Scientists Say Ocean Warming May Greatly Reduce Sea Life

The world's oceans will likely lose about one-sixth of their fish and other creatures within 100 years if climate change continues on its current path.

These are the findings of a wide-reaching, computer-based study by an international team of marine biologists.

Every degree Celsius that the world's oceans warm, their biomass — or the total weight of all the marine animal life — is expected to drop five percent, the study also found.


In this Wednesday, July 8, 2015 file photo, herring are unloaded from a fishing boat in Rockland, Maine. (AP Photo/Robert F. Bukaty, File)

The study predicts that if there is no change in the rate of worldwide greenhouse gas production, there will be a 17-percent loss of biomass by the year 2100.

But, if the world reduces carbon pollution, biomass losses could be limited to only about 5 percent.

William Cheung is a marine ecologist at the University of British Columbia in Canada. He co-wrote the study, and told the Associated Press, "There are already changes that have been observed."

Warming temperatures are the biggest issue, Cheung said. But climate change also produces oceans that are more acidic and have less oxygen. This also harms sea life.

Much of the world depends on the oceans for food or work, the scientists say.

University of Victoria biology professor Julia Baum was not part of the study, but she said the findings make sense. She noted that the possible effects of the predicted losses of animal life are huge.

"Climate change has the potential to cause serious new conflicts over ocean resource use and ... food security ... as [the] human population continues to grow," said Baum.

Marine biologist Boris Worm, who helped run the study, added that the "building blocks of marine life – plankton and bacteria – may decline less heavily."

That is the good news, he said. The bad news?

"Those marine animals that we use directly, and care about most deeply, are predicted to suffer the most," said Worm. He works at Canada's Dalehousie University.

Scientists had already believed climate change would likely reduce future ocean life. But past computer-based studies looked at only part of the picture or used only one model. The latest study used six different computer models to give the best picture look yet, William Cheung said.

University of Georgia marine biologist Samantha Joye was not part of the research. But she praised the study as well researched and extremely detailed, and called it "an urgent call for action."

"Healthy oceans are required for planetary stability," Joye said.

I'm ­Pete Musto.

Seth Borenstein reported this story for the Associated Press. Pete Musto adapted it for VOA Learning English. Ashley Thompson was the editor.