Estimation of terrestrial ecosystem carbon sinks and identification of carbon sink conservation areas under future climate change scenarios: A case study of Zhejiang province

Abstract

Enhancing the carbon sequestration capabilities of terrestrial ecosystems by optimizing territorial spatial layout is a feasible approach to achieving the "carbon neutrality" goals. However, accurately identifying and characterizing the spatial differentiation of terrestrial ecosystem carbon sinks on a regional scale remains a challenge. As a result, effective territorial spatial management measures have yet to be established. To address this issue, this study uses Zhejiang province as an example, employing the Integrated Biosphere Simulator (IBIS) to simulate terrestrial ecosystem carbon sinks at 1-km grid resolution. Based on simulation results under different future climate change scenarios, we identify and delineate carbon sink conservation areas with adaptive features in response to climate change. The analysis results show that terrestrial ecosystems within carbon sink conservation areas exhibit a significant carbon sequestration advantage. Within these areas, the average Net Ecosystem Productivity (NEP) per unit area of forests, shrubs, and grasslands exceeds approximately 15%, 10%, and 5%, respectively. Under medium to high social vulnerability and radiative forcing scenarios, the carbon sequestration advantage of the terrestrial ecosystems within carbon sink conservation areas is further amplified. Additionally, by contrasting the carbon sink conservation areas with the existing Ecological Conservation Redline (ECR) in the study region, it is discovered that more than half of the areas have not yet been incorporated into the ECR. In comparison to the ECR, it is estimated that the total Net Ecosystem Productivity (NEP) within the carbon sink conservation areas is over 7 MtC annually, with the average carbon sequestration efficiency of forested regions surpassing the ECR by 15-22 g C/m2. This study underscores the importance and necessity of integrating and enhancing the consideration of ecosystem carbon sink function in optimizing territorial spatial patterns and existing ECR systems from a quantitative standpoint. Furthermore, we put forward corresponding policy recommendations.