Adapting to a New Normal
When it comes to water, the past is no longer a reliable guide to the future
Water, like energy, is essential to virtually every human endeavor. The growing number of water shortages around the world and the possibility of these shortages leading to economic disruption, food crises, social tensions, and even war suggest that the challenges posed by water in the coming decades will rival those posed by declining oil supplies.
In fact, our water problem turns out to be much more worrisome than our energy situation, for three main reasons. First, unlike oil and coal, water is much more than a commodity: it is the basis of life. Our decisions about water – how to use, allocate, and manage it – are deeply ethical ones; they determine the survival of most of the planet's species, including our own. Second, also unlike oil and coal, water has no substitutes. The global economy is transitioning away from fossil fuels, but there is no transitioning away from water. And third, it is through water that we will experience the impacts of climate change most directly.
The rise in global temperatures driven by the last 150 years of humanity's greenhouse gas emissions is fundamentally altering the cycling of water between the sea, the atmosphere, and the land. Climate scientists warn of more extreme floods and droughts and of changing precipitation patterns that will make many dry areas drier and wet areas wetter. They warn of melting glaciers and ice caps that within a few decades could severely diminish the river flows upon which nearly a third of the world's people depend.
The effects of climate change are already calling into question the very assumptions that have underpinned water planning and management for decades. In 2008, seven top water scientists argued persuasively in the journal Science that "stationarity" – the foundational concept that natural systems vary and fluctuate within an unchanging set of boundaries-is no longer valid for our understanding of the global water system. In other words, when it comes to water, the past is no longer a reliable guide to the future. The data and statistical tools used to plan $500 billion worth of annual global investments in dams, flood-control structures, diversion projects, and other big pieces of water infrastructure are no longer trustworthy.
The water challenges confronting us locally, regionally, and globally are unprecedented. They call for fundamental changes in how we use, manage, and even think about water. The good news is that it's within our economic and technological ability to have a future in which all food and water needs are met, healthy ecosystems are sustained, and communities remain secure and resilient in the face of changing circumstances. The path most of the world is on, however, will not lead to this more desirable state.
How we got here
Although renewable, freshwater is finite: The quantity available today is virtually the same as when civilizations first arose thousands of years ago. As world population grows, the volume of water available per person decreases; thus, between 1950 and 2009, as world population climbed from 2.5 billion to 6.8 billion, the global renewable water supply per person declined by 63%.
For most of modern history, water management has focused on bringing water under human control and transferring it to expanding cities, industries, and farms. Since 1950, the number of large dams has climbed from 5,000 to more than 45,000. Globally, 364 large water-transfer schemes move 400 billion cubic meters (1 cubic meter equals about 264 gallons) of water annually from one river basin to another – equivalent to transferring the annual flow of 22 Colorado Rivers. Millions of wells tap underground aquifers, using diesel or electric pumps to lift vast quantities of groundwater to the surface.
But the benefits of water development have not been shared equitably. More than 1 billion people lack access to safe drinking water, and some 850 million people are chronically hungry. Moreover, many regions have overshot their sustainable limits of water use. An unsettling number of large rivers-including the Colorado, Rio Grande, Yellow, Indus, Ganges, Amu Darya, Murray, and Nile-are now so overtapped that they discharge little or no water to the sea for months at a time. The over-pumping of groundwater is causing water tables to fall across large areas of northern China, India, Pakistan, Iran, the Middle East, Mexico, and the western United States. As much as 10 percent of the world's food is produced by over-pumping groundwater. This creates a bubble in the food economy far more serious than the recent housing, credit, or dot-com bubbles, for we are meeting some of today's food needs with tomorrow's water.
In a world of changing rainfall patterns and river flows, substantial hydrologic uncertainty, and rising energy costs, such projects are risky. They often worsen social inequities, such as when poor people are dislocated from their homes to make way for the dams and canals and "downstream" communities lose the flows that sustained their livelihoods. And serious environmental damage routinely follows on the heels of such projects. Moreover, large-scale infrastructure built to accommodate river flows today may be poorly matched to climate-altered flows of the future.
In addition, giant water projects require giant quantities of energy. Pumping, moving, treating, and distributing water take energy at every stage. The energy required to provide drinking water to a typical southern California home can rank third behind that required to run the air conditioner and refrigerator.
A Smarter Path toward Water Security
As with many challenges, finding the best solutions requires first asking the right questions. Typically, when planners and engineers see a water shortage on the horizon, they ask themselves what options exist to expand the supply. The typical answer: Get more water from a distant river, deeper wells, or a desalination plant.
But as the limitations of these "supply-side" options have become more apparent, a vanguard of citizens, communities, farmers, and corporations has started asking a different question: What do we really need the water for, and can we meet that need with less? The upshot of this shift in thinking is a new movement in water management that is much more about ideas, ingenuity, and ecological intelligence than it is about pumps, pipelines, dams, and canals.
This smarter path takes many forms, but it embodies two strategic attributes. First, solutions tend to work with nature, rather than against it. In this way, they make effective use of "ecosystem services" – the benefits provided by healthy watersheds, rivers, wetlands, and other ecological systems. And second, through better technologies and more informed choices, these solutions seek to raise water productivity - the benefit derived from each liter of water extracted from a river, lake, or aquifer.
Working with nature is critically important to building resilience and reducing the energy costs associated with water delivery and use. Healthy rivers and watersheds, for instance, filter out pollutants, mitigate floods and droughts, recharge groundwater supplies, and sustain fisheries. They do this work with free energy from the sun. By contrast, all the technological alternatives - building and running a treatment plant to remove pollutants, artificially recharging groundwater, constructing dikes and levees, raising fish on farms -require external inputs of increasingly expensive energy.
Of course, one of the most important "services" healthy watersheds perform is the provision of clean drinking water. If a watershed is doing the work of a water treatment plant – filtering out pollutants, and at a lower cost to boot – then it often pays to protect that watershed. New York City, for instance, is investing some $1.5 billion to restore and protect the Catskills-Delaware watershed (which supplies 90% of its drinking water) in lieu of constructing a $6 billion filtration plant that would cost an additional $300 million a year to operate.
Other innovative ideas are coming from Latin America, where some cities are establishing watershed trust funds. For instance, Rio de Janeiro in Brazil collects fees from water users to pay upstream farmers and ranchers $71 per hectare ($28 per acre) to protect and restore riparian forests, safeguarding the water supply and preserving habitat for rare birds and primates. A public watershed protection fund in Quito, Ecuador, started in 2000 in partnership with the Nature Conservancy, receives nearly $1 million a year from municipal water utilities and electric companies. Quito's water fund has become a model for other Latin American cities.
There are many ways communities can work with nature to meet their water needs while reducing energy costs and building resilience. Communities facing increased flood damage, for instance, might achieve cost-effective flood protection by restoring a local river's natural floodplain. After enduring 19 flood episodes between 1961 and 1997, Napa, California, opted for this approach over the conventional route of channelizing and building levees. In partnership with the Army Corps of Engineers, the $366 million project is reconnecting the Napa River with its historic floodplain, moving homes and businesses out of harm's way, revitalizing wetlands, and constructing levees and bypass channels in strategic locations.
Many communities are revitalizing their rivers by tearing down dams that are no longer safe or serving a justifiable purpose. Over the past decade some 430 dams have been removed from US rivers, opening up habitat for fisheries, restoring healthier water flows, improving water quality, and returning aquatic life to rivers. In the ten years since the Edwards Dam was removed from the Kennebec River near Augusta, Maine, fish populations have returned in astounding numbers, reviving a recreational fishery that adds $65 million annually to the local economy.
Of all the water we withdraw worldwide from rivers, lakes, and aquifers, 70 percent is used in agriculture, 20 percent in industries, and 10 percent in cities and towns. With water supplies tightening, we will need roughly a doubling of water productivity by 2025 to satisfy human needs while sustaining nature's life-support systems. Fortunately, opportunities to get more benefit per drop abound through greater investments in conservation, efficiency, recycling, and reuse, as well as through shifts in what is produced where and when.
Water for Food
Feeding the world is a very water-intensive enterprise. It takes about 3,000 liters of water to meet a person's daily dietary needs. In the United States, with its high consumption of meat (especially grain-fed beef), the average diet requires some 5,000 liters of water per day. Under some very conservative assumptions, it could take as much water as the annual flow of 73 Colorado Rivers to meet the world's dietary needs in 2025.
Once again, the search for solutions needs to begin with a reframing of the question. Instead of asking where we can find 73 Colorado Rivers' worth of water, the question is: How do we provide healthy diets for 8 billion people without going deeper into water debt?
There are many ways we can grow more food for the world with less water. Here are a few examples.
Irrigate more efficiently: For the last two centuries, societies have focused on expanding irrigation as a key to raising crop production. Today, much of the water withdrawn for farming never benefits a crop. Some of it seeps back into aquifers or nearby streams, while some evaporates back to the atmosphere. There are many ways to reduce the waste: Irrigation can be scheduled to better match crop water needs, for example, or drip irrigation can be used to curb evaporation losses. Reducing irrigation demands by even 10% could free up enough water to meet the new urban and industrial demands anticipated for 2025.
Boost yields on rain-fed lands: By one estimate, 75% of the world's additional food needs could be met by increasing harvests on low-yield farms to 80% of what high-yield farms achieve on comparable land. Most of this potential is in rain-fed areas, and it's achievable through small-scale technologies and improved field methods - including, for example, capturing and storing local rainwater to apply to crops via low-cost irrigation systems. Because the majority of the world's poor and hungry live on rain-fed farms in South Asia and sub-Saharan Africa, raising the farms' productivity would directly boost food security and incomes.
Choose less water-intensive diets: Foods vary greatly both in the amount of water they take to produce and in the amount of nutrition they provide. It can take five times more water to supply 10 grams of protein from beef than from rice, for example, and nearly 20 times more water to supply 500 calories from beef than from rice. If all US residents reduced their consumption of animal products by half, the nation's total dietary water requirement in 2025 would drop by 261 billion cubic meters per year, a savings equal to the annual flow of 14 Colorado Rivers.
One of the biggest untapped potentials for smarter water management in all types of enterprises lies in more creative use of information technologies: meters, sensors, controllers, computers, and even cell phones. In Ugandan villages, farmers lacking computers are getting access to the wealth of information on the Internet by calling their questions in to a free telephone hotline called Question Box. The operators, who speak the local language, search for the answers and call the farmers back. A project of Open Mind, a California-based nonprofit, Question Box enables poor farmers, whose only communication device may be a village phone, to connect to the wired world for information on crop prices, weather forecasts, plant diseases, and more.
The potential uses of information technology to enable smarter water decisions are extensive and have only begun to be tapped. Using GIS (geographic information system) technology, for example, the World Wildlife Fund (WWF) recently identified more than 6,000 traditional water tanks (small reservoirs to capture rainfall or runoff) in a single sub-watershed in western India. WWF determined that if the tanks were restored to capture just 15 to 20 percent of local rainfall, they could hold some 1.74 billion cubic meters of water - enough to expand irrigated area in the region by 50% and at a cost per hectare just one-fourth that of an irrigation dam-and-diversion project proposed for the region.
Resetting the Signals
Most of the world's water shortages have arisen because the policies and rules that motivate decisions about water have encouraged inefficiency and misallocation rather than conservation and wise use. Without big dams and river diversions subsidized by taxpayers, for example, rivers and streams in the western United States would not be so severely depleted today. And without low, flat rates for electricity, India's groundwater would not be so severely over-pumped.
Allowing markets to do what they can do well – send a price signal about water's value – is critical for encouraging investments in water efficiency and more sensible uses of water. Most governments in rich and poor countries alike, however, continue to send the wrong signal by heavily subsidizing water, especially for irrigation, the biggest consumer. While better pricing is essential, it doesn't automatically account for the many important benefits of rivers, lakes, wetlands, and streams that are not recognized in the marketplace. It is the job of governments, as custodians of the public trust in water, to protect these important but often unrecognized values, and it is the job of citizens to demand that their elected officials get busy crafting creative solutions.
Current pricing and policy signals are deeply misaligned with the realities of our water predicament, but this means that there are untold opportunities for improvement. For example, a cap on groundwater pumping from the Edwards Aquifer in south-central Texas has motivated farmers, businesses, and citizens to conserve. San Antonio has cut its per capita water use by more than 40%, to one of the lowest levels of any western US city.
It is critical that policy-makers begin to grapple with the inconvenient truth that supplying water takes energy and supplying energy takes water. Energy and water are tightly entwined, and all too often public policies to "solve" one problem simply make the other one worse. For example, the 2007 mandate of the US Congress to produce 15 billion gallons of corn ethanol a year by 2015 would annually require an estimated 6 trillion liters of additional irrigation water – a volume exceeding the annual water withdrawals of the state of Iowa. Even solar power creates a demand for water, especially some of the big solar-thermal power plants slated for the sunny Southwest. Clearly any action we take to build local renewable energy sources must be careful not to add additional strain to our already-stressed rivers and aquifers.
The win-win of the water-energy nexus, of course, is that saving water saves energy, and saving energy saves water. The more a community lives on water, energy, and food produced locally, the more options arise for solving multiple problems simultaneously, building resilience through resourcefulness, and preparing for future uncertainties.
Sandra Postel directs the Global Water Policy Project and is a fellow of the Post Carbon Institute. She is the author of several books, including Last Oasis: Facing Water Scarcity, and a member of International Rivers. A longer version of this article, including references, appears in the Post Carbon Institute Reader.