Water – essential, finite, and increasingly scarce – has been dubbed “the new oil.” Experts debate whether human societies are approaching “peak water,” beyond which lies a bleak future of diminishing supplies and soaring demand. Others observe that, for many, the water crisis has already arrived.

Indeed, if any resource poses a serious limit to growth on human numbers and appetites, it would have to be water. The planet’s supply of freshwater is fixed, and there is no substitute for its life-giving qualities.

Still, a general water crisis is not inevitable. It is true that people are placing unsupportable stress on freshwater supplies in many areas, while climate change threatens the quantity and reliability of those supplies. And population dynamics, especially growth and migration, contribute to the problem in ways both obvious and less so. However, a broad range of supply- and demand-side solutions are available and implementing those solutions could relieve – and avert – tremendous human suffering.

The “water crisis,” as reported in the media, is actually two oft-conflated crises. First, there is the physical scarcity of water, experienced in arid areas from Yemen to the American Southwest. Second, there is the shortage of safe drinking water, typically caused by a lack of infrastructure in poor countries – even those with plenty of rainfall, such as Uganda. Some regions – notably the Horn of Africa – struggle with both crises at once.

Assessing Scarcity

Physical scarcity of water is a significant and growing problem. Although we live on a planet that is covered with water, very little of that is fresh: in fact, if all of the world’s water could fit into a gallon jug, the freshwater available for our use would equal only about one tablespoon. In addition, that tiny sip of water is distributed very inequitably. So, while there is no global shortage, a growing number of regions are chronically parched.

Today, about one third of the world’s population lives in countries with moderate to high water stress; by 2025, largely because of population growth, fully two out of three of the world’s people will live under those conditions. A recent McKinsey and Company report warns that within two decades, demand for water will exceed supply by 40 percent.

Human numbers are growing most rapidly where water is scarce. The World Bank’s Water and Development report identified 45 “water poor” countries that are both physically short on water and economically impoverished. Those countries have an average fertility rate of 4.8 children per woman – nearly twice the world average – and their populations are expected to double by 2050. “Rapid population growth makes water problems more complicated and difficult to solve,” said Sandra Postel, director of the Global Water Policy Project, in an interview.

When water-stressed countries lack surface water supplies, they typically resort to overpumping underground aquifers, drawing down wells faster than they can be replenished. As a result, groundwater levels have dropped precipitously in many places over the past nine years, and wells have gone dry in parts of India, China, and Pakistan.

The depletion of groundwater is an ominous sign for world food production, which must increase 70 percent by 2050 to meet the demands of a growing world population. Postel estimates that 10 percent of world food production now depends on the overpumping of groundwater.

And then there is the wild card of climate change, which has already begun to disrupt rainfall patterns and intensify drought in many parts of the world. The famine ravaging the Horn of Africa may be a harbinger of what is to come for fragile nations. Many countries, including Kenya and Ethiopia, are likely to experience longer, harsher droughts, which – superimposed on existing water scarcity, rapid population growth, poor governance, and poverty – could create the conditions for widespread starvation and misery.

In another grim development, climate change is melting glaciers and snowpack on the world’s great mountain ranges, including the Himalayas, Hindu Kush, and Andes, which supply drinking water for one in six of the world’s people. New evidence shows that those glaciers are disappearing faster than expected, leading to water shortages in Peru and elsewhere.

Quality and Delivery

The other water crisis – the shortage of clean drinking water – is not simply about the physical scarcity of water. Nor is it simply about poverty, though more funds are needed to address the problem.

Today, nearly a billion people lack access to clean drinking water; 2.5 billion lack adequate sanitation; and some 5 million die every year due to preventable water-related diseases.

Nowhere is the crisis more evident than in the fast-expanding cities of the developing world. Cities have seen explosive growth in recent decades, and the UN predicts that by midcentury the world’s urban population will nearly double, from 3.5 to 6.3 billion – an increase equivalent to the current population of China, India, and the United States combined. Developing regions as a whole will account for 93 percent of that growth; more than 80 percent will be in the cities of Asia and Africa.

It is safe to say that they are not ready. Most of those cities are already failing to provide basic services – including water and sanitation – to new arrivals, who typically occupy informal slums and shanty towns beyond the reach of municipal services.

For example, Dhaka has grown sixfold since 1975 and is now home to nearly 17 million people but has “water supply network coverage for only a small fraction of this population,” according to Pier Mantovani, lead water supply and sanitation specialist at the World Bank. As a result, in areas not served by official services, including the city’s slums, people pay exorbitant prices to middlemen with tankers selling water of dubious quality.

Here, too, population dynamics play a role. Migration, mostly from rural areas, accounts for roughly 40 percent of urban growth. That migration is spurred, in part, by rapid growth in the countryside, where the total fertility rate (average number of children born per woman) is usually higher. The remaining 60 percent of urban growth results from “natural increase,” meaning simply that there are more births than deaths. Population growth, then, is a driving force behind the breakneck pace of urbanization and compounds the challenges of providing safe water to city dwellers.

Silver Linings

Today’s twin water crises pose enormous challenges for human well-being and even survival. Without a dramatic change of course, water could indeed pose a severe “limit to growth” of the human enterprise. As Margaret Catley-Carlson, vice-chair of the World Economic Forum Global Agenda Council on water security, has written:

[I]f “business as usual” water management practices continue for another two decades, large parts of the world will face a serious and structural threat to economic growth, human well-being, and national security.

But there are alternatives to “business as usual.”

Consider this: despite its growing scarcity, vast amounts of water are wasted through inefficiency; growing water-intensive crops in dry areas or using drinking water for purposes (like flushing toilets) where non-potable “grey” water would suffice, for example. Such waste is a “silver lining,” said Postel. By reducing waste, “we can get the most value from limited water supplies.”

Rethinking pricing is key. Irrigation is heavily subsidized in many parts of the world; farmers typically pay just 15 to 20 percent of the cost of the water they use, according to Postel. Reducing those generous subsidies would make conservation more cost-effective.

Meeting the need for safe drinking water will require greater attention to the needs of the poor, especially in informal urban settlements. That, in turn, will require a mobilization of resources and political will. “In every country,” said Mantovani, “politicians swear that ‘water is life,’ and that providing safe drinking water is a critically important policy priority…but in many countries water supply is not adequately funded or supported.”

On the demand side, slower population growth would help reduce pressure on limited water supplies, providing some breathing room to develop creative solutions. As it happens, many water-poor countries also have high levels of “unmet need” for family planning – they are home to millions of women who want to prevent or postpone getting pregnant but aren’t using modern contraception. Investments in family planning programs could improve women’s health and well-being, slow population growth, and reduce vulnerability to water stress.

In short, solutions abound. “We can meet the water needs of seven billion and have healthy aquatic ecosystems at the same time,” said Postel. However, she added, “We are not moving toward those solutions at a rate commensurate with the problem.”