Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 8 16 2008 10.5194/acp-8-4605-2008 http://www.atmos-chem-phys.net/8/4605/2008/ http://www.atmos-chem-phys.net/8/4605/2008/acp-8-4605-2008.html http://www.atmos-chem-phys.net/8/4605/2008/acp-8-4605-2008.pdf 4605 4620 2008-08-08 Why are estimates of global terrestrial isoprene emissions so similar (and why is this not so for monoterpenes)? A. Arneth almut.arneth@nateko.lu.se R. K. Monson G. Schurgers Ü. Niinemets P. I. Palmer Dept. of Physical Geography and Ecosystems Analysis, Geobiosphere Science Centre, Lund University, Lund, Sweden Dept. of Ecology and Evolutionary Biology, and Coop. Inst. for Environ. Sci., University of Colorado, Boulder, CO, USA Inst. of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia School of GeoSciences, University of Edinburgh, King's Buildings, Edinburgh, UK Emissions of biogenic volatile organic compounds (BVOC) are a chief uncertainty in calculating the burdens of important atmospheric compounds like tropospheric ozone or secondary organic aerosol, reflecting either imperfect chemical oxidation mechanisms or unreliable emission estimates, or both. To provide a starting point for a more systematic discussion we review here global isoprene and monoterpene emission estimates to-date. We note a surprisingly small variation in the predictions of global isoprene emission rate that is in stark contrast with our lack of process understanding and the small number of observations for model parameterisation and evaluation. Most of the models are based on similar emission algorithms, using fixed values for the emission capacity of various plant functional types. In some cases, these values are very similar but differ substantially in other models. The similarities with regard to the global isoprene emission rate would suggest that the dominant parameters driving the ultimate global estimate, and thus the dominant determinant of model sensitivity, are the specific emission algorithm and isoprene emission capacity. But the models also differ broadly with regard to their representation of net primary productivity, method of biome coverage determination and climate data. Contrary to isoprene, monoterpene estimates show significantly larger model-to-model variation although variation in terms of leaf algorithm, emission capacities, the way of model upscaling, vegetation cover or climatology used in terpene models are comparable to those used for isoprene. From our summary of published studies there appears to be no evidence that the terrestrial modelling community has been any more successful in "resolving unknowns" in the mechanisms that control global isoprene emissions, compared to global monoterpene emissions. Rather, the proliferation of common parameterization schemes within a large variety of model platforms lends the illusion of convergence towards a common estimate of global isoprene emissions. This convergence might be used to provide optimism that the community has reached the "relief phase", the phase when sufficient process understanding and data for evaluation allows models' projections to converge, when applying a recently proposed concept. We argue that there is no basis for this apparent relief phase. Rather, we urge modellers to be bolder in their analysis, and to draw attention to the fact that terrestrial emissions, particularly in the area of biome-specific emission capacities, are unknown rather than uncertain. Abbot, D. S., Palmer, P. I., Martin, R. V., Chance, K. V., Jacob, D. J., and Guenther, A.: Seasonal and interannual variability of North American isoprene emissions as determined by formaldehyde column measurements from space, Geophys. Res. Lett., 30, 1886, doi:10.1029/2003GL017336, 2003. Adams, J. M., Constable, J. V. H., Guenther, A. B., and Zimmerman, P.: An estimate of natural volatile organic compound emissions from vegetation since the last glacial maximum, Chemosphere, 3, 73–91, 2001. Arneth, A., Miller, P., Scholze, M., Hickler, T., Smith, B., and Prentice, I. C.: CO₂ inhibition of global terrestrial isoprene emissions: Potential implications for atmospheric chemistry, Geophys. Res. Lett., 34, L18813, doi:18810.11029/12007GL030615, 2007a. Arneth, A., Niinemets, Ü., Pressley, S., Bäck, J., Hari, P., Noe, S., Prentice, I. C., Serça, D., Hickler, T., and Wolf, A.: Process-based estimates of terrestrial ecosystem isoprene emissions: Incorporating the effects of a direct CO₂-isoprene interaction, Atmos. Chem. Phys., 7, 31–53, 2007. Arneth, A., Schurgers, G., Miller, P., and Hickler, T.: Effects of species composition, land surface cover, CO₂ concentration and climate on isoprene emissions from European forests, Plant Biology, 10(1), 150–162, 2008. Ashmore, M. R.: Assessing the future global impacts of ozone on vegetation, Plant, Cell and Environment, 28, 949–964, 2005. Atkinson, R.: Atmospheric chemistry of VOCs and NO_x, Atmospheric Environment, 34, 2063–2101, 2000. Atkinson, R. and Arey, J.: Gas-phase tropospheric chemistry of biogenic volatile organic compounds: A review, Atmos. Environ., 37, 197–219, 2003. Bai, J., Baker, B., Liang, B., Greenberg, J. and Guenther, A.: Isoprene and monoterpene emissions from an inner Mongolia grassland, Atmos. Environ., 40, 5753–5758, 2006. Chance, K., Palmer, P. I., Spurr, R. J. D., Martin, R. V., Kurosu, T. P., and Jacob, D. J.: Satellite observations of formaldehyde over north America from GOME, Geophys. Res. Lett., 27, 3461–3464, 2000. Claeys, M., Graham, B., Vas, G., Wang, W., Vermeylen, R., Pashynska, V., Cafmeyer, J., Guyon, P., Andreae, M. O., Artaxo, P., and Maenhaut, W.: Formation of secondary organic aerosols through photooxidation of isoprene, Science, 303, 1173–1176, 2004. Cramer, W., Kicklighter, D. W., Bondeau, A., III, B. M., Churkina, G., Nemry, B., Ruimy, A., Schloss, A. L., and the the participants of the Potsdam NPP Model Intercomparison: Comparing global models of terrestrial net primary productivity (NPP): Overview and key results, Global Change Biology, 5(S1), 1–15, 1999. Derwent, R. G.: Air chemistry and terrestrial gas emissions: A global perspective, Philosophical Transactions of the Royal Society of London: Phys. Sci. Eng., 351, 205–217, 1995. 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., Schultz, M., van Dorland, R., et al.: Changes in atmospheric constituents and radiative forcing, in: Climate Change 2007: The Physical Science Basis, contribution of Working Group I to the Fourth Assesment Report of the Intergovernmental Panel on Climate Change, edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K. B., Tignor, M., and Miller, H. L., Cambridge University Press, Cambridge, UK and New York, USA, 2007. Fu, T. M., Jacob, D. J., Palmer, P. I., Chance, K., Wang, Y. X., Barletta, B., Blake, D. R., Stanton, J. C., and Pilling, M. J.: Space-based formaldehyde measurements as constraints on volatile organic compound emissions in east and south asia and implications for ozone, J. Geophys. Res.-Atmos., 112, D06312, doi:10.1029/2006JD007853, 2007. Geron, C., Guenther, A., Sharkey, T. D., and Arnts, R. R.: Temporal variability in basal isoprene emission factor, Tree Physiology, 20, 799–805, 2000. Greenberg, J. P., Guenther, A., Harley, P., Otter, L., Veenendaal, E. M., Hewitt, C. N., James, A. E., and Owen, S. M.: Eddy flux and leaf-level measurements of biogenic voc emissions from Mopane woodland of Botswana, J. Geophys. Res.-Atmos., 108, 8466, doi:10.1029/2002JD002317, 2003. Guenther, A.: Seasonal and spatial variations in natural volatile organic compound emissions, Ecol. Appl., 7, 34–45, 1997. Guenther, A., Zimmerman, P. R., Harley, P. C., Monson, R. K., and Fall, R.: Isoprene and monoterpene emission rate variability - model evaluations and sensitivity analyses, J. Geophys. Res., 98, 12 609–12 617, 1993. Guenther, A., Hewitt, C. N., Erickson, D., Fall, R., Geron, C., Graedel, T., Harley, P., Klinger, L., Lerdau, M., McKay, W. A., Pierce, T., Scholes, B., Steinbrecher, R., Tallamraju, R., Taylor, J., and Zimmermann, P.: A global model of natural volatile organic compound emissions, J. Geophys. Res.-Atmos., 100, 8873–8892, 1995. Guenther, A., Baugh, B., Brasseur, G., Greenberg, J., Harley, P., Klinger, L., Serça, D., and Vierling, L.: Isoprene emission estimates and uncertainties for the central African Expresso study domain, J. Geophys. Res., 104, 30 635–30 639, 1999. Guenther, A., Karl, T., Harley, P., Wiedinmyer, C., Palmer, P. I., and Geron, C.: Estimates of global terrestrial isoprene emissions using MEGAN (model of emissions of gases and aerosols from nature), Atmos. Chem. Phys., 6, 3181–3210, 2006. Hanson, D. T. and Sharkey, T. D.: Rate of acclimation of the capacity for isoprene emission in response to light and temperature, Plant, Cell and Environment, 24, 937–946, 2001. Hakola, H., Rinne, J., and Laurila, T.: The hydrocarbon emission rates of tea-leafed willow (salix phylicifolia), silver birch (betula pendula) and european aspen (populus tremula), Atmos. Environ., 32, 1825–1833, 1998. Henze, D. and Seinfeld, J. H.: Global secondary organic aerosol from isoprene oxidation, Geophys. Res. Lett., 33, L09812, doi:09810.01029/02006GL025976, 2006. Hickler, T., Smith, B., Prentice, I. C., Mjö, K., Miller, P., Arneth, A., and Sykes, M.: CO₂ fertilization in temperate face experiments not representative of boreal and tropical forests, Global Change Biol., 14, 1–12, 2008. Hoffmann, T., Odum, J. R., Bowman, F., Collins, D., Klockow, D., Flagan, R. C., and Seinfeld, J. H.: Formation of organic aerosols from the oxidation of biogenic hydrocarbons, J. Atmos. Chem., 26, 189–222, 1997. Janson, R. and de Serves, C.: Acetone and monoterpene emissions from the boreal forest in northern europe, Atmos. Environ., 35, 4629–4637, 2001. Kaplan, J. O., Folberth, G., and Hauglustaine, D. A.: Role of methane and biogenic volatile organic compound sources in late glacial and Holocene fluctuations of atmospheric methane concentrations, Global Biogeochem. Cy., 20, GB2016, doi:10.1929/2005GB002590, 2006. Kesselmeier, J. and Staudt, M.: Biogenic volatile organic compounds (VOC): an overview on emission, physiology and ecology, J. Atmos. Chem., 33, 23–88, 1999. Kuhn, U., Rottenberger, S. T. B., Wolf, A. G. S., Ciccioli, P., Brancaleoni, E., Frattoni, M., Tavares, T. M., and Kesselmeier, J.: Seasonal differences in isoprene and light-dependent monoterpene emission by Amazonian tree species, Global Change Biol., 10, 663–682, 2004. Kulmala, M.: How particles nucleate and grow, Science, 302, 1000–1001, 2003. Kuzma, J. and Fall, R.: Leaf isoprene emission rate is dependent on leaf development and the level of isoprene synthase, Plant Physiol., 101, 435–440, 1993. Lamb, B., Pierce, T., Baldocchi, D., Allwine, E., Dilts, S., Westberg, H., Geron, C., Guenther, A., Klinger, L., Harley, P., and Zimmerman, P.: Evaluation of forest canopy models for estimating isoprene emissions, J. Geophys. Res., 101, 22 787–22 797, 1996. Lathière, J., Hauglustaine, D. A., Friend, A., De Noblet-Ducoudré, N., Viovy, N., and Folberth, G.: Impact of climate variability and land use changes on global biogenic volatile organic compound emissions, Atmos. Chem. Phys., 6, 2199–2146, 2006. Le Quéré, C.: The unknown and the uncertain in earth system modeling, Eos T Am. Geophys. Un., 87, 496–496, 2006. Leemans, R. and Cramer, W.: IIASA database for mean monthly values of temperature, precipitation, and cloudiness on a global terrestrial grid: Digital raster on a 30 minute geographic (lat/long) 320 times 720 grid, NOAA National Geophysical Data Center, Global Ecosystems Database Version 1.0, Disc A, 1992. Levis, S., Foley, J. A., and Pollard, D.: Potential high-latitude vegetation feedbacks on co2-induced climate change, Geophys. Res. Lett., 26, 747–750, 1999. Levis, S., Wiedinmyer, C., Bonan, G. B., and Guenther, A.: Simulating biogenic volatile organic compound emissions in the community climate system model, J. Geophys. Res.-Atmos., 108, 4659, doi:4610.1029/2002JD003203, 2003. Liao, H., Cheng, W.-T., and Seinfeld, J. H.: Role of climate change in global predictions of future tropospheric ozone and aerosols, J. Geophys. Res.-Atmos., 111, D12304, doi:12310.11029/12005JD006852, 2006. Lichtenthaler, H. K., Schwender, J., Disch, A., and Rohmer, M.: Biosynthesis of isoprenoids in higher plant chloroplasts proceeds via a mevalonate-independent pathway, FEBS Lett., 400, 271–274, 1997. Loreto, F. and Velikova, V.: Isoprene produced by leaves protects the photosynthetic apparatus against ozone damage, quenches ozone products, and reduces lipid peroxidation of cellular membranes, Plant Physiol., 127, 1781–1787, 2001. Loreto, F. and Fares, S.: Is ozone flux inside leaves only a damage indicator?: clues from volatile isoprenoid studies, Plant Physiol., 143, 1096–1100, 2007. Millet, D. B., Jacob, D. J., Turquety, S., Hudman, R. C., Wu, S. L., Fried, A., Walega, J., Heikes, B. G., Blake, D. R., Singh, H. B., Anderson, B. E., and Clarke, A. D.: Formaldehyde distribution over north America: Implications for satellite retrievals of formaldehyde columns and isoprene emission, J. Geophys. Res.-Atmos., 111, D24S02, doi:10.1029/2006JD007287, 2006. Mitchell, T. D. and Jones, P. D.: An improved method of constructing a database of monthly climate observations and associated high-resolution grids, Int. J. Climatol., 25, 693–712, 2005. Monson, R., Harley, P., Litvak, M. E., Wildermuth, M., Guenther, A., Zimmerman, P. R., and Fall, R.: Environmental and developmental controls over the seasonal pattern of isoprene emission from aspen leaves, Oecologia, 99, 260–270, 1994. Monson, R. K., Jaeger, C. H., Adams, W. W. I., Driggers, E. M., Silver, G. M., and Fall, R.: Relationship among isoprene emission rate, photosynthesis, and isoprene synthase activity as influenced by temperature, Plant Physiol., 98, 1175–1180, 1992. Monson, R. K., Trahan, N., Rosenstiel, T. N., Veres, P., Moore, D., Wilkinson, M., Norby, R. J., Volder, A., Tjoelker, M. G., Briske, D. D., Karnosky, D. F., and Fall, R.: Isoprene emission from terrestrial ecosystems in response to global change: Minding the gap between models and observations, Philos. T. Roy. Soc. A, 365, 1677–1695, 2007. Monteith, J. L. and Unsworth, M.: Principles of environmental physics, 2nd ed., Arnold, London, UK, 1990. Mueller, J. F.: Geographical-distribution and seasonal variation of surface emissions and deposition velocities of atmospheric trace gases, J. Geophys. Res.-Atmos., 97, 3787–3804, 1992. Naik, V., Delire, C., and Wuebbles, D. J.: Sensitivity of global biogenic isoprenoid emissions to climate variability and atmospheric CO₂, J. Geophys. Res.-Atmos., 109, D06301, doi:06310.01029/02003JD004236, 2004. Niinemets, U., Tenhunen, J. D., Harley, P. C., and Steinbrecher, R.: A model of isoprene emission based on energetic requirements for isoprene synthesis and leaf photosynthetic properties for \textitLiquidambar and \textitQuercus, Plant Cell Environ., 22, 1319–1335, 1999. Olson, J.: World ecosystems (WE1.4): digital raster on a 10 minute geographic 1080×2160 grid, NOAA National Geophysical Data Center, Global ecosystems database, Version 1.0, Disc A, 1992. Palmer, P. I., Jacob, D. J., Chance, K., Martin, R. V., Spurr, R. J. D., Kurosu, T. P., Bey, I., Yantosca, R., Fiore, A., and Li, Q. B.: Air mass factor formulation for spectroscopic measurements from satellites: Application to formaldehyde retrievals from the global ozone monitoring experiment, J. Geophys. Res.-Atmos., 106, 14 539–14 550, 2001. Palmer, P. I., Jacob, D. J., Fiore, A. M., Martin, R. V., Chance, K., and Kurosu, T. P.: Mapping isoprene emissions over North America using formaldehyde column observations from space, J. Geophys. Res.-Atmos., 108, 4180, doi:10.1029/2002JD002153, 2003. Palmer, P. I., Abbot, D. S., Fu, T. M., Jacob, D. J., Chance, K., Kurosu, T. P., Guenther, A., Wiedinmyer, C., Stanton, J. C., Pilling, M. J., Pressley, S. N., Lamb, B., and Sumner, A. L.: Quantifying the seasonal and interannual variability of North American isoprene emissions using satellite observations of the formaldehyde column, J. Geophys. Res.-Atmos., 111, D12315, doi:10.1029/2005JD006689, 2006. Potter, C. S., Alexander, S. E., Coughlan, J. C., and Klooster, S. A.: Modeling biogenic emissions of isoprene: Exploration of model drivers, climate control algorithms, and use of global satellite observations, Atmos. Environ., 35, 6151–6165, 2001. Possell, M., Hewitt, N. C., and Beerling, D. J.: The effects of glacial atmospheric CO₂ concentrations and climate on isoprene emissions by vascular plants, Global Change Biol., 11, 60–69, 2005. Prather, M., Ehhalt, D., Dentener, F. J., Derwent, R., Dlugokencky, E. J., Holland, E., Isaksen, I., Katima, J., Kirchhoff, V., Matson, P., Midgley, P. et al.: Atmospheric chemistry and greenhouse gases, in: Climate change 2001: the scientific basis, Contribution of working group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Houghton, J. T., Ding, Y., Griggs, D. J., Noguer, M., van der Linden, P. J., Dai, X., Maskell, K., and Johnson, C. A., Cambridge University Press, Cambridge, UK, 238–287, 2001. Rinne, J., Tuovinen, J. P., Laurila, T., Hakola, H., Aurela, M., and Hypen, H.: Measurements of hydrocarbon fluxes by a gradient method above a northern boreal forest, Agr. Forest Meteorol., 102, 25–37, 2000. Rosenstiel, T. N., Potosnak, M. J., Griffin, K. L., Fall, R., and Monson, R. K.: Increased CO₂ uncouples growth from isoprene emission in an agriforest ecosystem, Nature, 421, 256, 2003. Sanderson, M. G., Jones, C. D., Collins, W. J., Johnson, C. E., and Derwent, R. G.: Effect of climate change on isoprene emissions and surface ozone levels, Geophys. Res. Lett., 30, 1936, doi:1910.1029/2003GL017642, 2003. Schaab, G., Steinbrecher, R., and Lacaze, B.: Influence of seasonality, canopy light extinction, and terrain on potential isoprenoid emission from a mediterranean-type ecosystem in france, J. Geophys. Res.-Atmos., 108, 4392, doi:4310.1029/2002JD002899, 2003. Shim, C., Wang, Y., Choi, Y., Palmer, P., Abbot, D., and Chance, K.: Constraining global isoprene emissions with global ozone monitoring experiment (GOME) formaldehyde column measurements, J. Geophys. Res.-Atmos., 110, D24301, doi:24310.21029/22004JD005629, 2005. Shindell, D. T., Faluvegi, G., and Bell, N.: Preindustrial-to-present-day radiative forcing by tropospheric ozone from improved simulations with the GISS chemistry-climate GCM, Atmos. Chem. Phys., 3, 1675–1702, 2003. Sitch, S., Smith, B., Prentice, I. C., Arneth, A., Bondeau, A., Cramer, W., Kaplan, J. O., Levis, S., Lucht, W., Sykes, M. T., Thonicke, K., and Venevsky, S.: Evaluation of ecosystem dynamics, plant geography and terrestrial carbon cycling in the LPJ dynamic global vegetation model, Global Change Biol., 9, 161–185, 2003. Sitch, S., Cox, P. M., Collins, W. J., and Huntingford, C.: Indirect radiative forcing of climate change through ozone effects on the land-carbon sink, Nature, 448, 791–794, 2007. Smith, B., Prentice, I. C., and Sykes, M. T.: Representation of vegetation dynamics in the modelling of terrestrial ecosystems: Comparing two contrasting approaches within european climate space, Global Ecol. Biogeogr., 10, 621–637, 2001. Staudt, M. and Seufert, G.: Light-dependent emission of monoterpenes by holm oak (\textitQuercus ilex l.), Naturwissenschaften, 82, 89–92, 1995. Stevenson, D. S., Dentener, F. J., Schultz, M. G., Ellingsen, K., van Noije, T. P. C., Wild, O., Zeng, G., Amann, M., Atherton, C. S., et al.: Multi-model ensemble simulations of present-day and near-future tropospheric ozone, J. Geophys. Res.-Atmos., 111, D08301, doi:10.1029/2005JD006338. 2006. Tao, Z. and Jain, A. K.: Modeling of global biogenic emissions for key indirect greenhouse gases and their response to atmospheric CO₂ increases and changes in land cover and climate, J. Geophys. Res.-Atmos., 110, D21309, doi:10.1029/22005JD005874, 2005. Tunved, P., Hansson, H. C., Kerminen, V. M., Strom, J., Maso, M. D., Lihavainen, H., Viisanen, Y., Aalto, P. P., Komppula, M., and Kulmala, M.: High natural aerosol loading over boreal forests, Science, 312, 261–263, 2006. Turner, D. P., Baglio, J. V., Wones, A. G., Pross, D., Vong, R., McVeety, B. D., and Phillips, D. L.: Climate change and isoprene emissions from vegetation, Chemosphere, 23, 37, 1991. Valdes, P. J., Beerling, D. J., and Johnson, D. E.: The ice age methane budget, Geophys. Res. Lett., 32, L02704, doi:10.1029/02004GL021004, 2005. Velikova, V., Pinelli, P., Pasqualini, S., Reale, L., Ferranti, F., and Loreto, F.: Isoprene decreases the concentration of nitric oxide in leaves exposed to elevated ozone, New Phytol., 166, 419–426, 2005. Wang, K. Y. and Shallcross, D. E.: Modelling terrestrial biogenic isoprene fluxes and their potential impact on global chemical species using a coupled LSM-CTM model, Atmos. Environ., 34, 2909–2925, 2000. Wang, Y., Jacob, D. J., and Logan, J. A.: Global simulation of tropospheric O₃-NO_x-hydrocarbon chemistry – 1: Model formulation, J. Geophys. Res.-Atmos., 103, 10 713–10 726, 1998. Wiberley, A. E., Linskey, A. R., Falbel, T. G., and Sharkey, T. D.: Development of the capacity for isoprene emission in kudzu, Plant Cell Environ., 28, 898–905, 2005. Wiedinmyer, C., Guenther, A., Harley, P., Hewitt, C., Geron, C., Artaxo, P., Steinbrecher, R., and Rasmussen, R.: Global organic emissions from vegetation, in: Emissions of atmospheric trace compounds, edited by: Granier, C., Kluwer Publishing C., Dordrecht, The Netherlands, 121–182, 2004. Wiedinmyer, C., Tie, X., Guenther, A., Neilson, R., and Granier, C.: Future changes in biogenic isoprene emissions: How might they affect regional and global atmospheric chemistry?, Earth Interactions, 10, 1–19, 2006.