Overview of The world has a groundwater problem. Can we solve it? (Shortwave, NPR)
This Shortwave episode explains why groundwater — the water stored in underground aquifers that supplies about half of the world’s freshwater use — is declining in many places, what that means for people and ecosystems, and how some communities are trying to manage or restore aquifers. Reporting mixes a global scientific study with on-the-ground perspective from a Kansas farmer (Hayes Kelman) who relies on the Ogallala/High Plains Aquifer.
Key findings from the global study
- Researchers compiled monitoring data for ~1,700 aquifer systems (covering roughly three-quarters of land tapped for groundwater).
- About one-third of those aquifer systems show declining groundwater levels.
- Average declines in affected aquifers: >4 inches per year; about one-third of declining aquifers lose more than ~20 inches per year.
- Regions with rapid declines include parts of India, the U.S. (e.g., Ogallala), China, Mexico, and Saudi Arabia — often dry regions with lots of irrigated agriculture.
Why groundwater is declining
- Over-extraction, especially for irrigation in agriculture, is the primary driver.
- Drier conditions and reduced precipitation cut recharge (supply) while increased demand (rivers/reservoirs low) pushes people to pump more groundwater — a double hit.
- Many aquifers cross political borders, complicating management and enforcement.
- Data gaps and inconsistent monitoring make global assessment difficult.
Consequences of depletion
- Wells drying or becoming too deep/costly to pump, harming drinking water supplies and livelihoods.
- Reduced aquifer storage → loss of wetland habitat and ecosystem services.
- Land subsidence (ground sinking) where aquifer materials compact after water is removed.
- Saltwater intrusion in coastal aquifers when freshwater levels fall.
- Agricultural and economic ripple effects: crop choices, livestock feed supplies, local economies built around irrigation.
Measurement methods and limitations
- Ground monitoring wells provide local, detailed water-level records but coverage and frequency vary widely.
- GRACE satellites measure changes in Earth’s gravity field caused by water mass movement, useful for broad regional trends but not fine-scale, absolute groundwater levels.
- Reconciling different monitoring methods, inconsistent reporting, and political reluctance to share data made the global synthesis painstaking.
Case study: Hayes Kelman (western Kansas farmer)
- Fifth-generation farmer over the Ogallala Aquifer who observed wells dropping, forced irrigation reductions, and shifting yields based on rainfall.
- Economic tension: water-efficient crops like milo have low market demand, forcing farmers to keep growing water-intensive corn and wheat to survive economically.
- He’s working with local hydrologists to understand sustainable extraction rates and is willing to reduce usage for future generations — but notes the complex downstream effects on local towns, feed supply chains, and meatpacking.
Examples of management and hope
- Some aquifers (about 16% of systems studied) that had declined in the 1980s–90s are now gaining water, often where active water management and reduced extraction were implemented.
- International agreements exist (example: 2010 agreement on the Guarani Aquifer among Argentina, Brazil, Paraguay, Uruguay) focusing on data sharing and sustainable, equitable use — though implementation and measurable outcomes can be slow.
Practical actions and policy recommendations
- Improve monitoring: more, consistent well-data and continued use of satellite data to fill gaps.
- Data sharing and transparency, especially for transboundary aquifers.
- Implement and enforce sustainable extraction limits based on local recharge rates.
- Promote water-efficient farming practices and crop choices, combined with economic incentives or markets so farmers can switch sustainably.
- Recharge strategies where feasible (managed aquifer recharge, reservoir/rainwater capture).
- Cross-sector planning to account for downstream economic impacts of reducing irrigation (food supply, livestock, local employment).
Notable quotes
- Hayes Kelman: “Everything we do is for our kids and for the future.”
- Scientist on satellites (paraphrase): changes in Earth’s gravity field over time reveal seasonal and long-term movement of water — useful for detecting trends but not for detailed, local well-level monitoring.
Bottom line
Groundwater depletion is widespread and serious in many agricultural, dry regions, but it’s not uniformly irreversible. Better data, coordinated management (local to international), economic mechanisms to support water-efficient choices, and targeted recharge/usage reduction have led some aquifers to stabilize or recover. Solving the problem will require science-informed policy and difficult economic trade-offs, particularly in farming-dependent communities.