The world's underground water systems have been responding to the impact of climate change for decades
Scientists are warning future generations that they face an environmental "time bomb". According to Phys.org, the world's groundwater systems have been responding to the impact of climate change for decades.
Groundwater is the largest freshwater source on the planet, according to Phys.org. More than two billion people depend on groundwater to drink and irrigate crops.
According to the site, groundwater reserves are already under pressure as the world's population explodes and crop production increases greatly.
According to a study by Nature Climate Change, extreme weather events, such as drought and record rainfall, could also have a lasting impact on the speed with which reserves are recovered.
According to Phys.org, an international team of researchers used computer models of groundwater datasets to establish a time scale in the way that reserves can respond to climate change.
"Groundwater is out of sight and out of mind, this hidden mass resource in which people do not think much but support world food production," said Mark Cuthbert, of the School of Earth Sciences and the Ocean of Cardiff University.
According to Phys.org, Cuthbert and his team found that only half of all groundwater supplies are likely to be fully replenished or re-balanced within the next 100 years, which could create shortages in the drier areas.
"This could be described as an environmental time bomb because any impact of climate change on the recharge that is occurring now will only completely affect the flow from the base to the rivers and wetlands," Cuthbert said.
The process through which rainwater seeps through the bedrock and accumulates underground can take centuries and varies greatly depending on the region, according to the site. As climate change produces longer droughts and larger superstorms, the extremes of rainfall become more pronounced, affecting the groundwater reserves for future generations.
"Parts of the underground water that is under the Sahara is still currently responding to climate change 10,000 years ago, when it was much more humid there," Cuthbert told the site. "We know there are these massive delays."
The team said its research showed one of the "hidden" impacts of climate change, and called for immediate action to ensure that future generations are not left high and dry.