NASA Earth Observatory image modified by SkyTruth
Uncovering Chronic Oil Pollution Hotspots in Southeast Asian Waters
Chronic oil pollution from the global shipping industry is a vastly underreported threat to ocean health and marine biodiversity. Financial Times reporters worked with SkyTruth to uncover and visualize chronic oil pollution hotspots in Southeast Asian waters and beyond.
Bintan Island, part of the larger Riau Archipelago in Indonesia, is a small coastal community near Singapore renowned for white sand beaches, picturesque greenery, and its bustling tourism, fishing, and aquaculture industries.
One of Indonesia’s national priority areas for building climate resilience, Bintan has a high concentration of coral reefs, seagrass beds, and mangrove ecosystems. However, these richly biodiverse ecosystems – and the surrounding islands – are facing the threat of oil pollution from nearby shipping vessels.
Aerial photo of Bintan Island. Photo credit: Kirill Petropavlov via Unsplash.
In early 2024 a thick, black sludge washed ashore along Bintan’s coastline, severely impacting local water quality and halting tourist activity. The incident, initially flagged by concerned residents reporting oil coming in “little by little” over weeks, was independently verified by local officials and by fishers who discovered the same substance coating their gear. Satellite imagery of the incident suggested that the oil pollution may have drifted in from nearby shipping lanes.
This is not an isolated event, as research suggests there is a chronic oil pollution problem in Bintan. Chronic marine oil pollution refers to the frequent presence of smaller oil spills – often from vessels intentionally dumping oily bilge waste into the ocean. This type of oil pollution causes damage over time to marine and coastal ecosystems, and severely impacts the livelihood of local fishers.
Unlike major oil spills, the true impact of chronic pollution may not be fully understood due to the isolated nature of each incident, and lack of clear information on the pollution source makes it difficult to nail down a culprit or prevent this pollution from happening in the first place.
Since 2020, SkyTruth has been at the forefront of uncovering the global scale of this issue by building and deploying Cerulean, a first-of-its-kind, machine learning-driven public platform designed to detect chronic oil pollution and identify the likely sources.
Using Cerulean, SkyTruth supported reporters from the Financial Times (FT) in investigating the issue of chronic oil pollution, particularly in Southeast Asian waters. We identified hotspots of chronic oil pollution – areas of the ocean in which a large number of separate oil slick events appear in close proximity to one another over time.
Our expert analysts closely examined all of the probable oil slicks detected by Cerulean’s machine learning model since July 2020, and we found that more slicks occur in the Indonesian Exclusive Economic Zone than in the next five countries combined. Of the 2,700 oil slicks throughout the ocean reviewed and verified by our analysts, about 500 were found near Indonesia.
For 40 of these slicks, SkyTruth was also able to identify a possible source vessel, and provide a unique registration number that could be verified and tied back to that vessel using Automatic Identification System tracks from Global Fishing Watch.
The FT reporters were then able to use this data to identify the top 10 global hotspots by exclusive economic zone in their article – naming Indonesia as the worst-affected region, and suggesting that the chronic oil pollution experienced by Indonesia may be the result of busy global shipping lanes throughout their territorial waters.
Of particular interest is the Malacca Strait, located between the Indonesian island of Sumatra and the Malay Peninsula, one of the world’s busiest shipping lanes serving as a vital artery between Asian economies in the Indian and Pacific Oceans.
The route has over 40 ports, and around 94,000 ships pass through the Strait each year.
While no firm ‘culprit’ has yet been determined for any of the oil pollution events we’ve detected in Bintan, we hope the growing body of evidence of chronic oil pollution in these waterways – including verified oil slick data from Cerulean – will give enforcement agencies and policymakers the motivation and tools to take meaningful action to curb oil pollution and hold polluters accountable.
SkyTruth’s role as a reliable data partner to investigative journalists continues to push the needle forward on exposing chronic oil pollution in Southeast Asia and beyond.
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