Global warming creating a groundwater 'time bomb', say scientists

Global warming is a problem and countries are coming together to find solutions on the causes that are leading to climate change. Scientists predict global warming may create a ‘groundwater time bomb.’

A group of scientists published on the Nature Climate Change that more than half of the world’s groundwater systems could take many years to respond to the current environmental changes causes due to global warming. Groundwater, which is the most significant source of useable water may take over a century to respond to global warming, they add.

Groundwater is replenished by rainfall through a process known as recharge wherein water exits or discharges from groundwater sources into lakes, streams and oceans to maintain an overall balance. When there is less rainfall, the groundwater levels go low until the levels are restored.

“Our research shows that groundwater systems take a lot longer to respond to climate change than surface water, with only half of the world’s groundwater flows responding fully within ‘human’ timescales of 100 years," Mark Cuthbert, lead author and research fellow at Cardiff University’s School of Earth and Ocean Sciences and Water Research Institute said.

He also stated that in many parts of the world, changes in "groundwater flows due to climate change could have a very long legacy.” He described this situation as an environmental "time bomb" because climate change will impact the recharge cycle not only now, but also in the future affect the base flow to rivers and wetlands a long time later.

Cuthbert mentioned that the researchers used hydrologic datasets coupled with groundwater model results to analyse on how long the groundwater systems might take to respond to the climate change.

He mentioned that Amazon and Florida Everglades, where the groundwater levels are higher, and the climate is humid, maybe the first ones to experience recharge/discharge problems sooner while arid locations like the Sahara Desert might take longer.

"It is essential that the potential for these initially hidden impacts is recognised when developing water management policies, or climate change adaptation strategies for future generations," Cuthbert said.