As climate change drives rising temperatures and changes in rainfall, Mexico and the US are in the middle of a conflict over water, putting an additional strain on their relationship. Partly due to constant droughts, Mexico has struggled to maintain its water deliveries for much of the last 25 years, in keeping with a water-sharing agreement between the two countries that has been in place since 1944 (agreements between the two regulating water sharing have existed since the 19th century). As part of this 1944 treaty, set up when water was not as scarce as it is now, the two nations divide and share the flows from three rivers (the Rio Grande, the Colorado and the Tijuana) that range along their 2,000-mile border. The process is overseen by the International Boundary and Water Commission.

Other U.S.-Mexico water news:

• Mexico Business News: US, Mexico sign US$93 million deal to fix Tijuana River Sewage
• Surfrider Foundation: Blog: US & Mexico commit to expediting solutions to Tijuana River sewage crisis