地 址：北京市朝阳区德胜门外祁家豁子华严里40号 竺南中心
Past to future drylands in China[2023-05-31]
Global warming has continued since the Industrial Revolution. Simultaneously, the global hydrological cycle has accelerated, the frequency of extreme weather and climate events, such as drought, has increased. The expansion of drylands and the intensification of aridification can inhibit agricultural development and endanger food security. Thus, it is necessary to fully understand dryland changes with various climate backgrounds and the underlying reasons. However, the instrumental data are relatively limited. With the acceleration of global warming, the future climate will be bound to exceed the extreme value of current instrumental data. Therefore, we need to analyze paleoclimate changes at longer time scales, particularly for periods when the climate change compared to the present was as large as the anticipated future change, to improve our understanding of future climate change and the credibility of future projections.
In this study, we investigate the aridity changes in China and the associated mechanisms during the last interglacial (LIG; the most recent warm period at approximately 127 ka BP), last glacial maximum (LGM; the recent period of the maximum extent of the ice sheet at approximately 21 ka BP), and mid-Holocene (MH; the latest interglacial period at approximately 6 ka BP), as well as the three future scenarios of the shared socioeconomic pathways of SSP1-2.6, SSP2-4.5, and SSP5-8.5 through aridity index (AI; a ratio between annual precipitation and potential evapotranspiration) by using CMIP6 multi-model simulations. The results show that relative to the preindustrial period, the total dryland area in China varies by −15%, 6%, and −13% during the LIG, LGM, and MH, respectively, and slightly varies in the three future scenarios. Over China, LGM dryland expansion and future dryland contraction are mainly attributed to precipitation changes, MH dryland contraction is mainly caused by PET changes, and LIG dryland contraction is comparably caused by PET and precipitation changes. Regarding the LGM and three future scenarios, temperature is the leading factor of PET changes, while during the MH and LIG, the change in relative humidity is the main factor. The simulated aridity changes in China are generally consistent with the reconstructed moisture changes for the three past periods, although uncertainties exist in reconstructions during the LGM and MH.
Shi, J., Z. Tian, X. Lang, and D. Jiang, 2023: Past to future drylands in China: A multimodel analysis using CMIP6 simulations. Journal of Climate, 36, 2735–2751, https://doi.org/10.1175/JCLI-D-22-0720.1.