In early February, the Biden administration announced several shifts in U.S. policy toward the war in Yemen — a conflict that has left 20 million near starvation and 80 percent of Yemen’s population dependent on humanitarian assistance. The changes include ending U.S. support for Saudi-led offensive operations; reversing the Trump administration’s last-minute designation of the Houthi forces as a foreign terrorist organization; and supporting a special envoy to Yemen and diplomatic efforts to end the conflict.

After 2015, the United States played a critical role in sustaining the Saudi-led intervention in Yemen. U.S. support provided Saudi Arabia with intelligence, targeting data, in-air refueling of Saudi aircraft (this ceased in 2018), sales of precision-guided munitions and other arms, and ongoing maintenance and support for Saudi aircraft.

How we did our research

For a recent article in International Affairs, we used a variety of data sources to track the targeting of energy, water and sanitation, agriculture, and health infrastructure by all parties to the conflict — from Saudi air attacks to shelling by political militias and Houthi forces. Our database tracks 1,941 incidents between 2011 and 2019. Here’s what we found.

From 2010 to 2014, the relatively few attacks on infrastructure were conducted primarily by armed tribal groups focused on sabotaging gas and oil pipelines and electricity installations. Targets included the Marib-Ras Isa oil pipeline and the Yemeni liquefied natural gas pipeline.

The destruction ramped up after 2015

The data shows significant escalation in the destruction of civilian infrastructure after the Saudi-led coalition entered the war in 2015. The coalition attacked an increasing number and type of civilian objects — including hospitals, agricultural infrastructure, roads, bridges and water systems. Between 2011 and 2019, the coalition was responsible for 67.2 percent of the incidents in our data set, with 20 percent identified as “unknown,” and the Houthi, pro-President Abed Rabbo Mansour Hadi forces, political militias and armed groups identified as responsible for the rest.

The Saudi-led air campaign targeted Yemen’s agriculture sector, in particular — and accounted for 67 percent of the attacks in this sector. Most attacks were on farms and houses, many located in areas of intense fighting, and almost all produced direct civilian casualties. Our data also includes 30 attacks by Saudi-led coalition forces on fishing boats, mostly around the ports of al-Hudayda and al-Mukha and the Red Sea islands.

Attacks on food producers and food processing and storage and transportation infrastructure undercut livelihoods and food security, contributing to Yemen’s humanitarian crisis. In addition to widespread childhood malnutrition, Yemenis are vulnerable to epidemics of cholera, diphtheria and other water- and food-borne diseases.

Attacks in one sector can have broad repercussions

Our data also includes 150 attacks on energy infrastructure. Saudi-led coalition airstrikes accounted for 28 of the 61 incidents of the reported attacks on electricity infrastructure. But destruction of one type of infrastructure, particularly energy, has “reverberating” and interlinked effects on other types of infrastructure necessary for the welfare of the civilian population.

Here’s an example: Bombing a single power plant can shut down electricity needed to run drinking water systems, sewage treatment facilities and hospitals. The lack of electricity can also undermine economic activity needed to generate income and purchase food. Lack of access to water or food produces compounding vulnerabilities for households and individuals. Malnourishment in children, for example, is not simply due to the lack of access to food but also comes from contracting waterborne diseases such as cholera.

Experts predict cholera will persist in Yemen as long as water treatment remains inadequate and widespread malnutrition makes individuals more vulnerable. In the water sector, we tracked attacks on water pipelines, wells, dams, desalination plants, well drilling sites, water pumps, irrigation canals, water storage tanks, water bottling facilities, water trucks and public water utilities. We found 105 incidents in which water infrastructure was targeted — including 95 Saudi coalition airstrikes on all types of water infrastructure, including humanitarian water supply projects and warehouses.

Yemen’s health infrastructure was also particularly vulnerable. Coalition airstrikes on hospitals and medical centers account for many of the health-sector incidents in our database. The remainder concerned facilities damaged in shelling and clashes between Houthi forces and their opponents, particularly in Taizz. The vast majority of the targeted medical facilities (114 out of 128 incidents) were public hospitals and clinics, but hospitals and mobile clinics owned by international humanitarian groups such as Doctors Without Borders were not spared, despite providing precise coordinates to the Saudi-led coalition through the deconfliction mechanism designed to ensure the safety of humanitarian activities and personnel.

A cascading humanitarian crisis

But parties to the conflict also obstructed vital imports and deliveries of humanitarian aid. Yemen relies on imports of grain and fuel to meet the basic needs of the vast majority of the population; the Saudi coalition’s blockade on the major ports and airfields has raised the prices of both. Shortages of fuel hindered the operation of electricity plants and water treatment facilities and forced bakeries in the capital to use scarce firewood cut from the highland mountains, rather than diesel and gas, to bake bread. Deforestation is thus another cost of war.

As the Biden administration’s policy toward Yemen shifts from supporting a military offensive toward finding a diplomatic solution, the humanitarian costs of the war will help inform the immediate and long-term priorities. The United Nations has declared Yemen’s humanitarian crisis the worst in the world — more Yemenis are in need than at any time over the past five years, and thousands are starving, particularly in rural areas.

But emergency assistance is not enough. While staving off a large-scale famine, international aid has not reduced the number of Yemenis suffering from acute hunger and food insecurity as a result of the ongoing war. Hunger is just one symptom of the broader human security impacts that result when parties to protracted conflicts destroy civilian infrastructure with impunity.

Jeannie Sowers (@jeannielsowers) is a professor and chair of the Political Science Department at the University of New Hampshire. She is author of “Environmental Politics in Egypt: Activists, Experts and the State” and co-author of “Modern Egypt: What Everyone Needs to Know.”

Erika Weinthal (@esweinthal) is a professor of environmental policy and public policy at Duke University. She is author of “State Making and Environmental Cooperation: Linking Domestic and International Politics in Central Asia” and co-editor of “Water and Post-Conflict Peacebuilding: Shoring Up Peace.”