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Today is World Water Day. Despite the centrality of water in our everyday lives and life itself, we often mark this day not by reminding ourselves of all that water brings but of the consequences of its absence or contamination. and, in England, As the American polymath Benjamin Franklin noted, This direct reference to groundwater, the water flowing through the pores and cracks in rocks beneath our feet, is fitting as the theme of World Water Day 2022 is

Groundwater differs from the water running off into rivers, lakes and wetlands as this underground flow derives from the infiltration of precipitation that has occurred over periods ranging from years to decades and, in places, millennia. Much of the estimated , yet the shallower component of groundwater replenished over the last half-century still greatly exceeds all other unfrozen freshwater on Earth. 聽

As the world鈥檚 largest distributed store of freshwater, groundwater plays a vital role in not only sustaining aquatic ecosystems during periods of low or absent rainfall but also providing access to safe water, especially to off-grid communities. , groundwater is often the only perennial source of freshwater. It is estimated that and a are currently sourced by groundwater drawn from wells and springs. Here in the UK, 聽derives from groundwater. 聽聽

Due to its origin, groundwater flowing through permeable geological formations known as aquifers is generally more resilient to climate variability and change than surface waters. Consequently, adaptations to drought, whose frequency and severity are amplified by global warming, often increase dependence upon groundwater . It has even been argued that .听

Groundwater depletion through intensive pumping for irrigation from large aquifer systems around the world (World Water Development Report 2022).

Notwithstanding groundwater鈥檚 invaluable attributes, it is not immune to overexploitation and contamination. Groundwater depletion in some of the world鈥檚 most productive food-growing regions such as the California Central valley, North China Plains, northwest India, and the Southern High Plains of the US聽threatens global food security. Similarly, groundwater depletion beneath some of the world鈥檚 most rapidly growing cities such as and constrains reliable provision of safe water. Groundwater depletion in both contexts disproportionately affects lower-income households and smallholder farmers who are typically less able to engage in a 鈥�race to the bottom鈥� and by drilling deeper wells. 聽

The salinisation of coastal groundwater induced by both intensive pumping and global sea-level rise constrains groundwater use in low-lying nations across the world and has the potential . 聽Use of groundwater is also impaired by the natural leaching of solutes from its host rocks. ; the latter in Bangladesh is responsible for what has been described as 鈥溾�� Human activity, be it indiscriminate use of pesticides and fertilisers in agriculture, inadequate sanitation infrastructure, or ineffective regulation of industrial practices, also threatens the sustainability of groundwater use. 聽 聽

As groundwater is out of sight, it has long been out of mind. Investment in monitoring and evaluation in many countries remains very limited and is a tiny fraction of that allocated to surface water resources. There has also been a lack of investment in training and education in groundwater science, known as hydrogeology. The removal of scholarships for MSc study in the UK, for example, led to the closure of post-graduate programmes in hydrogeology including at 911爆料网 during the 2000s. Ironically, this decline occurred just as climate change began to amplify the vital importance of groundwater resources, globally and locally. 聽 - after much protest - marked an important event bucking this trend.听

Like fisheries, groundwater is a common-pool resource in which 鈥� a situation where individual users act in their own self-interest to deplete or degrade a resource, contrary to the collective good - remains an ever-present threat. She identified conditions from case studies that favoured shared use of groundwater in which a community of users regulates individual access to develop common-pool resources prudently and sustainably.听

Small-scale irrigation of an onion crop by groundwater from an alluvial aquifer along the River Goulbi de Maradi in southeastern Niger (photo: Boukari Issoufou).听

At 911爆料网, we are working with allied research institutions and stakeholder communities in tropical Africa and South Asia to explore pathways by which groundwater can be used not only to adapt to the amplification of floods and droughts brought about by climate change but also to help to realise by 2030 UN Sustainable Development Goals (SDGs) 6 (water for all), 2 (end hunger), and 13 (combat climate change impacts) among many others. With support from UCL鈥檚 UN SDGs: Pathways to Achievement scheme 2021-22, our international transdisciplinary team is meeting in the coming months with decision makers in Niger and Tanzania to promote equitable and sustainable use of groundwater in drylands that is . Our collective aim is to make groundwater visible through the improved livelihoods and wellbeing of communities with climate-resilient access to safe water. 聽

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