Regional Water Security Threatened by Stalled South America Agreement
The politicization of the vital shared source, fresh water, is threatening human and environmental well-being in South America, and may be jeopardizing the future of transboundary cooperation among regional actors.
The Guarani Aquifer, one of the largest reserves of fresh water in the world, extends underground for 460,000 square miles (1.2 million square kilometers)—an area more than three times the size of Germany. The aquifer crosses beneath sovereign territory belonging to Argentina, Brazil, Paraguay and Uruguay, all four of which rely on it as a source of water for agriculture, industry, and human consumption.
In 2012, the governments of Argentina and Uruguay ratified an agreement that, if enacted, would establish joint management of transboundary water resources. Brazil and Paraguay, the other two parties whose signatures are necessary for the full adoption of the agreement, have thus far refused to offer their endorsements. Without these final two signatures, the aquifer will remain vulnerable to exploitation and contamination.
If enacted, the Guarani Aquifer Agreement would impose binding legal restrictions on water extraction from the aquifer. The four countries subject to the agreement would have to respect an “obligation of not causing significant harm to the other Parties or the environment.” The agreement requires countries to exchange information related to their respective use of the aquifer, as well as any technical or scientific information gathered with respect to the aquifer.
Shared access and sustainability are key components of the stalled agreement, which calls for all four countries to engage in the “conservation and environmental protection” of the Guarani Aquifer System in order to ensure the “multiple, reasonable, sustainable, and equitable use of its water resources.”
Brazil’s reluctance to sign the agreement stems from its disproportionately high reliance on water drawn from the aquifer, and an apparent desire to secure more favorable terms than those outlined in the current version of the agreement. The Brazilian government’s intransigence with respect to the agreement has been reinforced by a two-year period of drought that began in 2014 and that has been felt most severely in the southeastern portion of the country. The drought compelled the government to impose water supply restrictions in Brazil’s most populous state, São Paulo, which is home to about 45 million people. Brazil currently accounts for approximately 94 percent of all Guarani water extraction. 71 percent of the aquifer (325,000 square miles, or 840,000 square kilometers) is located beneath Brazil, occupying just 9.8 percent of Brazil’s total area. In contrast, 25 percent of Uruguay is located above the aquifer, yet its consumption is less than five percent of Brazil’s.
Paraguay formally rejected the agreement shortly after Uruguay and Argentina accepted it, citing a violation of national sovereignty. This outright rejection, combined with Brazil’s continued unwillingness to accept the terms of the current agreement, jeopardizes the future of transboundary cooperation in the region, as well as the future of the Guarani aquifer itself.
The Guarani aquifer, by some measurements, is the largest discrete body of groundwater anywhere in the world. The aquifer contains approximately 8,900 cubic miles of water (37,000 cubic kilometers). The aquifer contains 56 percent more water than is contained in Russia’s Lake Baikal, the largest freshwater lake in the world by volume, and 63 percent more water than is held in all five of North America’s Great Lakes combined.
In practical terms, the Guarani Aquifer will not run out of water any time soon. The aquifer is continually replenished by groundwater that falls as rain or that flows in rivers above it. This water slowly seeps through porous earth, eventually joining the main body of the aquifer. Even if no new water were to reach the aquifer, it would still be able to provide water for potentially hundreds of years at current rates of consumption. In the long term, overexploitation of Guarani water would likely result in local “dry spots”—areas where gradual top-to-bottom depletion of the aquifer brings subterranean water levels below what can be feasibly accessed from drilled wells. Wells can always be dug deeper, but such improvements require time and money. While the aquifer as a whole may not ever run out of water, monitoring of local consumption is critical in order to ensure a continuous supply. The Guarani Aquifer Agreement would mandate the sharing of such information across borders, improving the quality of geological and hydrological data available to local governments and water management authorities.
Overall, only about 1 to 2 percent of all rainfall above the aquifer ever actually reaches it. Over the last few decades, changes to the landscape above the aquifer have reduced this figure. Research indicates that agricultural activity has significantly decreased the amount of rainfall entering the aquifer in some areas. Only about 10 percent of the land area above the aquifer is permeable enough to allow surface water to seep through and recharge the water supply. If allowed to proliferate, agricultural activity in these areas will continue to reduce the amount of water that replenishes the aquifer, in some cases reducing recharge rates to less than 50 percent of natural levels.
Agriculture, as well as industrial production, also threatens to pollute these “recharge zones,” introducing hazardous chemicals into a water supply relied upon by millions of people. Approximately 90 million people live above or near the Guarani Aquifer, with about half residing in the Brazilian state of São Paulo. Pollution of such a large water source would occur slowly, with hazardous substances from agricultural runoff and industrial waste gradually accumulating over many decades. Health effects associated with the consumption of contaminated water would likely only become apparent on a generational scale, reducing the perceived urgency of aquifer pollution as a public health crisis.
Poor and rural regions that lack sufficient water treatment infrastructure will be the worst affected by groundwater pollution. A concentration of wealth makes urban centers better equipped to adapt quickly to declining water quality, although rapid population growth will make ensuring a clean and consistent water supply more difficult in terms of cost and technology as time goes on.
Cooperation over shared water resources among Southern Cone countries is far from unprecedented. In 1979, Argentina, Brazil, and Paraguay agreed to terms that outlined a cooperative regime governing use of water from the Paraná River, the second-longest river in South America. The Agreement on Paraná River Projects effectively put an end to numerous international disagreements related to the river, as well as creating the legal foundation for major transboundary infrastructure projects. One of these projects, the Itaipu Dam, provides approximately 75 percent of the electricity consumed in Paraguay and 15 percent of the electricity consumed in Brazil.
Cooperative management of the Guarani Aquifer could ensure the protection of a critical water resource in a region where development and population growth is increasing water demand, and where traditional supply sources are threatened by drought. Brazil’s disproportionate reliance on the aquifer gives it a strong incentive to preserve unfettered access to the shared resource. Likewise, Paraguay’s appeals to principles of national sovereignty may mask a desire to exploit the aquifer to promote growth, a desire perhaps justified by Paraguay’s poor economic standing among its regional peers (in terms of GDP per capita, Paraguay places far behind Argentina, Brazil, and Uruguay). For all countries that rely on the Guarani Aquifer, however, short term stake-claiming makes little sense compared to the potential long-term value of a sustainable source of fresh water that lies quite literally beneath the feet of millions of people.