New tactics and strategies deployed by States and non-state armed groups using naval and aerial (drone) strikes against ships may have far reaching impacts on marine ecology. The accumulation of oil spills and naval activities contributes to this ‘slow violence’, a less visible type of destruction that threatening the seas and oceans in conflict areas. Over the past six months, a series of deliberate and incidental attacks in and around conflict-zone waters has caused widespread pollution from fossil fuels and other contaminants, posing serious risks to people and the environment alike.
This August, states are gathering in Indonesia as part of the ICRC’s Global Initiative to Galvanize Political Commitment to International Humanitarian Law (IHL) to discuss how to strengthen legal protection of the environment during naval warfare. PAX will contribute its research and legal policy proposals on how to future-proof international humanitarian law for the protection of the marine environment.
Today’s ongoing conflicts only underline how urgent this is. New technologies such as naval drones, together with shifting tactics by states and non-state actors, have driven a growing number of attacks on civilians, naval vessels, and offshore and onshore fossil-fuel facilities. The US and Israeli war on Iran, backed by regional allies, and the Iranian retaliatory strikes that followed, brought marine traffic to a halt, leaving thousands of ships moored in the Persian Gulf and raising the risk of leaks and spills across the region. To highlight the urgency of responding to conflict-linked marine pollution, PAX has produced a short briefing on the environmental impact of current naval warfare, building on our report on naval warfare and the environment, published in early 2026.
Persian Gulf and Strait of Hormuz: the Iran war at sea
Following the outbreak of the US–Israel war on Iran on 28 February 2026, Tehran declared the Strait of Hormuz closed, and shipping in the Persian Gulf came to a near-standstill. Merchant vessels became front-line targets almost immediately. By 20 July, the International Maritime Organisation had noted 59 attacks on civilian vessels, with several causing significant pollution, including spills from oil tankers and cargo ships off the coasts of Oman, the United Arab Emirates, Iran, Kuwait and Iraq. Meanwhile, strikes on Iranian naval ships near Bandar Abbas caused massive pollution: heavy fuel oil leaked from a sunken aircraft carrier from March until July, drifting into critical marine protected areas that are home to rich aquatic life, including dolphins, turtles and bird-nesting grounds.
The threats do not come only from attacks on ships. Airstrikes also hit onshore oil installations, such as those on Lavan Island, producing a large crude-oil slick around the island that reached nearby Sheedvar Island, a Ramsar Convention protected site, a designated Important Bird Area and a known nesting site for green and hawksbill sea turtles. Heavy fuel oil and crude oil have already affected protected marine areas in Iran, with video footage showing birds and fish coated in dark slicks at Sheedvar Island.
In early June, a Russian crude-oil tanker was reportedly hit by explosions of unknown origin and abandoned by its crew off the coast of Yemen in the Gulf of Aden. By early July, the same ship was found stranded and leaking in the bay around Al-Qibliyah Island off the coast of Oman, part of the Arab Sea Reserve, a designated marine protected area.
Beyond these direct impacts, the blockade of the Strait of Hormuz drove a sharp rise in spills, with more than 2,000 ships stranded at the peak, while a lack of maintenance and repairs and other conflict-induced mismanagement worsened leaks from offshore oil and gas rigs. Researchers at the University of South Florida found that oil spills covered roughly four times the area in March 2026 as in March 2025, with persistent leakage from trapped vessels and damaged infrastructure. The tanker mooring area in the Gulf of Oman on the east coast of the United Arab Emirates and Oman, and the port of Bandar Abbas in Iran saw numerous spill incident. Meanwhile, likely due to absence of maintenance caused by the conflicts, major visible oil sheens from the drilling rigs were spotted at the Abuzar and Fars oil fields in the Persian Gulf, that became another major source of pollution.
Environmental risks in the Persian Gulf and wider area
The Persian Gulf is shallow, hot and hypersaline. It is a a semi-enclosed sea whose waters take several years to flush fully into the open ocean. A major spill therefore does not simply disperse; it circulates, concentrates and settles, poisoning the ecosystem for decades. Scientists note that the Gulf’s heat-adapted corals, seagrass beds, mangroves, dugongs and whale sharks are globally significant precisely because they show how marine life might survive climate stress. The region also still carries tar-stained shorelines left by the 1991 Gulf War spill. The Strait of Hormuz and the adjacent waters of the Persian Gulf and the Gulf of Oman hold coral reefs, mangrove forests and seagrass meadows. The crown jewel is Iran’s Hara Biosphere Reserve around Qeshm Island, the Gulf’s largest Avicennia mangrove system, a UNESCO reserve and Ramsar site that supports roughly 80% of the Gulf’s marine spawning grounds and serves as a wintering site for Dalmatian pelicans and a feeding ground for green turtles. On the Arab side, the Southern Gulf IMMA, the Marawah Marine Biosphere Reserve and the Al-Yasat Marine Protected Area in Abu Dhabi, and Qatar’s roughly 1,650 km² Dugong and Seagrass Marine Protected Area all lie within reach of drifting slicks.
The southern Gulf holds the world’s second-largest population of the vulnerable dugong and as many as 700 endangered Indian Ocean humpback dolphins, alongside Indo-Pacific bottlenose dolphins and finless porpoises that feed in the same seagrass and mangrove channels an oil slick would blanket. Green and hawksbill turtles’ nest on Gulf beaches, and the region’s fisheries, which sustain coastal communities, would face mass die-offs, reproductive failure and contamination from toxic hydrocarbons. Because oil smothers the mangrove roots and seagrass beds that act as nurseries, and because the reefs cannot tolerate the toxic load, the damage would cascade through the food web far beyond the initial kill. The transboundary nature of the Strait means no single country’s waters can be shielded from a spill.
Strikes on desalination plants and intakes from contaminated sea water pose a further, distinctly humanitarian risk: nearly 100 million people in the region depend on desalination plants whose filtration systems can be fouled by oil slicks, so strikes at sea threaten drinking-water supplies on land.
Lastly, restrictions on reporting in the Gulf states make it hard to gauge the war’s full consequences on the naval environment. Oman denied that there had been any oil leak from the stranded Russian tanker, even though satellite imagery clearly showed spills of substances around the island.
Black Sea and Sea of Azov: the shadow-fleet war
Ukraine’s campaign against Russia’s “shadow fleet” of ageing, sanctions-evading tankers escalated from isolated strikes in late 2025 into a systematic naval- and aerial-drone offensive by mid-2026. By 22 July 2026, Ukraine reported striking 183 Russia-linked vessels, including more than 114 tankers. On 16 July, long-range naval drones hit two large crude carriers, the Louise 1 and the Banda, off Russia’s Black Sea coast; both were under sanctions for carrying Russian crude. Satellite imagery showed burning vessels and a large spill in the Black Sea. Satellite imagery analysis with Sentinel-1 radar data by PAX shows the decrease of ships present in the Kerch Strait, with many damaged ships likely moved to nearby or port further away, including movement towards Mariopol in occupied Ukraine and Russian ports southeast of the Strait. Russia, for its part, has continued to strike Ukrainian ships, port infrastructure and grain corridors, while its degrading tanker fleet poses spill risks of its own to the Black Sea marine environment.
A parallel area of risks is the coastline itself. In April 2026, repeated Ukrainian drone strikes on the Tuapse refinery and oil terminal in Krasnodar Krai ignited large fires, killed at least three people, and produced an oil slick in the Black Sea, along with “black rain”, an oily and soot-laden precipitation, over the city and surrounding areas, with pollution reported to be spreading towards Sochi. Weeks later, wildlife deaths and fouled beaches were still being cleaned up.
The conflict between Russia and Ukraine has also reached far beyond the Black Sea. Ukraine has targeted offshore drilling platforms and ships in the Caspian Sea, while a large LPG tanker, the Arctic Metagaz, was damaged in the Mediterranean off the coast of Malta and later drifted towards Libya, adding further risks to the wider environment.
Environmental risks in the Black Sea and Sea of Azov
The Sea of Azov is among the shallowest seas in the world. Reduced river inflow and rising salinity had already weakened its resilience, and wartime spills now compound chronic pre-war pollution from oil terminals and heavy shipping. A dense network of nature reserves lines the Azov–Black Sea coast, and much of it now sits inside the conflict zone. On the Ukrainian side, oil films from sunken vessels have spread across protected waters, including the Snake Island National Zoological Reserve, the Zernov Phyllophora Field National Botanical Reserve and the Black Sea Biosphere Reserve. Russian federal protected areas have not escaped either: the 2024 Kerch Strait mazut spill reached the Utrish Nature Reserve east of Anapa and the Priazovsky Refuge in the Kuban Delta, while the Zaporizhzhya-Tamansky Reserve in Taman Bay lies within a migration corridor used by up to two million waterfowl. The impacts are transboundary, too: the spills affected at least five IUCN Important Marine Mammal Areas across the basin, including the “Kaliakra to the Danube Delta” area reaching into Bulgarian and Romanian waters.
Cetaceans are the most visible casualties. All three Black Sea species — the bottlenose dolphin, the harbour porpoise and the common dolphin — depend on the Kerch Strait, which lies on their migration routes and near breeding-season feeding grounds. Thousands of dead dolphins have been found on beaches around the Black Sea, their deaths attributed to sonar, underwater explosions and conflict-linked pollution. The Kerch Strait spill of December 2024 alone killed at least 84 dolphins and 700 birds, while the sinking heavy mazut also increased the exposure of aquatic life and the seabed, in particular the Zernov Phyllophora Field with its unique algae species.
Transboundary impacts of conflict pollution
The Ukrainian strikes on the Kairos and the Virat oil tankers inside Turkey’s exclusive economic zone, condemned by Türkiye as posing “serious risks to navigation, life, property and environmental safety”, show how the campaign pushes environmental risk onto third-party coastal states. A similar case occurred off the coast of Sri Lanka, where the sinking of the Iranian vessel DENA by a US submarine caused a large oil slick that reached a coastal nature reserve; a rapid clean-up prevented wider damage. The government of Sri Lanka declined to name the party responsible, most likely to avoid jeopardising its relationship with the United States. Off the Libyan coast, meanwhile, local authorities lacked the capacity and resources to salvage the drifting Russian tanker Arctic Metagaz.
Current trends and the need to strengthen legal protection
Because access to reliable ground reports is so limited, Earth observation has been essential for monitoring and measuring these spills and leaks in both conflict areas. This data is fundamental to the preliminary risk screening that enables rapid response, clean-up and remediation. Based on ongoing assessments, the impacts across both the Middle East and the waters around Ukraine and Russia already look dire, and they demand a swift response from the international community to prevent and limit the worst environmental harm.
These conflicts underscore several trends that PAX highlighted in its naval-warfare analysis: the growing use of uncrewed systems, the increase in strikes on marine trade routes, and the emerging use of artificial intelligence for targeting. Uncrewed systems have been the weapon of choice in the recent wave of attacks on Russia’s shadow fleet, on Ukrainian ships, and on tankers passing through the Strait of Hormuz. As states focus on cheap yet effective ways to strike targets at sea, and as non-state armed groups gain access to these weapons, this tactic feeds directly into the second trend: attacks on marine trade routes. Fossil fuels and related infrastructure are a particular target, and one that brings wider environmental risks from spills. This raises unresolved questions about whether such targeting can respect the principles of proportionality and precaution towards the environment.
A third trend is that “dark” shipping multiplies the risk. In all three seas, vessels sail with their AIS transponders switched off, either to evade sanctions or to avoid attack. This undermines collision avoidance, spill attribution and environmental monitoring alike, which means official incident counts understate the true scale of the problem.
Notably, Ukraine’s drone force has publicly framed spill avoidance as an operational constraint: its commander stated that the aim is the “irreversible paralysis” of the tankers without breaching their hulls, because “the goal is not to pollute the sea.” Analysts observe, however, that AI-guided targeting has struggled to reliably avoid striking cargo holds, making this a concrete illustration of PAX’s warning that autonomous and uncrewed systems may be unable to factor environmental risk into targeting decisions.
Finally, the harm is landing on non-combatants and protected areas: Turkey’s exclusive economic zone, the approaches to Malta and Libya, Oman’s coast, Iraqi loading zones, Sheedvar Island’s wildlife refuge, the Azov’s collapsing ecosystem, and the desalination-dependent populations of the Gulf. The environmental costs of these naval campaigns are regional and generational, not confined to the warring parties.
Key recommendations from the current conflicts
- Clarify how the different branches of international law apply to naval warfare.
States should confirm that environmental obligations under international environmental law and the UN Convention on the Law of the Sea (UNCLOS) continue to apply during armed conflict at sea, and that where an environmental rule offers more protection than a parallel humanitarian-law rule, any conflict between them should be found only for clear reasons. UNCLOS Articles 192 and 194 (the protection of the marine environment and the prevention of pollution “from any source”), read together with the qualified military exemption in Article 236, should inform assessments of the tanker strikes in all three theatres. The International Court of Justice’s 2025 climate advisory opinion and the International Tribunal for the Law of the Sea’s 2024 opinion support such a harmonious, cross-regime reading. - Strengthen environmental protection in non-international armed conflicts and against non-state and hybrid actors.
Much of today’s violence at sea takes place in legally grey settings, be it shadow fleets, deniable drone strikes, blockade enforcement and attacks in the waters of third states. PAX recommends clarifying which humanitarian-law obligations bind non-state armed groups, making use of special agreements under Common Article 3, and drawing on the Martens Clause and PERAC Principle 12 as gap-filling protections, so that no “legal vacuum” is allowed to excuse harm to the marine environment. - Enhance protection for marine species and sensitive ecosystems, including through protected-zone designations.
Belligerents and coastal states should designate ecologically critical areas as off-limits, demilitarised environmental zones by agreement, building on Article 60 of Additional Protocol I, the ICRC’s 2020 Guidelines, and PERAC Principles 4 and 18. The San Remo Manual’s encouragement (in Article 11) to avoid hostilities in “rare or fragile ecosystems” should be upgraded into clear, operationally workable rules, and environmental-impact assessment should guide route planning, mine-laying decisions, sonar use and the timing of operations. - Improve compliance, accountability and monitoring rather than waiting for new treaties.
The international community should support the ICC Office of the Prosecutor’s December 2025 Policy on Addressing Environmental Damage through the Rome Statute as a route to accountability for the gravest marine harm, and interpret the Rome Statute’s “widespread, long-term and severe” threshold in light of current ecological knowledge. States should also conduct Article 36 weapon reviews that explicitly assess environmental risk for the naval drones and autonomous targeting systems now deployed in the Black Sea. Finally, they should put UNEA Resolution 6/12 into practice by extending UNEP’s technical guidance on conflict-linked environmental data to marine and coastal ecosystems, so that satellite-detected spills in the Persian Gulf, the Azov, Black and the Mediterranean Sea, as well as other affected marine areas, are systematically documented for future assessment, remediation and redress. - Reduce and report greenhouse-gas emissions from naval operations.
The mass naval deployments, blockades, escort operations and burning fossil-fuel infrastructure of 2026 all carry a climate cost that remains invisible, because military emissions reporting under the UN Framework Convention on Climate Change (UNFCCC) is voluntary. States should close this transparency gap, adapt the UNFCCC’s Pledge–Plan–Proceed–Publish framework to their navies, and integrate climate considerations into the ongoing revision of the San Remo Manual.
Underlying all five recommendations, PAX stresses, is political will: without genuine commitment from states, even the strongest legal frameworks will remain under-implemented. The alarming consequences of naval warfare for the marine environment over the past six months make the cost of that inaction all too concrete.
