IPCC AR6报告解读:地下水

Interpretation of IPCC AR6 report:groundwater

地下水已成为满足全球农业生产和生活用水需求的重要来源,也是实现联合国2030年可持续发展议程的关键资源。地下水的数量和质量会直接或间接地受到气候变化的影响。IPCC第六次评估报告(AR6)第二工作组报告对全球和区域历史时期及未来地下水变化趋势进行了评估。报告指出:(1)自21世纪初以来,由于地下水灌溉用水量增加,全球许多国家和地区地下水储量呈现下降趋势。(2)在气候变化背景下,地下水开采量将持续增加,包括全球主要含水层中不可再生的地下水。(3)在热带和半干旱地区,气候变化引起强降水发生频率加快,导致地下水补给量呈增加趋势;在高寒地区,受气候变化影响地下水主要补给期从春季向冬季演变,由于融雪周期和融雪量的减少造成高寒地区春季地下水补给量减少。在地下水退化区域开展渐进式生态修复,是应对气候变化和保障水安全的重要措施。

Groundwater is increasingly important for agricultural and domestic purposes.It is a key resource for achieving the United Nations’Sustainable Development Goals.The quantity and quality of groundwater can be directly or indirectly affected by climate change.The IPCC Sixth Assessment Report(AR6)provides a new understanding of trends in groundwater on a global and regional scale in the past and for the future.The results show that:(1)Groundwater storage has declined in many parts of the world,most notably since the beginning of the 21st century,due to the intensification of groundwater-fed irrigation;(2)Groundwater abstraction is projected to further increase in the future with climate change,including the withdrawals from non-renewable groundwater in major aquifers worldwide;(3)Across the tropics and semi-arid regions,intensification of precipitation is projected to increase due to climate change,and this may increase episodic recharge of groundwater;while in higher altitudes,warmer climates may have led to reduced spring-time recharge due to reduced duration and snowmelt discharges.Stepwise ecological restoration in degraded groundwater areas is an important measure to combat climate change and ensure water security.