Satellite study reveals massive oil slicks smothering oceans, especially near Europe

A recent satellite-based investigation by the nonprofit SkyTruth estimates that oil slicks blanket approximately 1.58 million square kilometres of the world’s oceans each year, an area comparable to three times Spain’s size. Using images collected between 2023 and 2025 and the organization’s Cerulean monitoring system, researchers found that more than 90 % of this pollution occurs within national waters, often close to coastlines.

Ships—particularly oil tankers and cargo vessels—are linked to about 81 % of slicks with identifiable origins, while offshore oil and gas facilities contribute roughly 18 %. The highest concentrations appear in the Red Sea, Persian Gulf, Mediterranean, Black Sea, West African waters and around Indonesia, with several vessels and facilities repeatedly associated with spills. Protected marine zones are not immune; although around three-quarters of marine protected areas have lower slick levels than surrounding seas, contamination still reaches sensitive habitats such as the Gulf of Mexico’s Rice’s whale region. Limited satellite coverage of the high seas and additional sources like war-related spills, accidents and aging shipwrecks suggest the true extent may be even larger.