Our Perspectives

The way forward for reducing marine pollution


Some 8-20 million metric tonnes of plastics reach our oceans every year, leading to ‘garbage patches’ as well as visible impacts on nearly all the world’s coasts and beaches.

In the run up to the Ocean Conference in June, this blog series explores issues related to oceans, seas, marine resources and the implementation of Sustainable Development Goal 14, “Life below water”.

The Ocean Conference taking place this June at UN headquarters is a unique opportunity to promote and accelerate action, partnerships, commitment and progress on Sustainable Development Goal (SDG) 14, Life below water. The outcome will be a concise, focused, intergovernmentally agreed declaration in the form of a "Call for Action" to support the implementation of Goal 14.

The SDGs and the ocean

Goal 14 is part of the 2030 Agenda, adopted by world leaders in September 2015. It calls on us to conserve and sustainably use the oceans, seas and marine resources for sustainable development. The SDGs set the global agenda for development through 2030 towards a vision of peace, prosperity and planetary health. And they include clear targets, against which we can measure progress.

The first target for SDG 14 is to “prevent and significantly reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution”.  Given the fact that 80 percent or more of the pollution reaching the ocean is land-based, SDG 14 is further complemented by two targets under SDG 6, on clean water and sanitation:

Target 6.3: improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally; and

Target 6.a: expand international cooperation and capacity building support to developing countries in water and sanitation related activities and programmes, including water harvesting, desalination, water efficiency, wastewater treatment, recycling and reuse technologies.

To achieve Target 6.3, wastewater treatment services need to be brought to an additional 2.32 billion people by 2030, an average of 154 million every year.

Nutrients – good for the ocean in limited quantities

Nutrients include various compounds of the chemicals nitrogen and phosphorus. These nutrients are essential to healthy marine ecosystems as they are utilized by marine phytoplankton, the floating, microscopic plants that are the base of the marine food chain.

However, in excess they cause a phenomenon called eutrophication, whereby excess nutrients lead to overgrowth of plankton. As they decay, plankton use up vital oxygen leading to low and even zero oxygen areas known as ‘hypoxic’ or ‘dead zones’, which can significantly damage ocean ecosystems and ocean-dependent economies and livelihoods. 

With the global increase in population and associated wastewater, much of it untreated, and the rapid growth in nitrogen fertilizer use (especially beginning with the 1950s ‘green revolution’), the overall burden of nutrients reaching our oceans has roughly tripled since pre-industrial times, and could double or triple again in the ‘business-as-usual’ scenario. This has led to a geometric increase in the number of hypoxic areas globally, now numbering over 500. In 2012, UNDP estimated that the annual socioeconomic damage from coastal hypoxia is between US$200 billion and US$800 billion per year, a major drag on economic progress and poverty reduction.

Plastics – the new ocean challenge

Paralleling the explosive growth of nutrient pollution and coastal hypoxia in the twentieth century was the tremendous growth in the manufacture and use of plastics in a wide myriad of products. Plastics pervade virtually every aspect of our material life.  Global production now exceeds 300 million metric tonnes per year; the global plastics recycling rate is roughly 25 percent.

Unfortunately, in recent years we have discovered that a sizeable fraction, some 8-20 million metric tonnes per year, of plastics are reaching our oceans, leading to the ‘garbage patches’ in the major ocean central gyres as well as visible impacts on nearly all the world’s coasts and beaches. UN Environment estimates that plastics in the ocean already causes damage to ecosystems valued at $13 billion per year, and this is likely an underestimate as we learn more about different impacts.

The way forward

Nutrients and plastics pollution share a common cause: both are evidence of market and policy failures. For instance, the costs of and actions required for effective nutrients and plastics management, that avoid and minimize ocean pollution, have not been incorporated into the prices of fertilizer, food, wastewater treatment and plastics-containing products.

For both pollutants, a paradigm shift from a largely linear production, use and disposal approach needs to systematically be replaced by a far more circular approach. Overall consumption can be minimized via efficiency improvements, and systems and incentives put in place that promote the recovery, reuse and recycling of nutrients and plastics.

This translates into transformational changes in several key sectors: for nutrients, the agriculture, wastewater treatment and fertilizer production sectors; for plastics, the plastics manufacturing and wide array of plastics utilizing sectors, as well as municipal waste management.  In both cases, there are clear opportunities for innovation (policy and economic tools, technology research and development), public-private partnerships and, notably, job creation.

Join the discussion!

As part of its series of virtual dialogues in support of the June 2017 Ocean Conference, the Ocean Action Hub is commencing its first e-dialogue on marine pollution on Monday, 6 March. We invite you to engage in this dialogue to share your ideas, proposals and experience as we all work together towards turning the tide on ocean nutrients and plastics pollution for a sustainable ocean.

Andrew Hudson Oceans blog series Blog post Agenda 2030 Sustainable Development Goals Sustainable development Oceans Environment Ecosystems and biodiversity