The World's Oceans Will Be Drastically Different by 2100

By: By Terrell Johnson

Published: October 17,2013

 

 

 

 

By the end of this century, the world's oceans will undergo drastic changes that will have major impacts both on undersea life and on hundreds of millions of people who depend on them for their food and livelihoods, especially people in poor and developing countries.
The changes are expected to have an impact at just about every point in the ocean food chain, from where fish and other sea animals can live to how big they can grow, and how large their populations can get – even whether they'll survive at all in the places we know them today.
These findings were announced in a study published this week in the scientific journal PLOS Biology, which analyzed more than 30 marine habitats around the world and found that all of them were experiencing shifts that pose a "high risk of degradation of marine ecosystems" and of "human hardship" all at the same time.
“When you look at the world ocean, there are few places that will be free of changes," Camilo Mora, an assistant professor of geography at the University of Hawai‘i at Manoa and the study's lead author, said in a university press release.
"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 culprit is a combination of environmental factors, from lower oxygen levels and warming sea surface temperatures to oceans that are becoming steadily more acidic, which depletes the oceans of important minerals and makes it more difficult for undersea life to form the shells and skeletons they need to build things like coral reefs, which play a vital role in ocean ecosystems.
What they have in common is the same root cause: the buildup of greenhouse gas emissions both in the atmosphere and the oceans – largely from burning fossil fuels – which have risen dramatically since the start of the Industrial Revolution more than a century and a half ago.
(MORE: Climate Change Pushing Sea Turtles, Crabs & Sharks Toward the Poles)
"What's happening is that many different climate variables are changing at the same time, ocean temp is going up, ocean pH is going down, oxygen is going down and productivity is going down," Lisa Levin, a study co-author and professor at the Scripps Institute of Oceanography, said in an interview with The Weather Channel.
"This means that we will be having different kinds of ecosystems and different fish yields out of the ocean," she added, noting that the changes could be "terribly destructive" for millions of people who live in small fishing villages along the world's coastlines and depend on the oceans for their food.
Between 470 million and 870 million people in the world's poorest regions rely on the oceans for their food and employment, the study notes.
To make their predictions, the study's authors used the latest models for projected climate change from the recently released Fifth Assessment Report by the Intergovernmental Panel on Climate Change.
The models allowed them to quantify the impact of several factors occurring simultaneously – higher temperatures, more acidic oceans, lower oxygen and lower ocean productivity – using two scenarios: one in which the world continues on its current path of greenhouse gas emissions, and one in which aggressive efforts are made to cut such emissions.
Only small parts of the world's polar oceans, they found, will escape the kinds of changes that the rest of the world will see by 2100.
“Even the seemingly positive changes at high latitudes are not necessary beneficial," noted study co-author Chih-Lin Wei of Canada's Memorial University. "Invasive species have been immigrating to these areas due to changing ocean conditions and will threaten the local species and the humans who depend on them."
Read the full study at PLOS Biology.

 

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