Chapter 1: Theories and Tools for the Assessment of Environmental Impacts of Human Activities

The rapid expansion of the global population in the last three centuries corresponds to our advancements in technology, improved medicines and healthcare, and the provision of goods and services.^1,2  Technological advancements began during the industrial revolutions in the 18th and 19th centuries. The first industrial revolution saw mechanisation and factory production driven by steam (coal). This was followed by the second industrial revolution, which utilised liquid fossil fuels and electricity to increase productivity in heavy and light industries.

Since then, we have seen the advancement of electronics and IT in the third industrial revolution, which has led to the automation of production, and we now stand at the frontier of the fourth industrial revolution, with advancements in digital technologies leading the way forward in unprecedented ways that are not yet fully comprehended.³ 

The increase in manufacturing capacity facilitated by our use of fossil energies was seen across a diversity of industries, from the iron and steel used in construction and transport, food production and processing, to consumer goods such as household wares, textiles and clothing. These phases of industrialisation also correspond to growing global concentrations of carbon dioxide (CO₂) and methane (CH₄) in the atmosphere, which can be measured by analysing the air trapped in polar ice over time.⁴ 

It has been suggested that this period marks the beginning of new geological epoch, termed ‘The Anthropocene’, which is governed by human activities (Figure 1.1). Whilst the term has not been formally recognised as a ‘Geologic Time Scale’ by the International Commission on Stratigraphy, it has become widely used to define the era in which we now live, where the impacts of human activities on the local and global environment have become a source of increasing concern to many.⁵ 

Finding ways in which to quantify the impacts of human activities on the environment has led to the development of several macro-level models and conceptual ways of thinking, however, the complexity of our interactions with the environment and the sheer number of developments in consumer-driven activities, has also led to thinking at a more granular level. In this chapter, we introduce some of the ‘big picture’ thinking about human impacts on the earth's systems and introduce the concept of the Circular Economy (Chapter 2 of this book will provide a detailed account of Circular Economy thinking). We also introduce ways in which we might understand and manage our impacts at the granular level and introduce Life Cycle Assessment (LCA) as a means of quantifying these impacts (Chapter 3 will provide a more detailed account of LCA methodology and principles). The following chapters in this book will describe case study approaches to LCA, covering a wide range of production systems which have developed to fulfil our needs for food, shelter and consumer products.

In 2017, the United Nations reported that the world population of 7.6 billion would be expected to reach 8.6 billion in 2030, 9.8 billion in 2050 and 11.2 billion in 2100.⁶  The potential outcome of the increasing human population has been theorised in several different ways. The Malthusian theory¹ proposes simplistically that, as population growth occurs exponentially whilst food production increases linearly, populations will outgrow their resources unless they are ‘checked’ through preventative checks (avoiding contributing to population) and positive checks [the reduction (possibly catastrophic) of populations as the result of disease, warfare, famine, and poor living and working conditions].⁸  Diamond (2004), has taken a broader outlook, considering the outcome of population increase to be drastic population collapse, as the result of eight ‘existing’ environmental factors that are impacted by human activities. These are: deforestation and habitat destruction; soil problems (erosion, salinisation and soil fertility losses); water management problems; overhunting; overfishing; effects of introduced species on native species; human population growth and increased per capita impact of people. Four ‘recent’ environmental factors are: the cumulative impacts of our population growth, activities and needs, i.e. human-caused climate change; the build-up of toxic chemicals in the environment; energy shortages, and maximised utilisation of the earth's photosynthetic capacity (or net primary production).⁹ 

With global population increase, in the simplest terms, more people will require more food, water and shelter and many have feared that famine and poverty will follow. Whilst this is undoubtedly true for some countries, global per capita Gross Domestic Product (GDP)² has grown 10-fold since the 1960s.¹⁰  The relationship between population growth and GDP is highly complex and can be contradictory, and the way in which it manifests in terms of environmental impact is difficult to quantify; however, access to disposable income clearly increases access to goods and services (once basic needs have been fulfilled) and leads to increased consumerism.¹¹  Larger numbers of people living on the planet has led to increased consumption of resource (land, food, water, air, fossil fuels and minerals) and increased generation of waste and pollution, as the result of our consumption activities.

A report by the United Nations Environment Programme in 2019 assessed global resource use and estimated that global material extraction in 2017 was 92 billion tonnes, increasing from 27 billion tonnes in 1970,³ i.e. more than 3 times the amount used in 1970.¹²  The assessment covers biomass (wood, crops and crop residues for food, energy and plant-based materials; grazed biomass; wild fisheries); fossil fuels (coal, gas and oil); metals (iron, aluminium, copper and non-ferrous metals) and non-metallic minerals (sand, gravel and limestone) as well as land (crop and pastureland) and water resources (for agriculture, industries and municipal use) (Table 1.1).

As a result of our use of resources, environmental impacts such as climate change, habitat loss, loss of biodiversity and the impacts of waste and pollution have been part of our everyday conversations and concerns in the late 20th/early 21st century, with climate change at the top of the agenda.^13 ,4 Many of the key environmental impacts are inter-related, e.g. land use change can contribute to climate change, as the conversion of forest to cropland causes a release of carbon stored in trees and the depletion of carbon sinks, reduced absorption of CO₂ may then occur as the result of replacement activities (e.g. different crops or livestock systems or, more directly, urbanisation) as well as loss of biodiversity and impacts on water cycles. Climate change, intensification of farming systems and over-farming may then result in desertification, water depletion and so on.⁵

In terms of waste and pollution, it has been estimated that one third of all food produced ends up as waste, due to inefficient consumer and retailer management, or through spoiling as the result of transportation and harvesting practices.¹⁵  According to the United Nations, the food sector accounts for 30% of the world's total energy consumption, 22% of total GHG emissions, and food waste equates to 1.3 billion tonnes of food.

It has been reported that solid waste generation (from broken household items, ash, food waste and packaging) is linked to urbanisation and affluence. A study published in 2013 states that in 1900, only 13% of the global population lived in urban settings (200 000 million people) and generated less than 300 000 tonnes of rubbish per day; by 2000, 49% of the global population were urban citizens (2.9 billion people), generating 3 million tonnes of solid waste per day. The same study estimates that by 2025, the amount of solid waste generated by our cities will reach 6 million tonnes per day.¹⁶  In recent years, the drastic impact of our use and mismanagement of the disposal of plastics has been realised and has taken a significant place on the environmental agenda. It has been reported that, since 1950, 8300 million metric tonnes of virgin plastics have been produced to date⁶ (Figure 1.2).¹⁷  Of this, 2500 million tonnes is in use, whilst 6300 million tonnes of plastic waste has been generated. Of this waste, 600 million tonnes have been recycled, 800 million tonnes have been incinerated and 4900 million tonnes have been discarded, to end up in landfill or the natural environment.¹⁷ 

Reports on the amount, and fate, of plastics that end up in the marine and terrestrial environments are of increasing concern, not only because of the direct impact on wildlife as the result of entanglement and digestion, but also due to the widespread infiltration of microplastics into the complex food webs of the land and the oceans, which can also eventually lead to human ingestion.^18,19  A framework has been developed to calculate the proportion of marine debris (solid waste) which originates from land,²⁰  by calculating the waste generated per capita in 192 coastal countries, the percentage of waste that is plastic and the percentage of plastic waste that is mis-managed and has the potential to enter the ocean. The report states that, of 275 million tonnes of plastic waste generated in 2010, 4.8–12.7 million tonnes has the potential to enter the marine environment.

Although concerns about the impact of industrialisation on the environment were already being recognised as an outcome of the industrial revolution (leading to the development of the first air pollution Act in the UK in 1814),²¹  it could be argued that the 20th century ‘environmental movement’ really began once our societies began to recover from the devastation of two world wars. Immediately after World War II, food production and manufacturing were being actively encouraged, with agriculture being supported by policies to promote self sufficiency,⁷ and technological advancements, e.g. the intensification of farming brought about by increased mechanisation and the use of artificial fertilisers and pesticides.²²  However, by the 1960s, publications such as Rachel Carson's Silent Spring²³  led to the recognition that modern farming systems⁸ and the chemicals used to achieve higher productivity were having significant effects on the surrounding ecosystems.²⁴  Other social and political issues are synonymous with the environmental, conservation and ecology movements of this era, e.g. the anti-nuclear and anti-war movement represented by many of the youth at this time. The period of social change that took place in the 1960s has greatly influenced the next generations, so that climate change and the environment are now an integral part of global thinking. For many, climate change and pressures on the environment are the key challenges for our future generations.²⁵  Environmental checks and, more broadly, sustainability, are increasingly being integrated into policy and corporate thinking (with varying degrees of actual, practical uptake).

‘Sustainability’ is defined in the Cambridge dictionary as ‘1: the quality of being able to continue over a period of time and 2 (environment): the quality of causing little or no damage to the environment and therefore able to continue for a long time’.²⁶  The concept of ‘Sustainable Development’ was first defined in the Bruntland report,²⁷  and recognises the link and need for interaction between economic, social and environmental concerns. Sustainable Development is defined as ‘development that meets the needs of the present without compromising the ability of future generations to meet their own needs’. It defines the concepts of ‘needs’ and ‘limitations’, addressing the essential needs of the world's poor as a priority, and the limitations that technology and social organisation will have on the environment's ability to meet present and future needs. As globalisation has continued, there has been increasing recognition that these issues cannot be addressed by individual countries, leading to seminal events such as the Rio de Janeiro Earth Summit⁹ in 1992.²⁸  The Earth Summit led to the development of Agenda 21, which was an action plan for sustainable development for the United Nations, multilateral groups and individual member states. Agenda 21 contains a section on the conservation and management of resources for development (Section II), which includes atmospheric protection; planning and management of land resources; management of fragile ecosystems; the promotion of sustainable agriculture and development; conservation of biological diversity; environmentally sound management of biotechnology; protection of the oceans; protection of the quality and supply of freshwater; management of toxic chemicals, hazardous wastes, solid waste and sewage-related issues, as well and the management of radioactive waves. Agenda 21 also addresses Social and Economic dimensions (Section I), such as co-operation to accelerate sustainable development; combating poverty; changing consumption patterns and identifies ‘Major Groups and their Roles’ (Section III), i.e. women, children and youth, indigenous people, workers and so forth.

Section IV of Agenda 21 addresses the means of implementing the challenges laid out in the Sections of the report, and led to the development of specific targets described in the Millennium Development Goals (MDGs).²⁹  The MDGs were eight challenges that were to be met by 2015, in order to ensure a sustainable future for the planet (Table 1.2).

Since then, the United Nations Conference of Parties (COPs) have been held annually, moving forward on such issues as climate change, with the Paris Agreement³⁰  and further development of the MDGs in Agenda 2030.³¹  Agenda 2030 now describes seventeen challenges, called the Sustainable Development Goals (SDGs), which are intended to be guiding principles and targets towards which all countries and stakeholders will work to achieve the equitable balance across countries for the three dimensions of sustainable development (i.e. economic, social and environmental). The seventeen SDGs have been defined (Table 1.3) and SDG 12 is highlighted in the context of this book. SDG 12 presents just some of the challenges faced in the development of a Circular Economy, and the means to quantify the impacts of changing activities, which will be applicable and practical for the sustainability of the planet and future generations.

Life Cycle Assessment (LCA) is a cradle-to-grave analysis tool, used to evaluate the environmental aspects and potential impacts associated with all the stages of the production, life and disposal of a product, system or service. An LCA typically includes raw material extraction, processing, manufacturing, distribution, use, reuse and disposal (i.e. cradle-to-grave). LCA can be utilised as a comparative tool for evaluating potential environmental impacts between different products, systems or services. It can be used to highlight opportunities to improve the environmental performance of products, systems and services, at various points in their life cycles, as well as informing decision-makers for effective strategic planning, priority setting or re-design of products or associated processes. LCA methodology can also be used as a tool to assist with the selection of appropriate indicators of environmental performance and ecolabelling marketing. The international standards ISO 14040:2006³²  and ISO 14044:2006,³³  provide the principles, framework and guidelines needed to conduct and report an LCA. The European Platform on Life Cycle Assessment has built on these standards to produce a series of comprehensive documents, collectively called the International Life Cycle Data Systems Handbooks (ILCD Handbooks)³⁴  which provide additional interpretation and guidance on each aspect of carrying out LCA. The ILCD Handbooks are essential references for those who seek in-depth understanding of each aspect of the processes involved in developing and carrying out LCA. Chapter 3 of this book will provide a further overview of the processes involved in LCA methodology.

Since the 1990s, much attention has been paid to LCA by individuals and organisations in the environmental field. However, the first attempts to look at the impacts of extended product systems can be traced back to the late 1950s and 1960s. The term ‘life cycle concept’ was first introduced by Novick in 1959,³⁵  in a report by the RAND Corporation that focused on ‘Life Cycle Analysis’¹⁰ of costs associated with the development and end of life of operations for activities under the US budget. Life Cycle Analysis then became a technique used by government bodies to improve budget management, linking the total cost of ownership to functionality.³⁶ 

In 1969, The Midwest Research Institute (MRI), today known as Franklin Associates Inc., developed a methodology know as Resource and Environmental Profile Analysis (REPA). In what is often cited as the first official use of LCA by a commercial organisation, the methodology was used to conduct an analysis on beverage containers for the Coca-Cola company, comparing different containers to determine which one produced the least effects on the use of natural resources and the environment.³⁷ 

LCA was also applied in response to the oil crisis of the early 1970s, as concerns over the limitations of raw materials and energy resources sparked interest in finding ways to cumulatively account for energy use, and to project future resource supplies and use. Both the USA and British governments commissioned industries to conduct extensive energy analysis studies.³⁸  Although the original emphasis was on the consumption of energy resources, several studies and conceptual workshops lead to a far broader framework, considering all raw material inputs, across the life cycle (i.e. associated with manufacture, processing, distribution etc.), as well as the associated emissions.³⁹ 

After a decline in interest in these studies in the late 1970s, the second rise of environmental awareness in the late 1980s saw attention focused again on LCA as a potential valuable environmental management tool.^38,39  Since then, a considerable amount of research has been conducted to develop the LCA methodology. Active players in the field of LCA include the Society for Environmental Toxicology and Chemistry (SETAC), the Joint Research Council (JRC) of the European Commission, the United Nations Environment Programme (UNEP) and the International Standards Organization (ISO), to name a few.

LCA has now evolved into a major support tool for decision-making in sustainable product and process design and management, as well as to monitor progress in improving environmental practices. From the beginning of LCA, with its application to making a relatively simple technical choice, i.e. choosing one material over another in relation to packaging, over time, there has been a shift in LCA thinking to more encompassing questions, such as the benefits of replacing fossil-based materials with biofuels and biochemicals in the fight against climate change. LCA remains the only existing logical methodology for quantifying the effects of human activities on the environment, from extraction of raw materials to production of a product, to end-of-life disposal. LCA can be applied to many products and services including agricultural systems and practices, industrial processes and waste management, among others, and can be used to assess a number of impact categories.

LCA has developed into a sophisticated tool that allows the quantitative assessment of a number of environmental impacts. LCA methodology is supported by the inputs and understanding of a large number of different disciplines, bringing together the engineers, scientists and economists from the spectrum of industries that support our daily lives, with the natural and social scientists, who are involved in developing our understanding of all aspects of our interactions with the natural world.¹¹ The stakeholder approach to LCA is essential to bettering our understanding of environmental impacts and assessment methodologies and over time a number of methodologies¹² have been developed that allow the quantification of these impacts. Broadly, the environmental impact categories are similar across the methodologies, and their relevance has been assessed and reported in the ILCD Handbook.³⁴  The mid-point environmental impact categories are related to ‘Areas of Protection’, or the end-point outcome of an environmental impact, i.e. on human health, the natural environment and/or on natural resources (Figure 1.3). However, there is currently no harmonised, singly recognised approach and methodology for quantifying life cycle impact categories. Chapter 3 of this book will go into more detail about the protocols for carrying out LCA, and the importance of clearly defining the approach taken in carrying out LCA. The need to follow the protocols for carrying out LCA, and for clearly defining the methodology used in making LCA calculations, is re-iterated here.

Understanding how far the resources of planet earth can be pushed in supporting human life is highly complex, and several macro-models and frameworks have evolved, which look to understand the natural systems of the earth, in the context of human activities. LCA is one tool that has been developed with the intention of quantifying environmental impacts, and can be considered as a metric to inform these macro-models and frameworks. The following section will provide examples of some of the conceptual ways in which we are trying to better understand the impacts of the Anthropocene period. The sections are not intended to provide a detailed review of all of these, as many are presented elsewhere in far greater detail than we can provide in one chapter, but we give an outline of some of the approaches, where LCA can be utilised as a tool in quantifying specifically defined activities within the complexity of human interactions with the environment.

Earth's Carrying Capacity has been used to define ‘the maximum number of individuals of population that the environment can support’,⁴⁰  considering the resources available in that environment (food, water, habitat) and the level of technology deployed to utilise resources. The concept of carrying capacity has been devised as a means of conceptualising and modelling the capacity to support populations of different species in given environments and, for humans, can be viewed from social and/or environmental perspectives within local, regional or the global framework. Several studies have attempted to model and quantify the maximum human population the earth can support based on various factors, and it has been reported that estimates range from 1 billion to 1000 billion people.⁴¹  A study based on population, biophysical resources¹³ (land) and photosynthetic capacity reports a figure of 11.4 billion people (assuming an annual per capita consumption of 1 million kcal).⁴¹  However, the diversity of the global human population and its varying ability to grow, manage and access food, resources, and additional provisions (access to medical care and sanitation) make this a far more complex prediction. Carrying capacity of the earth can also be considered in terms of social organisation encompassing human choice, economic and cultural conditions and quality of life (leading to lower predictions of maximum populations). Further studies have considered carrying capacity in terms of human population, ecosystems and ‘biocapacity’, which specifically considers the impact feedback mechanisms that ecosystems can provide, such the ability to absorb waste, and the limitations of resource provision as the result of carbon sequestration rates.⁴²  The link between carrying capacity and LCA has been highlighted in studies which aim to link the ‘normalisation’ stage of LCA across environmental impact categories which can be considered globally and regionally, e.g. climate change, ozone depletion and terrestrial acidification.^43,44 

The planetary boundaries concept is a further iteration of ways in which carrying capacity can be modelled and quantified, to understand the absolute limitations for human activities and the resulting impacts on the environment at the global scale. Planetary boundaries thinking considers planet earth as a self regulating system, which has been relatively stable during the Holocene era, but which is now transitioning into the Anthropocene,³  as human activities cumulatively impact on the systems which regulate the planet. Earth systems can be considered as the physical, chemical and biological processes (the biogeochemical cycles) that interact between the geosphere, the atmosphere, the hydrosphere and the biosphere, and within which we see the individual cycles that are essential to the planet's function (e.g. the carbon cycle; the nitrogen cycle; the water cycle and photosynthesis). The planetary boundaries concept was first defined in 2009,^45,46  and describes nine key earth systems which are seen as critical to maintaining the stable conditions that have allowed humanity to thrive and develop complex civilisations, through agricultural and societal development. The planetary boundaries systems have been considered with spatial and temporal perspectives and are summarised in Table 1.4.³⁶  Temporal and spatial perspective is also important when we are considering LCA, as it is part of the consideration of scope and systems boundaries, as a key element of the process of carrying out LCA (described in Chapter 3).

Analysis of the nine planetary boundaries systems has also been presented, in the first effort to quantify them and place boundaries beyond which there is an increasing risk of impacts to our current environment before ‘deleterious or even catastrophic’ impacts might be seen. The planetary boundaries systems define the safe operating space of the Holocene and consider the potential challenges facing us as we move towards the Anthropocene epoch. When the concept was published in 2009, the initial analysis suggested that three of the boundaries are already beyond the safe operating space, i.e. biodiversity loss (extinction rate of species), climate change (increased CO₂ levels in the atmosphere) and the nitrogen cycle (N₂ removal from the atmosphere for industrial and agricultural uses). A revision of the planetary boundaries systems and framework, and further quantification of the concept was published in 2015,⁴⁷  defining core boundaries for ‘safe operating space’; ‘zone of uncertainty’ (where there will be an increasing risk of adverse impacts); and ‘dangerous level’ (where there will be a high risk of serious impacts). The new assessment of planetary boundaries is shown in Figure 1.4,⁴⁷  demonstrating that we are already in the danger zone for biosphere integrity and biogeochemical flows, and in areas of uncertainty for climate change and land use systems. By defining a planetary boundary on the outer limit of the safe operating space, the intention is that actions can be taken to address the activities that are contributing to the shift in planetary boundaries systems.

In considering these macro-level concepts, we might also consider how we begin to understand the impacts human activities are having on these systems, as a result of e.g. growing food, providing energy and manufacturing products, a well as managing the waste generated by our societies. As seen in Table 1.4, the planetary boundaries concept takes a spatial and temporal approach, so it is possible to relate those systems to different human activities, in different locations, and consider methodologies that have been developed to assess the environmental impact at a more local level.

Environmental footprinting is a methodology that has been presented to quantify the impacts of human activities, linking to planetary boundaries thinking,⁴⁸  where both approaches benefit from input and feedback in an environmental assessment framework. In this case, the elements of footprint methodologies are considered in their context and contribution to planetary boundaries thinking, e.g. for blue water footprint; carbon footprint; chemical footprint; ecological footprint and grey water footprint.

It has been observed that many of the impacts of products and processes are seen and assessed at the ‘local’ level but accumulate at the global level (e.g. land-use change, P and N cycles). Building on the previous work cited, which relates LCA to carrying capacity,⁴³  LCA and specifically Life Cycle Impact Assessment¹⁴ is presented as a means of quantifying local level impacts that can be linked to the planetary boundaries framework.⁴⁹  The concept and limitations of linking the current LCA impact categories (Figure 1.3) to the nine planetary boundaries systems (Figure 1.4) are considered, and generally identify that the main differences and challenges are based on the approach taken for LCA, which considers the specific areas of protection – i.e. human health, the natural environment and natural resources – whilst planetary boundaries thinking considers the safe operating earth systems parameters which will maintain the pre-Anthropocene status of the planet. The development of a Planetary Boundaries-Life Cycle Impact Assessment (PB-LCIA) methodology has been reported,⁵⁰  and further iterates the links between life cycle impact categories and the control variables defined for planetary boundaries systems.

A recent framework, referred to as the Lyngby Framework,⁵¹  has been developed as a Life Cycle Engineering approach, which aims to address and link the top-down planetary boundaries approach with ground-up assessment of products and processes, the impacts of which can be defined using LCA. The framework is shown in Figure 1.5, to provide a visual representation that conceptualises the pathways and considerations that have to be made, to link LCA to the global planetary boundaries perspective.

There are a number of other worthy approaches which have been developed to address environmental impacts and sustainability in the manufacturing of products and associated processes, e.g. industrial ecology; cleaner production; life cycle management; industrial symbiosis and Circular Economy. The following sections in this chapter provide a brief introduction to industrial ecology and Circular Economy, after which, this book will consider LCA as a tool in Circular Economy thinking.

According to many scientific communities, human interference with global biogeochemical cycles has grown to a level that will trigger epochal changes, including climatic change and state shifts in the earth's biosphere. These changes have a substantial impact on humanity; they force humans to adapt or to be proactive and mitigate negative impacts on the environment. The spectrum of options for future action is wide. It includes technology development and deployment, economic instruments including taxes and subsidies, regulation and standards and changes in consumer behaviour and lifestyle.⁵² 

Industrial ecology, over the past decade, has successfully focused attention on improving the resource efficiency of systems of production. Reusing and recycling end-of-life products, redesigning products, processes and supply chains for improved efficiency, all offer clear environmental benefits to industries. However, addressing consumption in modern industrial society is deemed vital in reducing its impact to the environment.⁵³ 

Lifset and Graedel (2002) have defined industrial ecology as the study of the flows of materials and energy within industrial and consumer society, the associated effects of these flows on the environment, alongside its influence to the economic, political, regulatory and social factors on the flow, use and transformation of resources.⁵⁴  Industrial ecology emphasises the critical need for a systems perspective in environmental analysis and decision making. The goal is to avoid narrow, partial analyses that can overlook important variables that can lead to unintended consequences. There are ample testimonies to the analytical approach to quantify emissions and resource loss on a life-cycle basis, dating from the 1970s.^55,56  Nevertheless, LCA's rapid growth and its close relationship with industrial ecology began around 1990, and its initial codification came in a 1993 handbook,⁵⁷  which set out an agenda for industries to develop, taking account of both of these approaches.^58,59  The life cycle approach within industrial ecology examines the environmental impacts of products, processes, facilities or services, from resource extraction through manufacture to consumption and finally to waste management. The use of LCA and the attention to the details in its approach, demonstrates that the cradle-to-grave perspective has huge benefits, when applied in managerial and policy decision-making, as well as in a research context. This includes product chain analysis, integrated product policy, greening of the supply chain and extended producer responsibility.⁵⁴  The adoption of LCA as an industrial ecology tool has become increasingly widespread, both in industry, civic society and government.⁵⁷  No doubt, LCA will continue to provide a vital perspective on industrial product and process design activities within the field of industrial ecology.

There are clear conceptual resonances between industrial ecology and cleaner production. Both are motivated by concerns about the increasing environmental impacts of industrial economic systems. The concepts of cleaner production can be described as the continuous application of an integrated, preventative environmental strategy to both processes and products, to reduce risks to humans and the environment. On the other hand, industrial ecology is simply described as an integrated system, in which the consumption of energy and materials is optimised, and the effluents of one process serve as the raw material for another process.⁶⁰  Adaptation and mitigation will both lead to a transformation of the biophysical basis of our society, which includes agriculture, industry, infrastructure, building stocks and vehicle fleets, and consumer products; and of the way we build, maintain, and operate this basis. The coming transformation is the continuation of a historic sequence of socio-metabolic transitions of mankind; first, from the hunter/gatherer to the agrarian, and later from the agrarian to the industrialised. This transformation represents a special global challenge, however, because it is likely to happen under environmental conditions that are significantly different from those that enabled the previous two transitions.⁵² 

The general principles of prospective modelling describe the current development status of two prospective model types: extended dynamic material flow analysis and Technology-hybridised Environmental-Economic Model with Integrated Scenarios.⁵²  These models combine the high level of technological detail known from LCA and material flow analysis (MFA) with the comprehensiveness of dynamic stock models and input/output analysis (I/O). These models are capable of building future scenarios with a time horizon until 2050 and beyond. Pauliuk and Hertwich⁵²  outline future applications and options for model development and discuss the relation between prospective industrial ecology models and the related concept of consequential LCA (cLCA). The prospective models for industrial ecology can answer questions that were previously in the exclusive domain of integrated assessment models (IAMs). It is evident that IAMs have a more comprehensive scope than the prospective industrial ecology models, yet they often do not obey central industrial ecology principles such as the life cycle approach and mass balance consistency. Integrating core industrial ecology principles into IAMs increases the scientific quality and policy relevance of the scenarios of society's future metabolism generated by IAMs, while placing industrial ecology concepts more prominently at the same time.⁵² 

The concept of industrial ecology continues to be the most plausible model for the industrial-environmental nexus of the future. In addition, major corporations that are environmental leaders are, in effect, already putting industrial ecology into practice. Its component elements are evident in their policies and practices.⁵⁷  It has to be emphasised that industry in general is constantly moving into an era of new values concerning the environment, in which corporate environmentalism appears to be essential for profitability and business survival. The speed with which a corporation understands and addresses these changing norms and values will define a large part of its competitive edge in the future. The benefit offered by industrial ecology is that it provides a coherent framework for shaping and testing strategic thinking about the entire spectrum of environmental issues confronting industry. Executives and policymakers who take steps to absorb and appreciate this mode of thinking will continue to find themselves and their organisations at a very real advantage in the world of the future.

Since the beginning of the third industrial revolution, linear thinking, based on the logic of “take, make and dispose”, has dominated in our economy. Although it has led to growth and prosperity in many parts of the world, it is a contributing factor to our current sustainability problems, because the linear model implies using resources in an unsustainable way and producing large quantities of waste. Indeed, global resource use has almost tripled in the last 40 years and, if the current consumption trend continues, it is estimated that global resource use in 2060 could reach 190 billion tonnes, with an associated 43% increase in GHG emissions from 2015 levels.¹² 

The Circular Economy aims to decouple economic activities from the consumption of finite resources and to design waste out of the system. In contrast to the linear economy, the Circular Economy proposes a system where flows of materials are circular, and energy comes from sustainable sources.^61,62  The concept highlights the value opportunities associated with products, components and material re-use, repair, remanufacturing and ultimately recycling and recovery. It proposes a whole value chain and cradle-to-cradle scope in the way products, components and materials are utilised in the economy. By circulating materials for longer and keeping products and materials at their highest utility and value, the system is expected to contribute to reduced environmental impacts linked to resource and energy use, while generating opportunities for job creation and business development.⁶¹  The idea of circular use of resources is by no means new. Its foundations lie in the fields of planetary boundary, industrial ecology, cradle-to-cradle, environmental economics and related fields of knowledge. These concepts have promoted ideas about the preservation of energy and circular flows of resources, to reduce the entropy of socio-economic metabolisms, and new ways to sustainable production and consumption.

A particular interest of the Circular Economy concept lies in its compatibility and consistency with sustainable development through the three associated pillars (economic, social and environmental). Underpinned by a transition to renewable energy sources, the circular model builds economic, natural and social capital. Promoted by various countries and organisations, including the Ellen MacArthur Foundation (EMF), Circular Economy thinking is now an item on the top of the environmental agenda. A shift towards a Circular Economy will impact different sectors of the economy and at different scales. This poses questions about how different stakeholders might effectively assess the transition and monitor progress towards the long-term goals of circularity and sustainable development.

Various methods and frameworks for assessing the progress towards circularity have been proposed as decision-supporting tools. Most of these tools provide a systemic understanding of the environmental (and sometimes social and economic) implications of adoption of circular products, processes and/or strategies. Circular Economy strategies can be applied at the macro (i.e. region, nation, sector), meso (i.e. eco-industrial parks) and micro (i.e. product and organisation) levels. Most attempts to define indicators for measuring the Circular Economy strategy have so far addressed the macro and meso levels, and only a limited number of indicators are available at the product level.^63,64  Life cycle approaches can offer promising possibilities at the product level decision support.⁶⁵  Studies have already been developed, which show that LCAs play a key role in the development of meaningful indicators for the Circular Economy, regarding product level assessment.^63,66 

LCA has already been used as a metric to assess the environmental sustainability of different Circular Economy strategies, e.g. in narrowing resource flows,⁶⁷  slowing resource flows⁶⁸  and closing resource flows.⁶⁶  LCA-based metrics can be combined with other metrics, such as the assessment of industrial symbioses, food waste management systems, the evaluation of business models, or for the identification of more sustainable supply chain partners. This offers the flexibility of the LCA approach combined with other Circular Economy metrics. The Circular Economy concept has achieved widespread attention with the concepts, such as extending life cycles, creating multiple functionalities, and closing material loops. However, there are often multiple choices, for example, remanufacturing, recycling and reuse in closing the material loops. The environmental benefits, as well as economic benefits need to be assessed to support decision-making in Circular Economy choices. However, this presents challenges in LCA methodology, in particular in choosing functional units, expanding system boundaries and taking in account avoided environmental burdens etc. Inevitably, there are various challenges and barriers to incorporating LCA into Circular Economy strategies, which requires a clear understanding of the LCA approaches applied in different sectors, and calls for good LCA practices in transparency and consistency.

The process of carrying out LCA follows an established protocol, which allows the quantification of environmental impacts of products, processes and services. The range of applications of LCA to specific industries, products and processes continues to develop and on-going considerations include the collection and rationalisation of data to inform LCA studies, as well as consideration of temporal and geographical aspects of data collection and availability. The refinement of methodological approaches to quantify life cycle impacts also continues and there is a vibrant community of LCA practitioners in academia and industry who continue to move the LCA process forward.

Circular Economy thinking is conceptual way of thinking about the impacts of consumption. Taking a closed loop approach, it provides a framework for influencing behaviours and practices to minimise these impacts. As these two approaches converge, we can expect to see the development of more linked studies, between the boundaries set in the closed loop systems of the Circular Economy and the cradle-to-grave approaches of LCA methodology. A recent position paper from the UNEP Life Cycle Initiative highlights the opportunities presented by LCA as a metric for the Circular Economy but also emphasises the need for on-going activities to address current gaps in the methodology,⁶⁹  namely the need for:

• Consistent accounting for changes in stocks of resources respecting mass balance principles

• Consistent modelling of open recycling loops

• The inclusion of all relevant resources and impacts, i.e. a full economy-wide LCA perspective

• Transparency of assumptions, reliability of data, and critical interpretation of results and trade-offs between a globally agreed number of impact categories.

This book aims to review the principles of LCA methodology whilst extending LCA systems boundary thinking to create better metrics that link to the Circular Economy. The book is intended to provide a robust systematic approach to the Circular Economy concept, using the established methodology of LCA. The book will provide a practical guide and companion reading for those who wish to use LCA as a research tool or to inform policy, process, and product improvement. The following chapters of the book aim to provide more detailed and specific applications of LCA to different areas of industry on a case study basis, to provide examples of how to align LCA as a metric in Circular Economy thinking.

This first chapter has provided a general summary of the increasing demand for resources and increasing consumerism, and introduces the environmental impacts, sustainability as a concept and the impacts of waste, re-use and recycling of resources. It has described some of the ways in which the academic community try to rationalise our impacts in the new Anthropocene age.

Chapter 2 introduces the concept of Circular Economy thinking and present the Circular Economy map and framework, highlighting specific areas of resource insecurity and waste impacts. Chapter 3 presents technical guidance for carrying out LCA as a metric, describing the procedure required for robust LCA methodology and its application to Circular Economy thinking. The following chapters are industry-specific and detailed LCA approaches to studies for buildings and infrastructure, paper and packaging (traditional plastics and biobased options) and textiles, agriculture (crops and livestock), renewable energies and bioenergies, can be explored further by the interested reader. Finally, the last chapter provides an interesting perspective and contrast of Circular Economy as seen through the lens of the LCA methodological approach.