Shared from the 6/12/2019 The Denver Post eEdition
By Seth Borenstein
The Associated Press
WASHINGTON» The world’s oceans will likely lose about one-sixth of their fish and other marine life by the end of the century if climate change continues on its current path, a new study says.
Every degree Celsius (1.8 degrees Fahrenheit) that the world’s oceans warm, the total mass of sea animals is projected to drop by 5 percent, according to a comprehensive computer-based study by an international team of marine biologists. And that does not include effects of fishing.
If the world’s greenhouse gas emissions stay at the present rate, that means a 17 percent loss of biomass — the total weight of all the marine animal life — by the year 2100, according to Tuesday’s study in the Proceedings of the National Academy of Sciences. But if the world reduces carbon pollution, losses can be limited to only about 5 percent, the study said.
“We will see a large decrease in the biomass of the oceans,” if the world doesn’t slow climate change, said study co-author William Cheung, a marine ecologist at the University of British Columbia. “There are already changes that have been observed.”
While warmer water is the biggest factor, climate change also produces oceans that are more acidic and have less oxygen, which also harms sea life, Cheung said.
Much of the world relies on the oceans for food or livelihood, scientists say.
“The potential ramifications of these predicted losses are huge, not just for ocean biodiversity, but because people around the world rely on ocean resources,” said University of Victoria biology professor Julia Baum, who wasn’t part of the study but says it makes sense. “Climate change has the potential to cause serious new conflicts over ocean resource use and global food security, particularly as human population continues to grow this century.”
The biggest animals in the oceans are going to be hit hardest, said study co-author Derek Tittensor, a marine ecologist at the United Nations World Conservation Monitoring Center in England.