Look at those currents, man!

March 28, 2012 • 5:44 am

by Matthew Cobb

Most of our planet is covered in ocean, and throughout the history of life, the seas have played a decisive role in shaping biodiversity. In the future, a major effect of increasing CO2 levels will be felt through acidification of the sea (as CO2 dissolves into the water), which will have massive effects on sea life, even if there is a very small change in acidity.

One of the major ways that the oceans affect terrestrial life is through their effects on climate, via the major ocean currents. (I write this from a UK that should be freezing cold because of its latitude, but which is warmed by the Gulf Stream.) This rather trippy video (complete with appropriate chillout music) is from NASA and shows a model of the world’s ocean currents. Watch and wonder – wonder both in awe, and wonder what would happen if any of them stopped, or reversed… (Be patient – the video takes a long time to start, for some reason…)

12 thoughts on “Look at those currents, man!

  1. I never would have guessed that there would be so many persistent little vortices. The stong East-West currents at the equator also surprised me.

  2. Naturally Earth’s oceans (like Earth’s atmosphere) are in constantly circulating motion; thanks to the sun, Earth is a (geo)physical system that is far from thermodynamic equilibrium, and as all physics-savvy folks (…that’d be most all of us, yes?…) know and understand, it is thermal DISequilibrium which drives interesting dynamics (dynamics in which interesting things like order arising from disorder are apt to occur).

    “..and wonder what would happen if any of them stopped, or reversed… ”

    Radical things can happen (sometimes good, sometimes bad, depending of perspectives) when ocean currents change. The study of the history of Earth’s biosphere for the last 600+ million years reveals much about what happens when ocean currents (and global and local climates accordingly) change, and reveals that Earth’s ocean and climate have indeed often (geologic time-wise) changed.

    For climate history,See…
    http://www.scotese.com/climate.htm

    …and for ocean and continent history, see…
    http://www.scotese.com/earth.htm
    …click on the different named geologic periods listed down the left side to see depicted the configuration of Earth’s land-masses and ocean waters that correspond to those geological periods (including two projections based on current tectonic activity for the “near” future, geologic time-wise); note that the Atlantic Ocean did not always exist and likely will vanish or radically shrink in the geologic future.

    The natural history of Earth’s biosphere has rendered me (for one) a global climate change INEVITABLIST. We humans doubtless can and do contribute (+/-) to that change and thereby influence rates of change, but later if not sooner global climate WILL change no matter what we do or don’t do about it, just as it was pretty-much constantly changing all during the pre-human history of Earth’s biosphere (though yes, yes of course, generally way WAY slow relative to the life-pace of human generations and millennia).

  3. At 0:08, the current that sweeps south along the E coast of Greenland, then west across the S coast and back north a bit along the W coast before heading west to Baffin Island and then south again, down the coast of Labrador. This is the current that allowed the Leif Ericsson to easily reach L’anse aux Meadows by skirting the coasts of Baffin & Labrador.

    Otherwise, the currents in the video visually resemble something by van Gogh.

  4. The clockwise, counterclockwise thing is fun.

    One of the most curious things about co2 is how little there really is in the atmosphere. It always amazed me how close ir got to the lower limit for C3 photosynthesis during the recent glacial periods. That would have given some major mass extinction.

  5. Those currents are, it seems, the surface currents ; there are abundant, as powerful, and as climatically important deep sea currents that balance (eventually) the surface movement of water. The best known of these is the deep return current (the “Meridional Overturning Circulation” according to Wikipadia, though more often described as “the” thermo-haline circulation, as if there is only one) where cold, saline water sinks in the NE Atlantic, progresses the length of the Atlantic, then moves around into the other ocean basins keeping the whole system mixed.
    Much of the “deep water” that forms the downward leg of this system is formed between Iceland,Greenland and Norway, before draining south-west through gaps in submarine sills between Iceland and Greenland and from Iceland to the Faroes to Scotland and Norway.
    Water flows in this area seem to be decidedly variable, which is worrying, though also uncertain because of the short period of (public) measurements. (Various militaries have probably known about this for longer, because of the current’s effects on mass-murder submarines moving through the area. But they seem to not be talking.)
    I spent several weeks of last year watching (by satellite) a 70-km long iceberg circulating in some of those gyres in the Labrador Sea and wondering if it was going to come in the direction of our vessel.

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