With drought conditions continuing across most of the country, we are increasingly conscious of the need to conserve water. But most people are unaware that each individual’s full impact on water reserves extends far beyond what comes out of the tap.

Recent research carried out by the University of Sydney’s Centre for Integrated Sustainability Analysis found that, on average, each dollar of consumption is responsible for 28 litres of water “embedded” in products and services. Obviously, this figure varies enormously across different sectors.

 

The century of water scarcity

In 2000, an international gathering of water ministers at The Hague resulted in a joint declaration that emphasised the global importance of water security. Although in a worst-case scenario wars might be fought over diminishing water sources, countries have the opportunity to instead work together to find cooperative solutions.

Foreseeing a growing world population and increasing water demand, UNESCO has predicted that water shortages will become a major international problem by 2020 and that the available water per person will drop by a third over the next two decades. In the future, water will be a critical factor in determining how much food can be grown, particularly where irrigation techniques are being employed.

Somewhat alarmingly, the world produces twice as much food as it did in the 1960s, but requires three times as much water to grow it. The overall trend has been towards reduced rather than improved efficiency. Around the world, groundwater reserves are being unsustainably depleted, causing water tables to fall.

Many eyes are on China, where industrialisation, coupled with a continuing trend towards urbanisation, is putting pressure on water supplies, particularly in the more arid north of the country. Water demand from Chinese industry alone is expected to increase by 104 per cent between 2010 and 2030. Similar challenges exist in India, where industrial water demand is set to triple by 2025.

Despite being the world’s driest inhabited continent, Australia paradoxically has the highest per-capita water consumption. Yet before water-frugal city dwellers feel deeply guilty, they should bear in mind that around two-thirds of this total is used in irrigated agriculture and a remarkably large 80 per cent of agricultural commodities are grown for export. As individuals, our decisions do, however, determine the quantity of water embedded in the everyday purchases we make.

 

When is water not real water?

As thinking on the subject of global water management has evolved, some new concepts have been introduced as tools for relieving pressure on countries’ water resources, thereby helping to ensure food security. In 1993, London-based hydrologist Tony Allan originated the term “virtual water” (interchangeable with “embedded water”), which can be defined as the volume of water required to grow or manufacture a particular product. The term “virtual” was chosen to reflect the fact that only a negligible amount of the total water usage is contained within the finished item.

Virtual water can be divided into three components, each of which is identified by a colour. Green indicates rainwater, while blue can refer to either surface water or groundwater. Both blue and green water are ultimately lost via evaporation, while grey indicates water that is polluted by a particular activity. At present, nearly all water consumed by agriculture and industry is blue water. Pressure on this valuable resource could be relieved by a move towards greater use of green rainwater.

 

The virtual water concept is being continuously developed by WaterFootPrint, a joint initiative between the University of Twente in the Netherlands and UNESCO. Awareness-raising work in the same field is also being carried out by UK NGO, Waterwise. Some of the statistics they have uncovered are truly mind-boggling. According to Waterwise, one computer chip uses 75 litres of water in its manufacture, while a car requires 150,000 litres. But the farming sector dwarfs all the others.

Fred Pearce, author of When the Rivers Run Dry, believes crops could be grown with roughly a quarter of their current water usage, but the financial incentives to do so are lacking. Water prices are often kept artificially low through government subsidies, and Pearce believes water engineers have a “supply-side fixation” that ignores demand management.

To discover more, WaterFootPrint has been concentrating on the agricultural arena and, rather than repeat secondhand data, it has been carrying out its own independent research. The following virtual water figures are based on global averages:

 

How much water does it take?

• 1kg apples – 700 litres
• 1 glass of apple juice (200ml) – 190 litres
• 1kg barley – 1300 litres
• 1kg beef – 15,500 litres
• 1 glass beer (250ml) – 75 litres
• 1kg cheese – 5000 litres
• 1kg chicken – 3900 litres
• 1kg coconut – 2500 litres
• 1kg coffee – 21,000 litres
• 1kg cotton – 11,000 litres
• 1kg eggs – 3300 litres
• 1kg goat meat – 4000 litres
• 1kg leather – 16,600 litres
• 1kg maize – 900 litres
• 1kg millet – 5000 litres
• 1 litre milk – 1000 litres
• 1kg milk powder – 5000 litres
• 1kg oranges – 500 litres
• 1 sheet paper – 10 litres
• 1kg pork – 4800 litres
• 1kg rice – 3400 litres
• 1kg sheep meat – 6400 litres
• 1kg sorghum – 2800 litres
• 1kg soybeans – 1800 litres
• 1kg sugar – 1500 litres
• 1kg tea – 9200 litres
• 1kg wheat – 1300 litres
• 1 glass wine (125ml) – 120 litres

Other statistics that are specific to Australia have been compiled by Wayne Meyer, University of Adelaide Professor of Natural Resource Science. He points out that in the case of dryland cropping, the following water usages would be even higher if losses of irrigation water en route were taken into account:

 

Australian statistics

• 1kg beef – 50,000-100,000 litres
• 1kg clean wool – 170,000 litres
• 1kg maize – 540-630 litres
• 1kg rice – 1550-2000 litres
• 1kg soybeans – 1650-2,200 litres
• 1kg wheat – 715-750 litres

 

 

A brief glance at both lists shows the weakness inherent in quantifying virtual water volumes. Figures vary significantly from country to country based on climatic conditions and differences in farming practices. A choice of measurement criteria can also result in substantial variations.

As a rule, animal foods and byproducts generally require more virtual water than non-animal foods. This is largely due to animals’ appetite for grain, their thirst for non-virtual water and, in the case of intensive animal rearing, the grey water required to flush away their wastes. A vegetarian diet requires about 1500 litres per day, whereas a meat-based diet requires around 4000 litres. Modifying one’s eating habits is one means of relieving pressure on water supplies.

WaterFootPrint also looked at the industrial sector, but found that, because of differing production processes from country to country, the figures were too disparate. As a ballpark average, it assumes that approximately 80 litres is used for every US $1 (AU $1.12, correct at time of printing) of product. Again, this varies considerably according to the country of manufacture. A dollar’s worth of product made in the US has a virtual water content of approximately 100 litres, a figure that greatly exceeds the estimates for Germany and the Netherlands (50 litres), China and India (20-25 litres) and Australia, Japan and Canada (10-15 litres).

 

Water footprint

During the 1990s, Mathis Wackernagel and William Rees originated the concept of the ecological footprint, a term for the total area of productive land and ocean required to meet the demands of an individual or population. This useful concept can be used to determine whether personal or national consumption patterns are operating within, or overshooting, ecological limits. Today, the ecological footprint has taken centre stage in sustainability planning. See the Big W Catalogue as well.

In 2002, Dutch researcher Arjen Hoekstra came up with a similar idea. His “water footprint” is essentially the total volume of fresh water used to produce the goods and services consumed by an individual, business or nation. As with the ecological footprint, this area of investigation is attracting ever-increasing attention.

Like the ecological footprint, the water footprint is initially an unfamiliar concept for many people and a change in perception is required in order to shift consumer behaviour. Water footprint calculation tools are starting to appear and, not surprisingly, one can be found on the WaterFootPrint website.

A country’s water footprint can be further split into an “internal” component, representing the impact on its own water resources, and an “external” component, indicating the pressure on water resources in other countries. When applied to a nation, “water self-sufficiency” indicates the ratio of the internal water footprint to the total water footprint and measures the degree to which demand for products and services is met by water supplies found within its own territory. Conversely, “virtual water import dependency” represents the ratio of the external water footprint to the total water footprint. A number of European and Middle Eastern countries including the Netherlands, Malta and Kuwait are the most dependent on external water.

 

Trading in virtual water

With significant and growing international trade in products and commodities, countries are becoming increasingly interconnected in a globalised framework. WaterFootPrint estimates that around 15 per cent of all the world’s virtual water (about 1000 cubic kilometres a year!) is used for exports, and has dubbed this chunk the “virtual water trade”. In recent years, it has mapped the national imports and exports of virtual water and these can be quite revealing.

 

Where total virtual water exports are deducted from virtual water imports, this yields what has been termed a “virtual water balance”. A positive balance represents a net import of virtual water, whereas a negative balance indicates a net export. The top virtual water exporters (Australia, Canada and the US) are all industrialised countries with extensive land areas, while the major importers (Japan, Italy and the UK) are smaller, more densely populated industrialised nations.

Viewed from a global perspective, the largest chunk (67 per cent) of the virtual water trade relates to trade in crops, while 23 per cent is associated with livestock and animal byproducts and the remaining 10 per cent is embedded in industrial products. In some countries, including the US and Thailand, exported virtual water has been linked to the unsustainable exploitation of aquifers.

One final concept that has been developed by the WaterFootPrint team is “water saving through trade”. This indicates the use of the virtual water model to avoid depleting a country’s water by importing a particular water-intensive product rather than producing it onshore.

Overall, water supplies are conserved where such a product is exported from an area with high “water productivity” (lower virtual water use per unit of production) to an area with low “water productivity” (higher virtual water use per unit.) As an example, both Israel and Jordan have policies to curb the export of water-intensive products such as citrus fruit. Water-starved regions benefit from growing crops that require little water, such as dates, grapes and olives, as alternatives to thirstier options.

Professor Jennifer McKay of the University of South Australia has proposed the establishment of a virtual water trading council operating within the World Trade Organization that could benefit developing countries and help to alleviate poverty. This council would ensure that water diverted from use when products or commodities are imported is directed to improving sanitation arrangements in the importing country.

Unfortunately, water saving through trade is undermined by the understandable preference of countries such as China and India to remain as self-sufficient in food as possible rather than depend more deeply on the vagaries of global trade. The growing issue of climate change also provides a strong argument against boosting the international movement of agricultural commodities if they can be grown close to home.

At a real, rather than virtual, level, Turkey exports fresh water to Israel and Cyprus in giant balloons capable of holding up to 5 million gallons. Unfortunately, this surreal endeavour is unlikely to be sustainable. With an anticipated growth in the “real water” trade, a holistic strategy is needed that adjusts to limitations in water availability while curbing energy use from water transportation.

 

An Australian perspective

Compared with the global average water footprint of 1243 cubic metres per capita per year, Australia’s is slightly higher at 1393 cubic metres. This breaks down into 82 per cent self-sufficiency and 18 per cent import dependency. During the period 1997-2001, Australia was notable as the world’s largest exporter of virtual water, with a huge minus balance in the agricultural sector, particularly cereal products that represent the bulk of our farm exports.

While 8 per cent of Australia’s water consumption goes to industry, and 2 per cent to mining, irrigated agriculture dominates the picture with 70 per cent of the total. A significant proportion of all irrigation water is either lost via evaporation, seeps too deeply into the ground to reach plant roots or is lost as runoff. Essentially, the drying-up of inland areas such as the Murray Darling Basin has been exacerbated by our export-driven agricultural sector, prompting the recent moves towards a federal takeover.

 

Continuing drought conditions have prompted a fundamental shift in development thinking by government figures such as Senator Bill Heffernan, chair of the Prime Minister’s Northern Taskforce. He reminds us that, while agriculture (and also population) are concentrated in the water-scarce south, about 94 per cent of the country’s runoff is in the north. A shift towards increasing agricultural development in the tropics would match the availability of water.

Environmentalists, however, argue that most of the northern soils are unsuitable for agriculture, and water flow is concentrated in the wet season between December and February. Heffernan is looking at growing commercial crops such as cotton in the Ord Valley area of Western Australia near Broome, prompting concerns about the proposed use of genetically engineered varieties. With an eye on cotton cultivation in the north, the WA government has come under pressure from farmers’ groups keen to overturn its current moratorium on commercial GE crops.

 

Looking for solutions

The World Wildlife Fund has been looking carefully at these big-picture water issues. It urges the farming community to adopt more water-efficient practices such as growing crops that are suited to the area and reducing water losses through techniques such as ultra-efficient drip irrigation. Its Better Cotton Initiative is one such program.

One often-overlooked solution is organic farming, which across the board requires less water usage due to careful water management and mulching practices. Moreover, the avoidance of chemical use avoids the risk of turning blue groundwater into grey polluted groundwater.

As we face the challenge of achieving a sustainable global water management regime, virtual water is likely to play an increasingly central role. With a growing world population and shrinking water resources, we need to use this model to rethink current consumption and trade patterns while improving the efficiency of water-intensive activities.

Martin Oliver is a writer and researcher based in Lismore (northern NSW.) He is also an independent distributor for the Ecoflow range of fuel-saving units for cars and gas systems. E: moliver70@yahoo.com.au