


A team of 29 international scientists based at the University of Hawaii, Honolulu, have now developed more comprehensive projections of future ocean health, which take into account temperature, acidity, dissolved oxygen and productivity. To develop these projections, the researchers compiled more than 80,000 existing modeled maps of oceanic change, many of which informed the latest Intergovernmental Panel on Climate Change (IPCC) report.

The team found that mangrove and coral reef ecosystems near the tropics will likely experience the smallest cumulative change by 2100, whereas cetaceans (the group of mammals that includes whales, dolphins and porpoises), as well as pinnipeds (such as seals and walruses) will face the largest amount of change.


The team used the compiled maps to estimate the impact these changes will have on coastal human populations whose livelihoods depend on marine resources.

Researchers considered two different climate change scenarios: one in which humans significantly cut back carbon dioxide emissions and, as a result, global atmospheric carbon dioxide levels increase from the current 440 parts per million (ppm) to just 550 ppm; and one in which humans continue emitting carbon dioxide at the current rate, under a scenario known as "business as usual," which the IPCC projects will result in an atmospheric carbon dioxide accumulation of 900 ppm by the end of the century. (Parts per million is an indicator of the concentration of a chemical in, for example, air. So in this case, 440 ppm means that there are 440 molecules of carbon dioxide in every million molecules of air.)



The team notes that these estimates are rough, and that the specific ways in which ecosystems and communities adjust to change will remain largely unknown until the changes unfold.  


"Systems are very complex," Mora said. "You can't tell what species are going to go extinct, or the response of a specific species, but you can expect these changes to be quite massive."

The researchers hope to continue synthesizing new data as it becomes available, in order to continue honing the precision of their predictions.

The new findings were detailed on Oct. 15 in the journal PLOS Biology. 


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