At 1.2 million square kilometers, the Guarani is currently the source of drinking water for 15 million people, primarily in Brazil.2 Given projected increased demand for water and stress on supply in the region, the aquifer represents an essential strategic resource that requires careful management.3 Karin Kemper, a water resource specialist with the World Bank has described the Guarani system as "a striking example of an international water body threatened by environmental degradation. Without better management, the aquifer is likely to suffer from pollution and rapid depletion."4 The need for four countries to cooperate and coordinate management of this shared resource makes such protections all the more challenging.
Spurred on by assistance from the World Bank's Global Environment Facility and the Organization of American States, the four countries that share the Guarani Aquifer have taken significant steps towards a multinational governance model to manage the long-term sustainability of the aquifer. This effort represents a positive example of cooperation efforts beginning before pollution or depletion reach critical levels.5 In 2010, the countries signed the Agreement on the Guarani Aquifer, institutionalizing a cooperative governance model that includes regional, national, and local elements.6
The need for multinational governance approaches will only increase in importance as resource stress pressures accelerate over the coming decades. If the Agreement on the Guarani Aquifer is to serve as a model, it will need to continue to evolve in the face of changing circumstances. In particular, enhanced efforts to monitor and manage the impacts of agriculture activities on the "recharging" of the aquifer will be essential to future success.7 Furthermore, the new risks and challenges posed by climate change could place stress on the Agreement and other multinational governance arrangements such as Canada-US shared governance of the Great Lakes.8