World Water Day will be celebrated on Friday 22nd March in a bid to raise awareness of the critical importance of water and the fact that, for many, scarcity is a real problem, which climate change and over abstraction are set to exacerbate over coming years.

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According to Washington DC-based policy group Worldwatch, 1.2 billion people (almost a fifth of the global population) live in areas of physical water scarcity. On Tuesday, ahead of World Water Day, Worldwatch said that population growth, climate change, poor investment and management of water resources, and inefficient use of existing resources will result in 1.8 billion people living in countries or regions with absolute water scarcity* by 2025, with almost half of the world experiencing some level of water stress.

In August last year, a landmark study by an international team of researchers suggested that demand for water has already outstripped supply in the majority of the world's agricultural regions. The team's study was hailed as the first to account for environmental health, as well as human demand for water.

Furthermore, according to the United Nations Food and Agriculture Organization and UN Water, global water use has been growing at more than twice the rate of population increase over the last century. Currently, 70 percent of fresh water use worldwide is for agriculture (compared to 11 percent for municipal and 19 percent for industrial purposes).  

Complex pattern of withdrawals highlights need for tailored approach

However, Worldwatch said on Tuesday that overall figures may have been distorted by the high water withdrawals of countries such as China, India, and the United States and may therefore not accurately reflect the complexities of worldwide water use. It pointed out that countries which rely heavily on irrigated agriculture tend to be using much more water, in many cases from non-renewable or slow recharging underground aquifers.

Overall, 44 percent of total water withdrawal among OECD member countries is for agriculture, but amongst the eight that rely greatly on irrigated agriculture, the proportion rises to over 60 percent. In the four transitional economies of Brazil, Russia, India, and China, agriculture accounts for 74 percent of water withdrawals, but again this ranges from 20 percent in Russia to 87 percent in India.

Following on from recommendations made by UN FAO, Worldwatch suggested in its latest Vital Signs Online report that policy makers must introduce a sensitive approach to improving water management and dealing with scarcity.

Speaking in the Netherlands last week, FAO chief José Graziano da Silva expounded on the need for such an approach to sustainable agricultural reform. He said, "Agriculture is too sensitive and location specific. Soil, climate, water availability and so many other factors influence how one technology will work elsewhere. We need to ask farmers what they need, what they want, see what could fit, how it needs to be adapted and ensure that whatever we do ends up being 'owned' by the farmers themselves."

Even so, Worldwatch offered a series of policy recommendations in its report. These include supporting small-scale farmers rather than concentrating spending on large-scale irrigation systems, promoting a greater diversity of crops, better suited to local conditions, which will increase resilience in the face of water scarcity and climate change,  and adopting irrigation systems like "drip" lines that deliver water directly to plants' roots.

The report's authors recommended governments follow an integrated water resource management approach, which the Institute said "involves water management that recognizes the holistic nature of the water cycle and the importance of managing trade-offs within it."

Last week, a coalition of UN agencies launched an initiative aimed at improving vulnerable countries' management of water resources in Geneva. The agencies said their main aim is to shift national drought policies in drought prone areas from a reactive (crisis management) to a proactive (risk management) approach.

An FAO spokesperson said at the time, "Droughts cause the deaths and displacement of more people than cyclones, floods and earthquakes combined, making them the world's most destructive natural hazard. Yet while droughts are expected to increase in frequency, area and intensity due to climate change, effective drought management policies are missing in most parts of the world."

Effects of climate change on water resources

As the effects of climate change continue to be felt around the world, reductions in river runoff and aquifer recharge are expected in the Mediterranean basin and the semi-arid areas of the Americas. Australia and southern Africa, where resources are already often scarce, are expected to become more water-stressed.

In Asia, the large areas of irrigated land that rely on snowmelt and high mountain glaciers for water will be affected by changes in runoff patterns, while highly populated deltas are at risk from a combination of reduced inflows, increased salinity, and rising sea levels.

This is expected to conflict with an increased demand for irrigation for food and other crops, arising from higher global temperatures. In January, a team of Canadian Earth Scientists suggested that climate change is already beginning to affect groundwater resources in a number of countries.

Although in some regions such as Northern Europe may experience more rainfall as a result of climate change, this may not necessarily be a good thing for farmers in these areas, as evidenced by the disastrous effects extreme wet weather had on fruit and field crops in Western Europe in 2012.  

*Absolute water scarcity is reached when water supplies fall below 500 cubic meters per person per year.