Assessing Climate Impacts on Karst Vegetation Carbon Sink Change Worldwide

Climate change is the key factor driving the dynamic evolution of terrestrial vegetation carbon sinks, affecting the entire terrestrial carbon balance process. However, the impact and driving mechanisms of climate change on karst vegetation carbon sink evolution under global warming are still unclear, which hinders a deeper understanding of karst ecosystem carbon cycling. The impact of major climate factors on the dynamic evolution of global karst vegetation carbon sinks from 1983 to 2018 was quantitatively evaluated through coupling the methods of multiple linear regression and partial derivative contribution decomposition. Results demonstrated that (a) the net primary productivity (NPP) in the global karst vegetation coverage area (GKVCA) exhibited an overall increasing trend of 0.87 g C m −2 a −1 from 1983 to 2018; (b) for the GKVCA, CO 2 made the largest positive contribution to NPP changes, followed by temperature, while vapor pressure deficit showed the largest negative contribution value, followed by soil moisture; (c) the rapid growth in CO 2 concentration was responsible for increased GKVCA vegetation carbon sinks with a positive contribution of 37.62%, and controlled the NPP changes in 46.53% of NPP growth regions and 44.14% of NPP decrease regions, respectively; and (d) the unexplained variables showed an important impact, contributing 26.65% to NPP increases and −41.51% to NPP decreases, respectively. This study has provided an assessment of the impact of climate factors and other residual impacts on NPP change and offers guidance for the further implementation of vegetation carbon sink management in global karst ecosystems.