Climate Change Will Undermine The World's Oceans By 2100, Says Team Of International Researchers
Climate change will have an impact on every ocean system in the world by the year 2100, according to an international group of 28 oceanographers, climate modelers, biogeochemists and social scientists. While previous studies into climate change's effect on oceans has focused mainly on ocean warming and acidification, this study also looked at the social consequences of climate change.
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"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," said lead author Camilo Mora of the Department of Geography at the University of Hawaii at Manoa. "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."
The researchers based their study on climate change models developed for the Fifth Assessment Report of the United Nations' Intergovernmental Panel on Climate Change. That report will be released in 2014, but a draft which leaked last month says that it's "extremely likely that human influence on climate caused more than half of the observed increase in global average surface temperature from 1951 to 2010." The panel also wrote that there is "high confidence that this has warmed the ocean, melted snow and ice, raised global mean sea level and changed some climate extremes in the second half of the 20th century."
Using the UN models, Mora and his team explored how temperature, acidity, oxygen levels and ocean productivity would change as a result of climate change within the next hundred years. They found that by 2100, the global average of the upper layer of the ocean could increase by at least 34 degrees, with oxygen reduced by about two percent and phytoplankton production lowered by about four percent.
These changes in acidity, temperature and oxygen levels will have negative effects not only on coral reefs and resource-rich deep-sea communities, but humans too. Coastal communities worldwide which rely on fishing and marine life could be hit hardest. According to the study, 470 to 870 million of the poorest people in the world rely on the ocean for food and money; any major change to the oceans could be devastating for these people.
"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 study co-author Andrew Thurber of Oregon State University.
What exactly will happen when climate change alters the world's oceans isn't known. Mora told LiveScience that it's like falling off a ladder: you aren't sure what part of your body you'll hurt, only that you will almost certainly will be injured in some way.
"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 study, "Biotic and Human Vulnerability to Projected Changes in Ocean Biogeochemistry over the 21st Century," was published today in PLoS Biology.
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