* By Craig Simmons
As the world grapples with the problem of providing fresh water to a growing population, Australia has much experience we can share.
IF YOU WERE ASKED what the world's most precious underground resource is, you'd probably start listing minerals or petroleum deposits.
But it's far more ordinary, and valuable, than any diamonds or barrels of oil.
Groundwater is a life-and-death issue for tens of millions of people around the world. It has a huge influence on whether many nations can continue to grow their economies and feed their people. And, since water scarcity is sometimes a trigger for conflict, it is key to a more peaceful world.
Groundwater sits in porous rocks under the ground. Usually accessed by bores or wells, it is our planet's largest and most precious resource, making up 97 per cent of the world's available fresh water. Total global use is estimated by scientists at around 1,000 cubic kilometres a year, which is around 13 times the annual flow over the famous Niagara Falls.
The largest users are India, China and the USA. However Australia is an international leader in the technical art of modelling and predicting the future of groundwater resources, called hydrogeology. This places us in an enviable position of being at the forefront of global conversations about water scarcity.
Because groundwater is already running short in critical regions such as the western USA, Mexico, north-western Sahara, Middle East, Indus Basin and North China Plain. This is something everyone who eats should be concerned about because water scarcity affects global food prices for all of us.
Over the past century the world has dipped into its savings account, having drawn down its groundwater reserves by an estimated 4,500 cubic kilometres. Meanwhile demand continues to rise, especially in arid and heavily populated countries.
One of the reasons that groundwater is becoming less plentiful is that it is generally managed very poorly. Often we don't know how much we have, or how quickly it can be depleted, or how quickly it is recharged. And we have tended to ignore the unpleasant fact that a large part of it has become contaminated by toxic industrial wastes, rendering the water below many of the world's great cities undrinkable.
In the coming decades, as the climate changes and human water demand soars, there needs to be a much greater focus on groundwater governance; on putting in place the wisest and best practices for managing this precious resource. While poor governance has created the problem we now face, good governance, that is both responsible and sustainable, can cure it.
Over the past two years some of the world's largest organisations have joined forces to tackle this issue. Groundwater Governance - A Global Framework for Action (2011-2014) is a joint project supported by the Global Environment Facility (GEF) and implemented by the Food and Agriculture Organisation of the United Nations (FAO), jointly with UNESCO's International Hydrological Program (UNESCO-IHP), the International Association of Hydrologists (IAH) and the World Bank.
And Australia plays a valuable role in the Groundwater Governance project. Ours is one of the very few countries on Earth to have launched a successful bid to reverse a decline in a major groundwater resource when we capped bores in the Great Artesian Basin.
We are also pioneers in the field of 'water banking' — injecting surface water into underground aquifers during times of plenty, so it can be recovered and used in times of scarcity. And we are international leaders in hydrogeological modelling which is helping us avoid the sort of nasty shocks that have occurred elsewhere when nations have over-extracted water.
In Asia in particular, groundwater now provides around 30 per cent of all the freshwater used — if and when it runs short, it could threaten Asian food security, economic growth and the very existence of many huge cities. Countries where this is happening, like China and India, are keenly aware of the risks but this is not a simple issue to resolve: you can't just turn off the tap.
In south Asia and the nations of the Pacific, thanks to cheap diesel pumps, the unplanned and massive extraction of groundwater over the last 30 years has taxed groundwater reserves in many regions far beyond their ability to recharge or recover. As a result water tables have declined (in some cases by a metre or more each year) causing rivers to dry up.
Much of the Asia-Pacific's economic and population growth occurs in coastal and flood-prone areas and many small island states and countries like Bangladesh, with low-lying deltas and coastlines, are now at risk from rising sea levels which threatens to contaminate their freshwater aquifers with salt.
Under the great cities all round the world there has been a sustained deterioration in groundwater quality due to ever-increasing use of toxic chemicals and fossil fuels. These leach from landfills, chemical spills, roads and industrial sites and poison aquifers used by city people for drinking water. The Groundwater Governance project warns that, because groundwater usually moves very slowly, this pollution can be very long-lasting and hard to clean up.
For the world to avoid running short of clean, fresh water there is an urgent need for better governance of groundwater and the rapid global sharing of best practices, good laws and regulations, effective policy options, ideas, advanced technologies and greater public awareness.
Australia has much to contribute in this regard. As a dry country, beset by frequent droughts and surface water shortages, we know how precious water can be and how risky it is to take it for granted.
We understand how it underpins billions of dollars worth of food and industrial production, as well as our Australian landscapes. We appreciate the importance of prediction and planning to avoid future shortages. As a society, we share a water conservation ethic that is founded on the bedrock of experience.
All these qualities position Australia to play a leadership role in what is now emerging as one of the greatest challenges facing humankind: water scarcity. As a first-world country with a history of drought and water scarcity, the world looks to us to set examples and to find innovative solutions; the world expects us to lead and they watch what we do very carefully. This could be one of our greatest and most enduring contributions to humanity.
* Craig Simmons is Director of the National Centre for Groundwater Research and Training and Professor of Hydrogeology at Flinders University.
This opinion article has been run by ABC Environment Online