ANALYSISGlobal patterns of socioeconomic biomass flows in the year 2000: A comprehensive assessment of supply, consumption and constraints
Introduction
Biomass, the sum of recent, non-fossil organic material of biological origin, is one of the fundamental resources of any socioeconomic system. Plant based biomass accounts for more than one third of global material consumption, averaging 25% of domestic material consumption (DMC) in the OECD and more than two thirds in the world's least developed countries (see below, Schandl and Eisenmenger, 2006, MOSUS, 2007). In its most essential use, the provision of food for humans and feed for domesticated animals, biomass is not substitutable (Ayres, 2006). Biomass is also used as raw material in industrial processes, for manufacturing and construction and — despite the increasing dominance of the global energy sector by fossil fuels — is still the most important energy carrier for a large part of the population in low income countries. Globally, around 45% of the economically active population (incl. subsistence) are involved in biomass production (agriculture and forestry), contributing only 5% to global GDP. Currently, at least two thirds of the terrestrial surface of the earth are more or less intensively used by humans in order to produce biomass (Erb et al., 2007). Only about one fifth of the global land is still regarded as “wilderness” with little, if any, human interference (Sanderson et al., 2002). Biomass flows are intimately linked to the global biogeochemical cycles of carbon, nitrogen, phosphorous and other substances, and to the flow of trophic energy in ecosystems.
Biomass production is directly related to a large number of pressures on ecosystems including deforestation, fertilizer and pesticide application, with detrimental environmental effects such as groundwater depletion, ecosystem degradation or biodiversity loss (Chabra et al., 2006). There is empirical evidence that human appropriation of biomass is a major pressure on biodiversity (Evans et al., 2005, Gaston, 2000, Haberl et al., 2007a, Haberl et al., 2007b). On the other hand, biomass production is also related to the formation of cultural landscapes, mosaics of ecosystems directly dependent on human activities which are of high conservation value due to their species and habitat richness and their high importance for human well being. In recent years, the substitution of biomass for fossil fuels has received considerable attention as a strategy to reduce human-induced greenhouse gas emissions (Allgeier et al., 1995, European Commission, 1997). Biomass currently contributes some 9–13%, that is 35–55 EJ/yr (1 Exajoule = EJ = 1018 Joule), to the global supply of technical energy (Berndes et al., 2003, Nakicenovic et al., 1998, Turkenburg, 2000). Notable future increases in biomass demand are expected due to the expected growth of world population (Lutz et al., 2004), improvements in human diets and due to increases in the amount of biomass used for energy provision.
So far, few comprehensive accounts of global biomass flows exist. Most estimates of production or use of biomass either comprise only selected socioeconomic biomass flows (Scurlock and Hall, 1990, Smil, 1999, Wirsenius, 2003b, Lal, 2005) or are limited to aggregate global values (Hall, 1980, Vitousek et al., 1986, Imhoff et al., 2004, Haberl and Erb, 2006). To our knowledge, only two comprehensive studies have so far quantified global biomass harvest on a national level, a study by Schandl and Eisenmenger (2006) and the MOSUS (2007) dataset. In both cases, however, biomass flow estimates were parts of an overall material flow account (MFA) that applied only rather crude estimation methods, provided only aggregate sum totals of national biomass extraction and did neither consider indirect flows nor allow further analyses of biomass use (e.g., by distinguishing food, feed, fibre and energy).
This paper introduces a method to comprehensively account for global socioeconomic biomass flows on a national level, taking regional characteristics of the land use system and of biomass use patterns into account. The calculation extends existing approaches in various ways: a) It provides a comprehensive account of direct (i.e. primary harvest) and indirect biomass flows (i.e. biomass appropriated but not subject to further socio-economic use), b) it allows to calculate grazed biomass based on regional and country-specific feed balances that consider country-specific livestock characteristics, c) it includes region-specific estimates of used and non-used crop residues, d) it complements FAO data on wood harvest by an alternative estimate based on an extensive literature survey and e) it includes a consistent breakdown of biomass production into eight different types of biomass (of which four are indirect flows) and of biomass use in nine different types. Biomass flows were calculated for the year 2000 on the country level and summarized for 11 world regions. Patterns of production, use and trade of biomass are analyzed and discussed. The last section analyzes factors influencing regional patterns of biomass metabolism and draws conclusions on the potential to further increase biomass production. The full data set covering all countries can be downloaded from our webpage http://www.iff.ac.at/socec.
Section snippets
Methods and data
Our estimate of global (terrestrial) biomass flows is largely based on publicly available data on biomass production and consumption. Main data source is the Food and Agricultural Organisation (FAO), which has a long tradition in the compilation of international statistical data related to agriculture and is the only standardized database available on the global scale (Wood et al., 2000, WRI, 2004). FAO collects national data using questionnaires sent to member nations, additionally making use
Global biomass harvest: Used and unused extraction
Table 5 gives an overview of total biomass appropriation (TBA), used extraction (UE) and trade, together with socio-economic key variables, broken down to 11 world regions. Global TBA in the year 2000 amounted to approximately 18.7 billion tonnes (= Petagrams = Pg = 1015 g) of dry matter or about 16% of global terrestrial net primary production (NPP) (Haberl et al., 2007a, Haberl et al., 2007b). Almost two thirds (65%) of this biomass was directly used for socioeconomic purposes (used
Comparison of our results with other estimates
We made use of the best available international statistics and estimation procedures to estimate the global socio-economic biomass flows. Despite possible uncertainties in the primary data and factors used in estimation procedures (see above), we expect our overall results to be robust, in particular on the level of larger regions. Forestry data are found to be the least reliable, with considerable ranges between minimum and maximums estimates in some world regions. However, as under- and
Conclusions
Domestic consumption of biomass is less variable than that of other materials: Most aggregate variables for biomass extraction or consumption vary by a factor of roughly 10 across world regions, whereas per capita consumption of fossil fuels, for example, varies by a factor of 20 and that of industrial minerals and ores by a factor of 70 (Krausmann et al., in press). Our analysis suggest, moreover, that patterns of biomass consumption are less determined by affluence measured in terms of GDP
Acknowledgements
We acknowledge financial support by the Austrian Science Fund (FWF), project P-16692, This research contributes to the Global Land Project and to ALTER-Net, a network of excellence within FP6 of the EU. We wish to thank Alberte Bondeau, Veronika Gaube and Michaela Wiesinger for their cooperation and two anonymous reviewers for their valuable comments.
References (76)
- et al.
The contribution of biomass in the future global energy supply: a review of 17 studies
Biomass and Bioenergy
(2003) Environmental sustainability in agriculture: diet matters
Ecological Economics
(1997)- et al.
Carrying capacity in agriculture: global and regional issues
Ecological Economics
(1999) World crop residues production and implications of its use as a biofuel
Environment International
(2005)- et al.
Estimations of global terrestrial productivity: converging toward a single number?
- et al.
The Contribution of Biomass to Global Energy Use (1987)
Biomass
(1990) Efficiencies and biomass appropriation of food commodities on global and regional levels
Agricultural Systems
(2003)- et al.
Towards a European bio-energy strategy
On the practical limits of substitution
Ecological Economics
(2006)- et al.
Modelling the role of agriculture for the 20th century global terrestrial carbon balance
Global Change Biology
(2007)