Biogeosciences www.biogeosciences.net 1726-4170 1726-4189 6 4 2009 10.5194/bg-6-515-2009 http://www.biogeosciences.net/6/515/2009/ http://www.biogeosciences.net/6/515/2009/bg-6-515-2009.html http://www.biogeosciences.net/6/515/2009/bg-6-515-2009.pdf 515 533 2009-04-06 Imminent ocean acidification in the Arctic projected with the NCAR global coupled carbon cycle-climate model M. Steinacher steinacher@climate.unibe.ch F. Joos T. L. Frölicher G.-K. Plattner S. C. Doney Climate and Environmental Physics, Physics Institute, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland Oeschger Centre for Climate Change Research, University of Bern, Erlachstrasse 9a, 3012 Bern, Switzerland Dept. of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543-1543, USA now at: Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland Ocean acidification from the uptake of anthropogenic carbon is simulated for the industrial period and IPCC SRES emission scenarios A2 and B1 with a global coupled carbon cycle-climate model. Earlier studies identified seawater saturation state with respect to aragonite, a mineral phase of calcium carbonate, as a key variable governing impacts on corals and other shell-forming organisms. Globally in the A2 scenario, water saturated by more than 300%, considered suitable for coral growth, vanishes by 2070 AD (CO₂≈630 ppm), and the ocean volume fraction occupied by saturated water decreases from 42% to 25% over this century. The largest simulated pH changes worldwide occur in Arctic surface waters, where hydrogen ion concentration increases by up to 185% (ΔpH=−0.45). Projected climate change amplifies the decrease in Arctic surface mean saturation and pH by more than 20%, mainly due to freshening and increased carbon uptake in response to sea ice retreat. Modeled saturation compares well with observation-based estimates along an Arctic transect and simulated changes have been corrected for remaining model-data differences in this region. Aragonite undersaturation in Arctic surface waters is projected to occur locally within a decade and to become more widespread as atmospheric CO₂ continues to grow. The results imply that surface waters in the Arctic Ocean will become corrosive to aragonite, with potentially large implications for the marine ecosystem, if anthropogenic carbon emissions are not reduced and atmospheric CO₂ not kept below 450 ppm. Ammann, C M., Joos, F., Schimel, D S., Otto-Bliesner, B L., and Tomas, R A.: Solar influence on climate during the past millennium: Results from transient simulations with the NCAR Climate System Model, P. Natl. Acad. Sci. USA, 104, 3713–3718, \doi10.1073/pnas.0605064, 2007. Anderson, L A. and Sarmiento, J L.: Redfield ratios of remineralization determined by nutrient data analysis, Global Biogeochem. Cy., 8, 65–80, 1994. Bates, N R.: Interannual variability of oceanic CO₂ and biogeochemical properties in the Western North Atlantic subtropical gyre, Deep-Sea Res. Pt. II, 48, 1507–1528, 2001. Bettge, T W., Weatherly, J W., Washington, W M., Pollard, D., Briegleb, B P., and Strand, W G.: The CSM Sea Ice Model, NCAR Tech. Note NCAR/TN-425+STR, National Center for Atmospheric Research, Boulder, Colorado, USA, 1996. Bonan, G B.: The NCAR Land Surface Model (LSM version 1.0) coupled to the NCAR Community Climate Model, NCAR Tech. Note NCAR/TN-429+STR, National Center for Atmospheric Research, Boulder, Colorado, USA, 1996. Boville, B A. and Gent, P R.: The NCAR Climate System Model, version one, J. Climate, 11, 1115–1130, 1998. Brix, H., Gruber, N., and Keeling, C D.: Interannual variability of the upper ocean carbon cycle at station ALOHA near Hawaii, Global Biogeochem. Cy., 18, GB4019, \doi10.1029/2004GB002245, 2004. Caldeira, K. and Wickett, M E.: Anthropogenic carbon and ocean pH, Nature, 425, p 365, 2003. Cao, L., Caldeira, K., and Jain, A K.: Effects of carbon dioxide and climate change on ocean acidification and carbonate mineral saturation, Geophys. Res. Lett., 34, L05607, doi:10.1029/2006GL028605, 2007. Conkright, M E., Antonov, J I., Boyer, T P., Locarnini, R A., O'Brien, T D., Stephens, C., and Garcia, H E.: World Ocean Atlas 2001, vol. 49–52 of NOAA Atlas NEDIS, US Govt. Printing Office, Washington, D C., 2002. Dickson, A.: Handbook of methods of the analysis of the various parameters of the carbon dioxide system in seawater, US Dep. of Energy, Washington, D C., 2002. Doney, S., Lindsay, K., Fung, I., and John, J.: Natural variability in a stable, 1000-yr global coupled climate-carbon cycle simulation, J. Climate, 19, 3033–3054, 2006. Doney, S C., Fabry, V J., Feely, R A., and Kleypas, J A.: Ocean acidification: the other CO₂ problem, Ann. Rev. Mar. Sci., 1, 169–192, \doi10.1146/annurev.marine.010908.163834, 2009. Fabry, V J.: Marine Calcifiers in a High-CO₂ Ocean, Science, 320, 1020–1022, 2008. Fabry, V J., Seibel, B A., Feely, R A., and Orr, J C.: Impacts of ocean acidification on marine fauna and ecosystem processes, ICES J. Mar. Sci., 65, 414–432, 2008. Feely, R A., Sabine, C L., Kitack, L., Berelson, W., Kleypas, J., Fabry, V J., and Millero, F J.: Impact of Anthropogenic CO₂ on the CaCO₃ System in the Oceans, Science, 305, 362–366, 2004. Feely, R A., Sabine, C L., Hernandez-Ayon, J M., Ianson, D., and Hales, B.: Evidence for Upwelling of Corrosive "Acidified" Water onto the Continental Shelf, Science, 320, 1490–1492, \doi10.1126/science.1155676, published online 22 May 2008, 2008. Fine, M. and Tchernov, D.: Scleractinian Coral Species Survive and Recover from Decalcification, Science, 315, p 1811, 2007. Forster, P., Ramaswamy, V., Artaxo, P., Berntsen, T., Betts, R., Fahey, D W., Haywood, J., Lean, J., Lowe, D C., Myhre, G., Nganga, J., Prinn, R., Raga, G., Schulz, M., and Dorland, R V.: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, chap. Changes in Atmospheric Constituents and in Radiative Forcing, Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 129–234, 2007. Friedlingstein, P., Cox, P., Betts, R., Bopp, L., Von~Bloh, W., Brovkin, V., Cadule, P., Doney, S., Eby, M., Fung, I., Bala, G., John, J., Jones, C., Joos, F., Kato, T., Kawamiya, M., Knorr, W., Lindsay, K., Matthews, H D., Raddatz, T., Rayner, P., Reick, C., Roeckner, E., Schnitzler, K G., Schnur, R., Strassmann, K., Weaver, A J., Yoshikawa, C., and Zeng, N.: Climate-Carbon Cycle Feedback Analysis: Results from the C$^4$MIP Model Intercomparison: Evolution of carbon sinks in a changing climate, J. Climate, 19, 3337–3353, 2006. Frölicher, T L., Joos, F., Plattner, G K., Steinacher, M., and Doney, S C.: Natural variability and anthropogenic trends in oceanic oxygen in a coupled carbon cycle-climate model ensemble, Global Biogeochem. Cy., 23, 1–15, \doi10.1.1029/2008GB003316, 2009. Fung, I., Doney, S., Lindsay, K., and John, J.: Evolution of carbon sinks in a changing climate, P. Natl. Acad. Sci. USA, 102, 11201–11206, 2005. Gangst\o, R., Gehlen, M., Schneider, B., Bopp, L., Aumont, O., and Joos, F.: Modeling the marine aragonite cycle: changes under rising carbon dioxide and its role in shallow water CaCO3 dissolution, Biogeosciences, 5, 1057–1072, 2008. Gattuso, J.-P., Frankignoulle, M., Bourge, I., Romaine, S., and Buddemeier, R W.: Effect of calcium carbonate saturation of seawater on coral calcification, Global Planet. Change, 18, 37–46, 1998. Gehlen, M., Gangstt\o, R., Schneider, B., Bopp, L., Aumont, O., and Ethe, C.: The fate of pelagic CaCO₃ production in a high CO₂ ocean: a model study, Biogeosciences, 4, 505–519, 2007. Gent, P R., Bryan, F O., Danabasoglu, G., Doney, S C., Holland, W R., Large, W G., and McWilliams, J C.: The NCAR Climate System Model global ocean component, J. Climate, 11, 1287–1306, 1998. German Advisory Council on Global Change: The Future Oceans –Warming up, Rising High, Turning Sour, WGBU Special Report, German Advisory Council on Global Change (WBGU), Berlin, Germany, 2006. Guinotte, J., Orr, J., Cairns, S., Freiwald, A., Morgan, L., and George, R.: Will human-induced changes in seawater chemistry alter the distribution of deep-sea scleractinian corals?, Front. Ecol. Environ., 4, 141–146, 2006. Heinze, C.: Simulating oceanic CaCO₃ export production in the greenhouse, Geophys. Res. Lett., 31, L16308, \doi10.1029/2004GL020613, 2004. Hoegh-Guldberg, O.: Low coral cover in a high-CO₂ world, J. Geophys. Res., 110, C09S06, \doi10.1029/2004JC002528, 2005. Holland, M M., Bitz, C M., and Tremblay, B.: Future abrupt reductions in the summer Arctic sea ice, Geophys. Res. Lett., 33, L23503, \doi10.1029/2006GL028024, 2006. Iglesias-Rodriguez, M D., Halloran, P R., Rickaby, R E M., Hall, I R., Colmenero-Hidalgo, E., Gittins, J R., Green, D R H., Tyrrell, T., Gibbs, S J., von Dassow, P., Rehm, E., Armbrust, E V., and Boessenkool, K P.: Phytoplankton Calcification in a High-CO₂ World, Science, 320, 336–340, \doi10.1126/science.1154122, 2008. Jin, X., Gruber, N., Dunne, J P., Sarmiento, J L., and Armstrong, R A.: Diagnosing the contribution of phytoplankton functional groups to the production and export of particulate organic carbon, CaCO₃, and opal from global nutrient and alkalinity distributions, Global Biogeochem. Cy., 20, 2, GB2015, \doi10.1029/2005GB002532, 2006. Joos, F. and Spahni, R.: Rates of change in natural and anthropogenic radiative forcing over the past 20000 years, P. Natl. Acad. Sci. USA, 105, 1425–1430, 2008. Jutterström, S. and Anderson, L G.: The saturation of calcite and aragonite in the Arctic Ocean, Mar. Chem., 94, 101–110, 2005. Key, R M., Kozyr, A., Sabine, C L., Lee, K., Wanninkhof, R., Bullister, J., Feely, R A., Millero, F., Mordy, C., and Peng, T.-H.: A global ocean carbon climatology: Results from Global Data Analysis Project (GLODAP), Global Biogeochem. Cy., 18, GB4031+, \doi10.1029/2004GB002247, 2004. Kiehl, J T., Hack, J J., Bonan, G B., Boville, B A., Williamson, D L., and Rasch, P J.: The National Center for Atmospheric Research Community Climate Model, J. Climate, 11, 1151–1178, 1998. Kleypas, J A., Buddemeier, R W., Archer, D., Gattuso, J.-P., Langdon, C., and Opdyke, B N.: Geochemical Consequences of Increased Atmospheric Carbon Dioxide on Coral Reefs, Science, 284, 118–120, 1999. Kleypas, J A., Feely, R A., Fabry, V J., Langdon, C., Sabine, C L., and Robbins, L L.: Impacts of Ocean Acidification on Coral Reefs and Other Marine Calcifiers: A Guide for Future Research, report of a workshop held 18–20 April 2005, St. Petersburg, FL, sponsored by NSF, NOAA, and the US Geological Survey, 2006. Kwon, E Y. and Primeau, F.: Optimization and sensitivity of a global biogeochemistry ocean model using combined in situ DIC, alkalinity, and phosphate data, J. Geophys. Res.-Oceans, 113(C8), C08011, \doi10.1029/2007JC004520, 2008. Langdon, C.: Review of Experimental Evidence for Effects of CO₂ on Calcification of Reef builders, in: Proceedings 9th International Coral Reef Symposium, vol 2, 1091–1098, 2002. Langdon, C. and Atkinson, M J.: Effect of elevated pCO₂ on photosynthesis and calcification of corals and interactions with seasonal change in temperature/irradiance and nutrient enrichment, J. Geophys. Res., 110, C09S07, \doi10.1029/2004JC002576, 2005. Lueker, T. J., Dickson, A. G., and Keeling, C. D.: Ocean pCO₂ calculated from dissolved inorganic carbon, alkalinity, and equations for K-1 and K-2: validation based on laboratory measurements of CO₂ in gas and seawater at equilibrium, Mar. Chem., 70, 105–119, 2000. Lüthi, D., Le~Floch, M., Bereiter, B., Blunier, T., Barnola, J.-M., Siegenthaler, U., Raynaud, D., Jouzel, J., Fischer, H., Kawamura, K., and Stocker, T F.: High-resolution carbon dioxide concentration record 650 000–800 000 years before present, Science, 453, 379–382, 2008. Martin, J H., Knauer, G A., Karl, D M., and Broenkow, W W.: VERTEX – Carbon cycling in the Northeast Pacific, Deep-Sea Res., 34, 267–285, 1987. McNeil, B I. and Matear, R J.: Climate change feedbacks on future oceanic acidification, Tellus B, 59, 191–198, 2007. Meehl, G A., Stocker, T F., Collins, W D., Friedlingstein, P., Gaye, A T., Gregory, J M., Kitoh, A., Knutti, R., Murphy, J M., Noda, A., Raper, S C B., Watterson, I G., Weaver, A J., and Zhao, Z.-C.: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, chap. Global Climate Projections, Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 747–846, 2007. Mehrbach, C., Culberson, C H., Hawley, J E., and Pytkowicz, R M.: Measurement of apparent dissociation-constants of carbonic-acid in seawater at atmospheric-pressure, Limnol. Oceanogr., 18, 897–907, 1973. Millero, F J.: Thermodynamics of the carbon dioxide system in the oceans, Geochim. Cosmochim. Ac., 59, 661–677, 1995. Mucci, A.: The solubility of calcite and aragonite in seawater at various salinities, temperatures and 1 atmosphere total pressure, Am. J. Sci., 238, 780–799, 1983. Najjar, R G., Jin, X., Louanchi, F., Aumont, O., Caldeira, K., Doney, S C., Dutay, J.-C., Follows, M., Gruber, N., Joos, F., Lindsay, K., Maier-Reimer, E., Matear, R J., Matsumoto, K., Mouchet, A., Orr, J C., Sarmiento, J L., Schlitzer, R., Weirig, M F., Yamanaka, Y., and Yool, A.: Impact of circulation on export production, dissolved organic matter, and dissolved oxygen in the ocean: Results from Phase II of the Ocean Carbon-cycle Model Intercomparison Project (OCMIP-2), Global Biogeochem. Cy., 21, GB3007, \doi10.1029/2006GB002857, 2007. Orr, J C., Fabry, V J., Aumont, O., Bopp, L., Doney, S C., Feely, R A., Gnanadesikan, A., Gruber, N., Ishida, A., Joos, F., Key, R M., Lindsay, K., Maier-Reimer, E., Matear, R., Monfray, P., Mouchet, A., Najjar, R G., Plattner, G.-K., Rodgers, K B., Sabine, C L., Sarmiento, J L., Schlitzer, R., Slater, R D., Totterdell, I J., Weirig, M F., Yamanaka, Y., and Yool, A.: Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms, Nature, 437, 681–686, 2005. Orr, J C., Jutterström, S., Bopp, L., Anderson, L G., Fabry, V J., Frölicher, T L., Jones, P., Joos, F., Maier-Reimer, E., Segschneider, J., Steinacher, M., and Swingedouw, D.: Arctic ocean acidification, Nature, submitted, 2008. Plattner, G.-K., Knutti, R., Joos, F., Stocker, T F., von Bloh, W., Brovkin, V., Cameron, D., Driesschaert, E., Dutkiewiz, S., Eby, M., Edwards, N R., Fichefet, T., Hargreaves, J C., Jones, C D., Loutre, M F., Matthews, H D., Mouchet, A., Müller, S A., Nawrath, S., Price, A., Sokolov, A., Strassmann, K M., and Weaver, A J.: Long-term climate commitments projected with climate – carbon cycle models, J. Climate, 21, 2721–2751, \doi10.1175/2007JCLI1905.1, 2008. Prentice, I C., Farquhar, G D., Fasham, M J R., Goulden, M L., Heimann, M., Jaramillo, V J., Kheshgi, H S., Le~Quéré, C., Scholes, R J., and Wallace, D W R.: Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change, chap. The Carbon Cycle and Atmospheric Carbon Dioxide, Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 183–237, 2001. Randerson, J T., Thompson, M V., Conway, T J., Fung, I Y., and Field, C B.: The contribution of terrestrial sources and sinks to trends in the seasonal cycle of atmospheric carbon dioxide, Global Biogeochem. Cy., 11, 535–560, 1997. Revelle, R. and Suess, H E.: Carbon dioxide exchange between atmosphere and ocean and the question of an increase of atmospheric CO₂ during the past decades, Tellus, 9, 18–27, 1957. Ridgwell, A., Zondervan, I., Hargreaves, J. C., Bijma, J., and Lenton, T. M.: Assessing the potential long-term increase of oceanic fossil fuel CO₂ uptake due to CO₂-calcification feedback, Biogeosciences, 4, 481–492, 2007. Royal Society: Ocean acidification due to increasing atmospheric carbon dioxide, Policy Document 12/05, Royal Society, London, 2005. Sarmiento, J L., Dunne, J., Gnanadesikan, A., Key, R M., Matsumoto, K., and Slater, R.: A new estimate of the CaCO₃ to organic carbon export ratio, Global Biogeochem. Cy., 16, 4, 1107, \doi10.1029/2002GB001919, 2002. Schlitzer, R.: Ocean Data View (Software), http://odv.awi.de, 2007. Schneider, K. and Erez, J.: The effect of carbonate chemistry on calcification and photosynthesis in the hermatypic coral Acropora eurystoma, Limnol. Oceanogr., 51, 1284–1293, 2006. Siegenthaler, U., Stocker, T F., Monnin, E., Lüthi, D., Schwander, J., Stauffer, B., Raynaud, D., Barnola, J.-M., Fischer, H., Masson-Delmotte, V., and Jouzel, J.: Stable carbon cycle-climate relationship during the late Pleistocene, Science, 310, 1313–1317, \doi10.1126/science.1120130, 2005. Steinacher, M.: Ocean acidification and changes in marine productivity in simulations with the fully coupled 3-D climate model CSM1.4-carbon, Master's thesis, University of Bern, Bern, Switzerland, 2007. Strassmann, K M., Plattner, G.-K., and Joos, F.: CO₂ and non-CO₂ radiative forcings in climate projections for twenty-first century mitigation scenarios, Clim. Dynam., \doi10.1007/s00382-008-0505-4, published online 20 Dec 2008, 2008. Stroeve, J., Holland, M M., Meier, W., Scambos, T., and Serreze, M.: Arctic sea ice decline: Faster than forecast, Geophys. Res. Lett., 34, L09501, \doi10.1029/2007GL029703, 2007. Takahashi, T., Olafsson, J., Goddard, J G., Chipman, D W., and Sutherland, S C.: Seasonal-variation of CO₂ and nutrients in the high-latitude surface oceans – a comparative-study, Global Biogeochem. Cy., 7, 843–878, 1993. Taylor, K E.: Summarizing multiple aspects of model performance in a single diagram., J. Geophys. Res.-Atmos., 106, 7183–7192, 2001. Thomas, H., Prowe, A E F., van Heuven, S., Bozec, Y., de~Baar, H., Schiettecatte, L.-S., Suykens, K., Koné, M., Borges, A V., Lima, I D., and Doney, S C.: Rapid decline of the CO₂ buffering capacity in the North Sea and implications for the North Atlantic Ocean, Global Biogeochem. Cy., 21, GB4001, \doi10.1029/2006GB002825, 2007. Van~Vuuren, D P., Meinshausen, M., Plattner, G.-K., Joos, F., Strassmann, K M., Smith, S J., Wigley, T M L., Raper, S C B., Riahi, K., de~la Chesnaye, F., den Elzen, M., Fujino, J., Jiang, K., Nakicenovic, N., Paltsev, S., and Reilly, J M.: Temperature increase of 21st century mitigation scenarios, P. Natl. Acad. Sci. USA, 105, 15258–15262, \doi10.1073/pnas.0711129105, 2008. Walsh, J E.: A data set on Northern Hemisphere sea ice extent, World Data Center-A for Glaciology (Snow and Ice), Glaciological Data, Report GD-2, part 1, 49–51, 1978. Wang, Y M., Lean, J L., and Sheeley, N R.: Modeling the sun's magnetic field and irradiance since 1713, Astrophys. J., 625, 522–538, 2005. Weatherly, J W., Briegleb, B P., Large, W G., and Maslanik, J A.: Sea Ice and Polar Climate in the NCAR CSM, J. Climate, 11, 1472–1486, 1998. Yamanaka, Y. and Tajika, E.: The role of the vertical fluxes of particulate organic matter and calcite in the oceanic carbon cycle: Studies using an ocean biogeochemical general circulation model, Global Biogeochem. Cy., 10, 361–382, 1996.