How much carbon storage will loss in a desertification area? Multiple policy scenario analysis from Gansu Province

Carbon storage plays a pivotal role in addressing climate change, maintaining ecological equilibrium, and fostering sustainable development. Gansu Province, situated in the arid to semi-arid region of Northwestern China, is confronted with substantial carbon storage losses as a result of ongoing ecological land desertification processes. However, studies on carbon storage loss under various scenarios in desertified regions are seldom reported. In this study, we delineated the ecological red line using quantified indicators encompassing multiple ecosystem service functions and ecological vulnerability sensitivity. Furthermore, we projected future land use and carbon storage transformations under multiple policy scenarios employing the patch-generating land use simulation (PLUS) model. Lastly, we unveiled spatial disparities in the driving factors behind alterations in carbon storage by geographically weighted regression model. Our findings suggest that: (1) The delineated ecological red line covers an area of 11.8 × 10⁴ km², approximately 27 % of the total land area of Gansu Province. (2) Quantitative findings reveal that the overall accuracy of the PLUS model reached an impressive 0.975, accompanied by a Kappa coefficient of 0.964, thus affirming the model's exceptional applicability. (3) Under the base line scenario, Gansu Province's carbon storage witnesses a consistent decline from 2000 to 2050, with a substantial total loss of 1.62 × 10⁷ t over the ensuing three decades. The ecological red line scenario, by controlling 27 % of the land area in Gansu Province, achieves a 61.7 % effect of the global ecological scenario by 2050, thus reversing the declining trend in carbon storage. (4) Natural factors primarily influence carbon storage in the southeastern region, while human activity factors are distributed in the central region. This study offers scientifically robust policy recommendations to facilitate the attainment of carbon neutrality objective.