3
3.1
Ecological sustainability
3.1.1
Guard rail for climate protection
In WBGU’s view, climate change impacts are intoler-able if they are associated with a mean global rise in near-ground air temperatures of more than 2°C from pre-industrial levels, or a rate of temperature change of more than 0.2°C per decade. This guard rail has been explained in detail in earlier WBGU reports (WBGU, 1995b, 2006). Adherence to this guard rail requires the concentration of greenhouse gases in the atmosphere to be stabilized below 450 ppm CO2eq.
To achieve this, global greenhouse gas emissions need to be at least halved by the middle of the century.
A considerable proportion of the CO2 released by human activities dissolves in seawater and causes acidification there. In order to avoid undesired or dangerous changes in marine ecosystems, the pH level of the uppermost ocean layer should not fall in any major ocean region by more than 0.2 units against the baseline of pre-industrial levels. Adher-ence to the 2°C guard rail would automatically result in adherence to the acidification guard rail, provided that there is a sufficient reduction not only in the overall ‘basket’ of greenhouse has emissions but also in CO2 emissions as such (WBGU, 2006).
A use of bioenergy for which climate change miti-gation effects are claimed should be judged by the contribution it makes to adherence to the climate pro-tection and acidification guard rails. For adherence to the 2°C guard rail it is of no consequence whether a particular sector (such as transport) achieves a par-ticular reduction in emissions. The only deciding fac-tor is the development over time of global emissions and of greenhouse gas removals by sinks across all sectors. A realistic assessment of the contribution of bioenergy use to climate change mitigation must take account of the development of emissions in all sec-tors. To gauge adherence to the acidification guard WBGU derives a sustainable corridor for
bioen-ergy use primarily from its own guard rail concept (WBGU, 1995b). The Council uses the term ‘guard rail’ to refer to quantitatively defined damage limits, exceedance of which is intolerable or would have catastrophic consequences. An example of such a limit is an increase in global mean temperature by more than 2°C from pre-industrial levels. Sustain-able development pathways follow trajectories that lie within the range delimited by the guard rails. This approach is based on the realization that it is virtually impossible to define a desirable, sustainable future in positive terms – that is, in terms of a goal or state to be achieved. It is, however, possible to agree on the boundaries of a range that is acknowledged to be unacceptable and that society seeks to avoid. If the system is on course for collision with a guard rail, steps should be taken to change direction.
Adherence to the guard rails described in this chapter is, however, only a necessary and not a suf-ficient criterion for sustainability (WBGU, 2001a).
The constraints presented by both the socioeconomic and the ecological dimensions of sustainability can-not always be precisely formulated as guard rails. In the socioeconomic arena, for example, many of the requirements of a sustainable bioenergy policy are not quantifiable. Furthermore, the majority of the socioeconomic requirements that are in principle quantifiable cannot be converted into a global guard rail, because they are country- or situation-depend-ent. Ecological damage limits, too, cannot always be formulated as guard rails – perhaps because regional differences are too great or because no satisfactory global indicator can be specified. For these reasons WGBU specifies, in addition to the guard rails, other sustainability requirements; these provide additional criteria for the sustainable use of bioenergy that can-not be defined in terms of guard rails. They involve, for example, various aspects of land use or adherence to social standards.
28 3 Sustainability constraints upon bioenergy
ley and Stolton, 1999a) – that is, they are indeed pro-tected by ordinance, but local management is so inad-equate that it often cannot even halt the destructive exploitation of biological resources (e.g. illegal log-ging, predatory fishing). Furthermore, strictly speak-ing only the areas in IUCN categories I–IV should be included in the tally, since in categories V and VI the emphasis is more on sustainable use than on the con-servation of biological diversity. The call for an effec-tively managed system of protected areas is therefore met by only a fraction of the 12 per cent (Box 5.4-1).
In the same way as the objectives of the Global Strategy for Plant Conservation (GSPC) agreed in the context of the Convention on Biological Diver-sity, this global guard rail needs to be differentiated and operationalized on a regional basis (CBD, 2002a;
Section 10.5). The GSPC’s 16 global targets for 2010 include the following:
– at least 10 per cent of each of the world’s ecologi-cal regions effectively conserved.
– protection of 50 per cent of the most important areas for plant diversity assured. Criteria for the selection of these areas would include species rich-ness, endemism, and uniqueness of habitats and ecosystems.
– 60 per cent of the world’s endangered species con-served in situ (e.g. through protected areas).
– 70 per cent of the genetic diversity of socio-eco-nomically valuable plant species conserved (gene banks and on-farm conservation).
However, even a perfectly functioning system of pro-tected areas cannot halt the loss of biological diver-sity. It must be complemented by two processes: inte-gration of the protected areas or protected area sys-tems into the surrounding landscape (CBD, 2004b) and mainstreaming of conservation through differ-entiated application of the principle of sustainable land use to all land used for agriculture or forestry.
The objective is the ‘integrated, sustainable manage-ment of land, water and living resources’ (Ecosys-tem Approach: CBD, 2000, 2004a). This means that ensuring the sustainability of land use calls for addi-tional ecological sustainability requirements that take account of the nature conservation dimension (Section 3.1.4).
3.1.3
Guard rail for soil protection
In view of the importance of soil protection measures for future food security, it is worth elaborating guard rails for global soil conservation in the form of quan-titative values which if exceeded would be irreversi-ble and endanger human livelihoods (WBGU, 2004a;
UBA, 2008a). Schwertmann et al. (1987) set the tol-rail, the effect of bioenergy use on the global carbon
cycle must also be considered.
3.1.2
Guard rail for biosphere conservation
The Council has proposed the following guard rail for biosphere conservation: 10–20 per cent of the glo-bal area of terrestrial ecosystems (and 20–30 per cent of the area of marine ecosystems) should be desig-nated as parts of a global, ecologically representative and effectively managed system of protected areas (WBGU, 2001a, 2006). In addition, approximately 10–20 per cent of river ecosystems including their catchment areas should be reserved for nature con-servation (WBGU, 2004a).
This guard rail is based in part on the realization that ecosystems and their biological diversity are cru-cial to the survival of humanity, because they provide a variety of functions, services and products (MA, 2005a). Protected areas, in particular, are an indis-pensable instrument of sustainable development (CBD, 2004b; Section 5.4). It should be noted that the conservation and sustainable use of biodiversity are by no means mutually exclusive: they can be com-bined in various ways, depending on ecological cir-cumstances (WBGU, 2001a). The World Conserva-tion Union (IUCN, 1994) has accordingly drawn up a graduated category system for protected areas that allows specific relationships between conservation and sustainable use.
A particularly pressing issue is conservation in the hotspots of biological diversity. These are areas in which a large number of wild species is found within a small area or which contain a large number of endemic species or unique ecosystems; they are therefore particularly valuable for the conserva-tion of biological diversity (Mittermeier et al., 1999;
Myers et al., 2000). Conservation should in addition include species that are particularly worthy of protec-tion and areas that still contain undisturbed ecosys-tems on a large scale (wilderness areas, e.g. tropical and boreal forests). For global food security it is also important to maintain the ‘gene centres’ in which a wide genetic range of crops or related wild plants is found (Vavilov, 1926; Stolton et al., 2006).
The international community has agreed to estab-lish a protected area system of this sort by 2010 (Sec-tion 10.5; CBD, 2004b). A positive sign is that the number of protected areas and the proportion of the world’s surface covered by them has risen sharply in recent years, so that protected areas now cover around 12 per cent of the global land surface (Box 5.4-1). However, closer examination reveals many of these protected areas to be ‘paper parks’
(Dud-Socioeconomic sustainability 3.2 29
ecosystems. The Addis Ababa principles and guide-lines for the sustainable use of biological diversity can be referred to in this regard (CBD, 2004d; Sec-tion 10.5), as can the FAO’s definiSec-tion of sustain-able land use: ‘Sustainsustain-able land management com-bines technologies, policies and activities aimed at integrating socio-economic principles with environ-mental concerns so as to simultaneously: (1) main-tain or enhance production/services (Productivity);
(2) reduce the level of production risk (Security);
(3) protect the potential of natural resources and prevent degradation of soil and water quality (Pro-tection); (4) be economically viable (Viability); (5) and socially acceptable (Acceptability)’ (Smyth and Dumanski, 1993).
Rules and regulations at European and Ger-man level are formulated in significantly more spe-cific and concrete ways. In the EU, direct payments to farmers are linked to adherence to mandatory standards of environmental conservation, food and feed security, animal health and animal protection – a system known as cross-compliance (BMELV, 2006;
UBA, 2008a). This attachment of conditions to sub-sidy payments constitutes an environmental policy instrument (SRU, 2008). For German agriculture var-ious laws and ordinances define ‘good farming prac-tice’ in terms of ecological and safety standards that farmers must adhere to. However, many provisions relating to good farming practice are still formulated in highly indeterminate terms in statutes and ordi-nances (SRU, 2008).
The existing regulations and available landmark studies should be used as a basis for drawing up spe-cific, internationally recognized management rules or standards for sustainable land use (Section 10.3). Such standards should also take account of the greenhouse gas balance of the various farming systems, because – for example – intensification of land use results in nitrous oxide emissions as a consequence of nitrogen fertilizer use and CO2 emissions as a consequence of processes such as the conversion of grassland.
3.2
Socioeconomic sustainability
3.2.1
Guard rail for securing access to sufficient food Access to food for all
The expansion of bioenergy use can have an adverse effect on food production and – particularly in low-income developing countries that are net importers of food (Low-Income Food-Deficit Countries, LIFDCs) – on food security, because land, water resources and erance limit for human-induced soil degradation at a
level at which there is no significant deterioration in the natural yield potential of the soil over a period of 300–500 years. In concretizing this guard rail a dis-tinction needs to be made between the two greatest risks to which soil is exposed: degradation through erosion and through salinization.
WBGU has proposed tolerance limits for these two factors (WBGU, 2004a). For soil erosion this means that, strictly speaking, the quantity of soil removed or otherwise degraded must not exceed the quantity newly created, as this would reduce the yield poten-tial in the long term. However, since soil formation takes place on geological timescales, this can be only a distant objective. In the temperate zone, for exam-ple, WBGU sets a tolerance limit of 1–10 tonnes per hectare per year, depending on soil depth. As a tol-erance limit for soil salinization in irrigation farming WBGU (2004a) proposes that over a period of 300–
500 years the saline concentration and composition should not exceed the level that can be tolerated by crops in common use.
3.1.4
Additional ecological sustainability requirements Not all ecological sustainability dimensions can be formulated as globally valid guard rails. This may be because regional differences are too large or because no satisfactory global indicator is available.
In this section WBGU therefore describes additional requirements for sustainable bioenergy use.
For example, in considering the sustainable use of water resources in connection with bioenergy the main issue is the management of water used for irri-gation when there is a threat of competition with the use of water for food production. In WBGU’s view the water stress indicators found in the litera-ture are not suitable for quantifying a globally valid guard rail. Even in regions with high levels of water stress, many of the adverse effects of irrigation can be avoided and sustainability attained if systematic measures are put in place. A further consideration is that the indicators fail to take account of ‘green’
water – the water from precipitation that is available to plants in the form of soil moisture.
Even where guard rails are formulated in global terms – for example, in connection with biodiversity conservation or soil protection – their application must be considered in the specific context of local and agro-ecological conditions. In accordance with the ecosystem approach of the CBD (2000) the objective must be the ‘integrated, sustainable man-agement of land, water and living resources’, which includes humans as an integral component of many
30 3 Sustainability constraints upon bioenergy
potential of existing agricultural land depends to a large extent on the way in which the crop is used. For example, the majority of the maize harvest in North America and Europe is fed to animals. This means that the maize provides food for people only via the production of meat and milk. In the course of this
‘refinement’ a large proportion of the food calories originally present in the maize is lost. Around one-third of the world’s grain yield is currently used as animal feed. Overall, global food production must be increased by 50 per cent by 2030 and by around 80 per cent by 2050. This will need to be achieved mainly through increases in productivity per unit area of land (Section 5.2).
3.2.2
Guard rail for securing access to modern energy services
In WBGU’s view (WBGU, 2004a), securing elemen-tary energy services must involve access to modern forms of energy. WBGU therefore proposes the fol-lowing guard rail: access to modern energy for all peo-ple should be ensured. In particular, this must entail ensuring access to electricity and replacing the use of biomass that is harmful to health with modern fuels.
In the medium term WBGU considers the minimum quantity of final energy for basic individual needs to be 700–1000 kWh per capita per year.
There are considerable difficulties – from both nor-mative and methodological/technical points of view – in calculating minimum per capita energy needs. Cli-matological and geographical considerations must be taken into account, as must cultural, demographic and socioeconomic factors. In addition, convert-ing energy services into required energy quantities agricultural resources (such as machinery, fertilizers,
seed, feed, fuel) are withdrawn from food production and used instead to grow energy crops. In WBGU’s view securing the word food supply must take prece-dence over all other uses of those areas of the world’s land surface that are suitable for farming. While bioenergy can be substituted by other sources of fuel, there is no substitute for food. According to the FAO definition, food security exists when all people, at all times, have physical, social and economic access to sufficient amounts of safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life (FAO, 2008b). WBGU there-fore proposes here as a guard rail that access to suffi-cient food should be secured for all people.
A necessary but not a sufficient requirement for this is that enough food is produced to meet the calo-rie needs of all people. For operationalization of the guard rail it can thus be deduced that the amount of agricultural land available globally must at least be sufficient to enable all people to receive food with an average calorie content of 2700 kcal per person per day (equivalent to approximately 11.3 MJ per person per day) (Box 3.2-1). According to FAO fig-ures (FAO, 2003b) global food production currently amounts to approximately 2800 kcal per person per day (Beese, 2004). On a global scale, therefore, enough food energy is currently produced, so that hunger and malnutrition are primarily problems of access and/or distribution.
Land need depends on nutrition style and land productivity
Factors that are important for the extent of the potential for providing the world’s population with sufficient and nutritious food are people’s nutrition habits and the productivity of the land. The nutrition
Box 3.2-1
A person’s calorie requirements
In the run-up to the World Food Summit of 1996 there was extensive discussion of minimum levels of calorie avail-ability. The original plan was to specify the availability of 2700 kcal per person per day (equivalent to roughly 11.3 MJ per person per day) as a target. However, this was aban-doned on the grounds that an average per capita calorie level conceals inequalities of provision within a country and provides no information on food quality. Nonetheless, it is scarcely feasible to operationalize a ‘nutrition guard rail’
without recourse to a figure of this sort.
A person’s energy requirements are made up of compo-nents relating to basic energy consumption (basic metabo-lism, depending on age, gender and weight), physical activ-ity and individual life circumstances (pregnancy, lactation) (FAO, 2004). Physical activity accounts for a significant
pro-portion of a person’s energy consumption and is measured by the Physical Activity Level (PAL). Normal PAL scores range from 1.2 for people whose life is entirely sedentary to 2.4 for those who carry out the heaviest types of work (DGE, 2007). Guideline values for energy intake required by people aged 19–25 are 3000 kcal per person per day for men and 2400 kcal per person per day for women. For men engaged in heavy physical work this figure can rise to just under 4000 per person per day. For men and women aged 25–51 the guideline values for average energy intake are 2900 and 2300 kcal per person per day respectively, while for people aged 51–65 they are 2500 kcal per person per day for men and 2000 kcal per person per day for women.
In industrialized countries the actual average calorie intake is around 3400 kcal per person per day, while in many developing countries the figure is under 2000 kcal per per-son per day (Ethiopia, at 1600 kcal per perper-son per day, is at the bottom of the scale) (Meade and Rosen, 1997; FAO, 2006a).
Socioeconomic sustainability 3.2 31
In producing and using bioenergy, a number of soci-oeconomic factors need to be taken into account if the requirements for sustainable development are to be met.
WBGU therefore explores measures by which these factors may be addressed (standards: Section 10.3). Socioeconomic sustainability criteria are rel-evant in the context of bioenergy in both industri-alized and developing countries. However, there are three reasons for paying particular attention to developing countries. Firstly, the problems associated with traditional biomass use in developing countries are widespread and a major obstacle to development
WBGU therefore explores measures by which these factors may be addressed (standards: Section 10.3). Socioeconomic sustainability criteria are rel-evant in the context of bioenergy in both industri-alized and developing countries. However, there are three reasons for paying particular attention to developing countries. Firstly, the problems associated with traditional biomass use in developing countries are widespread and a major obstacle to development