Groundwater, which accounts for almost all of the planet’s freshwater supplies, is poorly understood and consequently undervalued, says the UN.
Only about 1% of the water on Earth is freshwater – mostly found in ice caps – with the rest being saline in the oceans.
Of the planet’s liquid freshwater, 99% is found underground, where the quality is generally good.
We must harness this ‘invisible’ water source to improve water security worldwide.
Water shortages, already affecting billions of people worldwide, are expected to worsen in the coming decades – linked to drought, pollution, rising sea levels and poor management – but an “invisible” solution may be hiding underground.
With water usage seen rising by 1% each year over the next three decades, a U.N. report predicted that so-called groundwater would grow as climate change and human exploitation shrink surface supplies like lakes and reservoirs.
Today, groundwater – which accounts for 99% of the planet’s freshwater supplies – is poorly understood and consequently undervalued, mismanaged and even abused, according to the U.N. World Water Development Report 2022.
Globally, 3.6 billion people had inadequate access to water for at least one month in 2018, and this figure is expected to top 5 billion by 2050, researchers say.
“What if the solution to the world’s water problems is sitting there right under our feet?” said Richard Connor, editor-in-chief of the new report published by UNESCO.
“There is an enormous opportunity to manage and exploit all this groundwater sustainably,” he told the Thomson Reuters Foundation.
As the global population grows, hiking pressure on water supplies, here’s why we should pay more attention to the vast potential of groundwater and take steps to manage it properly:
Why Is Groundwater Essential, And What Are Its Benefits?
Only about 1% of the water on Earth is freshwater, primarily found in ice caps – with the rest being saline in the oceans.
Of the planet’s liquid freshwater, 99% is found underground, where the quality is generally good. It can therefore be used safely, affordably and without requiring advanced treatment.
Water stored above ground, such as in reservoirs and dams, is a finite resource, often costly and vulnerable to pollution and climate change impacts like severe drought – and the ways it is exploited can have ecological and social consequences.
By comparison, 10-20% of groundwater renews naturally and is found at shallow depths, making it easily accessible.
The rest is “fossil water” that has been in the ground for thousands or even millions of years and, while not renewable, is abundant.
According to the U.N. report, groundwater systems are important for supporting nature-rich landscapes such as forests and provide about a quarter of all water used for farming.
Underground supplies also account for about half of the water used domestically by the world’s population. They are the cheapest source of drinking water for rural villagers, most of whom are not connected to public or private supply systems.
How Are Groundwater Supplies Abused, And What Are The Consequences?
Over-extraction can have dire consequences, including land subsidence and conflicts linked to scarce supplies.
In 2018, when India suffered what was seen as the worst water crisis in its history, a report by a government think-tank predicted that at least 40% of its 1.3 billion population would have no reliable access to drinking water by 2030.
Droughts are becoming more frequent as the climate heats up, creating problems for India’s rain-dependent farmers, while disputes between states are rising.
Meanwhile, in Indonesia’s capital, Jakarta, rapid urbanisation and disappearing water catchment areas mean most residents rely on wells that drain underground aquifers, causing the mega-city to sink by about 5-10 cm (2-4 inches) each year.
The planet’s groundwater can be contaminated by improper sanitation, pit latrines, and industrial pollution from tanning, mining, and agricultural chemicals.
U.N. report editor Connor noted that groundwater is less susceptible to pollution than surface supplies.
But once it happens, the contamination is hard to reverse, he said, calling for more action to protect groundwater by strengthening environmental agencies, regulation and enforcement.
What are the challenges of tapping more groundwater, and how can they be overcome?
A region like sub-Saharan Africa has poorly developed water infrastructure and little irrigation for farming, leaving it dependent on increasingly erratic rainfall and vulnerable to drought – which can fuel famine, poverty and mass migration.
Along with the Middle East, the region holds significant groundwater reserves that are largely untapped and, if extracted in a controlled manner, could help maintain water security.
The U.N. report said governments must invest in water infrastructure and institutions and train professionals to sustain access to those reserves.
It added that the development of groundwater sources could catalyse economic growth by expanding irrigated farmland and improving agricultural yields and crop diversity.
Outside Australia, Europe and the United States, little data exists on groundwater, including how much is available at different depths, its quality and level of salinity.
But companies involved in oil, gas and mineral exploration often gather huge amounts of information on the underground – including the water it holds.
Corporate responsibility pledges by such firms could include sharing groundwater information with agencies responsible for managing it to support sustainable use, said Connor.
“You have to have knowledge and data to know how much water (there) is and it’s quality. But where is it, and how fast is it recharging?” he added.
