Since November 2023, Yemen’s Houthis have held international shipping routes in and around the Red Sea hostage by launching hundreds of attacks against commercial vessels. The Houthis have framed the naval offensive as a military response to Israel’s war on Gaza, while the global community has firmly condemned the Houthi attacks as terrorist actions threatening freedom and safety of navigation. The disruption of Europe-Asia maritime trade routes has negatively impacted energy and commercial maritime supply chains, prompting several shipping companies to take longer and more expensive detours via South Africa’s Cape of Good Hope.
While security and economic considerations have topped the U.S. and European counter-Houthi strategies, the intentional targeting of merchant vessels by the Houthis represents an unprecedented ecological threat to the Red Sea and Gulf of Aden.
A Fragile Ecosystem
The Red Sea is a maritime region with unique oceanographic and ecosystemic characteristics. It extends for about 1,200 miles between two narrow chokepoints – the Suez Canal to the north and the Bab el-Mandeb strait to the south. The Red Sea’s considerable sea depth and the region’s two monsoon seasons create an optimal water circulation pattern. The Red Sea’s warm surface water temperature, combined with high salinity, offers an ideal environment for hundreds of aquatic life forms and a vast variety of habitats. Home to about 1,200 fish species and over 350 types of coral, the region’s coral reefs are one of the world’s richest marine ecosystems and most resilient environments to climate change. Additionally, the Red Sea’s high marine biodiversity generates multimillion-dollar revenue streams for the tourism and fishing industries of littoral countries.
Often overlooked Red Sea habitats, such as sea meadows, mangrove lagoons, and salt marshes, are equally critical to the socioeconomic well-being of local communities as they contribute to carbon sequestration, combating coastline erosion, and enhancing biodiversity conservation. However, the fast-paced urbanization of littoral areas, overfishing, and marine traffic pollution severely threaten these vulnerable habitats. And while the Red Sea’s unique water circulation pattern supports a healthy marine environment and rich aquatic life, it could become a deadly trap in the case of environmental hazards.
Houthis as Ecocriminals
On February 18, 2024, a Houthi anti-ship ballistic missile struck the Belize-flagged bulk carrier MV Rubymar, causing an 18-mile oil slick. Risks of explosion from the ship’s cargo and Houthi attacks on towing operations delayed salvage missions. Twelve days later, the ship sank off the Mokha coast. Laying at a depth of about 330 feet, the sunken bulk carrier poses a twofold environmental threat. First, it sank holding approximately 200 tons of heavy fuel oil and 80 tons of marine diesel. Oil slicks pose cascading threats to coastal communities, aquatic wildlife, and highly sensitive ecosystems, such as Yemen’s Farasan Islands and Eritrea’s Dahlak Archipelago. Second, the ship was transporting about 22,000 metric tons of ammonium phosphate sulfate fertilizer. Although the cargo holds are still sealed, a massive leak of fertilizer into the Red Sea waters would cause extensive algal blooms with harmful consequences for the entire ecosystem, including large-scale fish die-offs and seawater contamination.
On June 12, 2024, a Houthi naval drone and an unknown aerial projectile hit the Liberia-flagged coal carrier MV Tutor, which sank six days later. Fortunately, the bulk carrier navigated with no cargo, limiting the environmental damage to an approximately 12-mile oil spill from the ship’s engine fuel. However, a mid-July Houthi naval drone attack on the Liberia-flagged oil tanker Chios Lion caused severe damage to the ship’s port side, causing an approximately 136-mile oil slick between Yemen and Eritrea. Satellite images of the oil spill’s dispersion pattern and color suggest that the engine’s fuel oil, rather than the cargo of over 90,000 tons of straight-run fuel oil, caused the slick.
The Houthi sabotage of the Greek-registered oil tanker MT Sounion pushed the Red Sea closest to the brink of a regionwide environmental catastrophe. After attacking the oil tanker on August 21, 2024, the Houthis detonated explosive charges over the hatches of the ship’s oil tanks twice, causing several fires but failing to provoke any additional hull breach. However, as the flames heated up the ship’s structure, crude oil came out of the cargo tanks through the venting systems as highly inflammable oil vapors, which alimented the fires and provoked limited oil spills near the ship’s waterline. After letting the ship burn for over four weeks, the Houthis allowed the European Union Operation Aspides to launch a salvage operation, which, on its second attempt, successfully towed the Sounion to safe waters. If the Houthis had penetrated the ship’s double hull, causing the spillage of the 150,000 tons of crude oil on board, they would have provoked the fifth-largest oil spill in history.
Although the Houthis eventually greenlighted the EU-led salvage operation, they intentionally sought to trigger an environmental catastrophe. The Houthi assaults on shipping traffic are deliberate acts of marine pollution, weaponizing oil tankers and bulk carriers to advance their political and military agenda.
The FSO Safer’s Lesson
While the scale and pace of the recent Houthi naval offensive is unprecedented, the Houthis have repeatedly turned the Red Sea’s waters into a battlefield by targeting Saudi coastal energy infrastructure and commercial ships. The weaponization of the FSO Safer oil tanker is a prime example of the Houthis using the threat of environmental disasters as a bargaining chip to pursue strategic ends.
Moored off Yemen’s Ras Isa port city, the FSO Safer is a supertanker initially used by the Yemeni government as a floating storage and offloading facility. When the Houthis seized control of the Hodeidah governorate, the FSO Safer fell into their hands. The protracted lack of maintenance dramatically increased the risk of corrosion-induced spillage, turning its cargo of about 1.4 million barrels of crude oil into an environmental ticking bomb. While the Houthis held several rounds of talks with the United Nations to arrange a salvage mission, they often backtracked on agreements by openly undermining U.N. crowdfunding efforts and imposing last-minute conditions, including visa restrictions, changes in the U.N. inspection team composition, and hard-to-satisfy requests. In line with the group’s negotiating tactics, the Houthis deliberately torpedoed the FSO Safer’s rescue talks for years with the hope of building pressure on the U.N. and the Saudi-led coalition and extracting greater political concessions. Yet, after yearslong on-again off-again negotiations, the U.N. successfully spearheaded a $144 million ship-to-ship oil transfer operation in August 2023.
Looming Threat
Although no large-scale ecological catastrophe has occurred yet, any future Houthi attacks carry the considerable risk of triggering a mass pollution event, which could cause irreversible damage to the Red Sea region. The Houthis are likely to continue weaponizing maritime traffic as long as it serves their agenda.
Salvage operations and clean-up efforts are time consuming and expensive, and the Red Sea’s littoral countries are ill equipped to provide adequate and quick responses to environmental disasters alone. Therefore, the international community should step up joint efforts to bolster the disaster response, mitigation, and ecological restoration capabilities of regional countries. For instance, Western countries could support the work of Persga, the Regional Organization for the Conservation of the Environment of the Red Sea and Gulf of Aden, a marine life preservation-focused intergovernmental organization including all the Red Sea’s littoral countries except Israel. Since 1995, Persga has been a springboard for regional sea conservation efforts by running joint marine and coastal protection projects and organizing training modules and workshops.
Although the Houthis vowed to stop their attacks on Israel and commercial shipping following the Israel-Gaza cease-fire, the risk of environmental disasters remains considerable. The 15-month anti-shipping campaign has showcased that not only are the Houthis dangerous navigational disruptors, but they are also reckless ecocriminals.
