The 'environmental time bomb' caused by the effects of climate change on groundwater
Future generations face an 'environmental time bomb' caused by the effects climate change has on freshwater supplies, scientists have warned. It could take more than 100 years for the full impact of changes occurring today to be felt on the world's groundwater reserves, experts say. Groundwater comes from rainfall that is trapped underground in cracks and small holes in soil, sand and rock, as well as from springs and other natural sources. It also takes longer to respond to climate change than surface water but will diminish with lower levels of rainfall. This has major implications for the future availability of water for drinking, as well as farming and industry, say researchers. Experts from the University of Cardiff They found that groundwater in wetter, more humid, locations may respond to climate change over a relatively short time scales. In contrast, regions where water was naturally more scarce had much longer groundwater response times. The authors point out that groundwater was essential in drier parts of the world where surface water supplies were limited. Lead scientist Dr Mark Cuthbert, from Cardiff's school of Earth and ocean sciences, said: '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. 'This means that in many parts of the world, changes in groundwater flows due to climate change could have a very long legacy. '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. '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.' Groundwater is the world's largest distributed store of fresh water, playing a central part in sustaining ecosystems and human adaptation to climate variability and change. Groundwater is replenished by rainfall through a process known as 'recharge'. At the same time it is constantly discharged into lakes, streams and oceans. But the groundwater balance could be upset by climate change - for instance, as a result of reduced rainfall, said the researchers. Levels of water in the ground will then begin to change until a new equilibrium is reached. The full findings of the study were published in the journal .