GROUNDWATER is a key driver of the global economy - but water will be scarce in critical food production regions by 2030 unless urgent steps are taken to protect it from over-extraction and pollution, international water scientists have warned.
A satellite study has proven groundwater tables in the United States, North Africa, India, the Middle East and China, are falling.
Professor Craig Simmons, Director of Australia's National Centre for Groundwater Research and Training (NCGRT) and member of the UNESCO's global groundwater governance program, said global groundwater use had more than doubled between 1960 and 2000 and continued to soar.
"Groundwater currently makes up about 97 per cent of all the available fresh water on the planet and presently accounts for about 40pc of our total water supply," he said.
"Almost everywhere, there is clear evidence that water tables are falling.
"Not many people think of groundwater as a key driver of the global economy - yet it is.
"If it becomes depleted, entire industries may be forced to shut down or move. Whole regions could face acute water scarcity."
Professor Simmons said the groundwater crisis was driven by a competition for increasingly scarce water supplies between "megacities", the energy sector, manufacturing and farming.
"The blunt fact is that most countries and local regions did not know the size of their water resources when then began extracting them, nor how long it took to recharge. In some cases this can take centuries or even millennia.
"As a result they are now extracting their water unsustainably."
Water is emerging as potentially one of the main limits to Chinese economic growth. Groundwater supplies 40pc of China's food and 70pc of its drinking water, yet water levels in aquifers in some regions were sinking by a metre or more a year, with 660 cities approaching a critical situation.
In the Middle East, depleted aquifers have been a major driver of the relocation of agriculture to Africa and the so-called 'land-grab' by wealthy countries, Professor Simmons said.
In India the number of wells grew from less than one million in 1960 to 19m by 2000. Water tables in the key foodbowl were sinking beyond the reach of many farmers' pumps.
"The crisis in global groundwater is chiefly one of poor governance, exacerbated by a lack of knowledge of the size and condition of the resource, rates of recharge, lack of transparent policy, lack of ownership, lack of price signals to users and a lack of political will to do anything."
Groundwater science had improved dramatically in the last decade, giving us the ability to measure and manage the resource - but governance has yet to catch up.
"Unless it does, we can expect serious problems in the future," he said.
Unconstrained drilling of new wells in the United States -- as many as 800,000 per year - had caused
earth subsidence, fissures, and saltwater intrusion.
Leading international groundwater experts are set to meet in Sydney from January 23 to 27 to review Australian research.
The National Centre for Groundwater Research and Training is funded by the Australian Research Council and the National Water Commission. The Centre was established in June 2009, with Commonwealth funding of $29.5m over five years and a further $15m over four years to develop groundwater research infrastructure.