Through the provision of drinking and agricultural irrigation water, groundwater resources fundamentally underpin the existence of modern human society across large regions of the world. Despite this, decades of unsustainable exploitation have led to acute degradation of groundwater quantity and quality, creating pressing challenges that society must address if we are to maintain viable access to this crucial resource for future generations. Taking stock of the current situation, in this contribution we begin by reviewing some of the major global groundwater resource pressures, before exploring a range of technological, engineering, societal and nature-based solutions to address these challenges. We look at examples of emerging groundwater resource threats and potential innovative solutions to tackle them, before concluding with a forward look at future research opportunities that can ultimately enhance our management of this vital resource.

The current generation of climate models has proven very helpful in understanding and projecting anthropogenic climate change but has also shown to be insufficient for studying the interactions of tipping elements and their impact on overall climate stability. As a consequence, tipping elements are mostly absent from climate projections that are commonly used by the drinking water industry to test the resilience of their systems. There is, however, mounting evidence for the existence and potential (possibly even imminent) activation of some of these tipping elements. The drinking water sector is, by necessity, slow-moving as its infrastructure is meant to operate for many decades and in practice often does so even longer. The time scales of possible changes associated with tipping element activations may, however, be much shorter. We provide a review of the current understanding of climate tipping elements and present a simple model that investigates potential magnitudes and time scales of rapid climate change associated with tipping element activations. We study the potential consequences for drinking water supply systems, focusing on Europe, and argue that given the associated deep uncertainty and far-reaching consequences, it is essential to include tipping scenarios in the decision-making processes in the drinking water sector.