Sitting on a Cliff Vs. Falling Off a Cliff

The Steller’s sea cow is gone. This mega-manatee swam the North Pacific for millions of years, and then in the 1700s humans hunted them to extinction. Today on the front page of the New York Times, I write about a warning from a team of scientists that if we keep on doing what we’re doing now–industrializing the ocean and pouring carbon dioxide into the atmosphere in greater and greater amounts–a lot of other marine animal species will go the way of the Steller’s sea cow.

Yet this story is actually a fairly hopeful one. The scientists compared the pace of extinctions at sea to those on land and found that the oceans are basically where the land was in 1800–with relatively few extinctions yet, on the verge of massive changes to the habitat that could wreak much bigger havoc. The oceans still have a capacity to recover, if we choose to let them.

It’s hard to strike that balance, but it’s important. By coincidence, a group of marine biologists has just published a provocative opinion piece calling for more skepticism about “ocean calamities”–the claim that the oceans are getting hit with some global shock of one sort or another. (You can read the piece in Bioscience for free.) They complain that too often scientists see a small-scale change in one region of the ocean and blow it up to a global catastrophe. The scientists pick apart some of these cases, such as the belief that jellyfish are taking over the planet. The strongest evidence for their rise turned out to be a natural increase of one population of jellyfish that is part of a natural cycle.

That doesn’t mean that thee are no ocean calamities. The scientists see strong evidence for devastation from overfishing, for example. And that doesn’t mean that dangers that don’t seem to have had big impacts yet won’t have them in the future (see ocean acidification). But leaping to the apocalypse based on limited or ambiguous evidence is bad science and bad policy, the scientists argue:

We conclude that a robust audit of ocean calamities, probing into each of them much deeper than the few examples provided here, is imperative to weeding out the equivocal or unsupported calamities, which will confer hope to society that the oceans may not be entirely in a state of near collapse and which will provide confidence that the efforts by managers and policymakers targeting the most pressing issues may still deliver a healthier ocean for the future.

I wanted to check in with the authors of the Bioscience piece about the new study I wrote about for the Times. If they thought this new study was an egregious case of calamity-mongering, I needed to know that, and I would make it clear in my piece.

But that’s not what I found. When I spoke to Robinson Fulweiler, a marine biologist at Boston University, she said, “I was really excited to read their paper, and I actually felt good about their conclusions.” She thought the scientists did a good job of gauging what’s happened to the oceans so far, the risks they face in the future, and–importantly–the steps that we can take, armed with our knowledge of the situation.

When we’re contending with our effects on the planet, it may be tempting to go limp and say we’re all doomed, or to wave it off as some huge delusion. But the reality of the oceans calls for a different response altogether.

8 thoughts on “Sitting on a Cliff Vs. Falling Off a Cliff

  1. Why so rosy, Mr. Zimmer? Maui’s Dolphin now onky 50 in number. Vaquita Porpoise less than 90. They could be extinct in months, let alone in weeks. Baiji Diolphin extinct as of 2007. Who are you really writing for – oil interests?

  2. Thanks for the crucial cite of the Bioscience piece, Carl.

    Ocean losses are great these decades, but ocean extinctions are very rare, and probably will continue to be, because of all that connectivity. Most extinctions are on ocean islands and isolated bodies of fresh water.

  3. Devil’s advocate, Mr. Zimmer? Your New York Times article yesterday was impressive; better journalism and much more convincing, imo.

  4. Slightly tangential, but I’m curious why slow moving animals like Stellar’s sea cow weren’t just a giant buffet for predators. If you assume predators are at least partially limited by food supply, then they should exploit all available prey. In other words, saying that some other prey species is a better food source is not sufficient to explain why sea cows weren’t wiped out by predators.

    Hard to know the answer for Stellar’s sea cows now – we can’t do observations. The same question might apply to manatees, dugongs, and my favorite, unanswered prey question – birds sleeping on the water.

  5. The virtual mountains of scientific evidence presented now here, and elsewhere ubiquitously, of a human-driven global predicament are overwhelming. The relentless overproduction of necessary stuff; the reckless per capita overconsumption, hoarding and dissipation of limited resources; as well as the refractory growth of absolute global human population numbers are occurring synergistically at an accelerating rate. The gigantic scale and growth of these distinctly human activities, ones that are happening worldwide on our watch, can be readily identified as primary causes of some kind of impending ecological wreckage, the likes of which only Ozymandias has seen……. unless we do something that is different from the way we are doing things now. When a plan of action is determined, it needs to be a good one, the right one for task at hand. Any predicament human beings can produce is amenable to human actions in a different direction. Human knots can be untied, I suppose.

  6. Brian Schmidt, virtually all slow-moving prey animals have other defences against predators, whether it is some kind of group behavior, sheer bulk, foul-tasting flesh, or living in a habitat that somehow excludes predators from easily entering and is relatively free of native predators.

    With the Stellar’s Sea Cows being extinct now, it will be hard to know what kind of defences they might have had against predators.

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