This year, the world and, in particular, developing countries and the poor have been hit by both food and energy crises. As a consequence, prices for many staple foods have risen by up to 100 per cent.
When we examine the causes of the food crisis, growing population, changes in trade patterns, urbanisation, dietary changes, biofuel production, and climate change and regional droughts are all responsible. Thus, we have a classic increase in prices due to high demand and low supply. However, few commentators specifically mention the declining availability of water that is needed to grow irrigated and rainfed crops.
According to some, the often mooted solution to the food crisis lies in plant breeding that produces the ultimate high yielding, low water-consuming crops. While this solution is important, it will fail unless attention is paid to where the water for all food, fibre and energy crops is going to come from.
The causes of water scarcity are essentially identical to those of the food crisis. There are serious and extremely worrying factors that indicate water supplies are close to exhaustion in some countries. Population growth in the next approximately 40 years will see an increase from 6.5 to up to 9.0 billion. Essentially every calorie of food requires a litre of water to produce it. Therefore, on average we require 2,000-3,000 litres of water per person to sustain our daily food requirements.
We will have 2.5 billion extra mouths to feed by 2050 and will need to find at least 2,000 cubic kilometers more water annually to grow our food. This is no easy task given that it is over double what is currently used in irrigation and given that the availability of new fertile land in humid areas for rainfed farming is extremely limited.
Recent detailed investigations as part of the Comprehensive Assessment of Water Management in Agriculture have indicated that we will not be able to produce all the food, feed and fibre required in 2050 unless we improve the way we manage water.
A few years ago, IWMI (International Water Management Institute) demonstrated that many countries are facing severe water scarcity, either as a result of a lack of available freshwater, or due to a lack of investment in water infrastructure such as dams and reservoirs. What makes matters worse is that this scarcity predominantly affects developing countries where the majority of the world’s undernourished people (approximately 840 million) live.
However, there are potential solutions. These include more water storage, improved management of irrigation systems and increasing water productivity (e.g., more kg of crop per 1,000 litres of water) in irrigated and rainfed farming systems. All of these will require investment in knowledge, infrastructure and human capacity. Better water storage has to be considered.
Ethiopia, which is typical of many sub-Saharan African countries, has a water storage capacity of 38 cubic metres per person. In contrast, Australia has almost 5,000 cubic metres per person, an amount that in the face of current climate change impacts may be inadequate. While there will be a need for new large and medium-sized dams to deal with this critical lack of storage in Africa, other simpler solutions are also part of the equation. These include the construction of small reservoirs, sustainable use of groundwater systems including artificial groundwater recharge and rainwater harvesting for smallholder vegetable gardens.
Improved year-round access to water will help farmers maintain their own food security using simple supplementary irrigation techniques. The redesign of both the physical and institutional arrangements of some large and often dysfunctional irrigation schemes will also bring the required productivity increases.
Safe, risk free reuse of wastewater from growing cities will also be needed. Of course, these actions need to be paralleled by development of drought-tolerant crops, and the provision of infrastructure and facilities to get fresh food to markets.
Since the formulation of the UN Millennium Development Goals early this century, much of the water agenda has been focused on the provision of drinking water and sanitation. This water comes from the same sources as agricultural water and as we urbanise and improve living standards there will be increasing competition for drinking water from domestic and other urban users, putting agriculture under further pressure.
While improving drinking water and sanitation is vital with respect to health and living standards, we cannot afford to neglect the provision and improved productivity of water for agriculture.
Current estimates indicate that we will not have enough water to feed ourselves in 40 years time, by when the current food crisis may turn into a perpetual crisis. Just as in other areas of agricultural research and development, investment in the provision and better management of water resources has declined steadily since the green revolution. My water science colleagues and I are raising a warning flag that significant investments in both R&D and water infrastructure development are needed, if dire consequences are to be avoided.