Water-related challenges in El Salvador have acquired far greater significance over the past decade as they have intersected with other social problems including migration, criminal violence, and drug trafficking. When combined, these factors pose threats to domestic and regional stability. Damaging heavy rains, droughts, and rising temperatures are exacerbated by steadily intensifying El Niño oscillations and threaten the production of staple and export crops.  The declining viability of rural livelihoods is driving many farming families to migrate to urban centers or across borders. Food security is a constant concern across the region, and millions already rely on humanitarian assistance. Infrastructure has been damaged repeatedly by floods and raging rivers. El Salvador can mitigate many of these risks by employing ecological landscape restoration.  Improving the soil’s capacity to retain and regulate water will help maintain both agricultural and ecological viability.

Nigeria is ranked among the most fragile states in the world. The country faces significant water challenges, which vary greatly from one region to another. Weak governance exacerbates these water challenges, while conflicts over water resources make governance more difficult. There are three main geographical flashpoints where conflict over water is likely to break out. In the north and northeast, Boko Haram has waged a violent insurgent campaign since 2010; among their demands is government provision of clean water. In Nigeria’s Middle Belt, changing rainfall patterns are limiting the grazing area of Muslim Fulani herders, who then encroach on the land of predominantly Christian farmers. Conflict over these lands killed more Nigerians than Boko Haram in 2016. Finally, in the Niger Delta, militant groups are attacking oil infrastructure, partially motivated by conflict over rights to land and waterways. Oil spills also contribute to food insecurity and malnutrition in this region.

Pakistan is South Asia’s fifth most vulnerable country in terms of water availability, and Karachi is the sixth most water-stressed city in the world. Predictions indicate that the country will face absolute water scarcity (insufficient water supply to meet demand) as soon as 2025. While population and demand for water steadily increase, freshwater quantity and quality are decreasing.

The region at the base of the Himalayas faces difficult tradeoffs when allocating freshwater resources for energy production versus agricultural, industrial, and domestic uses. This is one of the most ecologically unstable areas on Earth, and weather patterns are becoming increasingly irregular. On one end of the spectrum, water shortages frequently disrupt energy production, which depends largely on water-intensive coal and hydropower plants. The opposite extreme is also a factor: Dozens of hydropower plants in the Himalayas have been damaged or destroyed by severe floods caused by unusually heavy rainfall in recent years. Construction of new power plants faces increasing resistance from local communities, resulting in social disruptions and instability. In order to ensure both energy security and water security for their countries, governments must look beyond hydropower and coal.

The Philippines faces a breadth of social and environmental challenges that threaten its economic and political stability. A long history of violent conflict stemming from ethnic, religious, and political tensions is further complicated by changing weather patterns that cause severe drought and damaging storms. Millions of people in Mindanao have been displaced by violence and extreme weather events, and their migration from rural areas leaves room for the expansion of terrorist groups that threaten regional stability. The United States currently has strong trade and cultural ties to the Philippines, and U.S. Pacific Command operates military facilities on the islands. This chapter examines the stakes for U.S. interests in Mindanao, and recommends a security approach that combines defense, diplomacy, and development efforts to promote improved governance, social stability, and climate resilience.