Clarification on zeolite/methane release: No combustion needed for release. Temperature or pressure swings will release the methane (per Dr. Smit). Temperature is tricky and so pressure swings should be the focus of engineering for zeolite/methane processing. Best, Michael
On Tuesday, July 30, 2013 9:12:09 AM UTC-7, Greg Rau wrote: > > http://www.cam.ac.uk/research/discussion/a-response-to-methane-mischief-misleading-commentary-published-in-nature > > The 24 July news story about the potential cost of Arctic methane release > has provoked widespread coverage, including a critique in the Washington > Post. Here, Professor Peter Wadhams responds to some of the comments that > were made. > > The 25 July post by Jason Samenow on the global economic impacts of > methane emissions in the East Siberian Sea portrays the findings of our > research as misleading, a statement with which I strongly disagree. Our > work is based on a prediction of the magnitude and timing of methane > emissions from the thawing of Arctic offshore permafrost by a scientist who > has done extensive field work on this part of the ocean bed and is a > globally recognized expert. We calculated the financial implications of > these emissions for the world economy over a century and also considered > the effect of the emissions on increasing overall global warming, > obtaining a 0.6C figure by 2040. We rightly consider these to be > substantial figures, which deserve wide circulation among climate > scientists, and Nature and its referees agreed with us. > > In our analysis we showed that the overall cost of a given volume of > methane release is relatively insensitive to the rate of release or, within > limits, its timing, BUT that the cost is roughly proportional to the > overall volume of release. Thus, even if you worked with a different > projection by a lesser qualified scientist than Shakhova, and revised down > the figure and scale of the 60 trillion dollars accordingly, I suspect the > cost will still be substantial – and that is one clear finding: The > planetary cost of Arctic warming far outstrips any possible benefits to > shipping or natural resource exploration. > > In support of its skepticism about methane emissions the article quoted > authors who wrote before the enormous retreat of summer Arctic sea ice and > its oceanographic effects became so evident. The mechanism which is causing > the observed mass of rising methane plumes in the East Siberian Sea is > itself unprecedented and the scientists who dismissed the idea of extensive > methane release in earlier research were simply not aware of the new > mechanism that is causing it. > > What is happening is that the summer sea ice now retreats so far, and for > so long each summer, that there is a substantial ice-free season over the > Siberian shelf, sufficient for solar irradiance to warm the surface water > by a significant amount – up to 7C according to satellite data. That > warming extends the 50 m or so to the seabed because we are dealing with > only a polar surface water layer here (over the shelves the Arctic Ocean > structure is one-layer rather than three layers) and the surface warming > is mixed down by wave-induced mixing because the extensive open water > permits large fetches. So long as some ice persisted on the shelf, the > water mass was held to about 0C in summer because any further heat content > in the water column was used for melting the ice underside. But once the > ice disappears, as it has done, the temperature of the water can rise > significantly, and the heat content reaching the seabed can melt the frozen > sediments at a rate that was never before possible. > > The 2008 US Climate Change Science Program report needs to be seen in > this context. Equally, David Archer’s 2010 comment that “so far no one has > seen or proposed a mechanism to make that (a catastrophic methane release) > happen” was not informed by the Semiletov/Shakhova field experiments and > the mechanism described above. Carolyn Rupple’s review of 2011 equally does > not reflect awareness of this new mechanism. > > Therefore I robustly defend our research and commentary, and hope that > rather than dismiss the substantial risk such a methane release poses, the > response might be to support more intensive research on this problem. > > - See more at: > http://www.cam.ac.uk/research/discussion/a-response-to-methane-mischief-misleading-commentary-published-in-nature#sthash.0ULHFzzl.dpuf > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/groups/opt_out.
