s climate change and global warming reports dominate the mass media almost daily, water issues clearly present a defining environmental challenge for the world of the 21st century. Little wonder then that the United Nations has declared 2005–2015 the International Decade for Action — Water for Life.

Water matters because without it, all life on this planet will perish. In many cultures and religions, water holds sacred significance in terms of its curative powers, cleansing functions, mystical qualities, and purifying virtues. For East Asians (Chinese, Koreans, and Japanese), the geomantic practice of feng shui (wind and water) underscores the importance of water for good health, fertility, and fortune in the orientation of homes, businesses, temples, and cities. Christians baptise themselves with holy water (symbolising rebirth), and Muslims wash with water before entering a mosque. Many traditions revere bodies of freshwater, particularly rivers. Thais call their rivers mae nam or mother of waters, and Hindus worship the Ganges (venerating the goddess Ganga) as a sacred river that begins in the heavenly abode (Mount Meru) of their gods and deities. The Mekong River serves as home to Naga, the serpent symbolising rain and fertility for Thais, Laotians, and Cambodians. For Dayaks of Sarawak, rivers act as the passageways between this world and the spiritual one.

Besides spiritual symbolism, water remains the basis of all life. Yet the amount of water that sustains our global community of 1.6 million known species to date has shrunk. Whereas water bodies cover 71% (13.6 billion cubic kilometres) of the earth's surface, 97.34% of that water takes the form of saltwater while 66% of freshwater stays frozen in glaciers and the polar caps (Table 1). Thus, the current 6.6 billion human population depends only on groundwater and non-frozen sources of freshwater, which together represent merely 0.61% of the total global water resources.

Although negative media may have exaggerated many scenarios, the global community should perhaps err on the side of caution rather than optimism when it comes to water, which heads the environmental agenda because its absence has dire consequences on health and life. Despite some ecologists’ attempts to maintain a biocentric or geocentric perspective on environmental issues, the worldwide community remains adamantly anthropocentric (human-centred) in its perceptions, policies, and prescriptions.

The World Bank estimates that 40% of the world's population lacks sufficient access to water, and the World Health Organization (WHO) reports that 1.1 billion people have no access to clean and safe water. The Chinese government, which certainly takes its water problems seriously, has compiled an 824-page analysis of China's water situation.

Based on the United Nations’ rather liberal estimates of 2,740 litres per person per day, global supplies of water from various sources should prove adequate, despite the fact that global water consumption has increased from 110km3 in 1700 to about 5,200km3 today, a 47-fold increase over the last 300 years. The optimistic viewpoint points out that current rates of global precipitation on land (113,00km3) should give the world community a net water deposit (after evaporation) of 41,000km3 every year or 30cm (one foot) of water across the world's entire land mass. The UN reports, however, a decline in available water: between 1970 and 1990, average water supplies per person dropped by one third.

Geographical, agricultural, political, economic, and social issues combine to call up the spectre of an impending water crisis. First, geography provides an immensely unequal distribution of precipitation and open water. Iceland has 2 million litres of water for every inhabitant daily whereas each Kuwaiti has to make do with 30 litres. Deserts and arid land expanses hold little water.

Within regions and countries, rainfall varies greatly. Northern China faces severe drought regularly, while southern China often experiences heavy flooding. Although Bangladesh may be water-rich, it is lashed by typhoons and monsoon downpours that claim hundreds, even thousands, of lives yearly. To understand the regional climatic differences requires what Australian palaeontologist and global-warming activist Tim Flannery calls “atmosphere telekinesis” in which regional climatic disruptions can have global consequences. For example, the El Niño–La Niña western-Pacific heating phenomenon has had a devastating impact worldwide in terms of hurricanes, floods, drought, and heat waves.

Second, agriculture and food security require water. Agriculture accounts for about 70% of total water consumed by human beings. Even though daily water intake averages 4 litres per person, 2,000 litres of water is required to produce his or her daily food. Thus, agrarian countries utilise a lot more water than industrial or service-orientated ones. In India, for example, farmers use pumps and wells to tap underground water for their crops. As population and agricultural production have grown, these wells have increased from 800,000 in 1975 to 22 million in 2002, thereby reducing the water table by one metre a year in some places.

In Uttar Pradesh, of the 2,700 wells the government dug between 1970 and 1985, 2,300 were dry by the 1990s. Without water, agricultural production falls. In northern China, a shortage of water led to a 30% drop in the wheat harvest between 1997 and 2003. Irrigation represents a boon for agricultural production but a bane for water consumption. Areas under irrigation have expanded from 8 million hectares in 1800 to 40 million hectares in 1900 and 275 million hectares in 2000. However, surface-water irrigation efficiency is low (translating into high wastage) in many less developed countries: 25 to 40% in India, Mexico, Pakistan, the Philippines, and Thailand.

Despite increases in irrigation in rural areas, the Malthusian dilemma — that population tends to increase faster than the food supply with inevitably disastrous results unless moral restraints or war, famine, and disease increase to check the population — seems to loom once again. Global food production rose 2.12% between 1950 and 1990 but decreased to 1.2% annually from 1990 to 2000. In contrast, the world population increases by 70 million annually. In China, the largest populated country (1.3 billion), grain production plunged from its historical high of 392 million tons in 1998 to an estimated 358 million tons in 2005. Water shortages resulted in more than 21% fall in Chinese rice and wheat production from 1997 to 2005. When China cannot confirm its food security by 10%, the figure translates to more than 100 million affected citizens.

Third, the growth of urban populations worldwide (49% in 2005) has resulted in massive changes in demand for water and other facilities. As more people flock to cities, the pressure on water resources builds. In developed countries, over 75% of the people live in cities; in the developing world, the rural migration to metropolises has also become more pronounced. A growing urban population depends on imported food and water. A household of five needs 120 litres per day (24 litres per person) to meet basic needs.

In many cities of the developing world, households lack ready access to clean water. In Africa and Asia, 35 to 50% of urban dwellers have insufficient water. One solution — building more dams to supply water and energy — can have drastic consequences on river ecology and surrounding areas. In the end, rivers might become severely affected and fail to supply the water essential for living organisms. Lester Brown, founder of the Worldwatch Institute, notes that many major rivers — the Colorado, Yellow River, Indus, Nile, and Ganges — have decreased water supplies and are indeed running dry. Similarly, major lakes around the world are disappearing as water tables fall rapidly: Lake Chad (Africa), Aral Sea (Asia), Sea of Galilee (Middle East), Mono Lake (US), Dead Sea (Jordan), Lak Dal (India), and Lake Chapala (Mexico).

Fourth, the simultaneous regional scarcity and oversupply of water have links to global warming, greenhouses gases, and climate change, all which deleteriously affect water budgets and precipitation output around the world. Climate and weather are no longer natural processes. The combination of motor vehicles (850 million cars worldwide in 2006), industrialisation, urban concentration, deforestation, agricultural activities, and fossil-fuel usage has contributed to the rise of carbon dioxide (CO2) over the last century. People can no longer discount the human impact on the environment with the exponential population growth of nearly five billion in the 20th century.

Chemistry Nobel laureate Paul Crutzen, known for his research on ozone depletion, has added a new geological epoch called the Anthropocene, the age of humanity, which studies human influence on climate. Tim Flannery poignantly explains that human beings have now become “the weather makers,” whose hands hold the future of biodiversity and civilisation. More shocking, according to Flannery, is that by 2050 human influence on climate will have surpassed all natural influences, and no future climatic acts of God will occur, only human-made climatic disasters. In short, water supplies will no longer be products of nature but, rather, will be man-made.

Like all issues that confront and challenge humanity, the global community needs to combine political, economic, cultural, and social initiatives to manage water scarcity and deal with the growing water crisis. One cannot isolate water from other environmental issues or separate it from the web of human activity.

Ironically, global environmental issues require countries and other stakeholders to sacrifice their national economic and political agendas for the global common good.

Water and the rise in CO2 constitute issues that affect everyone. Common-pool resources are global public goods with two characteristics: subtractability or rivalry, plus the temptation of free riders. In this author's opinion, when the US and Australia refused to sign the Kyoto Protocol limiting CO2, they displayed selfish national economic interests.

In this unequal world, economics determines who can afford the luxury of liberal water use. A European Union resident uses 566 litres of water per day, but an affluent American utilises 1,442 litres every day. Oil-rich Middle Eastern states can enjoy imported water despite living in the desert. Essentially, such Arab states possess the financial power to expand their water footprint thanks to their petrodollars. The people of poor countries such as the Sudan and Ethiopia find water unaffordable because nature has not blessed them.

For such water-scarce countries as Singapore that rely on imported water, political tensions and national security drive a quest towards self-sufficiency. To reflect the importance of water to Singapore, the Ministry of the Environment changed its name to the Ministry of the Environment and Water Resources. The city-state has explored diverse water sources — desalination, water recycling, reservoir expansion, rainwater-run-off trapping, and water-usage reduction. Its water supply now comes from four sources: water from local catchments, water imported from Malaysia, reclaimed water, and desalinated water. Technology for ensuring safe and clean water has come about at great cost in terms of research and investment.

Singapore's success story in managing water effectively and efficiently has now gained international recognition. The city-state received the Stockholm Industry Water Award 2007, and WHO has inked an agreement to use the country's water expertise to help other water-stressed countries.

Despite Singapore's achievements in developing self-sufficiency in domestic water consumption, it still imports water via food importation. Given that the production of one tonne of grain requires 1,000 tonnes of water, Singapore, like many food-importing countries, indirectly relies on overseas water sources as imported food becomes part of the international virtual water trade. Hence, as responsible global citizens, every individual's commitment counts towards protecting common global environmental resources, particularly water.

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