Bilge Dumping at Sea: What are SkyTruth and others doing about it?

With free public monitoring services and the help of watchdogs globally, bilge dumping can come to an end. SkyTruth’s new project Cerulean is one solution.

This is the last entry in a multi-part series revealing the significance of bilge dumping globally. You can read parts one, two, and three on SkyTruth’s blog.

Throughout this multi-part series on global bilge dumping, we have revealed how SkyTruth has identified oily pollution from ocean-going vessels, the range of harmful effects to coastal communities and marine ecosystems, and the challenges in prosecuting ocean offenders. We now address the future. What’s next? 

Recall that bilge dumping occurs when vessels bypass treating their oily wastewater and discharge it directly into the ocean. When we started this series, we reported on SkyTruth’s 2019 ocean monitoring efforts in which we recorded 163 oily slicks around the world. So far this year we have detected 98 new slicks. Now that we better understand what is occurring at sea, we are working hard to share that information with citizen watchdogs and others, enabling them to take action such as alerting authorities and publicly exposing wrongdoing in their coastal waters. With sustained pressure, we hope polluters will be forced to act responsibly.

Using radar satellite imagery, SkyTruth can observe and measure oil pollution in the ocean. Making a conservative assumption about an oil slick’s thickness, we can estimate the volume of oil, an indicator of the severity of an incident. The legal limit for discharging oily wastewater under international law outlined by the International Convention for the Prevention of Pollution from Ships (MARPOL) is 15 ppm for most cargo vessels and tankers. Trained observers on aircraft can see oil at concentrations of 50 parts per million (ppm) and above. It’s possible that under favorable sea-state conditions, radar satellite imagery is capable of revealing oil at lower concentrations, so we’ll be able to spot more potential violations. In a resolution to MARPOL specifying visibility limits of oil discharges, the Marine Environment Protection Committee “urgently requests authorities to consider the principle that a visible trace of oil is one element of proof that the 15 ppm discharge standard of Annex I of the MARPOL Convention may have been violated.” Similarly, under the U.S. Clean Water Act, oil discharges that cause a visible sheen are encouraged to be reported and are classified as potentially harmful to public health or welfare. 

Using advanced remote sensing techniques, we often can determine a likely source of pollution, whether from a vessel, a natural oil seep, or energy infrastructure like pipelines, drill rigs and production platforms. This kind of information can help oil-spill response efforts: If they know the location and source of oil pollution, responders are better able to take action and reduce the impacts of the pollution. In addition, if the pollution is from a vessel, near-real-time monitoring can help authorities catch a perpetrator who might still be nearby, or take administrative action when that vessel comes into port. Prosecuting criminal offenses for environmental crime requires robust evidence connecting a culprit to the crime. Satellite imagery can help: It collects evidence remotely, potentially providing an efficient way to prosecute ocean offenders.

To demonstrate this potential, in late 2019 SkyTruth launched project Cerulean to automate the detection of oil slicks on the world’s oceans and identify likely sources. Cerulean applies a machine learning technique called Deep Learning (a type of Artificial Intelligence) to make it possible to analyze thousands of satellite images every day to detect slicks and sources. We compare these slicks with public Automatic Identification System (AIS) vessel tracking data in order to identify the likely sources of this pollution (you can read more about our process here).

Image 1. Sentinel-1 radar satellite image of suspected bilge slick (black streak) in the Java Sea on February 15, 2020. AIS signals are shown for two potential sources. The likely source vessel is circled in red, with its AIS track (red) closely matching the slick in space and time. The other nearby vessel’s broadcasts (white) did not match the time and location of the slick.

Satellite data such as that provided by Cerulean could potentially help prosecutors convict oil polluters if it is approved for use in court. Remote sensing evidence is a relatively new tool in court cases. It must be authenticated and checked for integrity regarding the collection and storage of the data to ensure its validity. In the United States, cases using satellite evidence have not been widely published since many decisions about whether evidence is admissible can be made orally or pretrial. Because of this, we do not have a good estimate of how frequently satellite imagery is accepted as evidence. However, we do know that if the remote sensing technology is not new or novel it is more easily admissible. When trying to prove a fact, an expert witness with specialized knowledge can explain the reliability of the technology used and the data presented. In describing the detection of an oily slick, for example, an expert might need to explain a variety of factors that are considered in the analysis of ocean imagery, including weather conditions such as rain and wind speed, atmospheric and oceanographic features, and differentiating a vessel from ocean infrastructure in order to demonstrate the admissibility of image-based evidence

Satellite imagery has been used as evidence of other environmental crimes such as deforestation and illegal fishing. However, it is uncommon for imagery alone to provide conclusive evidence, or to prove guilt beyond a reasonable doubt in prosecution for environmental crime. Satellite imagery has provided corroborating evidence that has led to prosecutions of pollution at sea. However, we have found no cases where it provided conclusive (dispositive) evidence, meaning it alone is usually not enough to link a crime to a perpetrator, or even prove that a crime occurred at all. Currently, eyewitness reporting is more often used as evidence for prosecution of bilge dumping. Whistleblowers and vessel inspectors have been a common catalyst for prosecution. For example, between 1993 and 2017, 76% of prosecuted cases under the U.S. Act to Prevent Pollution from Ships came from whistleblowers. Overall, there are no restrictions on satellite imagery’s power to serve as evidence in court as long as the technology has been proven valid and trustworthy.

Europe currently has an ocean monitoring service called the CleanSeaNet that has led to several prosecutions using satellite imagery in combination with on-ground evidence, in which fines were imposed. The European Union Directive 2009/123/EC specifies types of prosecution for ship-source pollution. However many courts still rarely prosecute. Often they require official inspection on site where the pollution occurred and on the vessel in order to connect the evidence to the crime, which can be challenging when collecting on-ground evidence is time sensitive. (Oil can disperse within 12 hours, and ships can easily be long gone by then.) Additionally, the European Maritime Safety Agency (EMSA) states “(r)esolution of cases can take many years, and in some countries privacy issues prevent the full details being disclosed publicly.” 

Image 2. Suspected bilge slick in the Gulf of Guinea on February 23, 2020. The red AIS signals closely follow the linear slick to the likely source vessel (circled in red). Another nearby vessel’s broadcasts (white AIS signals) were also analyzed; however, this vessel was moving nearly perpendicular to the slick and is not a likely source.

But law enforcement agencies and citizen-activists aren’t the only stakeholders concerned about clean oceans. Companies have market-based incentives to be recognized as sustainable and socially responsible businesses, and they are liable to their stakeholders to uphold promises of corporate social responsibility. While the shipping industry produces ocean oil pollution, it is also the most energy efficient method for transporting goods. Such a large and fast-growing industry requires effective environmental regulation and enforcement. 

The International Maritime Organization’s (IMO) theme for 2020 provides a unique opportunity for the shipping industry to clean up its act. The theme is “Sustainable shipping for a sustainable planet.”  For example, part of this includes the IMO’s 2020 sulphur cap on ships’ fuel oil. In transitioning to lower sulphur fuel, some shipping companies must adjust their current operations and infrastructure, which requires financing. By choosing cleaner ships that meet current and future environmental standards, investors, banks and other stakeholders consider Environmental, Social, and Governance (ESG) criteria. ESG concerns have led to efforts such as the Sustainable Shipping Initiative (SSI), an international partnership that promotes sustainability between its members, from ship owners to insurers to NGOs. SSI’s “Save As You Sail” program partners ship owners with financial providers in order to update vessels with more efficient emission-reducing technology and save on fuel costs. 

Additionally, vessel companies can voluntarily use grading initiatives such as the Swedish Clean Shipping Index (CSI) to hold themselves accountable. CSI scores a vessel company and its operations from its supply chain to emissions to operational discharges, allowing investors, clean tech providers, and other stakeholders, such as freight forwarders, to partner with responsible vessels who can be trusted to comply with international standards. A similar program exists in North America called Green Marine. The Environmental Ship Index (ESI) is an international scoring option that provides vessel-specific scoring and offers incentives such as discounts on port dues and bonuses to clean ships. Its index currently evaluates over 7,000 ships globally. To help support responsible ships and shipping practices, investment frameworks such as The Poseidon Principles provide banks around the world with principles that align ship financing with climate interests. Several large European banks such as the European Investment Bank (EIB) are committed to providing green investments through Blue Economy Finance Principles. These principles were created by the EIB to uphold the United Nations Environment Programme’s Sustainable Development Goal “Life below water.” In 2018, two banks, EIB and ING, agreed to provide 300 million euros of financing to support green shipping in Europe. These initiatives provide evidence that sustainability and a blue economy aren’t mutually exclusive. 

Cerulean aims to support international clean sea initiatives as well as stakeholder interests by providing a platform for stakeholders to directly monitor oily discharges from vessels. Companies and coalitions like those listed above can use Cerulean to help ensure a greener supply chain. Scoring indexes can use Cerulean to make sure vessels hold true to their ratings, allowing investors and insurers to be more confident in their partnerships. Widespread transparency of activity in the oceans encourages vessel operators, owners, and crew to operate responsibly in order to continue to receive support from their clients and other stakeholders, as well as to avoid criminal penalties. 

Image 3. These bright lines, compiled from dozens of radar satellite images, reveal heavy vessel traffic through the Strait of Malacca, one of the world’s busiest shipping lanes, over the course of several months in 2019.

Our conversation with a resort director in Southeast Asia suggests Cerulean will support citizen activists as well. This resort director (first introduced in the second blog post in this series) reached out to SkyTruth to share some of his experiences with bilge dumping. He has regularly found oil and tar washing ashore on beaches near Singapore and the Strait of Malacca for several years. He believes that part of the reason ship operators act irresponsibly is that they don’t really understand that they can be monitored, and don’t realize that their AIS broadcasts can be collected by the public. As an environmental activist whose livelihood depends on a clean coast, he would like to make vessel operators more aware of the transparency of their behavior and is interested in doing more personal monitoring of the sea surrounding his property. He believes Cerulean can help him, stating  “(i)t is super compelling to pair satellite data with AIS.” Knowledge of potential oil slicks nearby, even at night, allows citizens to prepare for when oil hits the land and can alleviate some of the clean-up. “It would be useful to know if a slick is coming,” he said. “We could get people organized to stop it. If we had a warning — even 30 minutes, it would give us enough time to make a difference.”

While the first version of Cerulean won’t provide continuous monitoring of the ocean (because the satellites now in orbit can only cover a portion of the earth every day), it would allow insight into ocean pollution every several days and will build a one-of-a-kind record of incidents over time. One key objective of Cerulean is to establish a scalable pipeline that can process more and more images as new satellite constellations are launched and cover our oceans more continuously. 

Cerulean is currently under development, and we hope to have an operational product by 2021. Once up and running, Cerulean will be free and open to the public, providing a user-friendly interface that allows anyone, without any technical expertise, to monitor their areas of interest for oily slicks. Users can receive near real-time alerts for oil detected in their area of interest along with insights into who might be responsible for the pollution. Cerulean will identify features such as a slick’s location, date, time, and length, in addition to specific vessel characteristics such as a vessel’s ID number, destination, owner, operator, and flag country. We hope Cerulean will provide more insight into hotspots — where bilge dumping is particularly common — as well as track repeat offenders to enable more robust prosecutions. We anticipate Cerulean will be a useful tool for fleet owners, shipping companies, and international merchandise retailers that choose to be environmentally responsible: they’ll be able to use Cerulean to track the performance of their fleet and incentivize operators and crew to stay in compliance with ocean law. Additionally, law enforcement can use these near real-time alerts to catch perpetrators in port and in coastal waters. Finally, we hope it will be a tool that empowers citizen watchdogs, nongovernmental organizations (NGOs) and journalists  to keep an eye on what’s happening at sea, report wrongdoings, and rachet up pressure on governments and businesses to do a better job protecting our ocean. 

In the meantime, SkyTruth analysts will continue to monitor hotspots in the ocean and share our results on this blog. By continuing to report on pollution across the world, innovate user-friendly platforms, and spread awareness, we are working to stop oil pollution at sea and protect the world’s marine ecosystems and the coastal communities that depend on them.