Global patterns and dynamics of climate–groundwater interactions

Abstract

Groundwater is the largest available store of global freshwater , upon which more than two billion people rely 2. It is therefore important to quantify the spatiotemporal interactions between groundwater and climate. However, current understanding of the global scale sensitivity of groundwater systems to climate change 3,4-as well as the resulting variation in feedbacks from groundwater to the climate system 5,6-is limited. Here, using groundwater model results in combination with hydrologic datasets, we examine the dynamic timescales of groundwater system responses to climate change. We show that nearly half of global groundwater fluxes could equilibrate with recharge variations due to climate change on human (~100 year) timescales, and that areas where water tables are most sensitive to changes in recharge are also those that have the longest groundwater response times. In particular, groundwater fluxes in arid regions are shown to be less responsive to climate variability than in humid regions. Adaptation strategies must therefore account for the hydraulic memory of groundwater systems which can buffer climate change impacts on water resources in many regions, but may also lead to a long, but initially hidden, legacy of anthropogenic and climatic impacts on river flows and groundwater dependent ecosystems.

Projected Climatic and Hydrologic Changes to Lake Victoria Basin Rivers under Three RCP Emission Scenarios for 2015–2100 and Impacts on the Water Sector

“…Higher rainfall projected for the OND season is likely to increase groundwater recharge in the eastern and south eastern portions of the basin because groundwater in humid areas is sensitive to increased rainfall, though it is modified by the predominant land use/land cover [62]. Although basin scale studies are rare, regional scale studies using Gravity Recovery and Climate Experiment (GRACE) satellites have shown that the total water storage (lake and groundwater) in the LVB is positively correlated with rainfall and rainfall anomalies associated with ENSO and IOD [28,63].…”

Importance of Spatial Resolution in Global Groundwater Modeling

“…Groundwater is the largest source of available freshwater (Gleeson et al ). The assessment of global groundwater resources has been the subject of multiple studies recently, including impacts of groundwater abstractions (Wada et al ) and climate change (Portmann et al ; Cuthbert et al ). Furthermore, global hydrological models (GHMs) started to replace their bucket‐like linear groundwater storage models with (hydraulic) head gradient‐based models to better represent the interaction between surface water and groundwater as well as lateral and vertical flows, including capillary rise (de Graaf et al , , ; Reinecke et al , ).…”

Pervasive Desiccation of North American Lakes During the Late Quaternary

“…The modern pattern of water availability, including the steep east‐west midlatitude moisture gradient, is a departure from the mean of the late Quaternary, if not the past ~0.8–2.3 million years of repeated glaciation. The geological novelty of the current hydrologic state has implications not only for future water security but also for past ecological dynamics (Jackson & Blois, ), transience and response times in present‐day groundwater systems (Cuthbert et al, ), and the long‐term evolution of North America's critical zone under an often drier‐than‐modern state with moisture gradients different than today (Anderson et al, ; Brantley et al, ).…”

“…Ice sheet and proglacial-lake areas are shown in light and dark gray, respectively, and the change in ice sheet and proglacial-lake areas between timesteps are shown in light blue and gray-blue, respectively. state has implications not only for future water security but also for past ecological dynamics (Jackson & Blois, 2015), transience and response times in present-day groundwater systems (Cuthbert et al, 2019), and the long-term evolution of North America's critical zone under an often drier-than-modern state with moisture gradients different than today (Anderson et al, 2019;Brantley et al, 2017).…”