Marine oil spills have decreased by more than 90% in fifty years

Over the last 50 years, oil spills from tankers at sea have decreased by more than 90%.From the peaks of the 1970s, a period in which cases of large oil spills at sea occurred up to once every almost three days, problems relating to oil disasters have in fact decreased drastically, so much so that in 2023 there were just a case of a large spill.Furthermore, the 2023 data is not a mere isolated case, but is part of a general trend of containment of the phenomenon which has been going on for decades and which since the end of the early 2000s has never seen the number of averages and large spills reach double figures.This result was made possible by international policies and scientific progress, which led to the implementation of oil plants and cargo ships which made transport and storage systems more efficient, making them also safer.

Data relating to oil spills on board oil vessels are provided by International Tanker Owners Pollution Federation (ITOPF), which publishes a report on the topic every year.The ITOPF data reports the locations and causes of the accidents, the ships involved, and the type of spill that occurred, cataloged based on the quantity of oil released into the sea.As stated in the report, spills are categorized “for historical reasons” into different quantity brackets, ranging from "small spills" of less than 7 tonnes, to "medium spills" of up to 700 tonnes and up to "large spills" of 700 tonnes and above.As expected, the majority of accidents fall within small spills, and cases of large and medium leaks have now almost disappeared.Specifically, they occurred in 2023 only one large spill and nine medium spills and in general it seems that 2,000 tons of oil were lost at sea, compared to 15,000 in 2022.This decline confirms a trend that has been going on for years and which since 2008 has seen a number of medium and large spills of less than 10 accidents per year, compared to the hundreds that occurred in the 1970s.In fact, the 1970s were the period in which the quantity of oil that ended up in the sea reached its peak.The year with the highest number of spills was 1974 with 27 large spills and 90 medium spills for a total of 174,000 tons of oil, while the year that recorded the most serious spill was 1979 with its 636,000 tons of oil lost at sea.The single case of the greatest loss ever occurred in 1979 and involved the Atlantic Express ship, which due to the accident released 287,000 tons of oil in the waters.

The reasons behind this huge drop in oil spills at sea are of multiple nature and range from issues of technical and infrastructural improvements to others that can be considered in a certain sense of a political nature.From the point of view of technical improvements, one of the main causes of the reduction in oil accidents was the introduction of the double hull, a hull construction method which involves the erection of two different layers of watertight surface to increase safety;other technical improvements were the introduction - and evolution over the years - of GPS and in general the implementation of orientation systems, the different tracking of maritime routes, and other innovative construction methods.As for the administrative side, however, a first watershed was the International Convention for the Prevention of Pollution from Ships (MARPOL) signed in 1973 precisely to deal with the growing problem of oil disasters at the time.The MARPOL convention regulates the rules for the prevention and management of environmental disasters, which States and ships flying their flag must comply with when sailing the waters.In the United States, the MARPOL convention was followed byOil Pollution Act of 1990, which restricts the requirements of oil tankers for navigation in national waters, and which according to various studies was found to be “a significant factor in reducing the number of spills”.

Reducing oil spills in maritime waters is certainly a big step forward in reducing oil pollution, but it's not enough.In fact, although safety in maritime transport has significantly increased, accidents don't stop happening and their consequences remain disastrous in any case;without considering that the environmental impact of hydrocarbons does not derive only from their possible dispersion in the ecosystem, but from their own use, which in the case of maritime trade it is of massive proportions and increasingly shows the need to be rethought.In general, in short, the management and safety of the transport of substances harmful to the environment is certainly of fundamental importance, but it should be accompanied by a structural rethink that acts at the root of the problem and also affects its use.

[by Dario Lucisano]