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Source: Author: Aparna Bhaduri

The end of ocean wilderness

Humans have degraded the oceans everywhere. A conservation approach is no longer adequate

Earth has entered a new geological epoch—the Anthropocene—where humans are significantly altering the planet’s environment. The oceans are not immune. Human activities have changed the state of our oceans over hundreds, sometimes thousands, of years, and they are now vastly different from how they once were. From our 21st century perspective, these changes are almost impossible to comprehend.

Does ocean wilderness still exist?

The full extent of human-mediated alteration of our oceans was assessed in 2018 by a group of marine scientists led by Kendall Jones of the Wildlife Conservation Society in New York 1. These researchers used the most comprehensive data available for 19 human impacts, which they termed stressors, affecting the oceans to map areas of “marine wilderness”—places where marine ecosystems are functioning in a largely natural way mostly free from human disturbance. These stressors included overfishing, habitat destruction, various forms of pollution, the spread of invasive species, and climate change effects, including ocean warming and acidification.

The researchers divided the Global Ocean into 15 geographic regions and scored each region based on the number, intensity, and cumulative effects of these stressors. They analysed two scenarios—one that included all 19 stressors and one that excluded all four of the climate change stressors.

They showed that when climate change effects were excluded only about 13 per cent of the Global Ocean’s surface now meets the definition of ocean wilderness. These few areas of relatively pristine ocean are mainly restricted to open ocean regions in the Southern Hemisphere and to ice-covered parts of the Southern and Arctic Oceans. Virtually no marine wilderness remains in coastal areas which are home to important marine ecosystems, such as coral reefs and kelp forests, and where major fisheries are located.

These findings corroborate an earlier analysis by Enric Sala, a National Geographic Explorer-in-Residence, and his colleagues who concluded that less than 10 per cent of the Global Ocean’s surface is currently subject to low enough levels of human influence to be considered pristine2.

The impacts of climate change

As bleak as these findings are, things get worse when the effects of climate change are considered. When Jones and his fellow researchers included climate change stressors in their analysis, they found that no ocean wilderness remains anywhere on the planet since human-induced climate change now strongly affects all regions of Earth’s oceans.

The Arctic Ocean is a good example of how the unmanageable effects of climate change are affecting the last pristine ocean areas. When climate change effects are ignored, the Arctic Ocean can be considered a large expanse of ocean wilderness because its ice-covered surface prevents fishing, and the impacts of pollution and invasive species are currently small. But climate change is warming the Arctic Ocean rapidly and reducing the extent of seasonal ice coverage—it will be ice free in summer before 2040. This is affecting the productivity and food web of the Arctic Ocean in far-reaching ways and opening the door to fishing, shipping and oil and gas exploration3.

Rapid decline in Arctic summer sea ice extent. This satellite mage shows the minimum extent of sea ice in the Arctic at the end of the northern hemisphere summer of 2012.
Rapid decline in Arctic summer sea ice extent. This satellite mage shows the minimum extent of sea ice in the Arctic at the end of the northern hemisphere summer of 2012. The yellow outline represents the average sea ice minimum extent from 1979 through 2010. Source:

Conservation vs restoration

These studies clearly debunk the view that the oceans are too vast to completely spoil and that large expanses of pristine ocean still exist that can be conserved in a near natural state. Unquestionably, the few remaining patches of reasonably pristine ocean require urgent protection because their largely intact, and hence more resilient, ecosystems have the best chance of resisting the future effects of climate change. Furthermore, they serve as the only benchmarks we have left of what might have been the “natural” state of the oceans at some time in the past.

But given the grim condition of Anthropocene oceans, current conservation efforts alone will no longer provide meaningful improvement in the state of our oceans at the required scale. Those of us interested in a better future for our oceans must now advocate for a much more ambitious plan of large-scale ocean restoration. The time has come to use our intellect and ingenuity to undo some of the damage we have caused to our oceans and to shape an agreed and acceptable future for them. The mission of the Restoring Oceans website is to promote education and discussion on what we need to do to achieve this.


1 Kendall R. Jones, Carissa J. Klein, Benjamin S. Halpern, Oscar Venter, Hedley Grantham, Caitlin D. Kuempel, Nicole Shumway, Alan M. Friedlander, Hugh P. Possingham, James E.M. Watson. The Location and Protection Status of Earth’s Diminishing Marine Wilderness. Current Biology, 2018; DOI: 10.1016/j.cub.2018.06.010

2 Enric Sala, 2015. Pristine Seas. Journeys to the Oceans Last Wild Places. National Geographic, Washington, DC, page 265

3Mladenov, P.V. (2020) Marine Biology: A Very Short Introduction. 2nd Edition. United Kingdom: Oxford University Press.