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The physical ocean environment rapidly, and there is an urgency to better understand the combined effect of the ocean stressors. Photo: Jerry Tjiputra.

Mitigation slows down ocean stress

Ocean stress affects everything from the tiniest plants to the mightiest whales. But climate mitigation slows down the pace, a new study shows.


The marine ecosystems are recognized to provide the primary protein source for one in seven of the world’s population. These ecosystems will have more time to adapt to climate change, if mitigation measures are implemented. Stress-free conditions can be extended by twenty years, a recently published study in Nature Communicationsshows.

The study ”Rapid emergence of climate change in environmental drivers of marine ecosystems”, led by the National Oceanography Centre in UK, finds ”that in fifteen years’ time 60% of the ocean will be experiencing more than one of acidification, de-oxygenation and/or warming at once. However, the study also shows that if the climate change mitigation measures, outlined in the IPCC report, are implemented the time when the ocean was dominated by multiple ‘stressors’ will be delayed by twenty years”, the NOC writes in their press release.

Four ecosystem indicators

The study focuses on four ecosystem indicators, previously identified in the last IPCC report to be crucial for marine ecosystem health and biodiversity. They are:

  • higher temperatures
  • lower oxygen levels
  • altered primary production
  • lower pH

Jerry Tjiputra, researcher at Uni Research and the Bjerknes Centre for Climate Research is a co-author in the study. He marks that surface pH is on average projected to have the fastest pace of change related to anthropogenic climate change, followed by temperature and oxygen.

– The study alarmingly shows that in parts of the Nordic Seas, all four ecosystem indicators will emerge outside their natural variability envelopes by 2050, unless the current anthropogenic climate change is curbed dramatically, he says.

Because of this, Tjiputra emphasizes that there is an urgency in better understanding of how these simultaneous changes affect the different marine organisms and their roles in delivering ecosystem services.


Combined effect

The combining effects of the four studied stressors, has been uncertain. By analyzing numerical simulations, the researchers determined when the influence of these drivers leads to conditions where the ecosystem is unable to adapt and species migration is likely to occur.

Under a business-as-usual scenario, the authors show that by 2050, conditions in 86% of the ocean will exceed natural variability, threatening the marine ecosystem as we know it. The authors also run their simulations under a mitigation scenario (based on the Intended Nationally Determined Contributions submitted during COP21) and show that if this scenario is realized the proportion of ocean susceptible to multiple drivers within the next 15 years is reduced to 34%.

If implemented, such mitigating action could provide the marine ecosystem more time to respond to climate change, and protect human livelihoods and well-being, the authors conclude.



Stephanie A. Henson, Claudie Beaulieu, Tatiana Ilyina, Jasmin G. John, Matthew Long, Roland Séférian, Jerry Tjiputra & Jorge L. Sarmiento (2017), Rapid emergence of climate change in environmental drivers of marine ecosystems, Nature Communications, doi:10.1038/ncomms14682