Plastic Oceans: one of the challenges of the Decade of Ocean Science
The year 2021 started the Ocean Decade, whose purpose is the development of science to support countries to manage the oceans in a sustainable way and, especially, to reach the commitments of the 2030 Agenda for Sustainable Development, with focus on Goal 14.  One of the targets of the mentioned goal is to prevent and significantly reduce marine pollution of all kinds, including plastic pollution, which represents one of the main threats to marine life today.
Although the risks and losses arising from the excessive consumption of plastics, especially disposable ones, are relatively widespread in society, their use is not only far from over, but it also had a great increase during the coronavirus pandemic, with the intensification of electronic commerce and the use of disposable hospital supplies.  Unfortunately, a considerable portion of this waste produced reaches the oceans and, due to its slow decomposition, remains in it for centuries, causing severe damage to the marine environment.
A research conducted by the Australian scientific agency CSIRO’s Ocean and Atmosphere, published in October 2020, estimates that there are 14 million tons of microplastics on the seafloor.  These particles smaller than 5 millimeters in diameter are highly harmful to living beings, and can affect the growth, reproduction, development and survival of marine organisms, although it is not yet possible to quantify the extent of their effects on ecosystems and on biodiversity.
In addition to microplastics, the oceans still have an incalculable amount of packaging, bags, bottles and other waste and objects made from this material, which reach the seas in different ways. Among the various sources of marine pollution by plastics, we can emphasize the waste that is left on the beaches and in the cities, as these eventually end up in rivers that flow into the seas, ghost fishing, which is the abandonment of fishing equipment in the oceans, and cosmetic products, such as exfoliants, that have plastic microspheres, that after use are carried by the sewage to water courses and seas.
Plastics are ingested by aquatic animals both accidentally and voluntarily, as they are easily mistaken for food. According to a specialist from the Royal Dutch Institute for Maritime Research, this is because plastics acquire a smell (and even taste) of food for these animals inside the ocean.  In this way, they are quickly inserted into the food chain, starting to integrate not only the diet of marine fauna, but also birds and other animals that feed on it, including humans.
Despite the fact that the volume of plastic in the oceans is increasing at an alarming rate over the years, leaving animals increasingly vulnerable to the consequences of pollution, 168 States have already committed themselves to the protection and preservation of the marine environment, with the ratification of the United Nations Convention on the Law of the Sea (UNCLOS), which has an exclusive part to deal with the matter.
However, it should be noted that the Convention deals with the subject in a generic way, imposing only general duties for the preservation of the marine environment, without completely regulating it. For this reason, it is essential that the international community conclude specific agreements to provide for the prevention and mitigation of various sources of pollution.  The implementation of the rules of international law that deal with the conservation and sustainable use of the oceans as reflected in UNCLOS is also one of the targets of Goal 14 and is extremely urgent and necessary to achieve the “future we want”.
As noted, the issue of plastics in the oceans is a global problem and, therefore, cannot be tackled in isolation, with the cooperation of States being essential for the adoption of measures aimed at recycling and reducing the consumption and dumping of plastics in oceans. Such cooperation is, luckily, addressed in the Convention, which determines that States must cooperate to promote studies on pollution of the marine environment and, in the light of the information obtained, develop practices and recommended procedures to prevent, reduce and control this pollution.
In addition to joint action, States must also act individually to reduce the emission of harmful substances into the marine environment, especially non-degradable substances, as is the case with plastics, as well as reducing pollution from vessels and from working facilities and devices in the marine environment, pursuant to Article 194 of the Convention. It also determines that States adopt laws and regulations to control pollution of the marine environment, as well as adapt their policies for this purpose.
It is important to note that the Convention already emphasized that the measures taken by States to combat this pollution must not transfer damage or risks from one area to another, either directly or indirectly, nor transform one type of pollution into another. Therefore, the development of oceanic science becomes even more fundamental for achieving effective solutions to the problem of plastics, allowing an appropriate end to be given to those already in the environment and their use to be replaced by biodegradable materials, this being one of the main challenges of this generation.
 Available in: http://decada.ciencianomar.mctic.gov.br/decada-global/ Acess in feb. 22, 2021.
 Available in: https://www.bbc.com/portuguese/brasil-55131470 Acess in feb. 22, 2021.
 Available in:https://www.csiro.au/en/News/News-releases/2020/14-million-tonnes-of-microplastics-on-seafloor Acess in feb. 22, 2021.
 Available in: https://www.bbc.com/portuguese/geral-45519251 Acess in feb. 22, 2021.
 ZANELLA, Tiago V. Manual de Direito do Mar. Belo Horizonte: Editora D’Plácido, 2019.