World Ocean Systems to Undergo Major Upheaval by 2100 Due to Climate Change

A holistic new study examining the full series of changes that have and will be triggered in the world's oceans through human-derived greenhouse gas emissions shows that no corner will escape the effects of climate change by 2100.

Previous analyses, the researchers from the University of Hawaii at Manoa argue, have failed to incorporate all relevant variables, focusing mainly on ocean warming and acidification. Published in the journal PLOS Biology, the report also looks at the depletion of dissolved oxygen in seawater and reduced productivity among the ocean's many ecosystems.

"When you look at the world ocean, there are few places that will be free of changes; most will suffer the simultaneous effects of warming, acidification, and reductions in oxygen and productivity," lead author Camilo Mora, assistant professor at the Department of Geography in the College of Social Sciences, said in a statement. "The consequences of these co-occurring changes are massive -- everything from species survival, to abundance, to range size, to body size, to species richness, to ecosystem functioning are affected by changes in ocean biogeochemistry."

According to the study, 470-870 million of the world's poorest rely on the ocean either for food or revenue, both of which could be comprised as food chains, fishing and tourism face major upheavals due to the changes outlined in the analysis.

Using the most recent models of projected climate change developed for the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), the scientists quantified the overlapping of changes in temperature, pH, oxygen and primary productivity. They did this based on a business-as-usual scenario in which atmospheric carbon dioxide concentrations reached 900 ppm by 2100, and one in which they only reached 550 due to mitigation efforts.

"Other studies have looked at small-scale impacts, but this is the first time that we've been able to look the entire world ocean and how co-occurring stressors will differentially impact the earth's diverse habitats and people," said co-author Andrew Thurber, a postdoctoral fellow at Oregon State University. "The real power is in the quantitative, predictive approach using IPCC climate models that allow us to see how much it will all change, and also how confident we can be in our estimates."

Co-author Andrew Sweetman, who helped to convene the original team of investigators, called the extent of the potential impacts "truly scary," noting they will "be felt from the ocean surface to the seafloor."