But isn't the prime question - at least the one driving most discussions of "emergency" actions up north - catastrophic release?
Pretty clear this review damps down that concern, along with the papers last year pointing to post-2010 methane concentration rise being mainly tropical/biogenic. e.g.> http://www.sciencemag.org/news/2016/12/why-atmospheric-methane-surging-hint-its-not-fracking On Sun, Feb 12, 2017 at 10:11 AM, Hawkins, Dave <dhawk...@nrdc.org> wrote: > Th bigger risk for it reaching the atmosphere would be from producing it > commercially. Congress has directed our DOE to come up with a plan to do > exactly that. > > Sent from my iPad > > On Feb 12, 2017, at 9:34 AM, Ken Caldeira <kcalde...@carnegiescience.edu> > wrote: > > https://www.usgs.gov/news/gas-hydrate-breakdown-unlikely- > cause-massive-greenhouse-gas-release > http://onlinelibrary.wiley.com/doi/10.1002/2016RG000534/full > http://onlinelibrary.wiley.com/doi/10.1002/2016RG000534/pdf > > [image: Reviews of Geophysics] > <http://agupubs.onlinelibrary.wiley.com/hub/journal/10.1002/(ISSN)1944-9208> > > Review Article The interaction of climate change and methane hydrates > Carolyn D. Ruppel, John D. Kessler > Abstract > > Gas hydrate, a frozen, naturally-occurring, and highly-concentrated form > of methane, sequesters significant carbon in the global system and is > stable only over a range of low-temperature and moderate-pressure > conditions. Gas hydrate is widespread in the sediments of marine > continental margins and permafrost areas, locations where ocean and > atmospheric warming may perturb the hydrate stability field and lead to > release of the sequestered methane into the overlying sediments and soils. > Methane and methane-derived carbon that escape from sediments and soils and > reach the atmosphere could exacerbate greenhouse warming. The synergy > between warming climate and gas hydrate dissociation feeds a popular > perception that global warming could drive catastrophic methane releases > from the contemporary gas hydrate reservoir. Appropriate evaluation of the > two sides of the climate-methane hydrate synergy requires assessing direct > and indirect observational data related to gas hydrate dissociation > phenomena and numerical models that track the interaction of gas > hydrates/methane with the ocean and/or atmosphere. Methane hydrate is > likely undergoing dissociation now on global upper continental slopes and > on continental shelves that ring the Arctic Ocean. Many factors—the depth > of the gas hydrates in sediments, strong sediment and water column sinks, > and the inability of bubbles emitted at the seafloor to deliver methane to > the sea-air interface in most cases—mitigate the impact of gas hydrate > dissociation on atmospheric greenhouse gas concentrations though. There is > no conclusive proof that hydrate-derived methane is reaching the atmosphere > now, but more observational data and improved numerical models will better > characterize the climate-hydrate synergy in the future. > > Ken Caldeira > Carnegie Institution for Science > Dept of Global Ecology > 260 Panama St > Stanford CA 94305 USA > +1 650 704 7212 <(650)%20704-7212> > http://dge.stanford.edu/labs/caldeiralab > <http://dge.stanford.edu/labs/caldeiralab> > > Assistant, with access to incoming emails: Jess Barker > jbar...@carnegiescience.edu > > -- > 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 geoengineering+unsubscr...@googlegroups.com. > To post to this group, send email to geoengineering@googlegroups.com. > Visit this group at https://groups.google.com/group/geoengineering. > For more options, visit https://groups.google.com/d/optout. > > -- > 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 geoengineering+unsubscr...@googlegroups.com. > To post to this group, send email to geoengineering@googlegroups.com. > Visit this group at https://groups.google.com/group/geoengineering. > For more options, visit https://groups.google.com/d/optout. > -- *ANDREW C. REVKIN* *ProPublica Senior Reporter <https://www.propublica.org/site/author/andrew_revkin> (*climate and related issues) *Mobile: 914-441-5556 (Can be encrypted if Signal <https://whispersystems.org/> app on your end, too)* *@revkin <http://twitter.com/revkin>, Facebook <https://www.facebook.com/andrew.revkin.5>, Music <http://j.mp/revkinmusic>* -- 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 geoengineering+unsubscr...@googlegroups.com. To post to this group, send email to geoengineering@googlegroups.com. Visit this group at https://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
