SkyTruth satellite data reveals 610,000 square miles of annual ocean oil slicks

An analysis by the environmental technology non-profit SkyTruth estimates that oil slicks cover approximately 610,000 square miles (1.58 million square kilometers) of the ocean annually. The findings, based on satellite radar imagery from 2023 through 2025, indicate that this chronic pollution is driven by routine maritime and offshore activities rather than the rare, catastrophic accidents that typically receive media attention.

More than 90 percent of the estimated pollution occurs within national waters, often near vulnerable coastlines. Approximately 81 percent of the attributable slick area is linked to vessels, including tankers, cargo ships, and “dark vessels” that do not broadcast their positions via Automatic Identification System (AIS) signals.

Key pollution hotspots identified include the Red Sea, Persian Gulf, Mediterranean Sea, Black Sea, waters off West Africa, and seas around Indonesia. The report also notes that while most marine protected areas show lower slick density, certain habitats, such as those for Rice’s whale in the Gulf of Mexico and porpoise and dolphin habitats in the southeast Black Sea, remain at risk.