Wellington Theological Consortium

by Jonathan Boston, Professor of Public Policy
School of Government, Victoria University of Wellington

Abstract

This paper explores recent policy debates, particularly amongst ecologists and economists, over the nature of the Earth’s biophysical limits and the implications of these limits for global economic growth and human activities. Specific attention is given to the nature of economic growth, the setting of safe planetary boundaries, and whether continuous exponential economic growth is technically feasible on a finite planet and, if so, under what conditions. Additionally, the paper considers the contribution of key Christian doctrines and ethical imperatives to this debate, and offers some reflections on how moral theology might help inform the longer-term choices facing humanity.

Paper prepared for a seminar on ‘Infinite God, Finite Resources: The Economic, Ethical and Theological Implications of Growth in a Finite World’, hosted by the Wellington Theological Colloquium, St John’s Church, Wellington, 6 August 2011.

Economic Growth, Bio-Physical Limits and Christian Ethics

For a world of seemingly unlimited resources, mankind is gradually accustoming itself to the Earth as a limited, crowded and finite space, with limited resources for extraction and a narrowing capacity for waste disposal of pollution.

Jean-Claude Trichet (quoted in Jackson, 2009, p.67)

At present we are stealing the future, selling it in the present, and calling it gross domestic product. We can just as easily have an economy that is based on healing the future instead of stealing it. We can either create assets for the future or take the assets of the future. One is called restoration and the other exploitation.

Paul Hawken (quoted in Brown, 2009, p.15)

Introduction

This conference on ‘Infinite God, Finite Resources’ is both timely and important. It addresses some of the most urgent and serious issues currently facing humanity. One of these is empirical in nature: what are this planet’s biological and physical (or biophysical) limits and what are the practical implications of these limits for humanity? Another is normative: given the Earth’s biophysical properties and the laws of nature, how should we choose to live? In other words, how should the empirical reality of absolute constraints and ‘safe’ planetary boundaries of various kinds affect the nature of our goals and the means we choose to pursue these goals?

Accepting that there are absolute and non-negotiable limits – whether biophysical or moral – and choosing to live within them does not appear to come naturally for humanity. Indeed, even the assumption that there are biophysical limits and that resources are finite is often questioned. Instead, some assume that this planet is so large and its resources so plentiful that it has the capacity to sustain unrestricted human activity, not least limitless economic growth. After all, in scope and scale the biophysical world seems huge relative to the subsystem of human activity. Moreover, it is widely assumed that economic growth ought to be the primary goal of humanity, either because it is somehow intrinsically good or because of its many instrumental benefits. Hence, a continuous or exponential growth of incomes and wealth is assumed to be not merely technically feasible but also morally vital – in fact, some argue that economic growth should be pursued whatever the costs. But how valid are such empirical assumptions and normative claims?

Answering this question is not straightforward. First, there are various technical matters – such as the meaning of ‘economic growth’ and ‘biophysical limits’ – that require clarification. Very often those involved in debates about these matters have different definitions or understandings in mind, and hence talk past each other. Second, there remain areas of genuine scientific or technical uncertainty. For instance, it is far from clear what implications the laws of thermodynamics have for the scale and scope of future human economic activity. Third, the ethical question of what goals humanity ought to pursue – whether individually or collectively – has been the subject of debate for thousands of years. While Christians have important theological insights to bring to bear, there is certainly no consensus within the Christian community on such matters.

Needless to say, the debate about economic growth and environmental limits is not new. Nor are concerns over the capacity of this planet to sustain an ever increasing human population. More than two centuries ago, in 1798, Thomas Malthus published his important study, An Essay on the Principle of Population, in which he argued that the number of human beings would ultimately be limited by scarce resources, and especially by constrained food supplies. As he put it: ‘The power of population is indefinitely greater than the power in the earth to produce subsistence for man’ (1798, p.13). Thus far, Malthus has been wrong. The means of subsistence has continued to grow much faster than the human population. But what about the future?

In 1972, two landmark reports were published: The Limits to Growth (prepared by Meadows et al for the Club of Rome) and a special issue of The Ecologist entitled A Blueprint for Survival. Both documents questioned the capacity of the Earth’s limited resources and biophysical systems to sustain exponential economic growth. Both documents also generated vigorous and rigorous critiques (e.g. Cole et al., 1973). The fact that there are certain biophysical limits and laws of thermodynamics was not disputed. But serious questions were raised over whether these limits and laws will ultimately constrain economic growth and human progress. Almost 40 years later, the debate over the thesis advanced in the Limits to Growth continues (see, for instance, Turner, 2008).

Yet the ground does seem to be shifting. For instance, an increasing number of scientific experts and economists are concerned about the current impact of humanity on the planet’s ecosystems (see Garnaut, 2008; OECD, 2011; Stern, 2007; Sukhdev et al., 2008). Such concerns have been heightened by mounting evidence that humanity is living beyond the planet’s safe ecological limits (see Rockström et al., 2009a, 2009b) and that the costs of economic growth, at least in some cases, are exceeding the benefits. This evidence is reflected in the findings and recommendations of numerous recent reports from international organizations, scientific bodies and research institutions. Let me mention just two such reports.

First, in mid May, Sweden hosted the 3rd Nobel Laureate Symposium on Global Sustainability, attended by Nobel Laureates of various disciplines, renowned experts on sustainability and high-level representatives of national and international organizations. The gathering generated the Stockholm Memorandum on Tipping the Scales towards Sustainability. The document highlights that economic growth and human progress ‘has come at a very high price’. To quote:

Unsustainable patterns of production, consumption, and population growth are challenging the resilience of the planet to support human activity. At the same time, inequalities between and within societies remain high, leaving behind billions with unmet basic human needs and disproportionate vulnerability to global environmental change.

This situation concerns us deeply. As members of the Symposium we call upon all leaders of the 21st century to exercise a collective responsibility of planetary stewardship. This means laying the foundation for a sustainable and equitable global civilization in which the entire Earth community is secure and prosperous.

Science makes clear that we are transgressing planetary boundaries that have kept civilization safe for the past 10,000 years. Evidence is growing that human pressures are starting to overwhelm the Earth’s buffering capacity.

Humans are now the most significant driver of global change, propelling the planet into a new geological epoch, the Anthropocene. We can no longer exclude the possibility that our collective actions will trigger tipping points, risking abrupt and irreversible consequences for human communities and ecological systems.

We cannot continue on our current path. The time for procrastination is over. We cannot afford the luxury of denial. We must respond rationally, equipped with scientific evidence.

Second, in late May 2011, the Organisation of Economic Cooperation and Development (OCED) published a significant document, entitled Towards Green Growth. This report highlights, amongst other things, the finite nature of this planet, the vital importance to human well-being of natural capital, the huge value to humanity of the ecosystem services provided by the Earth’s biosphere, and the need to live within certain non-negotiable planetary boundaries. The production of such a report by the OECD is significant, and highlights a growing awareness amongst senior policy makers around the world that humanity must take ecological limits and resource scarcity seriously.

With this context in mind, this paper explores the ongoing debate surrounding environmental or ecological constraints on economic growth. It begins by considering the nature, measurement and implications of economic growth (including exponential growth). It then explores the planet’s biophysical limits and discusses the setting of safe boundaries. Next, it examines whether, and under what conditions, exponential global economic growth is technically possible in the context of a planet characterized by limited natural resources, waste absorption constraints and the laws of thermodynamics. Following this, it explores the political challenges of achieving sustainable economic growth. Finally, it offers some insights from the Christian faith and theological ethics on the debates over economic growth, biophysical limits and sustainability, and reflects on how Christian thinking might help inform the current choices facing humanity.

Summary of argument

Since my paper is relatively long, let me briefly summarize the argument here:

1. The nature of economic growth
   Economic growth involves an increase in the value of goods and services that are produced over a particular period of time in a defined area (e.g. a city, country, etc). Hence, if the value of goods and services rises in real terms relative to a previous period, it can be concluded that positive growth has occurred. Such growth can (and often does) occur without an increase in the size or volume of goods and services; what matters is simply the monetary value of the goods and services being produced and consumed. And the monetary value of an economy’s output is not directly related to the use of resources or the production of waste. Accordingly, continuing economic growth over long periods of time does not require the production of ever more (or bigger) goods and services; it simply requires that the goods and services being produced are constantly rising in value. Nevertheless, given various resource constraints (see below), continuing economic growth depends on humanity’s capacity to innovate and use resources with an ever increasing level of efficiency.
2. The costs and benefits of economic growth
   Economic growth, as measured by gross domestic product (GDP), has brought many benefits over the past few centuries. It has lifted billions of people out of poverty and enabled many to enjoy high living standards. Nevertheless, economic growth has been uneven across the globe, and its fruits have been unequally distributed. As a result, around one billion people continue to live in severe poverty and face regular hunger and malnutrition. Alleviating their suffering is an urgent priority. At the same time, growth has imposed substantial costs, not least environmental – the loss of biodiversity, ecological degradation, widespread deforestation, increasing desertification, rising levels of water, land and atmospheric pollution, the loss of valuable topsoil and fertile farmland, the depletion of fish stocks, fossil water supplies and valuable minerals, and climate change. These costs are rising rapidly and will, at some point, reduce the rate of global economic growth, if not stifle growth altogether. Where the marginal costs of economic growth (e.g. in the form of environmental harms and loss of natural capital) exceed the marginal benefits, such growth is clearly ‘uneconomic’. It is thus important to consider wider measures than GDP, such as changes in genuine investment (see Arrow et al., 2003).
3. Economic growth and human well-being

   The empirical evidence suggests that beyond a certain point (i.e. where basic human needs are satisfied), the marginal benefits of economic growth (e.g. in the form of increased human well-being, happiness and life expectancy) decline as per capita incomes rise (see Wilkinson and Pickett, 2009).

4. Economic growth and societal goals

   The pursuit economic growth and material affluence should not be the sole, or even the primary, goal of human society. Public policy should be guided by multiple goals including the common good, social (or distributive) justice (both globally and inter-temporally), the protection of human rights, the satisfaction of basic human needs, and the wise stewardship of the environment. The aim should be to enable human flourishing, well-being and prosperity (in a broad sense) on a sustainable basis over multiple generations and to protect biodiversity and geodiversity. This entails preserving, if not enhancing, five different kinds of ‘capital’ stocks: financial capital, built or manufactured capital, natural capital, human capital, and social capital. It also entails a just and proper sharing of the world’s resources and the opportunities these provide.

5. Planetary limits

   The Earth is a finite planet: it is materially closed and bound by the laws of thermodynamics. Its biophysical systems are complex, interconnected and interdependent; they are vulnerable and subject to abrupt and non-linear changes; they thus require careful management. The planet’s ‘sources’ and ‘sinks’ of environmental resources are fixed and limited. Hence, scarcity is real and non-negotiable. Indeed, without scarcity, there would be no economics – no depletion of resources, no need to allocate or ration material goods and no law of diminishing returns. From the perspective of global economic growth, there are three main types of planetary limits: material or resource inputs; waste absorption limits; and thermodynamic limits:

   1. Resource inputs: while some natural resources are unconditionally renewable and essentially inexhaustible (e.g. sunlight, marine energy and wind energy), many of the resources required for human well-being are non-renewable (at least on non-geological timeframes). This includes minerals (both metallic and non-metallic) and fossil fuels (oil, gas and coal). Many other resources are conditionally renewable: they regenerate at relatively slow rates (e.g. aquifers) and/or are limited in supply (e.g. fresh water, soil and wood). Resource scarcity rules out the possibility of unlimited exponential exploitation and use of non-renewable and conditionally renewable resources. Against this, assuming ongoing technological innovation and continuing improvements in the efficiency with which such resources are employed, infinite growth in output per unit of resource may be possible. Such improvements in resource efficiency are also desirable.
   2. Waste absorption limits: the planet’s ‘sinks’ are finite. This means that the capacity of the biosphere to absorb or assimilate the waste and pollution generated by economic activity is constrained. The planet’s limited absorptive capacity may well restrict global economic growth long before serious input constraints arise. Arguably, climate change represents the greatest current threat to ongoing exponential growth.
   3. Thermodynamic limits: within our solar system, the total quantum of matter and energy is essentially fixed and constant, and the level of entropy is in continuous, irreversible decline. Herman Daly (1973, 2010) and others have argued that the laws of thermodynamics place an absolute limit on the efficiency of resource utilization: in accordance with the first law, the production of material objects requires an irreducible minimum quantum of resources, while the second law rules out using the same matter-energy over and over again for similar purposes. But these claims remain a matter of contention, and it is unclear what the claimed limits imply for economic growth.
6. Preserving ecosystem services

   It is neither essential for sustainability purposes nor feasible in practice to preserve absolutely all forms of natural capital and all natural resources; moreover, some changes are inevitable, irrespective of human activity. But sustainability certainly requires the maintenance of some critical forms of natural capital, as well as vital ecological functions and processes. This includes the ecosystem services upon which human life depends – provisioning services (e.g. the production of energy, food and water), regulating services (e.g. water purification, pest and disease control, and climate regulation), supporting services (e.g. seed dispersal), and cultural services (e.g. recreational and spiritual benefits). These services are limited and vulnerable, and are being threatened by humanity’s insatiable greed and cavalier disregard.

7. Establishing safe biophysical boundaries

   There are real, non-negotiable biophysical thresholds or limits (local, regional and global) within which humanity must live; otherwise a sustainable, just and prosperous future is not possible. Determining what the various thresholds are and establishing ‘safe’ boundaries is of immense importance. Globally, any failure to live within these boundaries will eventually result in overshooting, with harmful ecological, social, economic and political consequences, including the potential for mass extinctions and hence an irreversible loss of biodiversity. Also, a major collapse of economic activity, including global food production, is highly likely, generating great suffering and loss of human life. Because of the magnitude and seriousness of the risks, proper weight should be placed on the precautionary principle in setting safe boundaries.

8. The technical feasibility of exponential economic growth

   There remains debate over whether exponential global economic growth for long periods of time (e.g. hundreds of years or millennia) is technically feasible within the confines of a finite planet. Indeed, many experts question whether even current levels of economic activity and patterns of consumption are sustainable (i.e. because the current consumption and depletion of natural capital is exceeding investment in other forms of capital, or because too much non-substitutable natural capital is being lost). Plainly, where resources and physical space are finite, exponential growth is not possible if it requires continuous, compound growth of material or physical objects (including their scope and scale); it is only possible if the relevant measure is market value. In other words, it must take the form of qualitative, not quantitative, growth (see Daly and Townsend, 1993). It is not possible, for instance, to have ever more people, ever more cars, ever larger houses, ever taller office blocks and ever more possessions. Further, there may be certain exhaustible and non-substitutable natural resources that are critical for the production and consumption of vital goods and services. If so, not merely is continuous exponential economic growth impossible, but so too is the long-term sustainability of current consumption levels.

9. Decoupling growth and environmental impacts

   To the extent that long-term exponential growth is technically feasible, it will need to be utterly consistent with the assimilative and regenerative capacities of the Earth’s biosphere. This implies that economic growth must be decoupled from ecological impacts and physical (or resource) throughputs. Where such impacts or resource use already exceed safe parameters, such decoupling must occur in absolute, not just relative, terms. In other words, there must be an absolute reduction in environmental pressures, not merely improvements in ecological impacts and/or resource use per unit of output. To sustain continuing growth over lengthy time periods, ever more extensive absolute decoupling will be required. In effect, the current carbon-intensive and resource-intensive global economy will need to be transformed through the application of resource-conserving technologies into one characterized by low resource-intensity and minimal environmental impacts. In practical terms, this means an economy which reuses or recycles virtually all its natural resource inputs, relies primarily, if not solely, on renewable sources of energy, preserves critical (or non-substitutable) natural capital, and ensures that all forms of pollution and other environmental impacts – including GHG emissions – remain within safe biophysical limits. In effect, this will entail reduced material intensity, with less reliance on the production and consumption of material products, and the provision of more ‘de-materialized’ services (Jackson, 2009, p.129). Both the scale and rate of the decoupling required is vastly greater than anything so far achieved in human history.

10. The policies required for sustainable growth

    Moving to an ecologically sustainable model of ‘green’ economic growth will require a massive shift in current patterns of investment, production and consumption, as well as continuing rapid technological innovation. To achieve the necessary shift will require a dynamic, flexible economy. It will also involve significant policy changes and new modes of governance, both nationally and internationally. Key policies will need to include the proper pricing of pollution and the use of natural resources (e.g. via taxes and tradable permits), better regulatory standards to minimize ecological damage and enhance economic efficiency, the removal of subsidies that encourage pollution and the excessive extraction of natural resources, a new regime of metrics for measuring economic, social and environmental progress, and a more equitable distribution of income, wealth and opportunities globally (as well as nationally). Failure to implement such policies may well result in economic growth being limited by negative biophysical feedbacks – and in a manner that is not of our choosing.

11. The political feasibility of achieving sustainability

    The policy and technological changes required for sustainable economic growth are immense. Whether such changes are possible within the limited (i.e. decadal) timeframes available is highly uncertain. The global economy is characterized by substantial path dependence and inertia (e.g. due to the long lifetime of much physical infrastructure and high carbon-intensive energy systems). But the main challenges may well be political and institutional, not technical. Politically, the capacity to implement fundamental policy shifts is limited by institutional resistance (due to powerful vested interests), global coordination problems and weak international institutions, and human myopia and self-interest. These political constraints are most evident in relation to the faltering efforts to ensure the sustainable management of our global collective goods (or common property resources), especially the atmosphere and oceans. In relation to climate change, for instance, atmospheric concentrations of carbon dioxide (CO2) are already in excess of what many scientists regard as ‘safe’ levels, and the rate of increase continues to accelerate (see Hansen, et al., 2008; Hansen, 2009; Rockström et al., 2009a, 2009b)

Part 1: The nature of economic growth

There is a vast literature on the subject of economic growth. This addresses many different issues: the nature and meaning of growth; the reasons why growth occurs or fails to occur; the strategies available to governments for increasing growth; the consequences of growth – both in terms of benefits and costs; the relationship between growth and other social outcomes, such as health status, inequality, educational achievement and well-being; and the ecological or biophysical limits to growth. While this paper focuses primarily on the last of these subjects, some brief comments on several other subjects are necessary at this juncture. These include the nature and measurement of economic growth, the nature of exponential growth, the costs and benefits of economic growth, the contribution of growth to human well-being, and the place of economic growth in the wider debate over societal goals and values.

The nature and measurement of economic growth
Put simply, economic growth involves an increase in the value of goods and services that are produced over a particular period of time in a defined area (e.g. a city, country, etc). Hence, if the value of goods and services rises in real terms relative to a previous period, it can be concluded that positive growth has occurred. Such growth can (and often does) occur without an increase in the size or volume of goods and services. Hence, to achieve growth does not mean that the goods being consumed, such as cars, houses or computers, have to get bigger in size or number. On the contrary, what matters is the value of the goods and services being produced and consumed. Thus, if particular bundles of goods and services are becoming more expensive – for example, because they are of a higher quality or complexity, or because they are considered more desirable by consumers for other reasons – then growth will be occurring. What this means, therefore, is that continuing economic growth over long periods of time does not require the production of ever more (or bigger) goods and services; it simply requires that the goods and services being produced are constantly rising in value (in real terms). And a rise in value may happen for several reasons: first, the mix of goods and services being produced may be constantly changing, with the new goods and services being of a higher value than the ones they replace; and second, the mix of goods and services may remain constant, but their quality may be constantly rising due to technological innovation. For instance, the volume of car production may remain the same but those being produced are ever more sophisticated and expensive.

Where the real value of the goods and services being produced is growing more rapidly than the population of the relevant area, per capita income will be rising. Conversely, of course, if population growth is rising more quickly that the value of goods and services, then per capita income will be falling. For much of human history, per capita economic growth was close to zero. This is because innovation and technological advances were extremely slow and sporadic. All this changed dramatically in the late 18th century with the industrial revolution, first in Britain and then gradually across much of the rest of the world. As a consequence, per capita income in Britain rose some twelve times from the beginning of the industrial revolution to the 21st century (Carden, 2007, p.34), while GDP (see below) increased over 40 times. Globally, the economy expanded close to 70 times between 1800 and 2008 (Jackson, 2009, pp.6-7). The main reason is human ingenuity: over the past two and a half centuries there have been no fewer than five major technological advances. These include the mechanization of textiles, the invention of the steam engine and rail transport, the development of steel and electricity, the exploitation of oil and the move to mass production, and the development of information and communication technologies (see Stern, 2011). We now stand on the cusp of a sixth major technological revolution, namely the widespread adoption of low-carbon technologies (i.e. green-tech, clean-tech, etc.). As a result of these major technological innovations, it has been possible to sustain a much larger population. At a global level, the population has increased from an estimated 200 million at the time of Jesus Christ to about 1 billion in early 1800s, and around 7 billion in 2011. In the course of the 20th century alone, the world’s population grew four times, economic output 22 times and fossil fuel consumption 14 times (OECD, 2011, p.18); life expectancy also increased dramatically in most parts of the world.

Economic growth can be measured in various ways. The most common contemporary measure is gross domestic product (GDP). This refers to the monetary value – as revealed through market transactions – of all final goods and services produced within a country over a specified period of time. As such, GDP does not concern itself with the merits of the transactions being undertaken or whether the market value is an appropriate measure of the real worth of the good and services in question. Hence, all kinds of transactions that many people regard as undesirable (e.g. excessive consumption of alcohol or the purchase of highly inefficient vehicles) are counted. Likewise, GDP includes the costs of rectifying the damage resulting from accidents, drunkenness and pollution – even though these costs are essentially a drain on society rather than welfare enhancing.

Having said this, as Jackson (2009, p.125) highlights, GDP relies on certain crucial normative judgements. One of these is that only those goods and services which are exchanged through market transactions are counted. But of course many activities (both positive and negative) occur outside the market economy; instead they occur in the informal and black economies. Hence, all unpaid services like caring for children, volunteering and housework are not measured by GDP. The failure of GDP to measure these valuable activities prompted Marilyn Waring’s landmark book, Counting for Nothing. Another normative assumption underpinning GDP is that for measurement purposes what matters is the market price, not the true social cost of the activities being undertaken. Thus, positive and negative externalities (whether social or environmental) that are not reflected in the market price of specific goods and services are not counted. This means that where individuals and firms do not pay for the ecological damage they inflict – or are charged inappropriately – these costs are not captured by the GDP measure. Attempts have been made to adjust GDP to take into account environmental costs and benefits, but such approaches raise numerous technical issues (e.g. measurement, valuation, etc.) (Boston, 2010; den Bergh, 2009; Stiglitz et al., 2009). Accordingly, ‘green’ GDP measures have not yet been fully incorporated into national accounting practices and official statistics.

It is also important to recognize that GDP measures the flow of goods and services over a particular period of time; it is does not measure the level of, or changes in, net wealth or the stock of assets available to a community. Such assets can take different forms: human capital (e.g. skills, capabilities and expertise), social capital (e.g. levels of trust and social networks), manufactured or built capital (e.g. infrastructure, buildings and equipment), financial capital (e.g. equity) and natural capital (e.g. ecosystem services). Because GDP measures the flow of goods and services, a society can lose a substantial amount of its stock of assets without this significantly affecting GDP. The damaging earthquakes in Canterbury from September 2010 provide a good example. These have caused a huge loss of infrastructure, along with commercial and residential buildings, but New Zealand’s GDP has been barely affected. Similarly, the planet is currently witnessing a massive loss of natural capital due to deforestation, desertification, pollution and the unsustainable exploitation of wild fisheries, but global GDP is continuing to rise. Hence, annual changes in GDP – whether nationally or internationally – tell us nothing about the quality or quantity of our natural resources or the risks to future economic growth as a result of the loss of ecosystem services.

With these considerations in mind, several recent major reports have argued for significant changes in what is measured and reported by governments for accounting and policy purposes (see Stiglitz et al., 2009; OECD, 2011). To quote the recent OCED Report on Towards Green Growth:

Ideally, strategies for growth should take account of all types of capital: natural (e.g. ecosystems), human (e.g. education and skills), physical (e.g. machinery and equipment), and the intangible assets which are so crucial to human progress like ideas and innovation. Accounting for growth in this way can produce quite different results compared to growth more conventionally defined … Perceived trade-offs between economic growth and environmental protection are attenuated when new measures that better capture well-being are used alongside GDP to measure progress (p.21) … A green growth strategy recognizes that focusing on GDP as a measure of economic progress overlooks the contribution of natural assets to wealth, health and well-being. It therefore targets a range of measures of progress, encompassing the quality and composition of growth, and how this affects people’s wealth and welfare (p.10).

The nature and implications of exponential economic growth
There is another aspect of economic growth that is crucial to understand. Even low rates of growth, such as an annual increase of 1-2%, can have large effects over time. This is because of the power of compounding – or exponential growth. Thus, an annual growth rate of 2.5% will lead to a doubling of GDP within 29 years, whilst an annual growth rate of 8% will cause GDP to double within 10 years. Note that China has experienced a real growth rate exceeding 8% throughout the past decade, and if this pattern continues its GDP will exceed that of the United States sometime during the 2020s. Or to give another illustration: between 1830 and 2008 the real GDP of the United Kingdom grew just under 2% per annum. As a result, by 2008 its GDP was 32 times higher than in 1830. Likewise, it is estimated that if the global economy expands at the same rate as during the second half of the 20th century, by 2100 it will be 80 times larger than in 1950 (Jackson, 2009, p.13). Furthermore, if the aim is to ensure that all the inhabitants of the planet in 2100 enjoy the same level of material affluence as those living in the OECD, the world economy would need to be 200 times bigger than in 1950. As Jackson (2009, p.14) asks: ‘What on earth does such an economy look like? What does it run on? Does it really offer a credible vision for a shared and lasting prosperity?’

The costs and benefits of economic growth
Economic growth, as measured by GDP, has brought many benefits over the past few centuries. It has lifted billions of people out of poverty and enabled many to enjoy high living standards. Nevertheless, economic growth has been uneven across the globe, and its fruits have been unequally distributed. As a result, around one billion people continue to live in severe poverty and face regular hunger and malnutrition. Alleviating their suffering is an urgent priority. At the same time, poorly regulated growth has imposed substantial costs, not least environmental – the loss of biodiversity, ecological degradation, widespread deforestation, increasing desertification, rising levels of water, land and atmospheric pollution, the loss of valuable topsoil and fertile farmland, the depletion of fish stocks, fossil water supplies and valuable minerals, and climate change. These costs are rising rapidly and will, at some point, reduce the rate of global economic growth, if not stifle growth altogether. Where the marginal costs of economic growth (e.g. in the form of environmental harms and loss of natural capital) exceed the marginal benefits, such growth is clearly ‘uneconomic’. It is thus important to consider wider measures than GDP, such as changes in genuine investment (see Arrow et al., 2003).

It is sometimes argued that economic growth is actually good for the environment. This is based on evidence that there is an empirical relationship between some measures of environmental quality and per capita income (see Arrow et al., 1995). But such a relationship only applies to a limited number of pollutants and does not apply to the overall state of the environmental resource base. Thus, as Arrow et al., (1995, p.520) have argued, while ‘economic growth may be associated with improvements in some environmental indicators, they imply neither that economic growth is sufficient to induce environmental improvement in general, nor that the environmental effects of growth may be ignored’.

Economic growth and human well-being
Just as GDP does not measure wealth, it is certainly not a reliable measure of well-being, happiness or living standards (broadly, rather than narrowly, understood). Indeed, there is good empirical evidence that beyond a certain point (i.e. where basic human needs are satisfied), a rising level of GDP per capita no longer enhances happiness to any degree (see Jackson, 2009; Wilkinson and Pickett, 2009). Put differently, the marginal benefits of economic growth (e.g. in the form of increased human well-being, life expectancy and so forth) decline as per capita incomes rise. This suggests that well-being, happiness or living standards are influenced by many factors that have little to do with the quantity or quality of material possessions. This should not be surprising; it has been recognized for millennia that high incomes and/or wealth do not necessarily buy happiness.

Economic growth and societal goals
Despite this, economic growth – as measured by GDP – has been a key objective of governments in democratic states (and elsewhere) for almost a century. In fact, for many people, interest groups and political parties, growth is regarded as the primary goal, not just of economic policy but of society as a whole. The rate of GDP growth, from this perspective, is seen as the main benchmark for measuring human progress. Accordingly, high GDP growth and a high GDP per capita are to be pursued as a matter of priority – if not absolute priority. In keeping with this, any failure to achieve robust growth is viewed negatively, and governments that fail to deliver such growth are typically punished by voters.

Against this, there are powerful reasons why the pursuit economic growth and material affluence should not be the sole, or even the primary, goal of human society. Nor should it be revered, let alone sanctified. For one thing, as argued above, the most common measure of growth, namely GDP, only captures part of what is important, even within the economic sphere. For another, there are many other important ethical values and societal goals that ought to guide and inform the policy choices by governments. Giving absolute priority to one goal (i.e. pursuing this goal at all costs), runs huge risks and appears to be fundamentally inconsistent with the various moral theologies derived from the Christian tradition. These ethical approaches are typically pluralist, rather than monist, in nature. In other words, they affirm the relevance and salience of many different ethical values, such as human dignity, liberty, justice, peace, community, beauty, the integrity of creation, sustainability, and so forth.

For such reasons, public policy should be guided by multiple goals. These include the common good, social (or distributive) justice (both globally and inter-temporally), the protection of human rights, the satisfaction of basic human needs, and the wise stewardship of the environment. The aim should be to enable human flourishing, well-being and prosperity (in a broad sense) on a sustainable basis over multiple generations and to protect biodiversity and geodiversity. This entails preserving, if not enhancing, five different kinds of ‘capital’ stocks: financial capital, built or manufactured capital, natural capital, human capital, and social capital. It also entails a just and proper sharing of the world’s resources and the opportunities these provide.

Part 2: Biophysical limits

Let us now consider the issue of the planet’s biophysical limits. In recent years the international debate over these limits has intensified. In part, this has been prompted by growing concerns within the scientific and policy communities over anthropogenic climate change and its likely (and potential) ecological, economic, social and political impacts. But there has also been mounting evidence – as revealed by the Millennium Ecosystem Assessment – that humanity is inflicting many other types of damage upon vital biophysical systems and living well beyond the planet’s means (i.e. consuming or damaging at a rate exceeding what nature can regenerate). There is now a vast literature on such matters. I can only scratch the surface here. In the space available, I will comment briefly on four central issues:

• the main types of planetary limits that humanity faces;
• the issue of substitutability;
• the importance of preserving ecosystem services; and
• the issue of setting safe biophysical limits.

Planetary limits

Whether we like it or not, humanity faces certain absolute limits. The Earth is a finite planet: it is materially closed and bound by the laws of thermodynamics. Its biophysical systems are complex, interconnected and interdependent; they are vulnerable and subject to abrupt and non-linear changes; they thus require careful management. The planet’s ‘sources’ and ‘sinks’ of environmental resources are fixed and limited. Hence, scarcity is real and non-negotiable. Indeed, without scarcity, there would be no economics – no depletion of resources, no need to allocate or ration material goods and no law of diminishing returns.
From the perspective of global economic growth, there are three main types of planetary limits:

• material or resource inputs;
• waste absorption limits; and
• thermodynamic limits.

Let me explore each of these limits briefly.

Resource inputs
While some natural resources are unconditionally renewable and essentially inexhaustible (e.g. sunlight, marine energy and wind energy), many of the resources required for human well-being are non-renewable (at least on non-geological timeframes). This includes minerals (both metallic and non-metallic) and fossil fuels (oil, gas and coal). Many other resources are conditionally renewable: they regenerate at relatively slow rates (e.g. aquifers) and/or are limited in supply (e.g. fresh water, soil and wood).

With respect to non-renewable and conditionally renewable natural resources, there has been vigorous debate about a range of matters. These include:

• the nature, quantity and quality of the reserves of the various minerals and fossil fuels used in production processes;
• the estimated life of these reserves at current and projected rates of consumption;
• the extent to which particular resources are substitutable (or likely to be substitutable with new and evolving technologies); and
• the consequences of natural resource constraints for continued economic growth (or even sustaining current consumption levels).

Experts disagree vehemently on each of these issues (see Hay, 2007). On the one hand, those on the optimistic end of the spectrum argue that a combination of market forces, technological innovation and prudent policies will ensure that any scarcity of resource inputs does not seriously constrain economic growth, certainly during the 21st century. On the other hand, those of a more pessimistic disposition believe that economic growth will be severely constrained by limited natural resources well before 2100, not least because of limits to substitutability (see below). As Jackson (2009, p.10) has pointed out:

If the whole world consumed resources at only half the rate the US does, for example, copper, tin, silver, chromium, zinc and a number of other ‘strategic minerals’ would be depleted in less than four decades. If everyone consumed at the same rate the US does today, the time horizon would be less than 20 years. Some rare earth metals will be exhausted in a decade even at current global consumption rates.

Such conclusions, however, must be treated with caution: new mineral deposits are constantly being found; commodity price rises (due to increasing scarcity) will affect the economics and viability of mining operations in various parts of the world; and improvements in mining technologies will enable deposits that were previously inaccessible to be exploited (e.g. deposits in the deep ocean). Nevertheless, most natural resources are finite and exhaustible (or only conditionally renewable). Hence, at some point scarcity will bite.

Certain resources have generated particular concern amongst policy makers, most notably oil, gas and coal. Thus, for example, the issue of ‘peak oil’ has been the focus of much debate in recent years, including the issue of when production is likely to peak (if it has not done so already), how rapidly production levels will fall after the peak, and what impact peak oil will have for energy prices and economic activity (see Department of Energy and Climate Change, 2009).

Global food production has also been in the spotlight in recent years (see Cribb, 2010). For instance, a number of leading scientists have argued that a combination of factors (including natural resource constraints) are likely to contribute to food shortages, perhaps as early as 2030. The chief scientific adviser to the British government, Sir John Beddington (2009, 2010), has referred to this as the ‘perfect storm’. Such factors include:

• Continuing population growth, especially in South Asia and Africa;
• A continuing loss of top soil and soil fertility due to poor agricultural and land management practices, rapid deforestation, desertification and erosion, pollution, the intensification of storms and droughts, etc. (Brown, 2009, pp.32-38);
• A growing loss of agricultural land due to urbanization and industrialization;
• A continuing loss of wild fisheries due to pollution, overexploitation, ocean acidification and rising sea temperatures. According to some estimates, about ¾ of oceanic fisheries are being fished at or beyond capacity or are recovering from overexploitation (Brown, 2009, p.15);
• Rising energy prices, due to peak oil. Acidification and rising sea temperatures, amongst other things, could result in a loss of 60% of coral by 2030 (Sukhdev, 2008, p.9), with huge implications for global fish stocks;
• Growing shortages of fresh water due to the effects of climate change, together with falling water tables and the loss of once huge fossil aquifers (due to the excessive mining of underground water). Declining supplies of groundwater are already contributing to the loss of millions of hectares of irrigated cultivated crop land;
• The loss of insect pollinators (especially bees) as a result of pollution and the excessive use of chemicals. Note that the value of pollination services provided by insect pollinators was estimated at EUR 153 billion in 2005 for the main crops that feed the world (OECD, 2011);
• Shortages of fertilizer. For instance, phosphorous reserves are likely to be exhausted within 80 years if consumption grows at 3% per annum; and
• The limits to photosynthesis (see Diamond, 2005, p.491).

Obviously, serious and protracted global food shortages could have major economic, social and political consequences – including civil disorder and violent conflict. If sufficiently widespread or destabilizing, such developments are bound to reduce the rate of economic growth, if not provoke a world-wide recession. Having said this, countries which are net food exporters, like New Zealand, stand to gain financially from such shortages (and the related price increases). But any such benefits need to seen against an otherwise bleak global context and severe human suffering.

One of the many important and unresolved issues relating to natural resource constraints is the extent to which different kinds of capital are substitutable. For instance, to what extent, and under what conditions, might it be possible to replace natural capital with other forms of capital (i.e. financial, manufactured, human, and so forth), or to substitute one form of natural capital (e.g. copper or zinc) for another. More specifically, there is the question of what forms of natural capital are ‘critical’ or non-substitutable, or at least non-substitutable for any given level of human knowledge and technology. And how might we best protect such forms of natural capital?

Waste absorption limits
The planet’s ‘sinks’ are finite. This means that the capacity of the biosphere to absorb or assimilate the waste and pollution generated by economic activity is constrained. Hence, even if limited natural resource inputs pose no major constraints on economic growth over the foreseeable future, waste absorption limits may well have adverse economic consequences. The limited capacity of the biosphere to absorb GHG emissions, especially CO2, is perhaps the greatest single threat on the horizon. As it stands, CO2 concentrations in the atmosphere are rising rapidly (at around 2.5 parts per million per annum) due to human activities; within a few years they will reach 400 parts per million (or more than 40% above pre-industrial levels). Global mean surface temperatures, which have already risen by about 0.8°C over the past century, are projected to increase by at least another 2°C this century, unless GHG emissions are substantially reduced. Such warming and related climate changes will have serious and potentially irreversible consequences, including substantial sea-level rise, more severe storms and droughts, and a massive loss of biodiversity. By the end of the century, the sea level could be as much as 1-2 meters higher. Such an increase will cause huge and widespread damage to coastal infrastructure and settlements (including roads, railway lines and ports). It is hard to believe that such damage could occur without impacting negatively on economic growth, as well as human well-being. Despite these risks, few governments have implemented significant or effective policy measures to reduce their domestic GHG emissions.

Thermodynamic limits
Within our solar system, the total quantum of matter and energy is essentially fixed and constant, and the level of entropy is in continuous, irreversible decline. Herman Daly (1973, 2010) and others have argued that the laws of thermodynamics place an absolute limit on the efficiency of resource utilization: in accordance with the first law, the production of material objects requires an irreducible minimum quantum of resources, while the second law rules out using the same matter-energy over and over again for similar purposes.

But these claims remain a matter of contention. For instance, as Hay (2007, p.114) notes, there are at least three counter-arguments to the claimed constraints imposed by the first law of thermodynamics:

1. As economies grow richer, consumer demand for services grow much more than those for products, and services generally require fewer material inputs.
2. Recent economic history indicates steadily increasing productivity in the use of material inputs as the value added by human and knowledge inputs increases.
3. Material inputs, especially energy inputs, can be used to reduce the impacts of residuals by reprocessing to render them harmless.

With respect to the second law of thermodynamics (or the law of entropy), the concern is that energy is dissipated through the production process while, at the same time, natural resources are degraded. Ultimately, it is argued, the law of entropy will limit economic growth. But the counter-argument is that it is possible to use solar energy to recover wastes and recycle dissipated materials (Hay, 2007, pp.114-5). The only constraint, from this perspective, is exactly how much energy can be captured from the sun. This is likely to depend on the level of technology. In short, it is by no means self-evident that the laws of thermodynamics will constrain exponential economic growth, and certainly not any time soon.

Substitutability

The issue of substitutability has been raised at various points in the preceding discussion. The subject is complex, the relevant literature is large, and it is only possible to touch on a few of the relevant issues here. Three matters deserve particular attention. First, there is a matter of definition: what does substitutability mean? Second, there is an empirical issue: to what extent can various non-renewable or conditionally renewable natural resources be fully substituted for other produced resources (or types of capital)? Third, there is a philosophical issue: to the extent that there are limits to substitutability, what ethical principles and considerations should guide our response?

With respect to the meaning of substitutability, in economics a substitute good is one that can replace (or be readily exchanged for or duplicated by) another good for the purposes of production or consumption. There are varying degrees of substitutability: a fully or perfectly substitutable good is one that has all the relevant properties of another good such that it can be used interchangeably and consumed in exactly the same manner. Imperfectly substitutable goods do not meet this demanding threshold. To illustrate, the timber from a particular native tree may be perfectly substitutable for that from an exotic tree. Nevertheless, an exotic forest may not be a perfect substitute for a native forest because the relevant ecosystems are very different. In discussions concerning the substitutability of environmental or natural resources, it is common to include not only substitute goods (e.g. replacing oil with coal for producing energy) but also technical changes that improve resource efficiency. As Hay (2007, p.113) explains, ‘the logic is that knowledge and human capital are being used to substitute material resources in production to produce the same outputs’.

The empirical issue concerning the limits to substitutability has been a matter of lively debate in recent decades. Optimists claim that human ingenuity will eventually make it possible for most, if not all, non-renewable and conditionally renewable resources to be substituted for other goods or, alternatively, enable continuous (and massive) improvements in the efficiency with which these resources are used. They also highlight that there is little evidence of scarce natural resources running out or becoming more expensive in real terms. Pessimists are more skeptical. They argue one or more of the following: that the availability of genuine substitutes for certain natural resources is limited (and will remain so); that efficiency improvements are ultimately limited by the very nature and properties of the physical world; and that there is growing evidence of resource constraints impacting on market prices and human activities (e.g. the rise in the price of rare earths, various food products and fossil fuels in recent years). To the extent that substitutability is an empirical issue, the evidence one way or another will become increasingly apparent over coming decades.

But there is a third, and important issue: to the extent that some natural resources (and ecosystems) are non-substitutable, what ethical principles and considerations should guide our response? For instance, advocates of ‘strong sustainability’ maintain that non-substitutable resources should not be used up or destroyed at all. This is not only because of their intrinsic worth but also because ‘intergenerational justice imposes stewardship obligations on the current generation to preserve options for future generations’ (Hay, 2007, p.115). Destroying non-substitutable resources (or ecosystems) thus violates the rights of future generations and is unjust. Accordingly, certain resources (and ecosystems) should be preserved in perpetuity. Against this, advocates of ‘weak sustainability’ maintain that it is acceptable to use up non-substitutable resources to a certain extent (although exactly how much is often unclear). Further, they argue that it is unrealistic to prevent humanity from using any resource that is potentially non-substitutable; such an approach would also be very costly.

But there is a further problem here: whatever the relevant ethical principles for determining the use or otherwise of non-substitutable resources, how might the global community give effect to any particular position? For without a universally agreed and properly enforced approach, the practical impact is likely to be very limited.

Preserving ecosystem services
Whatever the merits of maintaining the options of future generations, it is neither essential for sustainability purposes nor feasible in practice to preserve absolutely all forms of natural capital and all natural resources; moreover, some changes are inevitable, irrespective of human activity. Evolutionary and geophysical processes, for instance, will continue regardless of what humans do – or fail to do. Nevertheless, the sustainability of human civilization requires the maintenance of some critical forms of natural capital, as well as vital ecological functions and processes. This includes the ecosystem services upon which human life and well-being depends:

• provisioning services (e.g. the production of energy, food, water and life-saving drugs);
• regulating services (e.g. water purification, pest and disease control, and climate regulation);
• supporting services (e.g. seed dispersal); and
• cultural services (e.g. recreational and spiritual benefits).

These services are extremely valuable. For instance, it was estimated in the mid 1990s that the economic value of such services was about US$33 trillion, compared to global GDP at that time of around US$18 trillion (Sukhdev, et al., 2008, p.29). Unfortunately, this immense value is poorly recognized or understood, not least because such services are typically public goods; hence, they have no market price and are freely available. At the same time, most ecosystem services are limited and vulnerable, and are being threatened by humanity’s insatiable greed and cavalier disregard.

The magnitude of the damage being wrought was highlighted in the Millennium Ecosystem Assessment published in 2005. The Assessment, prepared under the auspices of the United Nations by over 1,300 leading scientists, furnished a state-of-the-art appraisal of the condition and trends in the world’s ecosystems. The Report contains profoundly disturbing evidence of how this planet is being afflicted. For instance, approximately 60% of the ecosystem services examined were found to be ‘degraded’ or being ‘used unsustainably’, including fresh water, capture fisheries, and air and water purification. Similarly, there is evidence of an increasing ‘likelihood of nonlinear changes in ecosystems (including accelerating, abrupt and potentially irreversible changes) that have important consequences for human well-being’. These include ‘abrupt alterations in water quality, the creation of “dead zones” in coastal waters, the collapse of fisheries, and shifts in regional climates’. Genetic diversity is declining, as is the number of species on the planet. It is estimated, for instance, that since around 1800 ‘humans have increased the species extinction rate by as much as 1,000 times over background rates typical over the planet’s history’. Currently, it is feared that up to 30% of mammal, bird, and amphibian species are threatened with extinction. To compound matters, the growing human population, projected to reach at least 9 billion by mid century, is bound to increase pressures on already fragile ecosystems. As a result, we run the risk of another great spasm of extinction – but this time caused by humanity, not natural forces (see also Sukhdev, 2008, p.12).

Related to this, a team of scientists concluded in 2002 that humanity’s collective demands began to exceed the earth’s regenerative capacity about 1980 (Brown, 2009, p.14). By 2009, the demands on natural systems exceeded their sustainable yield capacity by close to 30%. In effect, this means that human beings are depleting the Earth’s natural assets, and doing so at an increasing rate. Such trends can only continue for so long before various negative feedback mechanisms are triggered, critical thresholds are crossed, and irreversible ecosystem damage is inflicted. Hence, while the relevant timescales are uncertain, the long-term implications are clear.

Already, poor management of natural capital and losses in ecosystem functions and biodiversity are imposing large economic costs (OECD, 2011, p.25). To give a few examples:

• Soil erosion in Europe costs an estimated EUR 53 per hectare per annum;
• Water pollution causes an estimated 1.7 million deaths annually, with 90% of these amongst children under 5 years old;
• Air pollution is estimated to be causing the loss of 6.4 million years of life each year. Against this, the public health benefits of the Clean Air Act in the US were estimated in 2010 to be USD 1.3 trillion and outweigh related costs by a factor of 30 to 1; and
• The cost of cleaning up contaminated soils and oil spills is $US billions per annum.

To quote Lester Brown (2009, p. 15): ‘If we continue with business as usual – with overpumping, overgrazing, overplowing, overfishing, and overloading the atmosphere with carbon dioxide – how long will it be before the Ponzi economy unravels and collapse? No one knows. Our industrial civilization has not been here before’.

Establishing safe biophysical boundaries
It is abundantly clear from extensive scientific evidence that there are real, non-negotiable biophysical thresholds or limits (local, regional and global) within which humanity must live; otherwise a sustainable, just and prosperous future is not possible. Instead, we face the risk of overshooting, with harmful ecological, social, economic and political consequences, including the potential for mass extinctions and hence an irreversible loss of biodiversity. Also, as noted earlier, a major collapse of economic activity, including global food production, is highly likely, generating great suffering and loss of human life. Accordingly, it is of immense importance for humanity to identify the relevant thresholds that if crossed are likely to produce damaging environment changes with deleterious, if not catastrophic, consequences. On the basis of such thresholds, ‘safe’ biophysical boundaries need to be established. Because any overshooting carries such serious risks, proper weight should be placed on the precautionary principle when determining safe boundaries.

Table 1: Planetary Boundaries

To date, various efforts have been made to delineate safe biophysical boundaries. For instance, a group of distinguished scientists led by Johan Rockström (2009a, 2009b) recently published several significant articles exploring this matter. The group identified nine planetary boundaries (see Table 1). These include atmospheric carbon dioxide concentrations, extinction rates, the quantity of phosphorus flowing into the oceans and so forth. Their analysis suggests that humanity is already transgressing at least three of these boundaries (i.e. with respect to climate change, the rate of biodiversity loss and changes to the global nitrogen cycle).

As one might expect, the parameters proposed by Rockström et al have prompted vigorous debate. After all, setting safe boundaries is not a precise science, and we are at a relatively early stage in undertaking such an exercise. As a result, there is still much we do not know. Moreover, determining what is safe is not simply a scientific exercise. It also involves ethical judgements, some of which are profoundly difficult. For instance:

• How much harm, and of what kind, is morally acceptable? To be more specific, how many species should we be prepared to sacrifice on the altar of human ‘progress’?
• What risks should we be willing to tolerate? For example, should we be prepared to take the risk of inducing the irreversible melting of a major ice sheet, such as the Greenland and West Antarctic ice sheets – with the prospect of multi-meter sea-level rise?
• What costs should we be willing to bear in order to protect the interests of future generations and non-human species?
• What safety margin should we adopt in order to accommodate the possibility of abrupt, non-linear changes, other unexpected outcomes, and wider systemic risks?

Such questions are not amenable to simple answers. Nevertheless, the best available evidence suggests that if we persevere with existing policy settings we will face mounting environmental problems and run serious risks. For instance, if global emissions are not reduced substantially by 2050, it will be difficult, if not impossible, to prevent the loss of the Greenland and West Antarctic ice sheets. Indeed, we may already be very close to triggering irreversible melting of these ice sheets. Given the severely destabilizing impacts of such melting, it is hard to conclude that current policy settings are economically prudent or ethically responsible.

Part 3: Biophysical limits and exponential economic growth

Let me now attempt to bring together the various threads of the discussion thus far and draw some tentative conclusions. The preceding analysis has highlighted the nature and implications of exponential global economic growth, as well as the constraints which Earth’s limited sources and sinks place on such growth. In particular, it should be evident that on a finite planet economic growth cannot continue indefinitely unless such growth occurs without increasing environmental pressures and degradation. In simple terms, the link between ‘economic goods’ and ‘environmental bads’ must be broken and economic growth fully decoupled from any negative environmental impacts. As Jackson (2009, p.67) puts it:

The conventional response to the dilemma of growth is to appeal to the concept of ‘decoupling’. Production processes are reconfigured. Goods and services are redesigned. Economic output becomes progressively less dependent on physical throughput. In this way, it is hoped, the economy can continue to grow without breaching ecological limits – or running out of resources.

But is such radical decoupling technically feasible, and if so under what conditions? For instance, what policy frameworks will be required? Further, regardless of the technical feasibility of long-run exponential economic growth, is it likely that humanity will be able to establish the necessary governance structures and policy frameworks to enable such growth? In short, can the global community devise and implement a strategy of ‘growth with decoupling’ that facilitates ever-increasing incomes for an ever larger population while remaining within safe ecological limits? These questions are the focus of Part 3 of this paper.

The technical feasibility of exponential economic growth
As noted, there remains debate over whether exponential global economic growth for long periods of time (e.g. hundreds of years or millennia) is technically feasible within the confines of a finite planet. Indeed, many experts question whether even existing levels of economic activity and patterns of consumption are sustainable (i.e. because the current consumption and depletion of natural capital exceeds investment in other forms of capital, or because too much non-substitutable natural capital is being lost). Plainly, where resources and physical space are finite, exponential growth is not possible if it requires continuous, compound growth of material or physical objects (including their scope and scale); it is only possible if the relevant measure is market value. In other words, it must take the form of qualitative, not quantitative, growth (see Daly and Townsend, 1993). It is not possible, for instance, to have more people, more cars, larger houses, taller office blocks and more possessions forever and ever. Further, there may be certain exhaustible and non-substitutable natural resources that are critical for the production and consumption of vital goods and services. If so, not merely is exponential economic growth impossible, but so too is the long-term sustainability of current consumption levels. At present, we lack the necessary knowledge to be absolutely certain about such matters.

Decoupling growth and environmental impacts
To the extent that long-term exponential growth is technically feasible, it will need to be utterly consistent with the assimilative and regenerative capacities of the Earth’s biosphere. This implies that economic growth must be decoupled from ecological impacts and physical (or resource) throughputs. Where such impacts or resource use already exceed safe and sustainable parameters, such decoupling must occur in absolute, not just relative, terms. In other words, there must be an absolute reduction in environmental pressures per unit of output (e.g. GHG emissions or carbon intensity per unit of output), not merely improvements in ecological impacts and/or resource use per unit of output. Relative reductions will not be enough, certainly if overall output is increasing more rapidly than the improvements in resource efficiency or environment impact per unit of output. As Jackson (2009, p.71) explains, for absolute decoupling to occur, the rate of relative decoupling must exceed the rate of increase in overall output (or GDP).

Moreover, to sustain uninterrupted growth over lengthy time periods, ever more extensive absolute decoupling will be required (i.e. across an ever wider range of environmental impacts). In practical terms, this means that the current carbon-intensive and resource-intensive global economy must be transformed through the application of resource-conserving technologies into one characterized by low resource-intensity and minimal environmental impacts. Such an economy will need to reuse or recycle virtually all its natural resource inputs, rely primarily, if not solely, on renewable sources of energy, preserve critical (or non-substitutable) natural capital, and ensure that all forms of pollution and other environmental impacts – including GHG emissions – remain within safe biophysical limits. In effect, this will entail reduced material intensity, with less reliance on the production and consumption of material products, and the provision of more ‘de-materialized’ services (Jackson, 2009, p.129). Both the scale and rate of the decoupling required is vastly greater than anything so far achieved in human history. Let me illustrate.

As noted in Part 2, atmospheric GHG concentrations (especially those of carbon dioxide) already exceed levels that many scientists regard as safe. For instance, carbon dioxide concentrations currently exceed 390 parts per million (compared with pre-industrial levels of about 280 parts per million) and are rising at approximately 2.5 parts per million per annum. At this rate, they will reach 560 parts per million (i.e. double the pre-industrial level) by 2070. Such a concentration level, if maintained for an extended period of time, is likely to increase the globe’s mean surface temperature by around 3°C – with disastrous ecological, economic, social and political consequences. But even stabilizing at current concentration levels may well increase the temperature by 2°C – which is also likely to be highly damaging. For instance, it would result over time in a multi-meter rise in the sea level. Accordingly, many scientists argue that a safe stabilization target is likely to be no more than 350 parts per million (or even lower). Only at this level, it is contended, are the irreversible loss of the major ice sheets and the mass extinction of species reasonably assured.

Yet at this juncture in the argument we encounter a major dilemma. Even stabilizing carbon dioxide concentrations at around 560 parts per million will require a large reduction in emissions over the next half century. But to stabilize at 350 parts per million will require an absolutely massive cut in emissions. In fact, negative net emissions will be necessary for a protracted period. To achieve emissions reduction on this scale will require a dramatic fall in the carbon intensity of global output, even without further growth in the world economy. But if growth continues at post-war rates, then the fall in carbon intensity will need to be all the greater. Whether such reductions are technically achievable has been the subject of much debate in recent years, as has the issue of whether the global community can devise and implement the necessary policy measures to incentivize the required changes in investment, production and consumption.

Many experts are understandably skeptical, whether for technical or political reasons (or both). Jackson (2009) highlights the daunting nature of the challenge. Let me summarize his argument:

1. The amount of primary energy required to produce each unit of the world’s economic output has fallen more or less continuously for about half a century. Global energy intensity has fallen by a third since 1970 (p.69).
2. Carbon dioxide emissions per unit of output have also fallen. Global carbon intensity declined by almost a quarter from just over 1 kilogram of carbon dioxide per $US in 1980 to 770 grams per $US in 2006 (p.69). But while carbon intensity has declined on average by 0.7% per year since 1990, the global population has increased by 1.3% per annum and average per capita income has increased by 1.4% (in real terms) per annum. As a result, there has been a net increase of 2% per annum in carbon dioxide emissions (p.79).
3. To meet an atmospheric stabilization target of 450 parts per million (for carbon dioxide), annual emissions need to be reduced at an average rate of 4.9% per year until 2050. Given population growth (of about 0.7% per annum) and income growth (of about 1.4% per annum), this requires a technological (or carbon intensity) improvement of 7% per annum – this is 10 times faster than the current rate of improvement. Put differently, by 2050 the average carbon content of economic output will need to be less than 40g of carbon dioxide per $ of output, a 21-fold improvement on the current global average. This implies a totally different kind of economy.
4. Achieving an even lower, and safer, stabilization target, such as 350 parts per million (for carbon dioxide) would be even more demanding.

Thus, as Jackson (2009, p.86) concludes: ‘Those who promote decoupling as an escape route from the dilemma of growth need to take a closer look at the historical evidence – and at the basic arithmetic of growth’.

Overall, then, the challenges ahead are formidable and the prognosis looks grim. Continuing exponential economic growth will make it all the harder to achieve the emissions reductions required to stabilize carbon dioxide concentrations (certainly at anything close to the stabilization targets currently endorsed by the global community). Against this, without growth, moving to a safe concentration level will also be hard. This is because a dynamic and flexible global economy is needed if low-carbon technologies are to be developed and adopted on the scale and at the speed required. Quite apart from this, low or zero global growth will almost certainly lock at least a billion people into absolute poverty. We thus face a conundrum: assuming the correct policy settings (e.g. those which take environmental externalities properly into account), continuing economic growth will help deliver a fast reduction in GHG emissions; yet the faster the global economy grows, the greater the required reduction in emissions per unit of output.

While climate change poses a complex and formidable decoupling challenge, it is but one of the areas where the decoupling of growth and environmental pressures is required. The world’s mineral resources must also be used much more efficiently. But to date there has been little evidence of this happening. According to Jackson (2009, p.75), global trends in primary metal extraction reveal no absolute decoupling and hardly any relative decoupling. In fact, the extraction of iron ore, bauxite, copper and nickel, as well as the production of cement, has been increasing more rapidly than global GDP. Likewise, sustainable economic growth will require much better management of Earth’s fresh water resources (including aquifers), marine resources, soils, forests and grasslands. And in many cases this requires extensive restorative work, not simply reduced use. Some of this remedial work is urgent. Otherwise certain ecosystems, and the services they provide, will be permanently and irreparably damaged.

But do we have the technical capability, let alone the political will, to manage natural resources in a sustainable fashion? Much will depend on innovation and technological advances. As the OECD argued in its recent report, Towards Green Growth:

But developing and implementing new technologies and achieving the necessary improvements in the management of the planet’s natural resources will require tough policy choices. Unfortunately, recent evidence suggests that many governments (whether democratic or otherwise) are extremely reluctant, if not unable, to make such choices. This poses a further fundamental question: even if unlimited economic growth (as measured by GDP) is feasible in principle, does humanity have the capacity to devise and implement the public policies and governance structures required for such growth to be possible in practice? Let me quickly address this question.

The policies required for sustainable growth
As has been highlighted by many recent reviews by international agencies, moving to an ecologically sustainable model of growth will require significant policy changes. In its recent report, the OECD (2011) had the following to say:

A green growth strategy is centred on mutually reinforcing aspects of economic and environmental policy. It takes into account the full value of natural capital as a factor of production and its role in growth. It focuses on cost-effective ways of attenuating environmental pressures to effect a transition towards new patterns of growth that will avoid crossing critical local, regional and global environmental thresholds (p.10) … It is about fostering economic growth and development while ensuring that natural assets continue to provide the resources and environmental services on which our well-being relies (p.18).

The central feature of a green growth framework … is recognition of natural capital as a factor of production and its role in enhancing well-being (p.20). … Natural capital contributes to production by providing crucial inputs, some of which are renewable and others which are not. It also influences individual and social welfare in various ways, through the effect that the environment has on health, through amenity value and through the provision of ecosystem services … the contribution of natural capital to production is often not priced and the contribution of natural capital to individual welfare is not appropriately valued (p.23). …

From a production perspective, an assessment needs to be made of the extent to which natural capital can be depleted and replaced by other forms of capital. Different considerations will apply for different environmental assets (e.g. renewable and non-renewables); there is no single rule for determining whether assets should be preserved or not (p.23).

Greening growth will require much more efficient use of resources to minimise environmental pressures. Efficient resource use and management is a core goal of economic policy and many fiscal and regulatory interventions that are not normally associated with a “green” agenda will be involved. And in every case, policy action requires looking across a very wide range of policies, not just traditional “green” policies (p.10).

The report goes on to outline in detail the kinds of policies that will be needed to ensure that natural capital and ecosystem services are properly managed. Such policies, in brief, include:

• the proper pricing of pollution and the use of natural resources (e.g. via taxes and tradable permits) in order to internalize negative environmental externalities, minimize the over-exploitation of scarce natural capital and ensure that the true value of ecosystem services is reflected in decision-making frameworks (see Sukhdev, 2008);
• better regulatory standards to minimize ecological damage and enhance economic efficiency;
• the removal of subsidies that encourage pollution and the excessive extraction of natural resources;
• a new regime of metrics for measuring economic, social and environmental progress; and
• financial compensation for the least advantaged groups of society so that the distributional consequences of change are minimized.

Failure to implement such policies will almost certainly reduce incentives for business to invest in low-carbon technologies and new ways of using natural resources more efficiently. It will also undermine efforts to shift patterns of public investment (especially with respect to transport and energy infrastructure). And without a massive shift in private and public investment (and hence in production and consumption patterns), it is highly likely that an increasing number of ‘safe’ biophysical boundaries will be crossed (locally, nationally and globally). Eventually, the negative biophysical feedbacks from such overshooting will undermine global economic growth, if not generate a major economic crash.

But while it is relatively easy to itemize the kinds of policies required to encourage a greater level of environmental (and hence economic) sustainability, most of the policies in question pose significant technical issues and design challenges. For example:

• What criteria should we use to determine the appropriate quality standards for water, air and soils, and how should these standards be enforced?
• How should we value natural capital and ecosystem services? For instance, in addition to the value derived from the direct and indirect uses of such capital, what weight should be given to non-use values (such as ‘existence’ values)?
• How should we ascertain the appropriate amount to charge polluters? For instance, with respect to climate change, how should we decide the monetary value of the environmental damage caused by rising concentrations of GHGs, and hence the cost that polluters should pay for each unit of emissions?
• What should we do when there is inadequate information about the natural rate of regeneration (of various kinds of natural capital) or the assimilative capacity of local ecosystems?
• Precisely what new metrics should we introduce? And by what yardsticks should we measure and assess economic performance?
• In the case of global public goods (or global common property resources), effective policy interventions to protect such goods will require international cooperation and collaboration. But how is this to be achieved? Progress thus far has been slow and halting.

The political feasibility of achieving sustainability
As will be evident from the preceding discussion, the magnitude of the policy and technological changes required for sustainable global economic growth are immense. Whether such changes are possible within the available and quite limited (i.e. decadal) timeframes is highly uncertain. But the prospects are not good – for two main reasons.

To start with, the global economy is characterized by substantial path dependence and inertia. One reason for this is the long lifetime of most physical infrastructure, including carbon-intensive energy systems. For instance, the economic life of a coal-fired thermal power station is at least 40 years, and closing such plants early imposes substantial costs on their owners (i.e. unless compensation is provided). To compound matters, carbon capture and storage (CCS) technologies are still in their infancy and are unlikely to be applied on a widespread basis until at least 2030. Accordingly, most of the thermal power stations currently in operation will almost certainly remain in use for many years to come and will thus continue to emit large quantities of carbon dioxide. Much the same applies to ships, planes and heavy road vehicles. In short, high levels of GHG emissions and other environmentally damaging activities are ‘locked-in’ for decades. This makes rapid and radical changes both difficult and costly.

But the main barriers to adopting sustainable policies are political and institutional, not technical. Politically, the capacity to implement fundamental policy shifts is limited by institutional resistance (particularly from powerful vested interests), global coordination problems and weak international institutions, and human myopia and self-interest. These political constraints are most evident in relation to the faltering efforts to ensure the sustainable management of our global common property resources, especially the atmosphere and oceans. In relation to climate change, as already noted, atmospheric concentrations of CO2 are already in excess of what many scientists regard as ‘safe’ levels. Yet the rate of increase continues to accelerate, and most governments around the world are doing relatively little to curb GHG emissions within their borders.

As discussed elsewhere (see Boston and Lempp, 2011), there are at least four politically salient asymmetries which militate against governments – especially democratic ones – implementing vigorous policies to address climate change. First, there is a voting asymmetry: future generations, unlike current generations, do not have a vote, yet their interests are profoundly affected by the decisions being taken currently. Second, there is a cost-benefit asymmetry: the costs of action to reduce GHG emissions are certain, visible, direct and immediate whereas the benefits of such action are less certain, intangible, indirect and long-term. Third, reducing emissions will impose significant costs on powerful, concentrated interests (e.g. the fossil fuel industry). By contrast, the beneficiaries of such measures are dispersed over time and space, and have much less incentive to organize to protect their interests. Finally, as noted earlier, there is an accounting asymmetry: for firms and governments the loss of financial assets counts, the loss of natural capital does not. For such reasons, policy measures that make sense in environmental terms, and indeed also economically on a long-term basis, are extremely difficult to implement. Moreover, there are no simple or easy solutions to the four asymmetries identified above. If there were, we would surely have discovered them by now.

Such considerations lead to a further troubling question: will modern civilization destroy itself? In my view, such an outcome cannot be ruled out. Bear in mind that there is plenty of evidence of previous civilizations mismanaging their environment and suffering dire consequences – the Sumerians, Babylonians, Mayans, and so forth (see Berry, 2007b; Brown, 2009; Diamond, 2005). The main difference is that these civilizations had much less knowledge about the likely consequences of their actions than we do. But knowledge is one thing; a willingness to act prudently is quite another. And currently, prudence is sadly lacking. Nor does the history of humanity provide any comfort for those think that human ingenuity will always ‘prevent socioeconomic collapse’ (Brown, et al., 2011).

An alternative to exponential growth
One final thought before turning to matters of theology: if exponential economic growth is not possible on a long-term basis, there may be no option but to move to a global economy where the aggregate value of economic activity per capita remains relatively stable over extended periods of time. While this is consistent with a continuing process of innovation and efficiency improvements, together with ongoing changes in the pattern and consumption of economic activity (i.e. changes in the mix of goods and services being produced and consumed), it implies a different set of expectations, norms and policies. For instance, it implies a context where the pursuit of human well-being must occur in the absence of a constant expansion of the value of production per capita.

Summary
In Part 3 it has been argued that exponential economic growth, as measured by GDP, will only be feasible for any significant period of time if there is an absolute decoupling of growth and its negative environmental impacts. Without such decoupling, it seems inevitable that humanity will overshoot the planet’s biophysical limits, with dire consequences. To achieve the required level of decoupling it will be imperative to make substantial policy changes on a world-wide scale. Moreover, some of these changes need to be implemented urgently. Unfortunately, domestic political constraints and weak international institutions limit the capacity for such significant and rapid policy changes. Yet the longer we delay, the greater the risks, not least because of the path dependent nature of modern production systems.

I realize that I have not addresses a number of critically important issues, such as stabilizing the global population (ideally at no more than 8 billion) and eradicating abject poverty (see Brown, 2009, pp.23-24). Both deserve detailed attention, but are outside the scope of this paper.

Part 4: Theological and ethical issues

The preceding discussion raises a raft of important theological and ethical issues. Here are just a few:

• From a Christian perspective, what ought to be the relationship between humanity and the rest of the creator order?
• Should humanity endeavour to live within the planet’s biophysical limits or seek to transcend them?
• Is it reasonable to assume that an infinite God will provide for humanity without limit, or is God’s gracious provision conditional on humanity’s frugality, moderation and good stewardship?
• Is the mandate given to humanity in Genesis 1:28 (i.e. to be ‘fruitful and increase in number; fill the earth and subdue it. Rule over the fish in the sea and the birds in the sky and over every living creature that moves on the ground’) appropriately interpreted to imply ‘stewardship’ of creation, and if so, what exactly does this entail?
• What does it mean to have an abundant life in an ecologically constrained world?
• What principles should guide the allocation of the planet’s environmental resources (both sinks and sources), and in particular those in very limited supply or where safe biophysical limits have already been exceeded – such as the available atmospheric space for GHG emissions?
• What principles should guide the setting of ‘safe’ biophysical limits?
• What priority, if any, ought to be accorded to economic growth, and should such growth be viewed as an end in itself or merely of instrumental value?
• What attitude should Christians have to controlling the size of the human population, and the various policy issues this raises?
• What are the implications of Christ’s suffering, death and resurrection for how we should approach and respond to the current ecological crises, let alone the potential catastrophes that may await current and future generations?
• More specifically, does our eschatological hope lie in a completely new and radically different creation or, instead, in the renewal of the existing cosmos?

I am very mindful that there is already a large and growing volume of Christian scholarship on the what is called ‘ecotheology’ (or ecological theology) and ‘eco-justice’ (see Appendix 1), as well as the related sub-fields of theology: the doctrine of creation, the theology of nature, eschatology, public theology and theological ethics (see, for instance, Berry, 2007a; Berry and Clark, 1995; Boff, 1997; Edwards and Worthing, 2004; Habel, 2000; Hessel and Radford Ruether, 2000; Horrell et al., 2010; Northcott, 2007; Spencer and White, 2007). I cannot possibly do justice to this vast literature or the many issues that it addresses. In the space available I can do no more than offer a few brief observations on a selected range of issues.

Let me start with an observation about the literature in the area of ecological theology: overall, much more attention has been given to the question of why Christians should care for the environment than the question of how we should undertake this care. Perhaps this is not surprising. After all, the Bible is not a book about technology, resource management or public policy, and many of the policy challenges we confront today are utterly new; they are far removed from the world of the Biblical writers. Nevertheless, my impression is that Christian theologians and ethicists have thus far given too little attention to the various ethical principles, criteria and considerations that should guide our actions in relation to the matters addressed in this paper. Or to put it differently, Christian ethicists and economists do not, as yet, appear to have generated distinctively Christian perspectives on issues like the relative merits of strong versus weak sustainability or how we should go about determining ‘safe’ planetary boundaries. Instead, those Christians writing on such matters typically rely on the frameworks, approaches, categories and criteria advanced within the relevant ‘mainstream’ literatures (especially the discipline of economics). Maybe this is as it ought to be. Maybe Christian theology and ethics have no a distinctive contribution to make on these issues. But maybe the problem is that Christian scholars have not yet done sufficient thinking – and, in particular, thinking that is theologically and Biblically informed. Or maybe I have simply not yet encountered the relevant contributions by Christians on such matters.

On the issue of why Christians should care for the Earth, there is an abundance of thoughtful contributions from a variety of theological perspectives and traditions. Many of these start with the doctrine of creation. In this regard, traditional Christian theology emphasizes that the cosmos was created, and is sustained, by God, and that it was created ex nihilo (out of nothing). Because the cosmos, in all its extraordinary diversity and complexity, is divinely created, it has immense intrinsic worth or value. The scriptures also make it clear that the existing creation is an integral part of God’s eschatological purposes; it is not merely instrumentally useful for certain limited or specific goals (e.g. the enjoyment or salvation of humanity). Moreover, the world was not created for human beings; it was created for God. As Colossians 1.16 expresses it in reference to Jesus Christ: ‘all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things have been created through him and for him’. Or as Psalm 24:1 puts it: ‘The earth is the Lord’s and everything in it’.

On this basis, the Earth, and indeed the whole cosmos, should be viewed as an amazing and precious gift – to be nurtured and treasured, not damaged, plundered and defiled. It does not belong to humanity; we do not own it. Rather, we are trustees or guardians (Berry, 2007a, 2007b). In a sense, we hold it in trust for future generations, with all the connotations usually associated with a fiduciary duty – that is, good faith, a high standard of care, prudent oversight and wise management. Precisely what this means in practical terms, and at the policy level, is obviously open to debate. But as argued several decades ago in the World Conservation Strategy (quoted in Berry, 2007b, p.21):

Each generation should leave to the future a world that is at least as diverse and productive as the one it inherited. Development of one society or generation should not limit the opportunities of other societies or generations.

Traditional Christian theology also emphasizes that there is a radical difference between God and humanity. For instance, whereas God is infinite and unconstrained by material scarcity, time or the laws of thermodynamics, humanity is bound by a variety of fundamental and non-negotiable constraints. Above all, humans are an integral part of nature and utterly dependent on the resources of the Earth. As Bauckham (2009, p.86) has put it: ‘we are creatures of God alongside other creatures in the community of creation’. Accordingly, while human beings have a special and specific role, to be wise and diligent stewards of creation, we do not have, and should not seek, God-like mastery over nature. Instead, humans need to recognize their dependence upon the rest of the created order and accept the limits that this imposes. We should not disregard or seek to transcend these limits. Again, to quote Bauckham (2009, p.87), ‘In order to live within limits we must regain a sense of this dependence and renounce our alienation from the natural world’. Further, as Bill McKibben has argued: ‘Should we so choose, we could exercise our reason to do what no other animal can do: we could limit ourselves voluntarily, choose to remain God’s creatures instead of making ourselves gods’ (quoted in Bauckham, 2009, p.87)

Within this context, human beings have a unique capacity to affect life on this planet (and potentially outside our solar system). This impact has the potential to be both positive and negative. In reality, because of ignorance, greed, recklessness, moral disengagement, willful blindness, and calculated indifference humans have marred this planet – in all manner of ways. Here, Christian theology offers several valuable and important insights. First, it takes seriously the nature, power and problem of human evil or sin – in all its many and varied manifestations. These include the relentless quest for ‘more’, the addiction to novelty, a myopic focus on the present and the immediate at the expense of the longer-term, and a selfish disregard for the welfare of other people and other species. But second, Christian theology also emphasizes the opportunity for repentance and the capacity to change. Through the grace of God and the power of the Holy Spirit there is the potential for new beginnings, for renewal and redemption. Third, while the created order is essentially good, the Biblical tradition indicates that there is a deep problem besetting the cosmos, the precise causes and nature of which are not specified in any detail. Paul (in Romans 8: 19-22), for example, describes creation as waiting ‘in eager expectation for the children of God to be revealed’, as ‘groaning as in the pains of childbirth’, and as being ‘subjected to frustration, not by its own choice, but by the will of the one who subjected it, in hope that the creation itself will be liberated from its bondage to decay and brought into the freedom and glory of the children of God’. In this context, human beings are regarded not merely as co-groaners with the rest of creation, but also as co-healers. To quote Horrell et al. (2009, pp.137-8):

Those in Christ are involved in a process (involving co-groaning with the creation, and somehow comparable to the process of childbirth), and the liberation of the nonhuman creation in some way depends … on that process, one in which the children of God discover their own freedom, a freedom that has the character of glory.

Put differently, ‘only as humans are released from their sinfulness – by that deeper experience of God’s glory made possible by the work of Christ and in the power of the Spirit – will the rest of creation also be freed for its final incorporation into the life of the God who will be ‘all in all’ (1 Cor 15:28)’ (ibid., p.140).

Crucially, therefore, Christians have a reason for hope – even in the face of bleak projections and forecasts of ecological disasters, even in the face of a blatant disregard for the fate of future generations. What is the basis of this hope? Very simply, it is the birth, death and resurrection of Jesus Christ. The incarnation of God’s Son assures us that God not merely loves and embraces humanity but also the entire material world – indeed the whole cosmos – in all its evolving beauty, vastness and wonder. Equally, Christ’s resurrection provides concrete evidence not merely of the ‘resurrection of the body and the life everlasting’ but also the ultimate renewal and transformation of the whole created order (see Drew, 2010; Wright, 2007). A proper ‘ecology of the resurrection’, in other words, recognizes that God’s plan for this planet (and the entire cosmos) involves continuity, restoration and reconciliation, not complete discontinuity, destruction and replacement. Indeed, it involves the eventual ‘marriage’ of heaven and earth. Hence, the reconciliation that God has achieved in Christ should not be viewed as ‘a return to a previously ideal state characterized by peaceful relationships between humanity and other creatures, or even within the nonhuman community itself’ (Horrell et al., 2009, p.136). Rather, we should think in terms of God’s creative work being brought to full completion. To quote O’Donovan (1986, p.55):

The redemption of the world and of mankind does not serve merely put us back in the Garden of Eden … The eschatological transformation of the world is neither the mere repetition of the created world nor its negation. It is its fulfillment, it telos or end.

The proposition that God values and will ultimately renew, rather than destroy, the created order carries with it a number of important implications. For one thing, it means that we must reject any suggestion that it is acceptable for humanity to abuse the natural world and extinguish countless species. For another, we cannot use the expectation that there will one day be a new heaven and a new earth to justify ignorance and inaction in relation to the grave ecological challenges currently facing the world.

In short, Christians have a responsibility to serve as co-workers with Christ in redeeming creation and building a better tomorrow. To quote Sam Berry (2007b, p.34), ‘Creation care is not an option for zealots; it is an integral part of our obedience to Christ and our witness to the world’. Accordingly, we need to use our intelligence, creativity and imagination to find solutions to the challenges and problems we face and implement them. There is no justification for inaction founded on despair or hopelessness. Nor is there a case for inaction based on a self-interested rejection of solid scientific evidence. On the contrary, Christians should be a voice for reason in the public square and advocates for the proper use of the best available evidence. After all, we appeal to the evidence in the Gospels for the very basis of our faith and hope.

Conclusion

Is continuous exponential global economic growth possible on a finite planet? To be honest, I do not know. But one thing is very clear: such growth will only be possible under very strict conditions – above all, the resilience of vital ecosystem services and biophysical systems must be protected. Currently, the empirical evidence suggests that these conditions are not being met: we are overshooting key biophysical parameters and seriously degrading ecosystems on a planetary-wide basis. This can only continue for so long. Eventually, the negative impacts will overwhelm our capacity to cope, and de-growth will become inevitable. The resulting social and political tensions will be immense – and, I fear, unmanageable.

But does it really matter whether exponential economic growth, as measured by GDP, is possible or not? After all, GDP is a very flawed measure of human well-being or progress, and is almost irrelevant when it comes to assessing the state of the global environment. In my view, GDP growth is not inherently or intrinsically desirable; it is only instrumentally valuable, and even then, only under certain conditions (e.g. it must be environmentally sustainable).

Humanity has placed far too much weight on the goal of GDP growth over recent decades. We need to rethink what really matters. Christians have a crucial role to play in this process. But to do so, the church itself must be reformed; in particular, it urgently needs an ecological reformation. Christians need a stronger and more compelling theology of ecological responsibility and resilience, and they need to practice what they preach. The care and integrity of creation must become a key priority, not merely an optional extra. There is a long and difficult journey of reformation ahead, but precious little time.

Appendix 1: The Earth Bible

Six eco-justice principles

1. The principle of intrinsic worth
   The universe, Earth and all its components have intrinsic worth/value.
2. The principle of interconnectedness
   Earth is a community of interconnected living things that are mutually dependent on each other for life and survival.
3. The principle of voice
   Earth is a subject capable of raising its voice in celebration and against injustice.
4. The principle of purpose
   The universe, Earth and all its components, are part of a dynamic cosmic design within which each piece has a place in the overall goal of that design.
5. The principle of mutual custodianship
   Earth is a balanced and diverse domain where responsible custodians can function as partners, rather than rulers, to sustain a balanced and diverse Earth community.
6. The principle of resistance
   Earth and its components not only suffer from injustices at the hands of humans, but actively resist them in the struggle for justice.

References

Arrow, K. et al., (1995) ‘Economic Growth, Carrying Capacity, and the Environment’, Science, 268, 28 April, pp.520-1.

Arrow, K. et al., (2004) ‘Are We Consuming Too Much? ’ Journal of Economic Perspectives, 18 (3), 147-172.

Bauckham (2009) ‘Reading the Sermon on the Mount in an Age of Ecological Catastrophe’, Studies in Christian Ethics, 22 (1), pp.76-88.

Beckman, L. (2008) ‘Do global climate change and the interest of future generations have implications for democracy?’ Environmental Politics, 17 (4), 610-624.

Beddington, J. (2009) ‘Food, Energy and Climate: a perfect storm of global events’ Chief Scientific Advisor’s speech to the UK Government’s Sustainable Development UK Conference, March.

Beddington, J. (2010) ‘Key issues in agricultural science’. Oxford farming conference. Government Office for Science, 6 January.

Berry, R. (ed.) (2007a) When Enough is Enough: A Christian Framework for Environmental Sustainability Nottingham, Apollos.

Berry, R. (2007b) ‘Sustainability: God’s Way or Greenwash?’ In R. Berry (ed.) When Enough is Enough: A Christian Framework for Environmental Sustainability Nottingham, Apollos.

Berry, T. with T. Clark (1995) Befriending the Earth: A Theology of Reconciliation between Humans and the Earth Mystic, Connecticut, Twenty-Third Publications.

Boff, L. (1997) Cry of the Earth, Cry of the Poor Maryknoll, New York, Orbis Books.

Boston, J. (2010) ‘Holding humanity to account for the future state of the planet’, Stimulus: The New Zealand Journal of Christian Thought and Practice, 18 (1), 19-31.

Boston, J. and Lempp, F. (2011) Climate change: explaining and solving the mismatch between scientific urgency and political inertia”, Accounting, Auditing and Accountability Journal, 24, (8) forthcoming.

Boyd, J., Banzhaf, S. (2007) ‘What are ecosystem services? The need for standardized environmental accounting units’, Ecological Economics, 63, 616-626.

Bradsher, K. (2009) ‘China Tightens Grip on Rare Minerals’, New York Times, 31 August.

Brown, J. (2011) ‘Energetic Limits to Economic Growth’, BioScience, 61 (1), 19-26.

Brown, L. (2009) Plan B 4.0: Mobilizing to Save Civilization New York, W.W. Norton & Company.

Carden, A. (2007) ‘Christian Ethics, Formal Institutions, and Economic Growth’, American Review of Political Economy, 5, 1, 34-53.

Cole, H., Freeman, C., Jahoda, M., and Pavitt, K. (1973) Thinking About the Future: A Critique of The Limits to Growth Brighton, Sussex University Press.

Conradie, E. (2004) ‘An Agenda for Ecological Theology’, in D. Edwards and M. Worthing (eds.) Biodiversity and Ecology as Interdisciplinary Challenge Adelaide, ATF Press.

Cribb, J. (2010) The Coming Famine: The Global Food Crisis and What We Can Do To Avoid It Collingwood, Victoria, CSIRO Publishing.

Daly, H. (ed.) (1973) Towards a Steady-State Economy (San Francisco: W. H. Freeman).

Daly, H. (2010) ‘Thermodynamic roots of economics’, Energy Bulletin, 8 November.

Davidson, C. (2000) ‘Economic Growth and the Environment: Alternatives to the Limits Paradigm’ American Institute of Biological Sciences, 50 (5), 433-440.

Den Bergh, J. (2009) ‘The GDP paradox’, Journal of Economic Psychology, 30, 117-135.

Department of Energy and Climate Change (2009) Report on the risks and impacts of a potential future decline in oil production 1 June.

Drew, G. (2010) ‘Metaphor, meaning and the resurrection’, Stimulus: The New Zealand Journal of Christian Thought and Practice, 18 (1).

Diamond, J. (2005) Collapse: How Societies Choose to Fail or Survive Penguin.

Edwards, D. and Worthing, M. (eds.) (2004) Biodiversity and Ecology as Interdisciplinary Challenge Adelaide, ATF Press.

Garnaut, R. (2008) The Garnaut Climate Change Review: Final Report Melbourne: Cambridge University Press.

Habel, N. (ed.) (2000) Readings from the Perspective of Earth Sheffield, Sheffield Academic Press.

Hansen, J. (2009) Storms of My Grandchildren: The Truth about the Coming Climate Catastrophy and Our Last Chance to Save Humanity London, Bloomsbury.

Hansen, J. et al., (2008) Target atmospheric CO2: where should humanity aim? Open Atmospheric Science Journal, 2, 217-231.

Hay, D. (2007) ‘Sustainable economics’, in R. Berry (ed.) When Enough is Enough: A Christian Framework for Environmental Sustainability Nottingham, Apollos.

Hessel, D. and R. Radford Ruether (eds.) (2000) Christianity and Ecology: Seeking the Well-Being of Earth and Humans Cambridge, Mass., Harvard University Press.

Horrell, D. et al., (2010) Greening Paul: Rereading the Apostle in a Time of Ecological Crisis Baylor University Press.

IPCC (2007) Climate Change 2007: Synthesis Report Fourth Assessment Report of the Intergovernmental Panel on Climate Change.

Jackson, T. (2009) Prosperity without Growth: Economics for a Finite Planet (London, Earthscan).

Lockwood, M. (2010) The limits to Environmentalism-Part 1. Political climate. Visited at http://politicalclimate.net/2010/02/25/the-limits-to-environmentalism-part1/. On 03/02/2010

Malthus, T. (1798) An essay on the principle of population. Oxford World’s Classics reprint.

Meadows, D., Meadows, D., Randers, J. and W. Behrens (1972) The Limits to Growth: A report for the Club of Rome’s project on the predicament of mankind’ London, Compton Printing Limited.

Meadows, D., Meadows, D. and J. Randers (1992) Beyond the Limits: Global Collapse or a Sustainable Future? London, Earthscan Publications Limited.

Meadows, D., Meadows, D. and J. Randers (2004) Limits to Growth: The 30 year Update White River Junction, Vermont, Chelsea Green Publishing Company.

Mesarovic, M. and Pestel, E. (1975) Mankind at the Turning Point: The Second Report to The Club of Rome London, Hutchinson.

Nelson, J. (2009) ‘Uneconomic Growth: Steady State Economy’. http://steadystaterevolution.org/uneconomic-growth/ 16/12/2010.

Northcott, M. (2007) A Moral Climate: The Ethics of Global Warming New York, Orbis Books.

O’Donovan, O. (1986) Resurrection and Moral Order Leister, IVP.

OECD (2011) Towards Green Growth Paris, OECD.

Randers, J. (2008) ‘Global collapse: Fact or fiction?’ Futures, 40, 853-864.

Rockström, J., et al. (2009a) ‘Planetary boundaries: exploring the safe operating space for humanity’, Ecology and Society, 14 (2): 32.

Rockström, J., (2009b) ‘A safe operating space for humanity’, Nature, 461, 24 September, 472-5.

Schlesinger, W. (2009) ‘Thresholds risk prolonged degradation’, Nature, October, p.112. Available at http://www.nature.com/climate/2009/0910/pdf/climate.2009.93.pdf [25/03/10]. pg 112

Simms, A., V. Johnson and P. Chowla (2010) ‘Growth isn’t possible: why we need a new economic direction’, New Economics Foundation, available via http://www.neweconomics.org/publications/growth-isnt-possible [25/03/10].

Southgate, C. (2008) The Groaning of Creation: God, Evolution and the Problem of Evil Louisville, Westminster John Knox Press.

Spencer, N. and R. White (2007) Christianity, Climate Change and Sustainable Living London, SPCK.

Stern, N. (2007) The Economics of Climate Change: the Stern Review Cambridge, Cambridge University Press.

Stern, N. (2011) ‘How should we think about the economics of climate change?’ Lecture for Leonteif Prize, 8th March 2011.

Stiglitz, J., Sen. A. and J. Fitoussi (2009) Report by the Commission on the Measurement of Economic Performance and Social Progress Paris.

Sukhdev, P. et al. (2008) The Economics of Ecosystems and Biodiversity: An Interim Report European Communities.

Treasury (2011) ‘Working Towards Higher Living Standards for New Zealanders’, New Zealand Treasury Paper 11/02, May.

Turner, G. M. (2008) ‘A comparison of the Limits to Growth with 30 years of reality’, Global Environmental Change, 18, 397-411.

Wam, H. (2010) ‘Economists, time to team up with the ecologists!’ Ecological Economics, 69, 675-679.

Union of Concerned Scientists (1992) World Scientists’ Warning to Humanity. http://www.ucsusa.org/about/1992-world-scientists.html on 26/01/2011

Whitehead, J. (2008) ‘Growth in a World of Limits: Challenges and Opportunities for Businesses and the Economy’, World Environment Day Symposium, Auckland, 4 June.

World Commission on Environment and Development (WCED) (1987) Our Common Future New York, United Nations.

Wright, T. (2007) Surprised by Hope London, SPCK.