And so another geoengineering fix for climate change that sounds great in theory bites the dust on closer examination. The fix in question seems...

And so another geoengineering fix for climate change that sounds great in theory bites the dust on closer examination.

The fix in question seems promising at first glance: pump nutrient-rich deep ocean water to the surface, where it can provide a hearty food source for algae. The algae bloom in abundance, then die and sink deep underwater, taking the carbon they absorbed during photosynthesis with them.

In reality, though, the process isn’t likely to work so well, according to detailed modeling conducted by researchers at Germany’s Leibniz Institute of Marine Sciences (IFM-GEOMAR).

Putting the geoengineering strategy to the test, the scientists found it has little potential for making a serious dent in man-made carbon emissions. At best, they concluded, the method might help eliminate about three gigatonnes’ worth of carbon a year — a literal drop in the bucket, considering we send 36 gigatonnes of carbon dioxide into the atmosphere each year.

Even more interesting is the fact that some of that carbon reduction wouldn’t come from algae sinking to the ocean bottom, but from the atmospheric cooling effect of pumping cold deep water to the surface. The cooler air would cause a slowdown in decomposition of organic matter in soil, meaning less carbon sent back into the atmosphere.

“This effect is global and occurs even far away from the area where the pumps are used, which makes an assessment of success or failure of such a method extremely difficult in practice,” said Andreas Oschlies, lead author of the study.

Like many other geoengineering strategies that have been studied, this one also comes with a considerable downside: stop pumping cold water to the surface for whatever reason, and global warming returns with a vengeance.

“(W)henever the pumps stop, atmospheric CO2-concentrations and surface temperatures increase rapidly to values that are even higher than those of a control simulation that never employed the artificial pumps,” Oschlies said. (The map accompanying this article shows the additional surface warming (in degrees C) we could expect by 2100 if we pursued the deep-water pump strategy between 2011 and 2060, then stopped it.)

Greenbang

  • Bewildered_response

    February 22, 2010 #1 Author

    Why not use a geo technology that uses the worlds natural eco system to aid its recovery;

    Use 5x T4’s (Toshiba reactor) self contained 10mgw reactors each with a 40 year life cycle, giving 50mgw of energy for 40 years.
    10 in line centrifugal fans 15,000sq mtr on an old oil rig drawing air in from the atmosphere containing(CO2). Supercooling the air to -47 and direct firing it under the ice. Allowing it to bubble and reform ice under the ice sheet.
    This will stop it from thawing on the surface, the thawing process below the water has a beneficial part it maintains the ocean conveyor forces and maintains our oxygen, also locking up the CO2 in the newly formed ice.

    No chemicals just air and water.

    Reply

  • Robin Loxlie

    February 19, 2010 #2 Author

    “the method might help eliminate about three gigatonnes’ worth of carbon a year — a literal drop in the bucket, considering we send 36 gigatonnes of carbon dioxide into the atmosphere each year”

    Huh? How is 8.3% “literally” the same as a drop (around 50 microlitres) in a bucket (around 14 litres)?? That’s 0.35%.
    Is 0.35% really “literally” the same as 8.3%? Do you know what “literal” literally means?
    I’d have thought removing 8.3% of man-made emissions would be be rather impressive, and – you know – quite world-changingly important…
    And the proposal is cheap, and powered entirely by waves, so what reason is there to think they’d just be stopped? There’s not going to be one single giant pump…. If it has extra benefits in increasing fish populations (which it pretty surely would), that’s surely an extra reason for longevity.
    And why is it terrible that the effect happens over land? “which makes an assessment of success or failure of such a method extremely difficult in practice” – well, are you confident of your predictive computer model or not?
    I’ve no vested interested either way, and there may well be huge flaws in this approach, but neither this article, nor the summary of the article it’s based on, describe any valid concerns. Quite the opposite.
    That figure again – 8.3% reduction in man-made carbon emissions…

    Reply

  • tony lovell

    February 17, 2010 #3 Author

    Imagine if we had a process to remove billions of tonnes of CO2 from the atmosphere safely, quickly and cost-effectively – while at the same time building soil, reversing desertification, boosting biodiversity, enhancing global food security and improving the lives of hundreds of millions of people in rural and regional areas around our planet?

    We do – it’s called changed grazing management and soil carbon.

    Please take a look at the presentations on http://www.soilcarbon.com.au/ to learn more.

    Reply

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