Water stress & climate change

In Ground Water and Climate Change, international scientists explain how several human-driven factors, if not rectified, will combine with climate change to significantly reduce useable groundwater availability for agriculture globally. The paper was published in the journal Nature Climate Change.

The authors note that inadequate groundwater supply records and mathematical models for predicting climate change and associated sea-level-rise make it impossible to forecast groundwater's long-range fate globally. "Over-pumping of groundwater for irrigation is mining dry the world's ancient Pleistocene-age, ice-sheet-fed aquifers and, ironically, at the same time increasing sea-level rise, which we haven't factored into current estimations of the rise," says a team member. "Groundwater pumping reduces the amount of stored water deep underground and redirects it to the more active hydrologic system at the land-surface. There, it evaporates into the atmosphere, and ultimately falls as precipitation into the ocean."

Current research estimates oceans will rise by about a metre globally by the end of the century due to climate change. But that estimation doesn't factor in another half-a-centimetre-a-year rise, says this study, expected due to groundwater recycling back into the ocean globally.

Increasing climate-change-induced storm surges will also flood coastal areas, threatening the quality of groundwater supplies and compromising their usability. This is the second study from the team to assist the Intergovernmental Panel on Climate Change (IPCC) in assessing the impact of climate change on the world's groundwater supply.