By Aaron Wolf, Annika Kramer, Alexander Carius and Geoffrey Dabelko
Nations' water needs usually reflect each other
"Water wars are coming!" the newspaper headlines scream.
It seems obvious; rivalries over water have been the source of disputes since humans settled down to cultivate food.
Even our language reflects these ancient roots: "rivalry" comes from the Latin rivalis, or "one using the same river as another".
As the number of international river basins and impact of water scarcity has grown, so do the warnings that countries will take up arms to ensure access to water.
In 1995, for example, World Bank Vice President Ismail Serageldin famously claimed that "the wars of the next century will be about water," a sentiment echoed regularly ever since.
These apocalyptic warnings fly in the face of history.
No nations have gone to war specifically over water resources for thousands of years; the only documented case of war with such a specific cause was between the city states of Lagash and Umma on the Tigris River 4,500 years ago.
International water disputes - even among fierce enemies - are generally resolved peacefully, even as conflicts erupt over other issues.
Today, more than ever, it is time to stop propagating threats of 'water wars' and aggressively pursue a water peacemaking strategy
Why? Because water is so important that nations cannot afford to fight over it.
Instead, water fuels greater interdependence.
By coming together to manage their shared water resources jointly, countries can build trust and help prevent conflict.
By crying "water wars," doomsayers ignore a promising way to help prevent war: co-operative water resources management.
Of course, people compete - sometimes violently - for water, which is not only essential to life on Earth, but also increasingly scarce.
Developing countries, often located in arid and semi-arid regions experiencing high rates of population growth, are especially threatened by water scarcity.
These countries often lack the human, institutional, and technical capacity needed to manage water scarcity and its associated economic, agricultural, health, and political challenges.
Within a nation, users - farmers, hydroelectric dams, recreational users, environmentalists - are often at odds, and the probability of a mutually acceptable solution falls as the number of stakeholders rises.
History is littered with violent examples of internal disputes with water as major factor.
Just as Californian farmers bombed pipelines moving water from Owens Valley to Los Angeles in the early 1900s, Chinese farmers in Shandong clashed with police in 2000 to protest against government plans to divert irrigation water to cities and industries.
But these conflicts usually break out within nations. International rivers are a different story.
The world's 263 international river basins cover 45.3% of the Earth's land surface, host about 40% of the world's population, and account for approximately 60% of global river flow.
And the number of internationally-shared basins is growing, largely as a result of political changes like the break up of the Soviet Union, as well as improved mapping technology.
As many as 17 countries share one river basin, the Danube.
Contrary to received wisdom, evidence indicates this interdependence does not lead to war.
Researchers at Oregon State University compiled a dataset of every reported interaction (conflictive or co-operative) between two or more nations that was driven by water in the last half-century.
The crux of water disputes is still little more than opening a diversion gate or garbage floating downstream
They found that the rate of co-operation overwhelms the incidence of acute conflict.
In the last 50 years, only 37 disputes involved violence, and 30 of those occurred between Israel and one of its neighbours.
Outside the Middle East, researchers found only five violent events, while 157 treaties were negotiated and signed.
The total number of water-related events between nations also favours co-operation: the 1,228 co-operative events dwarf the 507 conflict-related events, despite the often fiery rhetoric of politicians, which is in reality aimed more often at their own constituencies than at the enemy.
Simply put, water is a greater pathway to peace than conflict in the world's international river basins.
International co-operation around water has a long and successful history; some of the world's most vociferous enemies have negotiated water agreements, and the institutions they have created are resilient, even when relations are strained.
The Mekong Committee, for example, established by Cambodia, Laos, Thailand and Vietnam in 1957, exchanged data and information on the river basin throughout the Vietnam War.
Israel and Jordan have held secret "picnic table" talks to manage the Jordan River since 1953, even though they were officially at war from 1948 until the 1994 treaty.
The Indus River Commission survived two major wars between India and Pakistan.
And all 10 Nile Basin riparian countries are currently involved in senior government-level negotiations to develop the basin co-operatively, despite the verbal battles conducted in the media.
Southern African countries signed river basin agreements while the region was embroiled in a series of wars in the 1970s and 1980s, including the "people's war" in South Africa and civil wars in Mozambique and Angola.
Now that most of the wars and the apartheid era have ended, water management forms one of the foundations for co-operation in the region, producing one of the first protocols signed within the Southern African Development Community (SADC).
In North America, regional water shortages have strained relationships between the US and its neighbours - Canada to the north and Mexico to the south.
However, long-standing water-sharing agreements govern these disputes, keeping them civil and preventing them from erupting into violent conflict.
Today, more than ever, it is time to stop propagating threats of "water wars" and aggressively pursue a water peacemaking strategy.
Why? Well, water war warnings force the military and other security groups to take over negotiations and push out development partners, like aid agencies and international financial institutions.
Water management, on the other hand, offers an avenue for peaceful dialogue between nations, even when combatants are fighting over other issues.
Water co-operation forges people-to-people or expert-to-expert connections, as demonstrated by the trans-boundary water and sanitation projects that Friends of the Earth Middle East conducts in Israel, Jordan, and Palestine.
Water management is, by definition, conflict management.
For all the 21st Century technical wizardry - dynamic modelling, remote sensing, geographic information systems, desalination, biotechnology, or demand management - and the new-found concern with globalisation and privatisation, the crux of water disputes is still little more than opening a diversion gate or garbage floating downstream.
Obviously, there are no guarantees that the future will look like the past; water and conflict are undergoing slow but steady changes.
How availability, use and needs are changing across the world
An unprecedented number of people lack access to a safe, stable supply of water.
The water supply is shifting to less traditional sources such as deep fossil aquifers and wastewater reclamation.
Conflict, too, is becoming less traditional, driven increasingly by internal or local pressures or, more subtly, by poverty and instability.
These changes suggest that tomorrow's water disputes may look very different from today's.
But no matter what the future holds, we do not need violent conflict to prove water is a matter of life and death.
Aaron T Wolf is professor of geography in the Department of Geosciences at Oregon State University and director of the Transboundary Freshwater Dispute Database; Annika Kramer is research fellow and Alexander Carius is director of Adelphi Research in Berlin; and Geoffrey D Dabelko is director of the Environmental Change and Security Program at the Woodrow Wilson International Center for Scholars in Washington DC