Oceans cover over 70 percent of Earth and form 95 percent of its biosphere. Yet human activities, from overfishing to plastics pollution to oil and gas extraction to climate change, are degrading the world’s oceans and threatening food security for fish-dependent populations, warns the UN’s Second World Ocean Assessment (WOA II), a sweeping new report on the world’s oceans.
The number of “dead zones” – ocean areas where insufficient oxygen allows nothing to survive – are increasing; ocean water levels are rising, warming and becoming increasingly acidic; and important mangroves and coral reefs are being degraded. About 90 percent of the world’s mangrove, seagrass and marsh plant species are threatened with extinction.
Released on 21 April 2020, the WOA II was developed with input from more than 300 experts. It builds upon the first WOA – which was published in 2015 – charting trends in the ocean since 2010 and adding further focus on humanity’s relationship with the ocean. Together, the two assessments form the most comprehensive source of information on oceans as they exist today.
“Human impacts have become very serious and are affecting the health of the ocean,” says Alan Simcock, joint co-ordinator of the Group of Experts responsible for the Assessment. “It’s not yet beyond repair, but we are getting to critical levels in many areas.”
At about 1,000 pages divided into two volumes, the Assessment examines oceanic biodiversity, ocean foods, economic ties to oceans, and specific ocean ecosystems spanning from salt marshes to high-latitude ice. It also expounds the number of intersections between society and the ocean, from impacts on human health to ocean management.
This year marks the start of the UN Decade of Ocean Science for Sustainable Development as well as the UN Decade on Ecosystem Restoration, and the Assessment serves as a baseline document for each, as well as for the Sustainable Development Goals. Each chapter is linked to specific outcomes of the ocean science decade and the SDGs, as well as highlights the most pressing gaps in ocean knowledge, which are critical to fill in order to develop effective policy and conservation tactics.
“Scientific understanding of the ocean, its functioning and the impacts on it grows ever faster. However, in many parts of the ocean, knowledge and capacity-building gaps remain, in particular in areas beyond national jurisdiction,” states the report.
Oceans provide the “life-support systems of our planet,” said UN Secretary-General António Guterres, who called for a “green and blue” recovery for land and oceans from the damage of the COVID-19 pandemic as he released the Assessment. Although the pandemic has temporarily eased pressures on marine ecosystems, that effect is expected to be short-lived.
The most significant drivers of change in the planet’s oceans are overfishing, pollution, and climate change, says Simcock. Other forces include population growth and demographic changes, economic activity, technological advances and geopolitical instability.
Overfishing means an annual loss of USD 88.9 billion in net benefits to societies and threatens food security for populations that rely on fish products for protein – particularly hitting countries where hunger is widespread. About 17 percent of all animal protein consumed by humans comes from the oceans, which also supports about 12 percent of human livelihoods. Yet one-third of the world’s fish stocks are being harvested at unsustainable levels, threatening their longer-term existence.
Ensuring sustainability in the main sectors of the growing “blue economy” is key, says the report, citing seabed mining, extraction of offshore hydrocarbons, tourism and recreation, marine genetic resources and marine renewable energy as the prominent sectors in countries’ increasing economic use of the ocean.
Waves of change
To prevent further destruction of oceans, greater cooperative and integrated action must be taken by world leaders, through joint research, capacity development and sharing data, information and technology, said Guterres, echoing the report’s call for a coherent overall approach to addressing the cumulative impacts of human behaviour on oceans and marine ecosystems.
Guterres said these provide opportunities to reverse the damage that has already been done and “underscores the urgency of ambitious outcomes in this year’s UN biodiversity, climate and other high-level summits and events.”
That is essential, given that the world’s oceans are basically one enormous entity, and what happens in one region will spread around the planet, says Simcock. Ocean currents move untreated wastewater, marine litter, pollutants and non-Indigenous species over long distances, worsening their deleterious impact. For example, nutrients from the Amazon River have formed a seaweed bloom off the coast of West Africa that now exceeds 20 million tons 8,850 kilometers.
“Everything is connected,” adds Simcock. “As water moves continuously, what is under the Gulf of Mexico will come up in Norway, then sink down to the bottom of the Atlantic, and then across the Pacific and eventually come back to the Gulf of Mexico.”
Postponement in implementing solutions will only worsen matters and unnecessarily increase environmental, social and economic costs, says the WOA II. Its findings are not recommendations but instead aim to inform governments and policymakers.
“The answers to many problems are known. We must not delay in implementing them,” says Simcock.
Ending overfishing (including illegal, unreported and unregulated fishing) and rebuilding depleted resources could mean an increase of as much as 20 percent in fish yields, says the Assessment. However, the transition costs – economic and social – would be significant and politically unpopular.
Meanwhile, coastal developments, often for tourism, can create significant problems by replacing soft, nature coastlines with “armored,” or hard-surfaced, zones of concrete, asphalt and artificial light. That not only confuses and threatens species, such as sea turtles seeking land to lay eggs, but threatens the whole of the coastal ecosystem, says Simcock. To make matters worse, such developments often start with destructive clearing of important landscapes, including carbon-dioxide-absorbing mangroves.
“Economic pressures for development are phenomenal, and you can end up with coasts that are armored. Animals that could live on the soft shore find it difficult to live on an armored shore,” says Simcock.
“You may still have an ecosystem there, but it may not be as biodiverse or as attractive.”
Still, the Assessment shows some positive stories. In certain areas, particularly in Southeast Asia, “blue infrastructure development” and approaches such as “building with nature,” are being introduced as part of efforts to harmonize coastal protection and development with habitat and ecological protection.
One of the largest opportunities for success remains increasing our scientific knowledge base of the ocean. And progress is being made, says the report: new feats of technology, namely sensors and autonomous observation platforms, are collecting more granular data on oceans, including in remote areas.
“Since 2015, on average, one new species of fish has been described per week, highlighting how much remains to be discovered,” says the WOA II.