In a joint statement on April 28, Mexican and U.S. officials announced that Mexico will immediately transfer some of its water reserves to the United States and also allow a larger share of the Rio Grande River to flow into the United States. This concession from Mexico, which will last through at least October, seems to have averted the threat of additional tariffs and sanctions threatened by President Trump in early April.

Mexico and the United States share several major rivers, including the Rio Grande, the Colorado, and the Tijuana. Control over how much water each country receives from these rivers was set in a 1944 treaty. Under the treaty, Mexico must deliver 1.75 million acre-feet of water to the United States from six tributaries every 5 years, or an average of 350,000 acre-feet every year (An acre-foot is the amount of water needed to cover 1 acre of land to a depth of 1 foot.)

The United States and Mexico renegotiated parts of the treaty last year under the Biden Administration, allowing Mexico to meet its treaty obligations with water from other rivers, tributaries, or reserves. Yesterday’s announcement marks a commitment from Mexico to adhere to the amended treaty, rather than striking a new deal.

As climate change has worsened drought conditions in Mexico the country has struggled to meet the obligations of the treaty while supporting its farmers. Mexico’s current water debt to the United States is roughly 1.3 million acre-feet (420 billion gallons). Mexico’s president Claudia Sheinbaum acknowledged this water debt but said that Mexico has been complying with the treaty to “to the extent of water availability.”

In 2020, tensions over these water deliveries boiled over into violence: Mexican farmers rioted and seized control of a dam near the U.S.-Mexico border to halt deliveries. Mexican officials worry that increasing water deliveries during the hottest and driest months of the year will once again spark civil unrest among farmers.

This story originally appeared in EOS Magazine.