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Feb 22 2013

More boat than fish

How is it, living in the Anthropocene?

Sea levels will likely rise a few feet by the year 2100. Current fish wet biomass is about 2 billion tons, so removing them won’t make a dent either. (Marine fish biomass dropped by 80% over the last century, which—taking into consideration the growth rate of the world’s shipping fleet—leads to an odd conclusion: Sometime in the last few years, we reached a point where there are, by weight, more ships in the ocean than fish.)

The current world shipping fleet has a displacement of about 2.15 billion tons (most of which is oil and ore), so yeah, we humans are now bulking out more volume in the oceans than the fish do (we’ve got a long ways to go before we overtake invertebrates and bacteria, I suspect).

The other depressing point in the article is that global warming is adding more water to the oceans every second, and that every 16 hours we’re adding more than that 2 billion tons of water to the ocean.

10 comments

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  1. 1
    chigau (違う)

    The boats bring cars from Germany and shoes from Italy.
    What have those slimy, seawater-suckers ever done for you?

  2. 2
    erick

    Did they suggest that removing the fish could have made a difference, even aside from total mass? And where does the water in the fish come from?

  3. 3
    SallyStrange

    I wonder how the volume of extra water added by melting glaciers and whatnot compares to the volume of carbonic acid created by the CO2 entering the water from the atmosphere.

  4. 4
    throwaway, never proofreads, every post a gamble

    Do sea-creatures really displace water much at all? They spend their life-cycle in the wet (mostly), so I see their displacement as roughly equal to their repourposing of materials which already displace a certain mass of water (or may in fact be water itself repurposed).

  5. 5
    throwaway, never proofreads, every post a gamble

    Never mind. I need to wake up still.

  6. 6
    michaelbusch

    @SallyStrange:

    The sea level rise from thermal expansion and ice melt is far greater than that from excess CO2 mixing into the water. Currently there is ~110 ppm of excess CO2 in the atmosphere (390 ppm v. 280 ppm); a comparable amount has dissolved into the surface water of the ocean – which is in equilibrium with the atmosphere. 0.110 millibar of CO2 is ~1 kg/m^2, or about 1 mm of sea level rise. The actual rise from adding CO2 to the water is less than that – it depends on the density of the resulting mixture.

    Currently, sea level is rising by 3.3 ± 0.4 mm/year. In other words, the CO2 mixed into the ocean is less than 4 months of sea level rise.

    Another fact about the Anthropocene:

    As the land ice sheets melt, they move mass from near the poles to nearer to the equator, increasing the length of the day. Right now, that contribution is a few milliseconds (if all of the ice sheets melt, it could go as high as ~1 s). So thanks to us burning things, noon today arrived about a minute later than it would otherwise have.

  7. 7
    yubal

    A couple of years ago I read that there would be more viruses on this planet than humans. In terms of biomass (metric tons), not numbers. Never figured out how they estimated that.

  8. 8
    Amphiox

    What have those slimy, seawater-suckers ever done for you?

    For me personally? Probably account for a few percent of my body weight….

  9. 9
    John Morales

    yubal, because they’re in all other cells, from microscopic organisms on up.

    A moment’s Googling brings up http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2897122/

  10. 10
    Ichthyic

    What have those slimy, seawater-suckers ever done for you?

    Embrace your inner fish, and find out.

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