As the world awakens to the harsh realities of climate change and food insecurity, much of it apparently remains oblivious to a looming global water crisis, which climate change will aggravate by making rainfall more erratic in many regions.
Australia has already gone a long way down the reform path and has much to teach the world in terms of modernising irrigation, efficient and productive on-farm water use and in improving governance arrangements for water. It's time for world leaders to face the facts and embrace major reforms in water use, as called for by experts now attending World Water Week in Stockholm.
Within 40 years, the world will have an additional 2.5 billion mouths to feed, most of them in developing countries. This reflects an expected doubling of Africas population and a 27 per cent increase in Asia, with far more dramatic growth in some countries, like Pakistan, whose population will jump by 85 per cent.
If we continue with current trends which have wealthier populations eating more livestock products (dairy and meat) and existing food losses between field and fork, global crop production will have to double to feed the growing population. Many farming experts believe this is technically feasible with or without genetically modified crops.
But to deliver on the promise of science, the agriculture of tomorrow will need a lot more water. Given that one litre (more for livestock products) is used to produce one calorie of food and taking food losses into account, it will take up to 6000 cubic kilometres of additional water annually to feed another 2.5 billion people 2500 calories per day. This is almost twice what we use today and is not sustainable.
It is not at all clear where this water will come from. Agriculture is already the global economy's thirstiest sector, accounting for 70 to 80 per cent of total water use. Yet, by 2050, its share will have declined to about 60 or 70 per cent, as a result of competing water demands on multiple fronts, such as urban expansion and industrial development.
In the face of worsening water scarcity in agriculture, the steady demise of Asia's regulated irrigation systems using surface water is especially worrisome. Built on a vast scale throughout East, Central and South Asia in the 1970s and 1980s, these systems have since suffered neglect and are no longer adequate.
They are rapidly being supplanted by anarchic water scavenging, based on the use of inexpensive pumps for irrigation, mainly using groundwater. Governments' inability to regulate this practice is giving rise to scary scenarios of groundwater exhaustion, which could lead to regional food crises and widespread social unrest.
A roll call of countries where water scarcity already undermines food security includes China, India, Pakistan, most of North Africa and the Middle East, and large parts of southern Africa.
In the coming decades, as countries struggle to feed their growing populations, many will have to import large amounts of food, putting a major drain on their economies.
About one third of the world's population already live in areas where water is physically scarce, or economically scarce due to limited investment in necessary water delivery infrastructure. This figure will rise significantly by 2050.
There is a way out of this predicament for water-scarce countries, but it will involve thorough policy reforms and major new investments. Though hardly as simple as just adding water, the recipe for success is fairly straightforward.
A critical first step is to create fair and effective policies for allocating water, as competing demands increase. This, in turn, requires a clearer definition of water rights and better measurement and modelling of water availability.
As governments adopt such policies, their historic tendency to focus mainly on water supplies for drinking and sanitation to the neglect of water for agriculture must come to an end.
This doesn't mean people should be deprived of their basic human right to clean water.
The point is that the amount of water needed for drinking and sanitation amounts to only about 10 per cent of total water use. The rest goes to a wide variety of equally beneficial uses, the biggest of which is agriculture.
Thus, the central challenge for governments is to make agricultural use of water more productive and efficient. Two ways of doing this are to refurbish irrigation systems and improve rain-fed agriculture through better soil management and expanded use of water harvesting and supplemental irrigation. New crop varieties that tolerate extreme conditions, like drought and flooding, can also help.
The hard part in the developing world is creating incentives for governments to implement reforms.
Current governance arrangements were generally designed around the middle of the last century, based on colonial models, in which water was viewed as an unlimited free good.
Though now absurdly inappropriate, these models are kept in place by strong vested interests. The water and agricultural sectors are permeated from top to bottom by fear of the political repercussions that reforms in water governance might bring.
Governments must now set aside those fears and adopt a new paradigm under which water is valued and ultimately priced.
In other words, societies must start to pay for the environmental and other benefits that water brings, to avert the water crisis.
Colin Chartres is director general of the International Water Management Institute, headquartered in Colombo, Sri Lanka and former chief science advisor to Australia's National Water Commission.
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