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WATER POLITICS

Via The Bulletin of Atomic Scientists, commentary on the definition of peak water in an era of climate change:

We live on a water planet, with vast amounts of water in the oceans, an extremely dynamic hydrologic cycle that brings renewable freshwater resources in the form of rain, snow, and river flows, and large stocks of groundwater. And because the Earth has pretty much the same amount of water today that it has had since the time of the very formation of the solar system more than 4 billion years ago, modern concerns about the so-called “scarcity” of water reflect not a change in the total amount of water, but the challenge of meeting the need for water and water services by growing populations and expanding economic demands. On top of these pressures is the challenge of human-caused climate change, imposed on an outdated system of water infrastructure and institutions created in an era of climate stability. The distribution and availability of water resources around the world are naturally highly variable, but climate change is making these variations worse. Addressing these water problems is one of the greatest challenges of our time.

“Water scarcity” means different things to different communities, but in its simplest form, it can be defined as a shortage of water required to meet a specific water demand—such as clean freshwater for drinking, cooking, cleaning, or growing crops, to name just a few. In recognition of this growing problem, the United Nations developed an explicit objective as part of their Sustainable Development Goals to “By 2030, substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity and substantially reduce the number of people suffering from water scarcity” (italics added).

Humans interact with the planet’s hydrologic cycle in multiple ways. We take water from rivers, lakes, and groundwater and use it directly or move it from one watershed to another. We use vast amounts of water to grow food, accounting for around 80 percent of all human uses of water. We build large dams on major rivers to generate hydroelectricity and protect against floods and droughts, but at the cost of damaging fisheries and free-flowing aquatic ecosystems. And we use our local water systems as dumps for our wastes of all kinds, contaminating vast quantities of water.

In recent years, resource crises around minerals, energy, food, and water have stimulated new debates over definitions and concepts of sustainability—including whether the world is reaching a point where natural limits will constrain growing populations and economic expansion. These concerns extend to worries about water scarcity, where regional water availability is no longer able to satisfy regional demands.

Peak water

One way to think about these water constraints is the concept of “peak water”—a term that refers to a situation where limits are being reached on expanding water withdrawals. (These withdrawals can come from either renewable sources, such as river flows, or from non-renewable stocks, such as groundwater aquifers that recharge very slowly. In both cases, the net effect is largely the same: Consumption is greater than the supply of what is readily and reliably available.)

For a growing number of watersheds around the world, peak water limits on rivers are already being felt. Many major river systems, such as the Colorado River in North America, the Huang He (otherwise known as the Yellow River) in Asia, the Jordan River in the Middle East, and others are at or are reaching peak water limits beyond which additional extraction isn’t possible—and water flows no longer reach their deltas for all or part of the year.

In some regions, a substantial amount of water used by humans comes from groundwater systems that are recharged naturally far less quickly than water is withdrawn by pumping. When water use exceeds recharge, stocks of groundwater are quickly depleted. The aquifers underlying the Great Plains and the Central Valley of the United States and those in northern China and parts of India and Pakistan are so heavily over-pumped that their water levels are falling rapidly, making further withdrawals physically and economically limited. Climate change is also playing a role in disrupting the availability of water resources and contributing to peak limits by altering demands and supplies of water, changing the intensity and frequency of extreme events, and affecting water quality.

When these kinds of renewable and non-renewable peak water constraints are reached, either new sources of water must be found through transfers from other regions, desalination, or water re-use, or demands must be reduced to sustainable levels. An important point about peak resource limits is that for some resources, such as oil, substitutes are available in the sense that energy demands can be satisfied by many alternatives. Unlike oil, however, fresh water is the only resource suitable for meeting most demands: There are no substitutes for water for most uses. These peak water concepts are important for efforts to sustainably manage and use freshwater resources and must now lead to fundamental shifts in thinking about water.

There is a third “peak water” constraint: the concept of peak ecological water. For many freshwater systems, even those not running out of water, human use or contamination of water is causing serious or irreversible ecological damages. When these damages exceed the economic benefit of water use, the system has passed the point of peak ecological water—and while economists are bad at evaluating ecological damage in economic terms, new efforts to quantify ecological costs and benefits (or define “planetary boundaries”) make it clear that new efforts to protect aquatic ecosystems are urgently needed.

A sign noting contaminated water in California’s Imperial Valley. Image courtesy Peter Gleick
The work on planetary boundaries began several years ago as an effort to identify and define the links between human activities and the carrying capacity of natural systems, to integrate physical, chemical, and biological factors with human actions, and to expand efforts to understand ecological dynamics and the resilience of natural systems to stresses. One of the key boundaries assessed is a measure of freshwater use because of the strong links between water, food, biodiversity, human health, and environmental factors. Assessments of the water indices suggest that humans are already transgressing the planetary boundary for sustainable water use, threatening the collapse of terrestrial and aquatic ecosystems.

The good news—if any exists in this area—is that as our understanding of water-related threats has improved, so have efforts to develop strategies for moving toward more sustainable water management and use. Concepts such as integrated water resources management and a “soft path for water” have been proposed to help restore the balance between long-term human needs and the health of hydrologic and ecologic systems.

The term “soft path for water” describes an alternative for water development that emphasizes integrated technological, economic, and institutional approaches to water sustainability. It does so by improving the overall productivity of water use, identifying non-traditional or alternative new sources of water, matching water quality to users’ needs, prioritizing basic human and ecosystem water needs, applying innovative economic and financing tools, and seeking meaningful local and community engagement in water management.

How to get there

The soft path for water lays out several categories of actions and priorities, including the fostering of alternatives, re-thinking the nature of the demand for water, improving efficiency, better protecting water quality, paying attention to the ecological needs for water, and re-thinking the financial and institutional approaches to water management. Let us look at each of these in more detail.

Alternatives. The first is to move away from the 20th-century focus on continually seeking out new traditional water-supply options—such as draining rivers and aquifers—and instead developing alternative water supplies such as de-salting brackish water and ocean water, treating and re-using wastewater, and expanding the intentional capture of stormwater.

These supply alternatives can expand water availability without taking more freshwater from already overtapped natural systems. Singapore and Israel already capture, treat, and re-use almost all of their wastewater, sometimes meeting very high quality demands. California currently re-uses around 18 percent of its wastewater and plans to double that in the coming years, while also expanding efforts to capture stormwater runoff during wet years to help expand recharge of over-drafted aquifers.

Re-thinking. The second category is to re-think the demand for water and to focus on meeting human needs as efficiently as possible by increasing water-use efficiency and cutting waste. Society’s goal should not be the use of water, per se, but improved social and individual well-being per unit of water-use. As supply options have become more constrained or costly, demand management is now understood to be far cheaper and faster to implement than other potential solutions, while also leading to co-benefits such as reduced energy use, lower wastewater treatment costs, and decreases in greenhouse gas emissions. Water that is saved can be used to meet new demands, kept in reserve for periods of drought, or re-allocated to the environment or other users.

Improving efficiency. The importance of water-efficiency improvements can be seen by actual declines in per-capita water use in many regions of the world despite continued growth in economies and production. Water withdrawals in the United States in 2015 (both total and per-capita water use), the last year for which national water-use data were reported, are far below the levels reported in 1980. These improvements in efficiency have resulted from a combination of policies and practices, including better water and wastewater pricing, regulations governing the efficiency of water-using appliances and devices, education and outreach, and direct financial investments and incentives. And they have greatly reduced pressure on natural hydrological systems. (See chart below.)

US water withdrawals and gross domestic product from 1900 to 2015US water withdrawals and gross domestic product from 1900 to 2015, courtesy of the Pacific Institute.
Better protection of the water quality. Another element of the soft path for water requires taking a different approach to protecting water quality, greatly expanding and enforcing regulations of pollutants, improving water treatment, and rethinking how best to match the quality of waters needed with the quality of water available. Not all human uses of water require potable water, but many of our institutions and much of our developed infrastructure are designed only to produce potable drinking water. Better matching needs with supplies can increase the amount and types of water available for use.

Water isn’t just for humans—paying attention to the rest of the environment. Another characteristic of more sustainable water strategies demands that ecological water needs no longer be ignored. A key lesson from the environmental crises of the late-twentieth and early twenty-first centuries is that protecting ecological health is central to global and local sustainability efforts. Some progress is being made in this area: Minimum-flow requirements are being developed for some watersheds, dams that previously blocked spawning runs are being removed to restore river flows and fisheries, and endangered and threatened species are being identified and protected. More than a thousand dams have been removed in the United States in recent years; in 2024, the world’s largest dam removal project began, to remove four dams on the Klamath River in California and Oregon to help restore the river’s ecological health and damaged salmon fisheries. (See image below.)

Re-thinking financial and institutional tools. The final tenet of the soft path for water requires re-thinking financial and institutional approaches to water management—a principle which is key to each of the previous elements. The financial and institutional tools used today were largely developed in the 19th and 20th centuries and reflect the priorities, knowledge, and ethics of those eras. It is time to re-develop and re-think these tools to reflect our newer understanding of the role and value of ecosystems, the peak-water constraints we’re now imposing on hydrologic systems, the risks of climate change, the inequities in failing to provide access to water services to large populations around the world, and the newer technologies and approaches now available to move away from the water crises that face us toward a new age of sustainability.

Many of our water challenges are more than simple limitations on water availability; they have their roots in economic, political, social, and ecological factors. While water on Earth is abundant overall, peak water limits are now being reached in watersheds in every region, with adverse consequences for human and ecological health, agricultural and industrial production, and social and political systems. It is time for a change toward the successful comprehensive and integrated soft-path solutions that are being tested and tried around the world. These successful efforts need to be identified, scaled-up, and applied as widely and quickly as possible.

Supplemental Reading
Gleick, P.H. 2002. “Water management: Soft water paths.” July 25. Nature, Vol. 418, pp. 373. https://www.nature.com/articles/418373a.

Gleick, P.H., and M. Palaniappan. 2010. “Peak Water: Conceptual and Practical Limits to Freshwater Withdrawal and Use.” June 22. Proceedings of the National Academy of Sciences, Vol. 107, No. 25, pp. 11155–11162 Washington, D.C. www.pnas.org/cgi/doi/10.1073/pnas.1004812107.

Gleick, P.H. 2023. The Three Ages of Water: Prehistoric Past, Imperiled Present, and a Hope for the Future. Public Affairs/Hachette: New York.

United Nations. 2024. UN World Water Development Report 2024. https://www.unwater.org/publications/un-world-water-development-report-2024