Scientists warn of climate 'time bomb' for world's groundwater

Researchers found that groundwater reserves in arid regions take much longer to respond to climate variability than those in wet
Researchers found that groundwater reserves in arid regions take much longer to respond to climate variability than those in wetter regions

Future generations face an environmental "time bomb" as the world's groundwater systems take decades to respond to the present day impact of climate change, scientists warned on Monday.

Found underground in cracks in soil, sand and rock, groundwater is the largest useable source of freshwater on the planet and more than two billion people rely on it to drink or irrigate crops.

It is slowly replenished through rainfall—a process known as recharge—and discharges into lakes, rivers or oceans to maintain an overall balance between water in and water out.

Groundwater reserves are already under pressure as the explodes and crop production rises in lockstep.

But the such as drought and record rainfall—both made worse by our heating planet—could have another long-lasting impact on how quickly reserves replenish, according to a study published in Nature Climate Change.

An international team of researchers used computer modelling of groundwater datasets to put a timescale on how reserves may respond to the changing climate.

"Groundwater is out of sight and out of mind, this massive hidden resource that people don't think about much yet it underpins global food production," said Mark Cuthbert, from Cardiff University's School of Earth and Ocean Sciences.

"The effect we are having now is going to have this really long lag-time in terms of climate change. There's a memory in the system—and the memory is very large in some places," he told AFP.

Cuthbert and his team found that only half of all groundwater supplies are likely to fully replenish or re-balance within the next 100 years—potentially leading to shortages in drier areas.

"This could be described as an environmental time bomb because any climate change impacts on recharge occurring now, will only fully impact the baseflow to rivers and wetlands a long time later," Cuthbert said.

'Massive lags'

The process through which rainwater is filtered through bedrock and accumulated underground can take centuries and varies greatly by region.

As climate change delivers longer droughts and bigger superstorms, the extremes of rainfall become more pronounced, impacting for generations to come.

The team found that reserves in arid areas took far longer—several thousand years in some cases—to respond to alterations in climate than reserves in more humid parts.

"Parts of the groundwater that's underneath the Sahara currently is still responding to change from 10,000 years ago when it was much wetter there," Cuthbert said. "We know there are these massive lags."

The team said their research showed one of the "hidden" impacts of , and called for immediate action to ensure aren't left high and dry.

"Some parts of the world might get wetter, some might get drier but it's not just the overall amount of rainfall that is important, it is also how intense the rainfall is," Cuthbert added.

"Climate science says that changes in intensity are very significant for ."


Explore further

Researcher gives a glimpse into a limited resource—groundwater

More information: Global patterns and dynamics of climate–groundwater interactions, Nature Climate Change (2019). DOI: 10.1038/s41558-018-0386-4 , https://www.nature.com/articles/s41558-018-0386-4
Journal information: Nature Climate Change

© 2019 AFP

Citation: Scientists warn of climate 'time bomb' for world's groundwater (2019, January 21) retrieved 17 June 2019 from https://phys.org/news/2019-01-scientists-climate-world-groundwater.html
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User comments

Jan 21, 2019
This comment has been removed by a moderator.

Jan 21, 2019
bomb? a better description would be a crawling turtle. But hype it up enough and people will get hysterical.

Jan 21, 2019
@Bart_A and @Anonym518498 Fuck you, you piece of shit denialist idiots.

Jan 21, 2019
'Bomb' is not the right word, it is indicative of violence. It might mislead the younger generation to any level.

Jan 28, 2019
Talking about time bombs:

The Spanish autonomous regions of Valencia, Murcia and Andalucía, the provinces of Alicante, part of Murcia and Almeria are on top of two of the biggest underground aquifers of Europe.

As our dear friend @Bart_A points out, it's more a crowling turtle... one with a turbocompresser built in:

My mother owns a palm tree plantation. As many people in the region she wanted to have a well drilled. When the well reached 30m depth it began seeping a pestilent grayish muck, The reason for that is that the whole enormous aquifer is contaminated with residues from agriculture and farming, completely eutrophicated (google that, but not in Breitbart). People in the region have to recur to water from a large aqueduct that connects the river Tajo in the north of Spain (not Mexico, this is Europe) with the south.

But sure, you are right, those Spaniards are just plain hysterical ! I gladly invite you to go there and drink a little of this underground water.

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