Truth about ocean plastics is elastic at WUWT

From turtles mistaking plastic bags for jellyfish, to dolphins getting entangeled in discarded fishing nets, and the injection of persistent organic pollutants absorbed into plastics, plastic pollution in the ocean is harmful to marine life.

Eriksen et al have a new paper out about the amount of plastic pollution in the oceans. The Guardian wrote about it, so did Willis Eschenbach at WUWT. No prizes for guessing whose coverage was more accurate.

Eriksen et al report that the world’s oceans contain about 270 thousand tonnes of plastic. Eschenbach divides this mass by the volume of the ocean (1.3 billion km3) and reports that 200 g km-3 is nothing to get passionate about. This is, after all, only an order of magnitude higher than the concentration of gold in the ocean.

However, Eschenbach is straining to mislead the reader. The data Eriksen et al synthesise comes from surface net-tows and visual observations of large plastic debris at the surface. This is data on the uppermost metre (or less) of the ocean, not the entire ocean volume. Consequently, Eschenbach’s estimated concentration is out by at least factor of 3790 (the average depth of the ocean is 3790 m).

Even for WUWT, this is a bad estimate.

About richard telford

Ecologist with interests in quantitative methods and palaeoenvironments
This entry was posted in Fake climate sceptics, Peer reviewed literature and tagged , . Bookmark the permalink.

3 Responses to Truth about ocean plastics is elastic at WUWT

  1. Henry says:

    Such an absurd schoolboy error by WUWT – not that I’d ever read it anyway, and certainly not having seen this…

  2. Eric Means says:

    Actually, I found the WUWT author quite clearly included the surface density as well as the volume density in his article. For example:

    “And as for the other small pieces of random plastic … well, I just can’t get all that passionate about the dangers of 200 grams of plastic for every BILLION tonnes of sea water, or if you prefer, the dangers of 900 grams of plastic for every square kilometre of ocean surface (1 cubic km = one billion tonnes).”

    Are there arithmetic errors here? True, the author led with the misleading ‘volume-density’ figure, but this is the blogosphere, after all. It appears to me that the author specifies the difference between volume vs. surface more than once. And to his credit, he concludes as follows:

    “In closing, I don’t like plastic in the ocean, and I’m very, very conscious about it when I’m at sea. I never throw plastic into the ocean. However, as an ocean problem, it’s way, way below things like overfishing and pollution. Those are the real dangers, not a couple hundred grams of plastic in each billion tons of sea water. That’s a small number.”

    I’ve seen a lot worse from the right-wingnut blogosphere.

    • Sure was not the worst anti-science writing at WUWT, but it follows the usual pattern of taking a scientific claim and rubbishing it on spurious grounds. Here the ocean surface concentration of plastic is misrepresented as the density in the entire volume of the ocean. He does mention the per-area figure, but that comes after the spurious per-volume claim. I don’t think the author even realised that this was surface data.

      Yes it could be worse, he could have advocated throwing plastic into the ocean because it makes a habitat for something.

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