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Aridification risks of global ecohydrological element increases under climate change
  • Yuan Zhang
Yuan Zhang
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences

Corresponding Author:[email protected]

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Abstract

Drought is the most widespread climatic extreme that has negative impacts on ecohydrology. Studies have shown that drought cause certain degrees of disturbances to different ecohydrological elements, but the magnitude with which drought leads to changes in ecohydrological elements at the global scale remains largely unknown. At the same time, it is not clear what kind of drought risk will be suffered by ecohydrological elements in the future under a high-concentration greenhouse gas emission scenario. Here, we derived the thresholds of evapotranspiration (ET), soil moisture (SM), the vapor pressure deficit (VPD), and the normalized difference vegetation index (NDVI) to drought in the historical period (1982-2015) and revealed the projected drought risks of the above ecohydrological elements. We found that a decrease in SM caused by drought is often accompanied by an increase in VPD in the area, and ET and NDVI are expected to decrease under drought conditions in most parts of the world due to increases in radiation (RAD) and temperature (TEMP) and decreases in SM during drought periods. When a drought lasted for 8-15 months and the corresponding drought severity reached 10-15, the drought caused changes in ecohydrological elements in most regions of the world. Compared with arid and semiarid regions, different ecohydrological elements are more sensitive to drought in humid and semihumid regions. Compared with 1982-2015, the drought risk of ecohydrological elements will increase gradually in the next three periods. By 2071-2100, more than half of the world’s ecohydrological elements will be more susceptible to drought disturbances.