Ocean warming warning

It’s a message that gets repeated in scientific reports so often that it’s almost rote: things just aren’t the same.

On Wednesday, federal Department of Fisheries and Oceans scientists released a technical briefing on the health of cod in a fishing zone known as 3PS, south of Newfoundland. The news is bad. The stock is in critical condition, and likely to stay that way.

In 3PS, cod are dying of natural causes three times more often than they are dying as a result of being caught.

But several pages in, there’s a familiar reference to a critical change that’s affecting oceans pretty much worldwide. It doesn’t matter if you don’t want to believe it; because of climate change, the ocean is warming.

“Various factors suggest that the 3PS ecosystem is undergoing structural changes,” the technical briefing said. “Some of the changes we have observed include: above-average bottom temperatures in the area; increase in proportion of cod in poor condition; reduction in the size of the spring phytoplankton bloom; changes in the zooplankton community; and, an increase in the biomass of warm water fishes (e.g. spiny dogfish and silver hake).”

The same paragraph, in more or less detail, crops up in a host of fisheries reports.

This is from a 2019 report on cod off Nova Scotia: “Increases in bottom water temperatures are accompanied by changes in groundfish landings, increases in landings of invertebrates and decreases in mean fish length from the … surveys for many stocks.”

A 2019 report on Greenland halibut: “Warming and oxygen depletion of the deep waters of the Gulf of St. Lawrence could result in habitat loss and habitat quality degradation for Greenland halibut.”

You get the idea: temperatures are changing, and that means changes in the types and numbers of fish and other sea creatures that inhabit an area. Those changes are now both more frequent and more drastic than they’ve been in past years. There are scores of well-documented movements of fish species further and further north along the Atlantic coast, and along the Pacific coast, even Alaska is not being spared from the effects of warming water on fisheries.

It is, in its own way, a slow-motion equivalent to Australia’s bush fires — a radical change to the norm that, given the massive size of the ocean and the amount of time it takes to shift all that water even a fraction a degree, is unlikely to be undone, even over generations.

The real question is whether the new ocean will be as generous to humans as the old ocean has been for centuries.

Will we be able to make a living from a warmer, more acidic, less-oxygenated, less productive ocean?

That’s a question the scientific reports haven’t given a completely definitive answer to — at least, not yet.

That might not be a report we’d be eager to read.