Over 400 million tons of plastic are produced every year (See figure 1), and at least 14 million tons end up in the ocean.1 This accounts for 80 percent of all marine litter. By 2040, it will nearly triple, adding 23-37 million metric tons of waste into the ocean per year.2 This means about 50kg of plastic per meter of coastline.
Ocean pollution is not limited to plastic waste; the oceans have become home to chemicals and biological materials including petroleum-based pollutants, toxic metals, manufactured chemicals, pharmaceuticals, pesticides, as well as a mixture of nitrogen, phosphorus, fertilizer, and sewage.3 Of these, plastic pollution is the most visible, but it is a part of a much wider problem.
Figure 1: Global plastics production4
The oceans cover more than 70% of the earth’s surface, hold 97% of the world’s water, host some of the planet’s most diverse ecosystems, and support economies around the world. They stabilise the climate and slow global warming, absorbing more than 90% of the excess heat released into the earth’s environment and nearly one-third of carbon dioxide emissions.5 This means plastic pollution in the ocean has a far-reaching impact across the planet.
As well as contributing to climate change, it is a threat to food safety and quality, marine ecosystems, coastal tourism, and human health. Manufactured chemicals, many of them released into the seas from plastic waste, can disrupt endocrine signalling, reduce male fertility, damage the nervous system, and increase risk of cancer.6
The level of plastic pollution is alarming. According to the European Environment Agency (EEA), pollution by toxic metals, industrial chemicals and plastic wastes is at problem levels in 96% of the Baltic Sea, in 91% of the Black Sea, in 87% of the Mediterranean Sea, and in 75% of the North-East Atlantic Ocean.7 One extensive review suggests that plastic levels will continue to grow even if significant action is taken now to stop such waste from reaching the world’s oceans.8
Plastic debris in the ocean is primarily from land-based sources, coming from urban and stormwater runoff, sewer overflows, littering, inadequate waste disposal and management, industrial activities, tyre abrasion, construction and illegal dumping. Meanwhile, ocean-based plastic pollution originates from the fishing industry, nautical activities and aquaculture.9
Plastic pollution is a problem of human origin, and so controlling this problem is possible. However, it is important to continually build an evidence base for urgent action on marine pollution in general, and plastic waste in the oceans in particular.
Plastic is not a key theme in the United Nations’ Sustainable Development Goals (SDGs)10, which were established in 2015. However, controlling plastic pollution is essential to achieving SDG12, which aims to ensure sustainable consumption and production patterns, and SDG14, aiming to conserve and sustainably use the oceans, seas and marine resources for sustainable development. The benefits of limiting plastic pollution also support other SDGs, such as SDG6 for clean water and sanitation, or SDG11 for sustainable cities and communities.
Most SDGs targets have been set for 2030, but many related to marine pollution were set for 2020 or 2025, recognising the particular urgency of this issue. Though important progress has been made on these early targets, ongoing action is still needed, as shown by this map of plastic beach litter between 2015 and 2020 (See figures 2 and 3).11 In 2015, China’s beaches had an average of over 14 million items of plastic litter per square kilometre, falling to 134,588 items in 2018. Meanwhile, some countries have made little progress on this front, or even increased their count of plastic beach litter.
Target 14.A, set for 2030, is to increase scientific knowledge, research and technology for ocean health. This will be measured by the proportion of total research budget allocated to the field of marine technology. In 2017, the United Nations’ Ocean Conference also stressed “the need to further increase marine scientific research to inform and support decision-making, and to promote knowledge hubs and networks to enhance the sharing of scientific data, best practices and know-how”.14 Research is clearly acknowledged as a critical factor in the advancement of SDGs related to the protection of our oceans.
Figure 2: Plastic beach litter per square kilometre, 201512
Figure 3: Plastic beach litter per square kilometre, 202013