Carbon dioxide may ‘intoxicate’ fish: study


By midcentury, higher levels of carbon dioxide (CO2) in ocean water could leave fish “intoxicated,” becoming lost at sea, a study said Wednesday.

The oceans absorb about a third of the carbon dioxide released by humanity’s burning of coal, oil and gas — their chemical composition changing over time to become more acidic.

Scientists from the University of New South Wales in Australia have now calculated that rising concentrations of carbon dioxide could cause a phenomenon known as hypercapnia in fish by 2050 — much earlier than once thought possible.

“Essentially, the fish become lost at sea,” lead author Ben McNeil said in a statement of the condition.

“The carbon dioxide affects their brains and they lose their sense of direction and ability to find their way home. They don’t even know where their predators are.”

McNeil and colleague Tristan Sasse based their projections on worst-case-scenario carbon dioxide trajectories, which assume that humans do nothing to curb their emissions.

“We’ve shown that if atmospheric carbon dioxide pollution continues to rise, fish and other marine creatures in carbon dioxide hot spots in the Southern, Pacific and North Atlantic oceans will experience episodes of hypercapnia by the middle of this century — much sooner than had been predicted, and with more damaging effects than thought,” said McNeil.

This implied profound and threatening impacts for commercial and subsistence fishing, the duo warned.

The world’s nations sealed a climate pact in Paris last month to limit average global warming to 2 degrees Celsius (3.6 degrees Fahrenheit) by cutting back on emissions.