Part 3
How can the planetary boundaries framework be used locally?
This third part looks at the use that can be made of the of planetary boundaries on other scales. Although this framework was not originally designed to be applied at finer levels , it can nevertheless be a useful frame of reference for understanding the environmental impact of specific territories or activities, with a view from a sustainable development perspective. Two examples are presented here: one concerns the the company's agri-food product portfolio; the other is a territorial coherence scheme (SCoT) of the Sud-Loire region.
Planetary boundaries and downscaling
The original planetary boundaries proposal focuses on "the Earth system" and considers the planet in its entirety. According to its authors, "the planetary boundaries framework is not designed to be downscaled or disaggregated to smaller levels, such as nations or local communities" (Steffen et al., 2015). It is, however, at the national or local scale that political action most often occurs.
Several works thus aim to translate "planetary boundaries thinking" into a set of indicators echoing planetary boundaries, but relevant at the local level, and sometimes linked to sustainable development goals. The question of "downscaling" the planetary boundaries framework, both at the level of territories and specific activities, has been the subject of several hundred scientific publications since 2015.
A first group of publications, particularly rich in content, proposes "Absolute Environmental Sustainability Assesment" (AESA) methods, which aim to combine life-cycle analysis and planetary boundaries to assess the sustainability of a given activity (service, product or company, for example).
A second group of publications aims to apply the planetary boundaries framework to the territorial level.
This section begins by describing the methods used to assess absolute environmental sustainability, with an illustration based on the food portfolio of a major retailer. Secondly, the application of the planetary boundaries framework to a territory is presented, using the example of the southern Loire department.
Life cycle assessment (LCA) |
Life cycle assessment is an environmental evaluation method that estimates the potential environmental impacts of a system (product or service), performing one (or more) functions, throughout its life cycle ("from cradle to grave"). This makes it possible to represent the pressures generated by the different phases of the system studied (manufacture, use, end-of-life) and to identify any transfers of impacts between phases or between environmental impacts. |
Absolute environmental sustainability assessment methods
Absolute environmental assessment (AESA) methods aim to evaluate whether a given production or consumption activity is ecologically sustainable by comparing its environmental pressures, estimated by life cycle assessment, with an "acceptable carrying capacity" that can be assigned to the activity under study, generally based on the framework of planetary boundaries (Bjørn et al., 2020). Several methods are currently being developed for this purpose (Diagram 2).
Acceptable carrying capacity can be defined as the maximum impact an ecosystem can withstand without suffering unacceptable damage to its functional integrity or, for the use of non-renewable resources, as the rate at which renewable substitutes can be developed (Bjørn et al., 2020).
Diagram 2: Framework for the absolute assessment method for environmental sustainability
Source: Bjørn et al., 2019
The methods differ in their choice of indicators. Some are based on the environmental impact indicators recommended by the European Commission (European Commission, 2010) and determine reference values that can be defined as the "acceptable environmental load" that would enable planetary boundaries to be respected if all human activities applied the same maximum load. This approach was proposed by Bjørn and Hauschild (2015) and has since been applied to many areas related to production and consumption activities, including EU household consumption (Sala et al., 2020).
It thus appears that European consumption is unsustainable for several indicators, such as climate change and land use change (Sala et al., 2020). It's not just a question of saying that Europeans' final consumption generates pressures on the planet's ecosystems, but of quantifying the level of these pressures in relation to the maximum capacity of ecosystems to withstand them.
Another approach is to compare the environmental impacts generated by a given system with the "Share of Space Operating Space" (SoSOS) that can be assigned to it (Ryberg et al., 2018). New impact "characterization factors" must therefore be defined in order to be able to directly compare the estimated impacts with the share of safe operating space that can be assigned to the system under study. This method thus directly expresses the results of life cycle assessments in the metrics of the planetary boundary control variables defined by Steffen et al. (2015).
Whatever the EASA approach, it requires the choice of sharing principles to distribute global impacts between different human activities. The choice of sharing principle is based on various ethical choices, which must be clearly documented and communicated. To present more robust results, AESA studies can test and present results using several choices of sharing principles (Diagram 3).
Diagram 3: Proposed downscaling process
Source: based on Hjalsted et al., 2021
The principle of sharing |
The sharing principle is a ratio that allocates a global quantity of "acceptable ecological budget" to a lower scale, which can be an individual, a company, a territory, etc. The choice of this principle can be appreciated from both technical and ethical points of view. The choice of this principle can be assessed from both a technical and ethical point of view. Technically, this involves identifying socio-economic variables which are available at both global and local scales, and which are deemed to be correlated with the environmental variable under study. For example, the ratio of a territory's local population to its global population is often used to allocate planetary boundaries to a territorial system, as it meets both technical criteria: population data are available at both local and global scales, and the higher a territory's population, the greater its pressures (although the increase is not necessarily proportional). As another example, for an industrial system, the share of the economic sector to which this system belongs in the value added generated by all sectors is a good proxy for the weight of this system in economic supply (on the demand side, we can use the breakdown of final consumer expenditure by economic sector). It is also possible to use several ratios in succession. In addition to the choice of the variable to be used for allocation, there is the question of the principle of justice underlying the use of such a ratio (Ryberg et al., 2020). The majority of publications use the principle of egalitarianism: the allocation of subsystems is proportional to their weight in the chosen allocation variable (for countries, their population, for example). Other principles are sometimes used, such as equity, which consists in favoring the most disadvantaged in the allocation of global carrying capacity (for example, to penalize countries responsible for historical greenhouse gas emissions, they are allocated quotas less than proportional to their size). |
An example of application to the agri-food product portfolio of a mass retailer
The planetary boundaries framework has been mobilized, for example, to estimate the pressures exerted by the production of agricultural products, from the extraction of the raw materials mobilized to the farm gate (i.e. without taking into account the industrial preparation of the products sold). The agricultural products analyzed here are food products leaving the warehouses of a large-scale distribution company, over a one-year period (Wolff et al., 2017) - (Figure 18).
Figure 18: Identification of unsustainable levels of pressure exerted by agricultural production on food products sold by the retailer
Source: after Wolff et al., 2017
Figure 18 shows the environmental impact of producing the raw materials that make up all the food products sold in a year by a supermarket chain. The blue bars represent the estimated impacts of an "average annual food basket", brought down to the "maximum ecological budget" that can be allocated to each person to collectively respect the planetary frontier. The vertical black line represents the margin of uncertainty associated with the estimation of these impacts. The red dotted line represents the total ecological budget that could be considered "acceptable" in 2018, to respect the planetary boundaries if all the planet's inhabitants released the same quantities of emissions.
A blue bar above 100% (as for climate change, for example) means that the agricultural resources mobilized to manufacture the food products sold exceed the emissions "budget" (or maximum carrying capacity) per person that would enable us to respect planetary boundaries.
As this "ecological budget" must be used not only for food, but also for housing, transport, etc., it is interesting to try to approximate the "ecological budget" of consumers that can be attributed to food. To do this, we also show agriculture's share of past emissions, for each impact category, represented by the horizontal orange lines (the different lines correspond to the minimum and maximum values of different possible data sources). It thus appears that for climate change, eutrophication and freshwater use, the pressures generated by agricultural production in the "average annual food basket" far exceed the "ecological budget" of consumers that can be attributed to food.
Applying the planetary boundaries framework to a territory: the example of the scot sud-loire
The territory is another interesting object of application, as the arena in which decisions are taken that can have an impact on our ability to respect, or not, planetary boundaries (land-use choices, thermal renovation of housing, economic and industrial incentives, for example).
Epures, the urban planning agency for the St Etienne region, has taken an interest in the territorialization of planetary boundaries on the scale of the Sud-Loire territorial coherence scheme (SCoT). This territory is made up of four public establishments for intercommunal cooperation (EPCI): Saint-Étienne Métropole, the Communauté de communes des Monts du Pilat, the Communauté d'agglomération Loire-Forez-Agglomération and the Communauté de communes de Forez-Est, representing 198 communes and 600,000 inhabitants, for a surface area of 300,000 hectares.
A territory can be considered as "an area on which a human group lives" (Paquot, 2011). This dual identity is important for environmental assessment. The "expanse"is an area that is relatively well-defined administratively, but which may be subject to change as a result of administrative modifications (addition or withdrawal of communes from the SCoT perimeter, for example).
This space presents a certain vulnerability to global changes, which are not evenly distributed throughout the world. The territorialization of the planetary boundaries framework can therefore focus on identifying this vulnerability. The human group living in the territory under consideration carries out activities that generate impacts that contribute to the attainment of planetary boundaries. The territorialization of these boundaries at the scale of a territory can thus consist in estimating the contribution of the territory to the attainment of planetary boundaries in order to identify the environmental stakes and alert local decision-makers so as to best respond to them in the policies they are in charge of.
It is mainly this second axis that was considered in the exploratory study conducted jointly by Epures, SCoT Sud-Loire and Mines Saint-Étienne (Epures, 2021).
This work required:
- on the one hand, declining the thresholds expressed on a planetary scale to a local scale: either by directly exploiting the indicators used by the original planetary boundaries framework (Steffen et al., 2015), or by relying on indicators developed by other territorialization work on local (often national) scales;
- secondly, to collect local data enabling pressures and carrying capacities to be quantified: depending on the limit considered (associated with an ecological phenomenon), the carrying capacity may correspond (1) to a share of the overall carrying capacity or (2) to a vulnerability threshold specific to the local functioning of ecosystems. As the local environmental observation system is not currently geared towards measuring local carrying capacities, mode (1) has been chosen.
The contribution of the impacts of human activities carried out on the territory was estimated in relation to eight planetary boundaries (the "new entities" boundary had not yet been quantified at planetary level at the time of the study). A representation has been proposed to show whether the territory's contribution makes it possible to remain within the "safe operating space" or whether, on the contrary, the territory contributes to an overstepping of the boundary.
This approach can be illustrated by looking at the limit for disrupting the nitrogen cycle.
An environmental problem is a causal chain that can be observed at each of its links: human activities (drivers) generate pressures that lead to a state of environmental degradation (state), resulting in local vulnerabilities (impacts) and ultimately calling for actions that address the activities concerned (responses)37. In the case of nitrogen, the state of degradation can be expressed by the occurrence of eutrophication episodes, and the main pressure is the excessive input of fertilizers to agricultural soils (partly fixed by the crops, but the excess is carried into freshwater reservoirs by runoff).
Episodes of eutrophication of aquatic environments are frequently observed in the Sud-Loire region, but they are not officially monitored, nor are they systematically measured where the problem emerges. Concentration levels of nitrates and phosphates in watercourses are only assessed on the basis of drinking water criteria, not ecological quality criteria. While the problems of chronic eutrophication in the region do indeed reflect the fact that local hydrological carrying capacities have been exceeded, there is a lack of knowledge about what local hydrosystems are capable of withstanding. The maximum load that hydrosystems are capable of accepting depends on the hydromorphology (flow velocity and flow rate) and hydrogeology of the watercourse (nature of the bed and interactions between surface water and groundwater), which are specific to each site.
In the absence of precise data, we have decided not to consider local environmental conditions when setting this limit, and to focus instead on the pressures exerted on the area by fertilizer inputs.
Figure19 illustrates the proposed representation of nitrogen emissions into freshwater, associated with the agricultural use of mineral fertilizers (synthetic fertilizers and soil improvers) and organic fertilizers (manure, slurry), as well as crops that enable symbiotic fixation (e.g. legumes). These emissions were estimated using the CASSIS-N model proposed by the Geosciences department of the University of Tours (Poisvert et al., 2016).
37 This causal chain is known as DPSIR.
Figure 19: Intensity of nitrogen cycle disruption in SCoT Sud-Loire
Note for the reader: annual inputs (for the year 2018) of symbiotically fixed nitrogen (by leguminous crops in particular) amount to 13 kg per hectare, and inputs by chemical inputs (so-called mineral nitrogen) contribute 26 kg per hectare, these figures being estimated on the basis of the types of crops present in Sud-Loire. The 2015 global boundaries do not include organic inputs, as they are deemed negligible compared to symbiotic and mineral inputs on a global scale. However, taking them into account in the Sud-Loire region is crucial to understanding nitrogen overloads in the local environment, particularly in the hydrographic system, which suffers from eutrophication in places. If we take into account this dominant organic input in the area, which is explained by a cropping system that is mainly focused on livestock farming, the area exceeds the zone of uncertainty associated with the local limit on the nitrogen cycle.
Source: CASSIS-N model with RPG 2018 data
Nitrogen inputs in the region are detailed for each input source: mineral fertilization corresponds to inputs from commercial chemical products, symbiotic fertilization is provided by crops capable of synthesizing nitrogen (e.g. legumes), and organic fertilization comes from the reuse of manure and compost.
The authors of the Planetary boundaries framework recommend focusing on mineral and symbiotic inputs, which are in the majority on a global scale and generally easier to estimate (to estimate organic fertilizer inputs, it is necessary to know the size and nature of livestock populations). However, the specificity of the farming system in southern Loire, where livestock is very much present, means that organic fertilizers (from animal excrement) are the main input. Thus, even without the use of mineral fertilizers and the cultivation of symbiotic-fixing plants, the contribution of organic fertilizers is such that the Sud-Loire region could continue to contribute to the dangerous level of the planetary limit for nitrogen and phosphorus.
Other pressures leading to eutrophication could also be taken into account, such as rising temperatures, linked to climate change, or other sources of nitrogen and phosphorus pollution (industrial and residential wastewater, although treated in wastewater treatment plants). What's more, the territory's hydrographic network does not stop at its administrative boundaries, so that the pressures of the administrative territory are not the only ones contributing to the state of aquatic degradation, with fertilizer inputs from the upstream Loire watershed (Ardèche and Haute-Loire) also playing an important role, just as the Sud-Loire territory contributes to the pressures of the downstream Loire (Saône-et-Loire, Allier).
The maximum threshold admissible by the territory's agricultural soils was thus defined by allocating to the territory a share of the global threshold proportional to the importance of the territory's agricultural area in the global agricultural area (this is therefore an allocation of the global carrying capacity according to a sharing principle, and not an ecologically and locally constructed limit). Pressures were assessed using agronomic models estimating nitrogen inputs according to the type of crops grown in the area.
Ultimately, the exercise has a pedagogical dimension by providing a point of comparison (based on the pressures exerted by a given territory); it also highlights certain shortcomings of local environmental observation systems by proposing a more transversal observation framework, complementary to the indicators traditionally monitored on a local scale. It also shows the value of reorienting the water quality monitoring observation system towards a joint measurement of pressures (nitrate and phosphate concentrations) and carrying capacities, in order to provide territorialized indicators of absolute sustainability.
Table12 shows the proposed assessment of the various boundaries in the area. More than the results of the assessment (which need to be studied in greater depth and confirmed), the main interest of this initial exploratory study lies in the framework proposed and the reliability of the data that can be mobilized for the exercise.
Table 12: Assessment of the various planetary boundaries on a global scale, the SCoT Sud-Loire and the quality of the local observation system
Source: Epures, Mines Saint-Etienne, 2021. How can Sud Loire contribute to reaching planetary boundaries?
Finally, it's worth noting that certain planetary boundaries may seem close to what is already taken into account in local environmental policies. However, while the subject matter (water, biodiversity, climate change, for example) is often similar, the approach is generally different.
The "climate change" limit is undoubtedly the limit closest to the objectives already supported by the territorial climate-air-energy plan (PCAET). Indeed, this plan aims to implement the national low-carbon strategy (SNBC), which is based on a goal of carbon neutrality in line with the Paris Agreements, with which the framework of planetary boundaries is also in line.
On the other hand, the objectives of other local environmental policies are further removed from the "planetary boundaries" approach. For example, in terms of biodiversity, the ecological corridor contracts defined for the Sud-Loire region aim to restore or maintain spatial continuity between "natural spaces" . The objective is therefore based on existing reservoirs and continuities, and not on ecosystem carrying capacities (global boundaries approach). However, maintaining a certain level of continuity does not guarantee that the territory will not exceed its maximum contribution to the loss of species richness and abundance on a global scale.
Ultimately, applying the global boundaries framework to the local level can offer interesting prospects, both in terms of research and decision support. Even if it requires a number of assumptions to be made in order to apply a framework of analysis initially conceived at global level, it can promote a more precise and cross-disciplinary awareness of the impact of decisions taken at local level on global impacts and "the Earth system".
Further information
- Bjørn, A., Chandrakumar, C., Boulay, A.-M., Doka, G., Fang, K., Gondran, N., Hauschild, M.Z., Kerkhof, A., King, H., Margni, M., McLaren, S., Mueller, C., Owsianiak, M., Peters, G., Roos, S., Sala, S., Sandin, G., Sim, S., Vargas-Gonzalez, M., Ryberg, M., 2020. Review of life-cycle based methods for absolute environmental sustainability assessment and their applications. Environ. Res. Lett. 15, 083001.
- Bjørn, A., Hauschild, M.Z., 2015. Introducing carrying capacity-based normalisation in LCA: framework and development of references at midpoint level. Int. J. Life Cycle Assess. 20, 1005-1018.
- Bjørn, A., Richardson, K., Hauschild, M. Z., 2019. AFramework for Development and Communication of Absolute Environmental Sustainability Assessment Methods. J. Ind. Ecol. 23, 838-854.
- Epures, 2021. How can Sud Loire contribute to reaching planetary boundaries?
- European Commission, 2010. International Reference Life Cycle Data System (ILCD) Handbook. Joint Research Center.
- Hjalsted, A.W., Laurent, A., Andersen, M.M., Olsen, K.H., Ryberg, M., Hauschild, M., 2021. Sharing the safe operating space: Exploring ethical allocation principles to operationalize the planetary boundaries and assess absolute sustainability at individual and industrial sector levels. J. Ind. Ecol. 25, 6-19.
- Paquot, T., 2011. What is a "territory" ? Vie sociale n° 2, pp. 23-32.
- Poisvert, C., Curie, F., Gassama, N., 2016. Assessment of nitrogen pressures.
- Ryberg, M.W., Owsianiak, M., Richardson, K., Hauschild, M. Z., 2018. Development of a life-cycle impact assessment methodology linked to the Planetary Boundaries framework. Ecol. Indic. 88, 250-262.
- Sala, S., Crenna, E., Secchi, M., Sanyé-Mengual, E., 2020. Environmental sustainability of European production and consumption assessed against planetary boundaries. J. Environ. Manage. 269, 110686.
- Wolff, A., Gondran, N., Brodhag, C., 2017. Detecting unsustainable pressures exerted on biodiversity by a company. Application to the food portfolio of a retailer. J. Clean. Prod. 166, 784-797.
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