1. Introduction: Sustainability—Recognising Constraints
It is widely accepted that for human activities to be sustainable, we must respect the ecological constraints on what we can do on and with planet Earth. Rockström et al. [
1] proposed a way of defining a ‘safe operating space for humanity’ in terms of a set of Planetary Boundaries (PBs), each framed in scientific terms: the idea being that keeping human activities within the PBs can maintain the Earth in the ‘Holocene-like’ state in which human societies have developed for millennia. The PB approach is based on scientific evidence on the likely resilience of various of the Earth’s systems in response to a set of environmental pressures, but encompasses value judgment in setting the target limits within the range of uncertainty between ‘safe’ and ‘dangerous’ [
2]. This framework opens up ways to conceptualise and operationalise what we term ‘absolute environmental sustainability’, with carrying capacity used as the benchmark to compare environmental impacts to what could be sustainable [
3]. This contrasts with most current approaches to environmental management, such as comparative Life Cycle Assessment of products and services [
4], which focus on reducing relative unsustainability. An approach to reconciling the social foundations of human development with the PBs has been proposed by Raworth [
5] and Dearing et al. [
6].
The PBs and the social foundations for just use of the safe operating space set out a basis in natural and social science for conceiving sustainable development trajectories, but they are framed at a high conceptual level and are global in scale. For operational decision-making, the PBs must be defined at an appropriate geographical scale, with metrics to indicate whether a PB has been or is likely to be transgressed. Approaches proposed in the literature have been directed mainly at specific geographical areas (
Section 2.1) with little consistency between the various approaches [
7]. Furthermore, a normative basis is needed for justice in the allocation of the environmental space for at least three classes of user: individuals, producing entities (e.g., industry), and governments [
3,
8,
9]. Some normative principles have been proposed [
7,
10,
11], drawing on the work of others including the Intergovernmental Panel on Climate Change [
12], but there is as yet no agreed mechanism or basis to allocate the space.
This paper explores the challenges in operationalizing the PBs approach for application in industry or other organisations. The work originated with Unilever, a multinational company in the Fast-Moving Consumer Goods (FMGC) sector. Companies providing goods and services are particularly significant through the decisions they make in designing products and managing supply chains that may link together different regions and impact many, if not all, PBs [
13]. Unilever is merely one example of a company that manages global supply chains and the conclusions and observations reached here apply much more generally. The focus here is on strategic planning and decisions which have large scale and long-term implications and impacts, as distinct from operational decisions: examples are developing new business areas which decouple growth from impact, rather than introducing specific new products; changing manufacturing technologies rather than making modifications to existing processes; and switching materials across a whole business area, as distinct from an ingredient change in a single product. The paper highlights gaps in understanding and scientific consensus, and outlines priority areas for further research to enable implementation of the PB concept. We recognise that there are complex, systemic interactions between the PBs but to facilitate strategic decision-making, the boundaries need to be assessed individually. We start from the PBs proposed by Rockström et al. [
1] and Steffen et al. [
2] and eschew aggregation of PBs typified by other approaches such as the Ecological Footprint [
14,
15,
16]. We explore how four of the boundaries might be operationalized: (1) climate change; (2) freshwater use; (3) biosphere integrity and (4) chemicals and other novel entities. The latter three are boundaries with a regional dimension, in contrast to climate change where, although the impacts may be different across regions, the contributions/activities are mediated globally.
Section 2 outlines the challenges in applying a PB-based framework across a commercial sector. Subsequent
Section 3,
Section 4,
Section 5 and
Section 6 focus on the four specific boundaries.
Section 7 compares approaches to defining the boundaries and the prospects for governing the ‘safe operating spaces’ and allocating them between different activities.
Section 8 presents general conclusions and prospects for further developments.
7. Allocation and Governance of the Spaces
In the case of climate change, the target value for GHG emissions is the outcome of extensive public debate (which conforms loosely with the ‘post-normal science’ approach; see
Section 3.1) on the basis of scientific evidence and socio-economic realities. These deliberations have involved transnational organisations such as UN and IPCC, national governments and non-governmental organisations such as the World Wide Fund for Nature (WWF) and the World Resources Institute (WRI). Even so, the consensus figure of 450 ppm CO
2e for the boundary is still regarded by some as contentious. The deliberations have also led to high level governance principles, such as ‘contract-and-converge’, introduced in
Section 3.2, that provide a basis for allocating the space between countries but do not provide a sufficiently specific basis for companies to set strategic targets. Collaborative initiatives such as Science-Based Targets (SBT—see
Section 3.2) demonstrate the willingness of some companies to engage in boundary setting, method development and action planning. The SBT initiative attempts to provide a basis by bench-marking GHG reductions against sectorial targets, but contains arbitrary fixed allocations within and between sectors and so removes an important aspect of strategic planning. An alternative basis, avoiding this limitation, is to relate impacts to turnover. Such an approach is available in the Overall Business Impact Assessment (OBIA) methodology in which the impact (e.g., GHG emissions) of a business area is evaluated per unit of economic value and compared with the average for the global economy. OBIA was originally developed by Unilever to assess the environmental performance of business areas, and was subsequently adapted for value chain analysis [
110,
111]. In the PB context, expressing the available ‘space’ as a permissible impact per unit of economic activity would provide a basis for company targets which recognise the need to remain within the boundary, relating aspirations for expanding markets to technological innovation. UNEP [
112] also considers using OBIA, among other examples of LCA at the organisational level, to prioritise actions.
The other three boundaries considered here are further from being rendered operational. The complex scale issues of the other PBs introduces problems in addition to those identified for climate change: governing ‘use’ of the ‘space’ requires local or regional management structures and development of cross-sectoral and transboundary working relationships which may not correspond to political boundaries or organisational structures [
113,
114,
115]. The complexity of ‘polycentric’ institutional design, funding, cooperation and boundary-spanning to operationalise individual PBs and their interactions is daunting [
115].
For freshwater use, suggestions have been made on how to approach the definition of the boundary at a watershed level; the scientific basis in local and regional assessment is set out in
Section 4.1. This is sufficient to provide a basis for companies to manage products, processes and production sites. However the definition has yet to be subjected to the same level of public debate as climate change, and approaches to aggregate these watershed level boundaries to provide a single planetary indicator are not yet mature. International river basins cover 45% of the land surface area of the world and supply 60% of the global freshwater supply [
116]. There are 267 international rivers basins and 148 countries whose territory overlaps with at least one international river basin. While use of the waters of international river basins can lead to tensions between countries, outright conflict is rare whereas cooperation between countries over shared water resources is common: at least 688 agreements have been signed between countries to manage shared water resources, including 250 independent freshwater treaties [
116]. Of the 217 treaties analysed by Giordano et al. [
116], 37% incorporate some form of water allocation mechanism; most recognise the issue of flow variability and 45% include some reference to either water quality or environmental issues. Many of the international agreements have established bodies to manage specific shared water resources across political boundaries, with examples on all the inhabited continents [
117]. However, the effectiveness of these organisations in governing water allocations and ensuring adequate environmental flows and avoiding ecological tipping points is variable. While mechanisms and organisations are in place for local allocation and governance of access to freshwater resources, there is no pre-eminent body at the international level to ensure consistency of approach. The UN has established UN-Water as the United Nations inter-agency coordinator for all freshwater related issues, with various individual UN agencies working on water issues and sometimes overlapping. Other international bodies include the Global Water Partnership, World Water Council, International Water Resources Association, and the International Water Association. The Global Water Partnership is perhaps the largest of the international organisations in terms of its number of member organisations but it lacks the authority of IPCC as a definitive voice or coordinating body. These international bodies can possibly push for water consumption limits in all river basins that are consistent with the global targets. However, at present, companies have no alternative to fragmented dealings with local bodies.
For biosphere integrity, there is also consensus that local and regional assessment and management are needed, as opposed to a single global approach as for climate change. However, whilst there has been some progress towards defining measures of biodiversity loss that could be used to define boundaries, simple accepted metrics are elusive: whilst the biodiversity crisis is global, biodiversity distribution and its conservation status is hugely variable across the planet [
118] while biodiversity itself is a multi-faceted concept (genetic vs. functional) spanning different levels of organization from species to populations to ecosystems. Therefore biodiversity has not been distilled into a small number of global (or even local) indicators [
119], although the two proposed proxy indicators and boundaries offered by the PB framework are a promising attempt. This makes the task of governing and allocating the safe operating space even more challenging than for water use. Much as for water use, policy measures for addressing biodiversity loss are in place locally (e.g., Sites of Special Scientific Interest (SSSIs) in Great Britain), and regionally (the Endangered Species Act in the U.S., Ecological ‘Red-Lining’ in China, biodiversity offsets required for development permits in Mongolia, Colombia, and other countries), but these measures are not based on a consistent global approach. For instance, U.S. policy only considers threat to individual species, not ecosystems (other than protecting habitat in which particular endangered species are found), while China considers a portfolio of representative ecosystems representing the diversity of the whole region. The conceptual framework offered recently by the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) may offer a means to highlight the commonalities in the world’s biodiversity and the benefits it provides to humans [
118] and so enable local and regional governance and policy measures to be formulated consistently. This is required if the safe operating space is to be allocated at a sufficiently fine scale. At least until a commonly-accepted basis has emerged, companies have no alternative to using proxy metrics for biosphere integrity, of which land use change appears to be the most practical and representative.
For chemicals, various international treaties and national and international bodies have been set up to control and reduce emissions contributing to other planetary boundaries, such as the Montreal Protocol for ozone depletion, as well for global promotion of chemical safety and management at national level, such as the Strategic Approach to International Chemicals Management (SAICM). However, such approaches do not address the challenges of multi-scale assessment displayed by the chemicals boundary, in common with water use and biosphere integrity. In addition to the problems arising from discrepancies between scientific and political scales, there is the additional complication that chemicals in products may be traded, used and disposed in multiple locations. For many individual chemicals, the safe space has been defined by setting permissible local concentrations to assure safe environmental quality defined in terms of species presence and ecosystem function. This leads to allocation of the space by the so-called ‘zero-allocation option’, whereby a company’s emissions are restricted or prohibited prior to entering the market to ensure that their realistic worst-case emission levels do not transgress the boundary for any individual chemical. This approach potentially leads to a ‘first come, first served’ allocation of the space or alternatively would require more complex cross-sectorial discussions of the allocation of the space. Companies are familiar with this type of preventive regulation, and have embedded the associated consequences of (trans)national regulations in their management, e.g., via the obligation under REACH [
91] to deliver data and risk assessments according to prescribed scenario calculations aimed at the safe production and use of chemicals.
Synergistic and antagonistic effects between chemicals are problems in developing a single aggregated metric or setting the safe space for the chemical pollution PB. Concentration addition is currently often the responsible and conservative choice to aggregate impacts across chemicals or mixtures and is the approach adopted in chemical footprint case studies [
97,
98]. Despite their underlying uncertainties, existing footprinting approaches can be utilized to establish whether local or regional compartments receive a net chemical load resulting in exposure levels transgressing the safe boundary. Environmental policies are then in place, as a second ‘defence layer’ adding to the preventive chemical policies, mandating counter-measures to be taken. For example, in the European Water Framework Directive, the absence of a good ecological status or good chemical status results in obligations to design and implement a program of measures in a river basin management plan. A major remaining challenge is to build a consensus on principles and processes for allocating the safe space of e.g., a river basin by considering the potential shares and roles of individuals, companies and governments [
120]. With the chemical footprint approach, companies can calculate their contribution to ‘filling the environmental space’, and take emission-reduction activities accordingly, either via safe product design (consumer-aspects) or via emission reductions measures. The implementation of the ‘circular economy’ concept might act as an extra trigger by minimising environmental exposure while promoting ‘benign by design’ chemicals [
83], as re-use of materials can result in unexpected human risks elsewhere in the cycling of products.
The problems arising from discrepancies between scientific and political scales underline why multi-national companies are important in moves to recognise and respect the Planetary Boundaries. In a globalised market, their supply chains run across geographical and administrative boundaries and so practical approaches to understanding their geo-spatial contributions and impacts are fundamental in the management of PBs with a regional/local dimension.
8. The Way Forward
The Planetary Boundaries framework as specified by Rockström et al. [
1] and Steffen et al. [
2] represents a major advance in conceptualising the ecological limits to human development and the risks posed by unsustainable production and consumption. The focus here has been on how the PB approach might be applied by businesses with global supply chains in strategic planning, particularly to decouple growth from environmental impact. Our analysis points to four scientific and technical challenges which remain priority areas for further research.
First, only climate change is truly planetary in scale; the other boundaries need to be quantified at a range of geographic scales—local, regional and planetary—defined by natural phenomena rather than political boundaries. Determining the right spatial units for analysis and defining the boundaries at an appropriate scale but consistent with a common global basis requires development of a shared system of metrics that can be applied consistently at and across different scales.
Second, a key step in operationalising PBs, particularly for life cycle sustainability assessment, is to set ‘distance from boundary’ measures. This has been demonstrated for climate change, which manifests on the global scale and for which there is a scientifically agreed way to quantify the boundary, some consensus on its numerical value and an emerging international governance framework. In principle, a precautionary ‘distance from boundary’ approach could also be used for boundaries characterised by multiple scales. However, this necessitates measurement and decision-making processes that apply at local and regional scales but recognise global targets, as exemplified by the water use boundary.
Third, continued and co-ordinated development of global, preferably open-source, databases and models is a priority, both to evaluate the current status of the earth’s systems relative to local, regional and global thresholds and to project future responses to pressures from human activities. This will underpin development of decision-making tools which can be used by companies and other organisations recognising the need to respect absolute sustainability.
Finally, although the PBs are currently treated as distinct, to provide a pragmatic start for designing ‘fair-share’ principles, the interactions between them must be better understood and the understanding integrated into the three priority research areas outlined above. We have noted some specific examples, such as that between climate change and biosphere integrity, and water use (scarcity), chemical pollution and biosphere integrity. The interactions are mediated in part by human actions (e.g., land-use change induced by changes in agricultural productivity), and therefore do need to be incorporated into company decision-making.
Overlaying the scientific and technical challenges in defining the safe operating space for each PB is the ethical problem of the normative basis for allocating shares of the safe operating space for each company or sector and for generating indicators and evaluation tools [
121]. Rather than assuming a share based on current sectorial composition and product portfolios, such as has been proposed for the climate change boundary in the ‘Science-Based Targets’ approach, there is a case for exploring approaches which are more flexible and therefore more suitable for strategic planning in companies. Relating the available space to economic activity might represent a practical way forward. One possible approach is to normalise impacts against turnover or added value as in the Overall Business Impact Assessment (OBIA) approach discussed in
Section 7. The ethical basis for such an approach is currently being explored by some of the present authors.
Part of the motivation for this paper is to identify the challenges and needs of the Planetary Boundaries concept from a business perspective and to provoke discussion. As noted in the Introduction, a further indispensable task is to relate the definition of a humanitarian ‘just space’ to the social foundations approach outlined by Raworth [
5] and Dearing et al. [
6] and to the global Sustainable Development Goals agreed by the UN [
21]. As noted in
Section 2.1, we recognise that this task is even more complex than allocating the environmental space, and requires clear and widely accepted normative principles. Even so, there is a clear need for commercial organisations to act now to recognize the existence of absolute planetary boundaries and to incorporate them into their planning and corporate values and reporting, even if the metrics have not yet achieved universal consensus. For example, sectoral commitments to ‘no net deforestation’ will contribute to maintaining aspects of biosphere integrity even in the absence of comprehensive measures of biodiversity. This commitment, however, carries some risk that pressure may be increased on the critical area thresholds of other biomes. Such risk represents a difficult potential trade-off, highlighting the importance of maintaining a systems-level perspective and the need for a science and knowledge base that is as complete and comprehensive as possible.
Where governance of the ‘safe operating space’ is absent or ineffective, there is a particular need for metrics and approaches to measurement and allocation that have a chance of achieving acceptance by business and others with the foresight to see that sustaining humankind is dependent on not violating the Planetary Boundaries and is a prerequisite for any future economy.