%)and urban land(0.3×10^(3)km^(2),0.01%).(2)Relative to the baseline period(1995-2014),the area of grassland is projected to decrease by 0.7%(SSP4-6.0)-5.4%(SSP2-4.5)(0.5-3.9%of the total area of the QTP),2.8%(SSP4-6.0)-12.5%(SSP3-7.0)(2.1-9.4%of the total area of the QTP)and 6.1%(SSP4-6.0)-21.7%(SSP4-3.4)(4.6-16.4%of the total area of the QTP)in the future three periods.In contrast,the forest land area is projected to increase,by approximately 2.5%(SSP4-6.0)to 30.1%(SSP3-7.0)(0.3-4.3%of the total area of the QTP),9.2%(SSP4-6.0)to 56.5%(SSP2-4.5)(1.3-8.0%of the total area of the QTP),and 21.2%(SSP4-6.0)to 72.8%(SSP2-4.5)(3.0-10.2%of the total area of the QTP)in the future three periods,respectively.(3)Approximately 0.4(SSP4-6.0)to 6.9%(SSP5-8.5),0.9(SSP4-6.0)to 2.7%(SSP4-3.4),and 0.04(SSP5-8.5)to 3.5%(SSP1-1.9)of land is expected to convert from grassland to forest land in the future three periods,respectively.The shift from grassland to forest land area is likely to enhance the carbon sink potential of the QTP in the future period.