Climate security

Climate Change May Be Creating a Groundwater 'Time Bomb,' Scientists Say

Climate change may be creating a groundwater "time bomb" as the world's underground water systems catch up to the impacts of global warming.

Researchers for a study published Monday in the journal Nature Climate Change say more than half of the world’s groundwater systems — the largest source of usable freshwater in the world — could take more than 100 years to completely respond to current environmental changes from global warming.

Groundwater is replenished primarily by rainfall through a process known as recharge. Concurrently, water exits or discharges from groundwater sources into lakes, streams and oceans to maintain an overall balance.

When there is a change in recharge due to a lack of rainfall, for example, levels of groundwater drop until balance is restored.

The problem facing scientists, government officials and water management planners is knowing exactly when recharge changes occurring now as a result of global warming will be reflected in discharge from groundwater sources into lakes, streams and oceans.