The growing role of biomass for future resource supply-prospects and pitfalls

Sustainability Assessment of Renewables-Based Products: Methods and Case Studies

Volumn , Issue , 2015, Pages 1-18

  Haberl, Helmut ^a,b  

^a UNIVERSITY OF KLAGENFURT   (Austria)

^b HUMBOLDT UNIVERSITY   (Germany)

Author keywords

Biodiversity; Bioenergy; Biomass; Food; Greenhouse gas emissions; Human appropriation of net primary production; Land system; Land use competition; Net primary production; Timber

Indexed keywords

EID: 85013021785     PISSN: None     EISSN: None     Source Type: Book    
DOI: 10.1002/9781118933916.ch1     Document Type: Chapter

References (95)

1. H. Lieth and R.H. Whittaker, Primary Productivity of the Biosphere. Berlin/Heidelberg/New York:Springer; 1975.
2. Y. Zhang, M. Xu, H. Chen, and J. Adams, “Global pattern of NPP to GPP ratio derived from MODIS data: effects of ecosystem type, geographical location and climate,” Global Ecology and Biogeography, 18, 3, 280-290 (2009).
3. S. Bonhommeau, L. Dubroca, O. L. Pape, J. Barde, D. M. Kaplan, E. Chassot, and A.-E. Nieblas, “Eating up the world’s food web and the human trophic level,” Proceedings of the National Academy of Sciences United States of America, 110, 51, 20617-20620 (2013).
4. F. Krausmann, K.-H. Erb, S. Gingrich, C. Lauk, and H. Haberl, “Global patterns of socioeconomic biomass flows in the year 2000: A comprehensive assessment of supply, consumption and constraints,” Ecological Economics, 65, 3, 471-487 (2008).
5. D. M. J. S. Bowman, J. Balch, P. Artaxo, W. J. Bond, M. A. Cochrane, C. M. D’Antonio, R. DeFries, F. H. Johnston, J. E. Keeley, M. A. Krawchuk, C. A. Kull, M. Mack, M. A. Moritz, S. Pyne, C. I. Roos, A. C. Scott, N. S. Sodhi, and T. W. Swetnam, “The human dimension of fire regimes on Earth,” Journal of Biogeography, 38, 12, 2223-2236 (2011).
6. C. Lauk and K.-H. Erb, “Biomass consumed in anthropogenic vegetation fires: Global patterns and processes,” Ecological Economics, 69, 2, 301-309 (2009).
7. P. Smith, M. Bustamante, H. Ahammad, H. Clark, H. Dong, E. A. Elsiddig, H. Haberl, R. Harper, J. House, M. Jafari, O. Masera, C. Mbow, N. H. Ravindranath, C. Rice, C. Robledo Abad, A. Romanovskaya, F. Sperling, and F. N. Tubiello, “Agriculture, Forestry and Other Land Use (AFOLU),” in Climate Change 2014: Contributions of Working Group III to the 5th Assessment Report of the IPCC, Cambridge, UK: Intergovernmental Panel on Climate Change, Cambridge University Press, 2014.
8. J. W. A. Langeveld, J. Dixon, and J. F. Jaworski, “Development perspectives of the biobased economy:A review,” Crop Science, 50, Supplement 1, S142-S151 (2010).
9. S. Coelho, O. Agbenyega, A. Agostini, K. H. Erb, H. Haberl, M. Hoogwijk, R. Lal, O. Lucon, O. Masera, and J. R. Moreira, “Land and Water: Linkages to Bioenergy,” in Global Energy Assessment, T. Johansson, A. Patwardhan, N. Nakicenonivc, and L. Gomez-Echeverri (Eds.), 1459-1525, Cambridge, UK: International Institute of Applied Systems Analysis (IIASA), Cambridge University Press, 2012.
10. F. Krausmann and H. Haberl, “The process of industrialization from the perspective of energetic metabolism: Socioeconomic energy flows in Austria 1830-1995,” Ecological Economics, 41, 2, 177-201 (2002).
11. V. Smil, General Energetics: Energy in the Biosphere and Civilization. New York: Wiley Interscience; 1991.
12. M. Fischer-Kowalski and H. Haberl, Socioecological Transitions and Global Change. Trajectories of Social Metabolism and Land Use. Cheltenham and Northampton: Edward Elgar; 2007.
13. R.-P. Sieferle, The Subterranean Forest: Energy Systems and the Industrial Revolution. Cambridge, UK: The White Horse Press; 2001.
14. R.-P. Sieferle, F. Krausmann, H. Schandl, and V. Winiwarter, Das Ende der Fläche: Zum gesellschaftlichen Stoffwechsel der Industrialisierung. Köln: Böhlau, 2006.
15. F. Krausmann, M. Fischer-Kowalski, H. Schandl, and N. Eisenmenger, “The global sociometabolic transition,” Journal of Industrial Ecology, 12, 5-6, 637-656 (2008).
16. H. Chum, A. Faaij, J. Moreira, G. Berndes, P. Dhamija, B. Gabrielle, A. G. Eng, W. Lucht, M. Makapo, O. Masera Cerruti, T. McIntyre, T. Minowa, and K. Pingoud, “Bioenergy,” in IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation, O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, and C. von Stechow (Eds.), 209-332, Cambridge, UK: Cambridge University Press, 2012.
17. F. Creutzig, N. H. Ravindranath, G. Berndes, S. Bolwig, R. M. Bright, F. Cherubini, H. Chum, E. Corbera, M. Delucchi, A. Faaij, J. Fargione, H. Haberl, G. Heath, O. Lucon, R. Plevin, A. Popp, C. Robledo Abad, S. Rose, P. Smith, A. Stromman, S. Suh, and O. Masera, “Bioenergy and climate change mitigation: an assessment,” Global Change Biology Bioenergy, doi: 10.1111/gcbb.12205, in press (2014).
18. GEA. Global Energy Assessment-Toward a Sustainable Future. Laxenburg, Austria/Cambridge, UK:International Institute of Applied System Dynamics, Cambridge University Press; 2012.
19. F. Krausmann, K.-H. Erb, S. Gingrich, H. Haberl, A. Bondeau, V. Gaube, C. Lauk, C. Plutzar, and T. D. Searchinger, “Global human appropriation of net primary production doubled in the 20th century,” Proceedings of the National Academy of Sciences United States of America, 110, 25, 10324-10329 (2013).
20. T. M. Mata, A. A. Martins, and N. S. Caetano, “Microalgae for biodiesel production and other applications:A review,” Renewable and Sustainable Energy Reviews, 14, 1, 217-232 (2010).
21. A. Ito, “A historical meta-analysis of global terrestrial net primary productivity: Are estimates converging?" Global Change Biology, 17 (10):3161-3175 (2011).
22. H. Haberl, T. Beringer, S. C. Bhattacharya, K.-H. Erb, and M. Hoogwijk, “The global technical potential of bio-energy in 2050 considering sustainability constraints,” Current Opinion in Environmental Sustainability, 2, 5-6, 394-403 (2010).
23. S. W. Running, “A measurable planetary boundary for the biosphere,” Science, 337, 6101, 1458-1459 (2012).
24. R. A. Houghton, “Keeping management effects separate from environmental effects in terrestrial carbon accounting,” Global Change Biology, 19, 9, 2609-2612 (2013).
25. H. Haberl, K.-H. Erb, and F. Krausmann, “Human appropriation of net primary production: Patterns, trends, and planetary boundaries,” Annual Review of Environment and Resources, 39, 363-391 (2014).
26. P. M. Vitousek, P. R. Ehrlich, A. H. Ehrlich, and P. A. Matson, “Human appropriation of the products of photosynthesis,” Bioscience, 36, 6, 363-373 (1986).
27. R. DeFries, “Past and future sensitivity of primary production to human modification of the landscape,” Geophysical Research Letters, 29, 7, 1132 (2002).
28. H. Haberl, K. H. Erb, F. Krausmann, V. Gaube, A. Bondeau, C. Plutzar, S. Gingrich, W. Lucht, and M. Fischer-Kowalski, “Quantifying and mapping the human appropriation of net primary production in earth’s terrestrial ecosystems,” Proceedings of the National Academy of Sciences United States of America, 104, 31, 12942-12947 (2007).
29. H. Haberl, “Competition for land: A sociometabolic perspective,” Ecological Economics, doi: 10.1016/j.ecolecon.2014.10.002 [online ahead of press] (2014).
30. P. Smith, H. Haberl, A. Popp, K. Erb, C. Lauk, R. Harper, F. Tubiello, A. de Siqueira Pinto, M. Jafari, S. Sohi, O. Masera, H. Böttcher, G. Berndes, M. Bustamante, H. Ahammad, H. Clark, H. Dong, E. A. Elsiddig, C. Mbow, N. H. Ravindranath, C. W. Rice, C. Robledo-Abad, A. Romanovskaya, F. Sperling, M. Herrero, J. I. House, and S. Rose, How much land based greenhouse gas mitigation can be achieved without compromising food security and environmental goals? Global Change Biology, 19:2285-2302 (2013).
31. K.-H. Erb, V. Gaube, F. Krausmann, C. Plutzar, A. Bondeau, and H. Haberl, “A comprehensive global 5 min resolution land-use data set for the year 2000 consistent with national census data,” Journal of Land Use Science, 2, 3, 191-224 (2007).
32. H. Haberl, C. Mbow, X. Deng, E. G. Irwin, S. Kerr, T. Kuemmerle, O. Mertz, P. Meyfroidt, and B. L. Turner II, “Finite Land Resources and Competition,” in Rethinking Global Land Use in an Urban Era, K. C. Seto and A. Reenberg (Eds.), 35-69, Cambridge, MA: MIT Press, 2014.
33. K.-H. Erb, H. Haberl, M. R. Jepsen, T. Kuemmerle, M. Lindner, D. Müller, P. H. Verburg, and A. Reenberg, “A conceptual framework for analysing and measuring land-use intensity,” Current Opinion in Environmental Sustainability, 5, 5, 464-470 (2013).
34. FAO. World Agriculture: Towards 2030/2050-Interim Report. Prospects for Food, Nutrition, Agriculture and Major Commodity Groups. Rome: Food and Agriculture Organization of the United Nations; 2006.
35. D. Tilman, C. Balzer, J. Hill, and B. L. Befort, “Global food demand and the sustainable intensification of agriculture,” Proceedings of the National Academy of Sciences of the United States of America, 108, 50, 20260-20264 (2011).
36. J. Gustavsson, C. Cederberg, U. Sonesson, R. van Otterdijk, and A. Meybeck, Global Food Losses and Food Waste. Extent, Causes and Prevention. Rome: Food and Agricultural Organization of the United Nations; 2011.
37. K.-H. Erb, A. Mayer, F. Krausmann, C. Lauk, C. Plutzar, J. Steinberger, and H. Haberl, “The Interrelations of Future Global Bioenergy Potentials, Food Demand and Agricultural Technology,” in Socioeconomic and Environmental Impacts of Biofuels: Evidence from Developing Nations, A. Gasparatos and P. Stromberg (Eds.), 27-52, Cambridge, UK: Cambridge University Press, 2012.
38. H. H. Rogner, R. F. Aguilera, C. L. Archer, R. Bertani, S. C. Bhattacharya, I. Bryden, R. R. Charpentier, M. B. Dusseault, L. Gagnon, Y. Goswami, H. Haberl, M. M. Hoogwijk, A. Johnson, P. Odell, H. Wagner, and V. Yakushev, “Energy Resources and Potentials,” in Global Energy Assessment: Toward a Sustainable Future, T. B. Johansson, N. Nakicenovic, A. Patwardhan, and L. Gomez-Echeverri (Eds.), 423-512, Laxenburg, Austria/Cambridge, UK: IIASA and Cambridge University Press, 2012.
39. E. F. Lambin and P. Meyfroidt, “Global land use change, economic globalization, and the looming land scarcity,” Proceedings of the National Academy of Sciences of the United States of America, 108, 9, 3465-3472 (2011).
40. C. B. Field, J. E. Campbell, and D. B. Lobell, “Biomass energy: The scale of the potential resource,” Trends in Ecology and Evolution, 23, 2, 65-72 (2008).
41. J. E. Campbell, D. B. Lobell, R. C. Genova, and C. B. Field, “The global potential of bioenergy on abandoned agriculture lands,” Environmental Science and Technology, 42, 15, 5791-5794 (2008).
42. K.-H. Erb, H. Haberl, F. Krausmann, C. Lauk, C. Plutzar, J. K. Steinberger, C. Müller, A. Bondeau, K. Waha, and G. Pollack, Eating the planet: Feeding and fuelling the world sustainably, fairly and humanely-a scoping study. Vienna, Potsdam: Social Ecology Working Paper No. 116, 2009. Available at http://www.uni-klu.ac.at/socec/downloads/WP116_WEB.pdf (accessed July 29, 2015).
43. WBGU. Future Bioenergy and Sustainable Land Use. London: Earthscan; 2009.
44. D. P. van Vuuren, J. van Vliet, and E. Stehfest, “Future bio-energy potential under various natural constraints,” Energy Policy, 37, 11, 4220-4230 (2009).
45. E. M. W. Smeets, A. P. C. Faaij, I. M. Lewandowski, and W. C. Turkenburg, “A bottom-up assessment and review of global bio-energy potentials to 2050,” Progress in Energy and Combustion Science, 33, 1, 56-106 (2007).
46. H. Haberl, K.-H. Erb, F. Krausmann, S. Running, T. D. Searchinger, and W. K. Smith, “Bioenergy:How much can we expect for 2050?" Environmental Research Letters, 8 (3):031004 (2013).
47. E. M. W. Smeets and A. P. C. Faaij, “Bioenergy potentials from forestry in 2050,” Climatic Change, 81, 3-4, 353-390 (2007).
48. W. K. Smith, M. Zhao, and S. W. Running, “Global bioenergy capacity as constrained by observed biospheric productivity rates,” BioScience, 62, 10, 911-922 (2012).
49. K.-H. Erb, H. Haberl, and C. Plutzar, “Dependency of global primary bioenergy crop potentials in 2050 on food systems, yields, biodiversity conservation and political stability,” Energy Policy, 47, 260-269 (2012).
50. H. Haberl, K.-H. Erb, F. Krausmann, A. Bondeau, C. Lauk, C. Müller, C. Plutzar, and J. K. Steinberger, “Global bioenergy potentials from agricultural land in 2050: Sensitivity to climate change, diets and yields,” Biomass and Bioenergy, 35, 12, 4753-4769 (2011).
51. K.-H. Erb, “How a socio-ecological metabolism approach can help to advance our understanding of changes in land-use intensity,” Ecological Economics, 76, 1, 8-14 (2012).
52. E. Stehfest, L. Bouwman, D. P. Vuuren, M. G. J. Elzen, B. Eickhout, and P. Kabat, “Climate benefits of changing diet,” Climatic Change, 95, 1-2, 83-102 (2009).
53. E. H. DeLucia, N. Gomez-Casanovas, J. A. Greenberg, T. W. Hudiburg, I. B. Kantola, S. P. Long, A. D. Miller, D. R. Ort, and W. J. Parton, “The theoretical limit to plant productivity,” Environmental Research Letters, 48, 16, 9471-9477 (2014).
54. W. K. Smith, C. C. Cleveland, S. C. Reed, and S. W. Running, “Agricultural conversion without external water and nutrient inputs reduces terrestrial vegetation productivity,” Geophysical Research Letters, 41, 2, 449-455 (2014).
55. M. Johnston, J. A. Foley, T. Holloway, C. Kucharik, and C. Monfreda, “Resetting global expectations from agricultural biofuels,” Environmental Research Letters, 4, 1, 014004 (2009).
56. S. Y. Searle and C. J. Malins, “Will energy crop yields meet expectations?" Biomass and Bioenergy, 65:3-12 (2014).
57. F. Creutzig, A. Popp, R. Plevin, G. Luderer, J. Minx, and O. Edenhofer, “Reconciling top-down and bottom-up modelling on future bioenergy deployment,” Nature Climate Change, 2, 320-327 (2012).
58. K.-H. Erb, H. Haberl, R. DeFries, E. Ellis, F. Krausmann, P. Verburg, S. W. Running, and W. K. Smith, “Pushing the planetary boundaries,” Science, 338, 1419-1420 (2012).
59. T. B. Johansson, H. Kelly, A. K. N. Reddy, and R. H. Williams, Renewable Energy, Sources for Fuels and Electricity. London: Earthscan, Island Press; 1993.
60. H. Haberl and S. Geissler, “Cascade utilization of biomass: Strategies for a more efficient use of a scarce resource,” Ecological Engineering, 16, Supplement 1, 111-121 (2000).
61. H. Blanco-Canqui and R. Lal, “Crop residue removal impacts on soil productivity and environmental quality,” Critical Reviews in Plant Sciences, 28, 139-163 (2009).
62. S. C. Bhattacharya, P. Abdul Salam, H. Runqing, H. I. Somashekar, D. A. Racelis, P. G. Rathnasiri, and R. Yingyuad, “An assessment of the potential for non-plantation biomass resources in selected Asian countries for 2010,” Biomass and Bioenergy, 29, 3, 153-166 (2005).
63. IAASTD. Agriculture at a Crossroads. International Assessment of Agricultural Knowledge, Science and Technology for Development (IAASTD), Global Report. Washington, DC: Island Press; 2009.
64. F. Cherubini, N. D. Bird, A. Cowie, G. Jungmeier, B. Schlamadinger, and S. Woess-Gallasch, “Energyand greenhouse gas-based LCA of biofuel and bioenergy systems: Key issues, ranges and recommendations,” Resources, Conservation and Recycling, 53, 8, 434-447 (2009).
65. D. Tilman, J. Hill, and C. Lehman, “Carbon-negative biofuels from low-input high-diversity grassland biomass,” Science, 314, 5805, 1598-1600 (2006).
66. R. J. Harper, A. E. A. Okom, A. T. Stilwell, M. Tibbett, C. Dean, S. J. George, S. J. Sochacki, C. D. Mitchell, S. S. Mann, and K. Dods, “Reforesting degraded agricultural landscapes with Eucalypts: Effects on carbon storage and soil fertility after 26 years,” Agriculture, Ecosystems and Environment, 163, 3-13 (2012).
67. V. Winiwarter and M. H. Gerzabeck, The Challenge of Sustaining Soils: Natural and Social Ramifications of Biomass Production in a Changing World. Vienna: Interdisciplinary Perspectives No. 1, Austrian Academy of Sciences Press; 2012.
68. P. Smith, P. J. Gregory, D. van Vuuren, M. Obersteiner, P. Havlík, M. Rounsevell, J. Woods, E. Stehfest, and J. Bellarby, “Competition for land,” Philosophical Transactions of the Royal Society B: Biological Sciences, 365, 1554, 2941-2957 (2010).
69. K. C. Seto, B. Güneralp, and L. R. Hutyra, “Global forecasts of urban expansion to 2030 and direct impacts on biodiversity and carbon pools,” Proceeding of the National Academy of Sciences of the United States of America, 109, 16083-16088 (2012).
70. D. Tilman, K. G. Cassman, P. A. Matson, R. Naylor, and S. Polasky, “Agricultural sustainability and intensive production practices,” Nature, 418, 6898, 671-677 (2002).
71. D. K. Ray, N. D. Mueller, P. C. West, and J. A. Foley, “Yield trends are insufficient to double global crop production by 2050,” PLoS ONE, 8, 6, e66428 (2013).
72. W. J. Ripple, P. Smith, H. Haberl, S. A. Montzka, C. McAlpine, and D. H. Boucher, “Ruminants, climate change and climate policy,” Nature Climate Change, 4, 1, 2-5 (2014).
73. A. Bouwman, K. Van der Hoek, B. Eickhout, and I. Soenario, “Exploring changes in world ruminant production systems,” Agricultural Systems, 84, 2, 121-153 (2005).
74. M. Herrero, P. Havlík, H. Valin, A. Notenbaert, M. C. Rufino, P. K. Thornton, M. Blümmel, F. Weiss, D. Grace, and M. Obersteiner, “Biomass use, production, feed efficiencies, and greenhouse gas emissions from global livestock systems,” Proceedings of the National Academy of Sciences of the United States of America, 110, 20888-20893 (2013).
75. S. Wirsenius, C. Azar, and G. Berndes, “How much land is needed for global food production under scenarios of dietary changes and livestock productivity increases in 2030?" Agricultural Systems, 103(9):621-638 (2010).
76. A. Popp, M. Krause, J. P. Dietrich, H. Lotze-Campen, M. Leimbach, T. Beringer, and N. Bauer, “Additional CO2 emissions from land use change-Forest conservation as a precondition for sustainable production of second generation bioenergy,” Ecological Economics, 74, 64-70 (2012).
77. FAO and IIASA. Global Agro-Ecological Zones-GAEZ, 2000. Rome and Laxenburg: Food and Agriculture Organization of the United Nations (FAO), Institute of Applied Systems Analysis (IIASA); 2000.
78. A. Young, “Is there really spare land? A critique of estimates of available cultivable land in developing countries,” Environment, Development and Sustainability, 1, 1, 3-18 (1999).
79. J. Baka and R. Bailis, “Wasteland energy-scapes: A comparative energy flow analysis of India’s biofuel and biomass economies,” Ecological Economics, 108, 8-17 (2014).
80. T. Kuemmerle, P. Olofsson, O. Chaskovskyy, M. Baumann, K. Ostapowicz, C. E. Woodcock, R. A. Houghton, P. Hostert, W. S. Keeton, and V. C. Radeloff, “Post-Soviet farmland abandonment, forest recovery, and carbon sequestration in western Ukraine,” Global Change Biology, 17, 3, 1335-1349 (2011).
81. F. Schierhorn, D. Müller, T. Beringer, A. V. Prishchepov, T. Kuemmerle, and A. Balmann, “Post-Soviet cropland abandonment and carbon sequestration in European Russia, Ukraine, and Belarus,” Global Biogeochemical Cycles, 27, 4, 1175-1185 (2013).
82. M. Nijsen, E. Smeets, E. Stehfest, and D. P. Vuuren, “An evaluation of the global potential of bioenergy production on degraded lands,” GCB Bioenergy, 4, 2, 130-147 (2012).
83. H. Haberl, “Net land-atmosphere flows of biogenic carbon related to bioenergy: towards an understanding of systemic feedbacks,” GCB Bioenergy, 5, 351-357 (2013).
84. K.-H. Erb, T. Kastner, S. Luyssaert, R. A. Houghton, T. Kuemmerle, P. Olofsson, and H. Haberl, “Bias in the attribution of forest carbon sinks,” Nature Climate Change, 3, 10, 854-856 (2013).
85. T. D. Searchinger, “Biofuels and the need for additional carbon,” Environmental Research Letters, 5, 2, 024007 (2010).
86. T. Searchinger, R. Heimlich, R. A. Houghton, F. Dong, A. Elobeid, J. Fabiosa, S. Tokgoz, D. Hayes, and T.-H. Yu, “Use of U.S. croplands for biofuels increases greenhouse gases through emissions from land-use change,” Science, 319, 5867, 1238-1240 (2008).
87. R. J. Plevin, M. O’Hare, A. D. Jones, M. S. Torn, and H. K. Gibbs, “Greenhouse gas emissions from biofuels’ indirect land use change are uncertain but may be much greater than previously estimated,” Environmental Science and Technology, 44, 21, 8015-8021 (2010).
88. B. Holtsmark, “Harvesting in boreal forests and the biofuel carbon debt,” Climatic Change, 112, 415-428 (2012).
89. C. Körner, “Biologische Kohlenstoffsenken: Umsatz und Kapital nicht verwechseln (Biological carbon sinks: Turnover must not be confused with capital),” Gaia-Ecological Perspectives for Science and Society, 18, 4, 288-293 (2009).
90. T. W. Hudiburg, B. E. Law, C. Wirth, and S. Luyssaert, “Regional carbon dioxide implications of forest bioenergy production,” Nature Climate Change, 1, 8, 419-423 (2011).
91. E. Schulze, C. Körner, B. E. Law, H. Haberl, and S. Luyssaert, “Large-scale bioenergy from additional harvest of forest biomass is neither sustainable nor greenhouse gas neutral,” GCB Bioenergy, 4, 6, 611-616 (2012).
92. L. Gustavsson and R. Sathre, “Energy and CO2 analysis of wood substitution in construction,” Climatic Change, 105, 1, 129-153 (2011).
93. F. Werner, R. Taverna, P. Hofer, E. Thürig, and E. Kaufmann, “National and global greenhouse gas dynamics of different forest management and wood use scenarios: a model-based assessment,” Environmental Science and Policy, 13, 1, 72-85 (2010).
94. H. C. J. Godfray, J. R. Beddington, I. R. Crute, L. Haddad, D. Lawrence, J. F. Muir, J. Pretty, S. Robinson, S. M. Thomas, and C. Toulmin, “Food security: The challenge of feeding 9 billion people,” Science, 327, 5967, 812-818 (2010).
95. T. Amon, B. Amon, V. Kryvoruchko, A. Machmüller, K. Hopfner-Sixt, V. Bodiroza, R. Hrbek, J. Friedel, E. Pötsch, H. Wagentristl, M. Schreiner, and W. Zollitsch, “Methane production through anaerobic digestion of various energy crops grown in sustainable crop rotations,” Bioresource Technology, 98, 17, 3204-3212 (2007).