Humanity's impact on global oceans nearly doubled in a just over a decade and could double again soon without urgent and sweeping international action, warns a study published Monday in the journal Scientific Reports.
"We can improve things. The solutions are known and within our grasp. We just need the social and political will to take action."
—Ben Halpern, study lead author
To determine the pace of change in cumulative human impacts on the world's oceans, researchers from University of California, Santa Barbara and Stanford University combined annual data from 2003 to 2013 on 14 human stressors and how they affected 21 marine ecosystems.
The team found that over the 11 years, 59 percent of the ocean experienced a significant increase in cumulative impact, "in particular due to climate change but also from fishing, land-based pollution, and shipping." Human impact significantly decreased for only five percent of the ocean.
"Impacts of human activities on the ocean have been shown to be substantial, ubiquitous, and changing," the study says, pointing to both existing uses of global oceans and emerging ones such as offshore energy production, aquaculture, and undersea mining. "The resulting cumulative impact of these activities often leads to ecosystem degradation or even collapse."
Researchers determined that during the analyzed period, "nearly all countries saw increases in cumulative impacts in their coastal waters, as did all ecosystems, with coral reefs, seagrasses and mangroves at most risk." However, some regions saw high impacts and are at greater risk for ecosystem collapse: the Black Sea, Eastern Mediterranean Sea, Canadian Eastern Seaboard, Southern Atlantic Ocean, and Southern/Western Australia.
With the new study, the team aimed to provide "a holistic perspective of where and how much human activities shape ocean change—for better or worse—which is essential to policy and planning," according to a statement from UC Santa Barbara announcing the research.
"If you don't pay attention to the big picture, you miss the actual story," said lead author Ben Halpern of the National Center for Ecological Analysis & Synthesis (NCEAS) at UC Santa Barbara. "The bigger picture is critical if you want to make smart management decisions—where are you going to get your biggest bang for your buck."
The apparent accelerating pace of human impacts on oceans around the world "creates even more urgency to solve these problems," Halpern added. "We can improve things. The solutions are known and within our grasp. We just need the social and political will to take action."
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As the study explains:
Despite these sobering results, messages of hope remain. During this time period, many countries, particularly in Europe, Asia, and parts of Africa, saw notable declines in impacts from commercial fishing, and many countries saw reduced impacts from land-based pollution. In a few cases, these declines were larger than increases in climate change and other stressors, leading to overall decreases in [cumulative human impacts] , and in all cases the declines helped mitigate increases.
"Coordinated, comprehensive management that accounts for multiple stressors can leverage decreases in single stressors," the study continues, noting that "results indicate that climate mitigation to meet targets of the Paris agreement would have major positive impact on the condition of marine ecosystems."
Co-author Melanie Frazier, a data scientist at NCEAS, pointed to the accelerating rate at which oceans are warming—because of global heating fueled by human activity—as a motivator for swift international action.
"You don't need fancy statistics to see how rapidly ocean temperature is changing and understand the magnitude of the problem," she said. "I think this study, along with many others, highlights the importance of a concerted global effort to control climate change."
"You don't need fancy statistics to see how rapidly ocean temperature is changing and understand the magnitude of the problem."
—Melanie Frazier, study co-author
The research was released just a week before United Nations delegates are scheduled to meet for the third time in less than a year to discuss "conservation and sustainable use of marine biological diversity of areas beyond national jurisdiction."
In an op-ed published Monday by The Hill, Mark Abbott of Woods Hole Oceanographic Institution and Chris Scholin of the Monterey Bay Aquarium Research Institute wrote that "so far, these negotiations have had a critical omission: the vast stretch of ocean known as the twilight zone" that spans from 660 to 3,300 feet deep.
"With the twilight zone, we have an opportunity to transform how humanity relates to little known—yet potentially indispensable—ecosystems and resources," they argued. "The ocean's midwater is remote enough that it has mostly remained shielded from human impacts. We do not have to make another mistake of epic proportions and find ourselves trying to repair the damage done by overexploitation when it is already too late."