I suspect that natural mixing processes exceed anything we can do mechanically, by a couple orders of magnitude. But that's just a guess. I suspect the way we can increase downward mixing of CO2 dissolved from air is by influencing large-scale weather patterns.
On Jan 13, 10:42 am, "John Nissen" <[email protected]> wrote: > Hi all, > > Could there be a case for geoengineering to increase sea "ventilation" and > thereby increase CO2 absorption by the sea? (I'm thinking of those millions > of wave-powered tubes suggested by Chris Rapley and James Lovelock to bring > deep cool water to the surface.) > > http://www.guardian.co.uk/environment/2009/jan/12/sea-co2-climate-jap... > > --- > > Sea absorbing less CO2, scientists discover > a.. David Adam, environment correspondent > b.. The Guardian, Monday 12 January 2009 > c.. Article history > Scientists have issued a new warning about climate change after discovering a > sudden and dramatic collapse in the amount of carbon emissions absorbed by > the Sea of Japan. > > The shift has alarmed experts, who blame global warming. > > The world's oceans soak up about 11bn tonnes of human carbon dioxide > pollution each year, about a quarter of all produced, and even a slight > weakening of this natural process would leave significantly more CO2 in the > atmosphere. That would require countries to adopt much stricter emissions > targets to prevent dangerous rises in temperature. > > Kitack Lee, an associate professor at Pohang University of Science and > Technology, who led the research, says the discovery is the "very first > observation that directly relates ocean CO2 uptake change to ocean warming". > > He says the warmer conditions disrupt a process known as "ventilation" - the > way seawater flows and mixes and drags absorbed CO2 from surface waters to > the depths. He warns that the effect is probably not confined to the Sea of > Japan. It could also affect CO2 uptake in the Atlantic and Southern oceans. > > "Our result in the East Sea unequivocally demonstrated that oceanic uptake of > CO2 has been directly affected by warming-induced weakening of vertical > ventilation," he says. Korea argues that the Sea of Japan should be renamed > the East Sea, because it says the former is a legacy of Japan's military > expansion in the region. > > Lee adds: "In other words, the increase in atmospheric temperature due to > global warming can profoundly influence the ocean ventilation, thereby > decreasing the uptake rate of CO2." > > Working with Pavel Tishchenko of the Russian Pacific Oceanological Institute > in Vladivostok, Lee and his colleague Geun-Ha Park used a cruise on the > Professor Gagarinskiy, a Russian research vessel, last May to take seawater > samples from 24 sites across the Sea of Japan. > > They compared the dissolved CO2 in the seawater with similar samples > collected in 1992 and 1999. The results showed the amount of CO2 absorbed > during 1999 to 2007 was half the level recorded from 1992 to 1999. > > Crucially, the study revealed that ocean mixing, a process required to > deposit carbon in deep water, where it is more likely to stay, appears to > have significantly weakened. > > Announcing their results in the journal Geophysical Research Letters, the > scientists say: "The striking feature is that nearly all anthropogenic CO2 > taken up in the recent period was confined to waters less than 300 metres in > depth. The rapid and substantial reduction ... is surprising and is > attributed to considerable weakening of overturning circulation." > > Corinne Le Quéré, an expert in ocean carbon storage at the University of East > Anglia, said: "We don't think the ocean is just going to completely stop > taking our carbon dioxide emissions, but if the effect weakens then it has > real consequences for the atmosphere." > > --- > > Cheers, > > John --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---
