Lunch Talk Series by Earth, Ocean and Atmospheric Sciences (EOAS) Thrust, HKUST (GZ) - The Changing Nature of Groundwater in the Global Water Cycle 地下水在全球水循环中的关键作用与变化

Groundwater, the largest accessible freshwater resource, constitutes an integral component of the global water cycle. Serving as a primary source of freshwater, groundwater provides potable water to billions of people worldwide. Currently, 40% of the global irrigation demand is directly met by groundwater, underscoring its increasing significance in irrigation practices. As a crucial element of the global water cycle, groundwater sustains river flows, lakes, wetlands, crops, forests, and ecosystems. Climate change and anthropogenic activities are altering the global water cycle at an unprecedented rate, rendering the role of groundwater in this cycle more dynamic and complex. A comprehensive understanding of groundwater variations and their influencing factors is imperative for ensuring the sustainable management of groundwater resources to meet human and ecological needs. This study elucidates the changes in groundwater within the global water cycle caused by climate change and anthropogenic activities over recent decades. It reviews the mechanisms through which these factors affect groundwater replenishment, discharge, runoff, storage, and distribution changes. Furthermore, the study assesses the contribution of groundwater variations to sea-level rise and the associated risk of groundwater inundation induced by rising sea levels. It anticipates the challenges and strategies for achieving the sustainable utilization of global groundwater resources.

地下水是最大的可利用淡水资源，是全球水循环的活跃组成部分。作为主要的淡水来源，地下水为数十亿人提供饮用水。目前全球灌溉需求的40%直接来自于地下水，并且地下水对灌溉的重要性越来越突出。作为全球水循环的关键组成部分，地下水维持着河川径流、湖泊、湿地、作物、森林和生态系统。气候变化和其他人类活动正以前所未有的速度改变着全球水循环，地下水在全球水循环中的作用变得更加动态和复杂。全面了解地下水的变化及其影响因素，对于确保为人类和生态系统提供可持续的地下淡水资源至关重要。本研究阐述了近几十年来，气候变化和其他人类活动造成的全球水循环中地下水的变化，回顾了这些因素对地下水的补给、排泄、径流、储存和分布变化的影响机制，评估了地下水变化对海平面上升的贡献及海平面上升引发的地下水淹没风险，展望了实现全球地下水资源可持续利用的挑战与策略。