Greg--This note reminds me of a paper I had to quickly read over after it came out and prepare a paragraph for OSTP (and VP Gore) suggesting it was not immediately relevant after one of the Skeptic groups put out a note indicating that global warming would lead to a lowering of sea level. To see the abstract that prompted the claim, go to http://geology.gsapubs.org/content/27/10/915.abstract ( Bratton, John F., 1999, Clathrate eustasy: Methane hydrate melting as a mechanism for geologically rapid sea-level fall, Geology, vol. 27, no. 10, p. 915 - 918). The lines that confused the Skeptic group were at the end of the paper where the author used terms to describe times for such changes to occur that have a different meaning in a geological context than in a popular context (e.g., for the Skeptics, ³ancient² times was interpreted to mean a few thousand years‹the time of the pyramids or something, whereas in the context of the author and geology, it meant 35M years). The attention to the Skeptics claim did not last long, as it turned out, once this was realized.
The notion that clathrate amount may be changed, however, opens up the possibility of an entire area of geoengineering that we have not discussed (and probably appropriately so), namely geoengineering intended to limit sea level rise (of course, limiting warming and the loss of ice sheets would do this, but are there other approaches). There were suggestions back in the 1970s (and since) about making channels so one could fill some of the Earth¹s depressions (e.g., Qattara Depression‹though a more interesting idea was how to use the gradient to generate hydroelectric power) or even to fill up apparent aquifer space below the Sahara Desert. Extracting clathrates would also qualify as a means to do this, although very limited, and especially if the space is re-filled by liquid CO2. Unfortunately, it does not appear as if there is any other way to stem offset sea level rise than by limiting/reversing large-scale warming and ice sheet mass loss. Mike On 5/3/12 11:36 AM, "RAU greg" <[email protected]> wrote: > Interesting how easy it is to get funding for CDR when fossil fuel extraction > is involved. - G > > Dept. of Energy extracts hydrocarbons from sea, sequesters CO2 in Davy Jones' > locker > By John Timmer | Published about 19 hours ago > Today, the US Department of Energy announced it had successfully completed a > test project that extracted a usable fuel (methane) from its resting place in > ocean sediments. The test, performed in conjunction with ConocoPhillips and a > Japanese team, could potentially point the way toward a vast new supply of > energy. And by linking the extraction with carbon sequestration, the DOE might > have found a way to add more hydrocarbons to the world's energy budget without > exacerbating climate change. > > The material in question is methane hydrates (also called clathrates). These > form at high pressure in water, which forms a cage-like structure around > pockets of methane. Although these remain solid even above the freezing point > of water, changes in pressure and temperature can melt them, releasing methane > and returning the water to a liquid state. Clathrate deposits are estimated to > be massive. If they can be extracted successfully, they would add a > significant boost to the world's hydrocarbon reserves. > > The recently completed project, which took place off the coast of Alaska, is a > test to determine if we can do that. The extraction technique involves > lowering the pressure at the site of the deposit, allowing the methane to > escape. At the same time, liquid CO2 was pumped in to occupy the space that > held the clathrate. At the pressures prevalent at the site, the CO2 should > remain liquid, held under the sediments that once trapped the methane. > > There are some big questions that will require followup work‹does the process > release methane that escapes into the atmosphere? Does the CO2 remain in place > long enough that we can consider it sequestered? To get answers to those > questions, the DOE has allocated another $6.5 million to further tests, and is > requesting $5 million in next year's budget. > -- 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.
