Recent estimations suggest that vast amounts of methane are locked in the Arctic Ocean bottom sediments in various forms of gas hydrates. A potential feedback from a continued warming of the Arctic region is therefore the release of methane to the atmosphere. This study addresses the relationship between a warming of the Arctic ocean and gas hydrate stability. We apply a theoretical model that estimates the base of the gas hydrate stability zone in the Arctic Ocean considering different bottom water warming and sea level scenarios. We model the present day conditions adopting two different geothermal gradient values: 30 and 40°C/km. For each geothermal gradient value, we simulate a rise and a decrease in seafloor temperature equal to 2°C and in sea level equal to 10？m. The results show that shallow gas hydrates present in water depths less than 500？m would be strongly affected by a future rise in seafloor temperature potentially resulting in large amounts of gas released to the water column due to their dissociation. We estimate that the area, where there could be complete gas hydrate dissociation, is about 4% of the area where there are the conditions for gas hydrates stability. 1. Introduction Vast quantities of methane are trapped in oceanic hydrate deposits, and there is a concern that a rise in the ocean temperature will induce dissociation of these hydrate accumulations, potentially releasing large amounts of methane into the atmosphere [1, 2]. In this context, the Arctic should be considered a critical area in a warming climate because massive amounts of methane are currently locked as gas hydrates in ocean sediments and in permafrost that could be released [3–6]. Moreover, in the Arctic ocean, the gas hydrate stability zone is especially sensitive to climate change because the degree of temperature change is greater than at lower latitudes [4]. For example, the gas hydrate stability zone along continental slopes is found to be sensitive to even small changes in ocean bottom temperature [4], and the Arctic Ocean most likely has a larger gas hydrate stability zone compared to other oceans because of its cold water and low geothermal gradients [7]. However, it is still unclear whether the recent discoveries of methane emissions in the Arctic shelf and slope region are a result of better mapping and detection methods or whether they reflect a natural variability or environmental conditions following the present climate change. Gas hydrates are solid crystalline compounds, in which gas molecules are lodged within the clathrate crystal lattice [8].
References
[1]
M. T. Reagan and G. J. Moridis, “Large-scale simulation of methane hydrate dissociation along the West Spitsbergen Margin,” Geophysical Research Letters, vol. 36, no. 23, Article ID L23612, 2009.
[2]
M. T. Reagan, G. J. Moridis, S. M. Elliott, and M. Maltrud, “Contribution of oceanic gas hydrate dissociation to the formation of Arctic Ocean methane plumes,” Journal of Geophysical Research C, vol. 116, no. 9, Article ID C09014, 2011.
[3]
N. Shakhova, I. Semiletov, A. Salyuk, V. Yusupov, D. Kosmach, and ？. Gustafsson, “Extensive methane venting to the atmosphere from sediments of the East Siberian Arctic Shelf,” Science, vol. 327, no. 5970, pp. 1246–1250, 2010.
[4]
G. K. Westbrook, K. E. Thatcher, E. J. Rohling et al., “Escape of methane gas from the seabed along the West Spitsbergen continental margin,” Geophysical Research Letters, vol. 36, no. 15, Article ID L15608, 2009.
[5]
B. Buffett and D. Archer, “Global inventory of methane clathrate: sensitivity to changes in the deep ocean,” Earth and Planetary Science Letters, vol. 227, no. 3-4, pp. 185–199, 2004.
[6]
E. A. G. Schuur, J. G. Vogel, K. G. Crummer, H. Lee, J. O. Sickman, and T. E. Osterkamp, “The effect of permafrost thaw on old carbon release and net carbon exchange from tundra,” Nature, vol. 459, no. 7246, pp. 556–559, 2009.
[7]
M. T. Reagan and G. J. Moridis, “Oceanic gas hydrate instability and dissociation under climate change scenarios,” Geophysical Research Letters, vol. 34, no. 22, Article ID L22709, 2007.
[8]
E. D. Sloan, Clathrate Hydrates of Natural Gases, Marcel Dekker, New York, NY, USA, 2nd edition, 1998.
[9]
E. D. Sloan, “Natural gas hydrate phase equilibria and kinetics: understanding the state-of-the-art,” Revue de l'Institut Francais du Petrole, vol. 45, no. 2, pp. 245–266, 1990.
[10]
J. P. Kennett, K. G. Cannariato, I. L. Hendy, and R. J. Behl, “Carbon isotopic evidence for methane hydrate instability during quaternary interstadials,” Science, vol. 288, no. 5463, pp. 128–133, 2000.
[11]
E. J. Brook, T. Sowers, and J. Orchardo, “Rapid variations in atmospheric methane concentration during the past 110,000 years,” Science, vol. 273, no. 5278, pp. 1087–1091, 1996.
[12]
J. P. Severinghaus, T. Sowers, E. J. Brook, R. B. Alley, and M. L. Bender, “Timing of abrupt climate change at the end of the Younger Dryas interval from thermally fractionated gases in polar ice,” Nature, vol. 391, no. 6663, pp. 141–146, 1998.
[13]
R. J. Behl, J. P. Kennett, K. G. Cannariato, and L. L. Hendy, “Methane hydrates and climate change: the clathrate gun hypothesis,” AAPG Bulletin, vol. 87, no. 10, article 1693, 2003.
[14]
J. P. Kennett, K. G. Cannariato, I. L. Hendy, and R. J. Behl, Methane Hydrates in Quaternary Climate Change: The Clathrate Gun Hypothesis, vol. 54, American Geophysical Union, Washington, DC, USA, 2002.
[15]
K. A. Kvenvolden, “Potential effects of gas hydrate on human welfare,” Proceedings of the National Academy of Sciences of the United States of America, vol. 96, no. 7, pp. 3420–3426, 1999.
[16]
T. Sowers, “Late quaternary atmospheric CH4 isotope record suggests marine clathrates are stable,” Science, vol. 311, no. 5762, pp. 838–840, 2006.
[17]
E. G. Nisbet, “Have sudden large releases of methane from geological reservoirs occurred since the Last Glacial Maximum, and could such releases occur again?” Philosophical Transactions of the Royal Society A, vol. 360, no. 1793, pp. 581–607, 2002.
[18]
G. R. Dickens, “The potential volume of oceanic methane hydrates with variable external conditions,” Organic Geochemistry, vol. 32, no. 10, pp. 1179–1193, 2001.
[19]
U. Tinivella, “The seismic response to overpressure versus gas hydrate and free gas concentration,” Journal of Seismic Exploration, vol. 11, no. 3, pp. 283–305, 2002.
[20]
M. Giustiniani, D. Accettella, M. F. Loreto, U. Tinivella, and F. Accaino, “Geographic information system—an application to manage geophysical data,” in Proceedings of the 71st European Association of Geoscientists and Engineers Conference and Exhibition, pp. 340–344, Society of Petroleum Engineers, Amsterdam, The Netherlands, June 2009.
[21]
U. Tinivella, M. Giustiniani, and D. Accettella, “BSR versus climate change and slides,” Journal of Geological Research, vol. 2011, Article ID 390547, 6 pages, 2011.
[22]
U. Tinivella and J. M. Carcione, “Estimation of gas-hydrate concentration and free-gas saturation from log and seismic data,” The Leading Edge, vol. 20, no. 2, pp. 200–203, 2001.
[23]
M. F. Loreto, U. Tinivella, F. Accaino, and M. Giustiniani, “Offshore Antarctic Peninsula gas hydrate reservoir characterization by geophysical data analysis,” Energies, vol. 4, no. 1, pp. 39–56, 2011.
[24]
D. Antoniades, P. Francus, R. Pienitz, G. St-Onge, and W. F. Vincent, “Holocene dynamics of the Arctic’s largest ice shelf,” Proceedings of the National Academy of Sciences of the United States of America, vol. 108, no. 47, pp. 18899–18904, 2011.
[25]
B. M. Vinther, S. L. Buchardt, H. B. Clausen et al., “Holocene thinning of the Greenland ice sheet,” Nature, vol. 461, no. 7262, pp. 385–388, 2009.
[26]
R. G. Graversen, T. Mauritsen, M. Tjernstr？m, E. K？llén, and G. Svensson, “Vertical structure of recent Arctic warming,” Nature, vol. 451, no. 7174, pp. 53–56, 2008.
J. Overpeck, K. Hughen, D. Hardy et al., “Arctic environmental change of the last four centuries,” Science, vol. 278, no. 5341, pp. 1251–1256, 1997.
[29]
P. R. Gent, “Preface to special issue on Community Climate System Model (CCSM),” Journal of Climate, vol. 19, no. 11, article 2121, 2006.
[30]
S. Solomon, D. Qin, M. Manning et al., Eds., “Climate change 2007: the physical science basis. Contribution of working group I to the fourth assessment report of the Intergovernmental Panel on Climate Change,” Assessment Report, Cambridge University Press, Cambridge, UK, 2007.
[31]
C. J. Willmott, S. M. Robeson, and K. Matsuura, “Short communication A refined index of model performance,” International Journal of Climatology, vol. 32, pp. 2088–2094, 2012.
[32]
G. A. Cherkashov and T. Matveeva, “Undiscovered Arctic gas hydrates: permafrost relationship and resource evaluation,” in Proceedings of the American Geophysical Union, Fall Meeting, San Francisco, Calif, USA, December 2011, abstract #GC52A-01.
[33]
V. M. Dobrynin, Y. P. Korotajeva, and D. V. Plyuschev, “Gas hydrates-one of the possible energy sources,” in Long-Term Energy Resources, R. G. Meyer and J. C. Olson, Eds., pp. 727–729, Pitman, Boston, Mass, USA, 1981.
[34]
K. A. Kvenvolden, “Methane hydrate—a major reservoir of carbon in the shallow geosphere?” Chemical Geology, vol. 71, no. 1–3, pp. 41–51, 1988.
[35]
G. J. MacDonald, “Role of methane clathrates in past and future climates,” Climatic Change, vol. 16, no. 3, pp. 247–281, 1990.
[36]
R. D. McIver, “Gas hydrates,” in Long-Term Energy Resources, R. G. Meyer and J. C. Olson, Eds., pp. 713–726, Pitman, Boston, Mass, USA, 1981.
[37]
G. D. Holder, R. D. Malone, and W. F. Lawson, “Effects of gas composition and geothermal properties on the thickness and depth of natural-gas-hydrate zones,” Journal of Petroleum Technology, vol. 39, no. 9, pp. 1147–1152, 1987.
[38]
E. D. Sloan and C. A. Koh, Clathrate Hydrates of Natural Gases, CRC Press, Boca Raton, Fla, USA, 3rd edition, 2008.
[39]
M. Jakobsson, L. Mayer, B. Coakley et al., “The International Bathymetric Chart of the Arctic Ocean (IBCAO) version 3.0,” Geophysical Research Letters, vol. 39, no. 12, Article ID L12609, 2012.
[40]
A. Giorgetti, A. Crise, R. Laterza, L. Perini, M. Rebesco, and A. Camerlenghi, “Water masses and bottom boundary layer dynamics above a sediment drift of the Antarctic Peninsula pacific margin,” Antarctic Science, vol. 15, no. 4, pp. 537–546, 2003.
[41]
F. W. Jones, J. A. Majorowicz, J. Dietrich, and A. M. Jessop, “Geothermal gradients and heat flow in the Beaufort-Mackenzie Basin, Arctic Canada,” Pure and Applied Geophysics, vol. 134, no. 3, pp. 473–483, 1990.
[42]
S. Chand, J. Mienert, K. Andreassen, J. Knies, L. Plassen, and B. Fotland, “Gas hydrate stability zone modelling in areas of salt tectonics and pockmarks of the Barents Sea suggests an active hydrocarbon venting system,” Marine and Petroleum Geology, vol. 25, no. 7, pp. 625–636, 2008.
[43]
C. Ruppel, G. R. Dickens, D. G. Castellini, W. Gilhooly, and D. Lizarralde, “Heat and salt inhibition of gas hydrate formation in the northern Gulf of Mexico,” Geophysical Research Letters, vol. 32, no. 4, pp. 1–4, 2005.
[44]
T. Bugge, G. Elvebakk, S. Fanavoll et al., “Shallow stratigraphic drilling applied in hydrocarbon exploration of the Nordkapp Basin, Barents Sea,” Marine and Petroleum Geology, vol. 19, no. 1, pp. 13–37, 2002.
[45]
U. Tinivella and M. Giustiniani, “Variations in BSR depth due to gas hydrate stability versus pore pressure,” Global and Planetary Change, vol. 100, pp. 119–128, 2013.
[46]
J. A. Higgins and D. P. Schrag, “Beyond methane: towards a theory for the Paleocene-Eocene thermal maximum,” Earth and Planetary Science Letters, vol. 245, no. 3-4, pp. 523–537, 2006.
[47]
U. R？hl, T. J. Bralower, R. D. Norris, and G. Wefer, “New chronology for the late Paleocene thermal maximum and its environmental implications,” Geology, vol. 28, no. 10, pp. 927–930, 2000.
[48]
K. A. Farley and S. F. Eltgroth, “An alternative age model for the Paleocene-Eocene thermal maximum using extraterrestrial 3He,” Earth and Planetary Science Letters, vol. 208, no. 3-4, pp. 135–148, 2003.
[49]
J. C. Zachos, M. W. Wara, S. Bohaty et al., “A transient rise in tropical sea surface temperature during the Paleocene-Eocene thermal maximum,” Science, vol. 302, no. 5650, pp. 1551–1554, 2003.
[50]
A. Tripati and H. Elderfield, “Paleoclimate: deep-sea temperature and circulation changes at the Paleocene-Eocene thermal maximum,” Science, vol. 308, no. 5730, pp. 1894–1898, 2005.
[51]
E. Thomas and N. J. Shackleton, “The latest Paleocene benthic foraminiferal extinction and stable isotope anomalies,” in Correlation of the Early Paleogene in Northwest Europe, R. O. Knox, R. M. Corfield, and R. E. Dunay, Eds., vol. 101 of Geological Society Special Publication, pp. 401–441, Geological Society of London, London, UK, 1996.
[52]
J. C. Zachos, K. C. Lohmann, J. C. G. Walker, and S. W. Wise, “Abrupt climate change and transient climates during the Paleogene: a marine perspective,” Journal of Geology, vol. 101, no. 2, pp. 191–213, 1993.
[53]
J. P. Kennett and L. D. Stott, “Abrupt deep-sea warming, palaeoceanographic changes and benthic extinctions at the end of the Palaeocene,” Nature, vol. 353, no. 6341, pp. 225–229, 1991.
[54]
R. J. Nicholls and A. Cazenave, “Sea-level rise and its impact on coastal zones,” Science, vol. 328, no. 5985, pp. 1517–1520, 2010.
[55]
M. J. Bentley, “Volume of Antarctic ice at the last glacial maximum, and its impact on global sea level change,” Quaternary Science Reviews, vol. 18, no. 14, pp. 1569–1595, 1999.
[56]
E. J. Rohling, M. Fenton, F. J. Jorissen, P. Bertrand, G. Ganssen, and J. P. Caulet, “Magnitudes of sea-level lowstands of the past 500,000 years,” Nature, vol. 394, no. 6689, pp. 162–165, 1998.
[57]
H. W. Menard and S. M. Smith, “Hypsometry of ocean basin provinces,” Journal of Geophysical Research, vol. 71, no. 18, pp. 4305–4325, 1966.
[58]
W. R. Peltier, “Ice age paleotopography,” Science, vol. 265, no. 5169, pp. 195–201, 1994.
[59]
W. Ludwig, P. Amiotte-Suchet, and J.-L. Probst, “Enhanced chemical weathering of rocks during the last glacial maximum: a sink for atmospheric CO2?” Chemical Geology, vol. 159, no. 1–4, pp. 147–161, 1999.
[60]
T. H. Shipley, M. H. Houston, R. T. Buffler et al., “Seismic reflection evidence for widespread occurrence of possible gas-hydrate horizons on continental slopes and rises,” American Association of Petroleum Geologists Bulletin, vol. 63, pp. 2204–2213, 1979.
[61]
K.-U. Hinrichs and A. Boetius, “The anaerobic oxidation of methane: new insights in microbial ecology and biochemistry,” in Ocean Margin Systems, G. Wefer, D. Billet, D. Hebbeln, B. B. Jorgensen, M. Schlüter, and T. C. E. V. Weering, Eds., pp. 457–477, Springer, Berlin, Germany, 2002.
[62]
T. Treude, A. Boetius, K. Knittel et al., “Anaerobic oxidation of methane at Hydrate Ridge (OR),” Geochimica et Cosmochimica Acta, vol. 67, article A491, 2003.
[63]
W. S. Reeburgh, “Oceanic methane biogeochemistry,” Chemical Reviews, vol. 107, no. 2, pp. 486–513, 2007.
[64]
K. Knittel and A. Boetius, “Anaerobic oxidation of methane: progress with an unknown process,” Annual Review of Microbiology, vol. 63, pp. 311–334, 2009.
[65]
C. D. Ruppel, “Methane hydrates and contemporary climate change,” Nature Education Knowledge, vol. 3, no. 10, article 29, 2011.
[66]
S. Mau, D. L. Valentine, J. F. Clark, J. Reed, R. Camilli, and L. Washburn, “Dissolved methane distributions and air-sea flux in the plume of a massive seep field, Coal Oil Point, California,” Geophysical Research Letters, vol. 34, no. 22, Article ID L22603, 2007.
[67]
J. A. Church, N. J. White, L. F. Konikow et al., “Revisiting the Earth's sea-level and energy budgets from 1961 to 2008,” Geophysical Research Letters, vol. 38, no. 18, Article ID L18601, 2011.
[68]
A. Biastoch, T. Treude, L. H. Rüpke et al., “Rising Arctic Ocean temperatures cause gas hydrate destabilization and ocean acidification,” Geophysical Research Letters, vol. 38, no. 8, Article ID L08602, 2011.
[69]
J. Hansen, M. Sato, R. Ruedy et al., “Dangerous human-made interference with climate: a GISS modelE study,” Atmospheric Chemistry and Physics, vol. 7, no. 9, pp. 2287–2312, 2007.
