Thomas Wiedmann, Manfred Lenzen, Lorenz T. Keyßer & Julia K. Steinberger
Nature Communications volume 11, Article number: 3107 (2020)
For over half a century, worldwide growth in affluence has continuously increased resource use and pollutant emissions far more rapidly than these have been reduced through better technology. The affluent citizens of the world are responsible for most environmental impacts and are central to any future prospect of retreating to safer environmental conditions. We summarise the evidence and present possible solution approaches. Any transition towards sustainability can only be effective if far-reaching lifestyle changes complement technological advancements. However, existing societies, economies and cultures incite consumption expansion and the structural imperative for growth in competitive market economies inhibits necessary societal change.
Recent scientists’ warnings confirm alarming trends of environmental degradation from human activity, leading to profound changes in essential life-sustaining functions of planet Earth1,2,3. The warnings surmise that humanity has failed to find lasting solutions to these changes that pose existential threats to natural systems, economies and societies and call for action by governments and individuals.
The warnings aptly describe the problems, identify population, economic growth and affluence as drivers of unsustainable trends and acknowledge that humanity needs to reassess the role of growth-oriented economies and the pursuit of affluence1,2. However, they fall short of clearly identifying the underlying forces of overconsumption and of spelling out the measures that are needed to tackle the overwhelming power of consumption and the economic growth paradigm4.
This perspective synthesises existing knowledge and recommendations from the scientific community. We provide evidence from the literature that consumption of affluent households worldwide is by far the strongest determinant and the strongest accelerator of increases of global environmental and social impacts. We describe the systemic drivers of affluent overconsumption and synthesise the literature that provides possible solutions by reforming or changing economic systems. These solution approaches range from reformist to radical ideas, including degrowth, eco-socialism and eco-anarchism. Based on these insights, we distil recommendations for further research in the final section.
Affluence as a driver of environmental and social impacts
The link between consumption and impacts
There exists a large body of literature in which the relationship between environmental, resource and social impacts on one hand, and possible explanatory variables on the other, is investigated. We review and summarise those studies that holistically assess the impact of human activities, in the sense that impacts are not restricted to the home, city, or territory of the individuals, but instead are counted irrespective of where they occur. Such an assessment perspective is usually referred to as consumption-based accounting, or footprinting5.
Allocating environmental impacts to consumers is consistent with the perspective that consumers are the ultimate drivers of production, with their purchasing decisions setting in motion a series of trade transactions and production activities, rippling along complex international supply-chain networks5. However, allocating impacts to consumers does not necessarily imply a systemic causal understanding of which actor should be held most responsible for these impacts. Responsibility may lie with the consumer or with an external actor, like the state, or in structural relations between actors. Scholars of sustainable consumption have shown that consumers often have little control over environmentally damaging decisions along supply chains6, however they often do have control over making a consumption decision in the first place. Whilst in Keynesian-type economics consumer demand drives production, Marxian political economics as well as environmental sociology views the economy as supply dominated7. In this paper, we highlight the measurement of environmental impacts of consumption, while noting that multiple actors bear responsibility.
Holistic studies of the environmental or social consequences of consumption usually involve the use of life-cycle assessment or input-output analysis that do not only account for direct (on-site, within-territory) but importantly also include indirect impacts occurring along global and complete supply chains8,9. The use of such methods is important, because failing to detect the outsourcing of indirect impacts (also called spill overs or leakage) has the potential to seriously undermine global environmental abatement efforts, e.g. on climate change10.
A significant proportionality between consumption and impact exists for a large range of environmental, resource and social indicators. The implications of consumption on scarce energy resources emerged already in the 1970s and was confirmed by many consumption-based analyses on indicators as varied as CO2 emissions, raw materials, air pollution, biodiversity, nitrogen emissions, scarce water use or energy5,11. Many of these studies employed multiple regression or similar techniques, yielding clear evidence for our first finding: that consumption is by far the strongest determinant of global impacts, dwarfing other socio-economic–demographic factors such as age, household size, qualification or dwelling structure12,13,14,15. Whilst the strength of the proportionality between consumption and impact decreases slightly towards higher incomes (measured by so-called elasticities), consumption was found to be a consistently positive driver. In other words, the impact intensity of consumption decreases, but absolute impacts increase towards higher consumption. Absolute decoupling, let alone an inverted-U-type Kuznets relationship, does not occur from a consumption-based accounting perspective11,16,17.
For some social indicators, causal associations between consumption and impact are weak or non-existent. For example, withdrawing consumption from countries with unequal wages, child labour, corruption or severe occupational hazards may not influence those conditions, and might even exacerbate social problems. Footprint studies on these indicators nevertheless characterise consumers of commodities from socially problematic origins as being implicated with detrimental impacts9,18,19,20.
Many indicators of global environmental and social impacts have been monitored over time, and time series data exist5. Numerous global studies decomposing time series of footprints of consumption into drivers of trends have been carried out over the past decades, for example on greenhouse-gas emissions, energy use, water use, materials or mercury emissions. These studies routinely decompose global impact trends into effects due to changes in a number of factors, such as technology, the input structure of production, the product mix in consumer demand, the level of per-capita consumption or population21.
The majority of studies agree that by far the major drivers of global impacts are technological change and per-capita consumption11. Whilst the former acts as a more or less strong retardant, the latter is a strong accelerator of global environmental impact. Remarkably, consumption (and to a lesser extent population) growth have mostly outrun any beneficial effects of changes in technology over the past few decades. These results hold for the entire world22,23 as well as for numerous individual countries11,24,25,26. Figure 1 shows the example of changes in global-material footprint and greenhouse-gas emissions compared to GDP over time. The overwhelming evidence from decomposition studies is that globally, burgeoning consumption has diminished or cancelled out any gains brought about by technological change aimed at reducing environmental impact11.
Furthermore, low-income groups are rapidly occupying middle- and high-income brackets around the world. This can potentially further exacerbate the impacts of mobility-related consumption, which has been shown to disproportionately increase with income (i.e. the elasticity is larger than one27). This means that if consumption is not addressed in future efforts for mitigating environmental impact, technological solutions will face an uphill battle, in that they not only have to bring about reductions of impact but will also need to counteract the effects of growing consumption and affluence28,29.
To avoid further deterioration and irreversible damage to natural and societal systems, there will need to be a global and rapid decoupling of detrimental impacts from economic activity. Whilst a number of countries in the global North have recently managed to reduce greenhouse-gas emissions while still growing their economies30, it is highly unlikely that such decoupling will occur more widely in the near future, rapidly enough at global scale and for other environmental impacts11,17. This is because renewable energy, electrification, carbon-capturing technologies and even services all have resource requirements, mostly in the form of metals, concrete and land31. Rising energy demand and costs of resource extraction, technical limitations and rebound effects aggravate the problem28,32,33. It has therefore been argued that “policy makers have to acknowledge the fact that addressing environmental breakdown may require a direct downscaling of economic production and consumption in the wealthiest countries”17,p.5. We will address this argument in the section on systemic drivers and possible solutions.
In what follows, we will explain why we characterise consumption as affluence. Inequality is commonly described by the Gini index, with 0 characterising total equality (all individuals equal) and 100 representing total inequality (one individual owning everything). World countries’ Gini indices of income inequality range between 25 (Scandinavia) and 63 (Southern Africa)34. The world’s Gini index of income inequality is around 75, higher than the corresponding index of any national population. Simply put, the world as a whole is more unequal than any individual country.
Since income is strongly linked with consumption, and consumption is in turn linked with impact (see previous section), we can expect existing income inequalities to translate into equally significant impact inequalities. Indeed, environmental, resource and social impacts are exerted unequally across the world population. Teixido-Figueras et al.35 report that international Gini coefficients for CO2 emissions, material consumption and net primary productivity (both measured from a production and consumption perspective) range between 35 and 60. These values mean that the world’s top 10% of income earners are responsible for between 25 and 43% of environmental impact. In contrast, the world’s bottom 10% income earners exert only around 3–5% of environmental impact35. These findings mean that environmental impact is to a large extent caused and driven by the world’s rich citizens36. Considering that the lifestyles of wealthy citizens are characterised by an abundance of choice, convenience and comfort, we argue that the determinant and driver we have referred to in previous sections as consumption, is more aptly labelled as affluence.
Teixido-Figueras et al.35 also find that carbon emissions and material use are globally more unequally distributed when accounted for as footprints. In contrast to territorial allocations, footprints attribute environmental burdens to the final consumer, no matter where the initial environmental pressure has occurred. Here, international trade is responsible for shifting burdens from mostly low-income developing-world producers to high-income developed-world consumers37. This phenomenon of outsourcing appears to exacerbate global disparities, at least in carbon emissions and material use contexts.
Systemic drivers and possible solutions
As the previous section shows, there is a positive relationship between biophysical resource use and affluence, as defined by income. Adding to this, the most affluent groups have higher incomes than expenditure, and their saving and investing leads to substantial additional environmental impact38. Therefore, and due to significant inter- and intra-national wealth and income inequality36,39, we differentiate between globally affluent groups, such as the European Union, and the most wealthy and affluent groups within countries, e.g. the <1–10% richest income segments36. As quantitative research36,40,41 shows, highly affluent consumers drive biophysical resource use (a) directly through high consumption, (b) as members of powerful factions of the capitalist class and (c) through driving consumption norms across the population. The next sections focus on affluent groups globally and on the intra-nationally most wealthy and affluent segments (hereafter called super-affluent).
Since the level of consumption determines total impacts, affluence needs to be addressed by reducing consumption, not just greening it17,28,29. It is clear that prevailing capitalist, growth-driven economic systems have not only increased affluence since World War II, but have led to enormous increases in inequality, financial instability, resource consumption and environmental pressures on vital earth support systems42. A suitable concept to address the ecological dimension is the widely established avoid-shift-improve framework outlined by Creutzig et al.43. Its focus on the end-use service, such as mobility, nutrition or shelter, allows for a multi-dimensional analysis of potential impact reductions beyond sole technological change. This analysis can be directed at human need satisfaction or decent living standards—an alternative perspective put forward for curbing environmental crises44,45. Crucially, this perspective allows us to consider different provisioning systems (e.g. states, markets, communities and households) and to differentiate between superfluous consumption, which is consumption that does not contribute to needs satisfaction, and necessary consumption which can be related to satisfying human needs. It remains important to acknowledge the complexities surrounding this distinction, as touched upon in the sections on growth imperatives below. Still, empirically, human needs satisfaction shows rapidly diminishing returns with overall consumption45,46.
As implied by the previous section on affluence as a driver, the strongest pillar of the necessary transformation is to avoid or to reduce consumption until the remaining consumption level falls within planetary boundaries, while fulfilling human needs17,28,46. Avoiding consumption means not consuming certain goods and services, from living space (overly large homes, secondary residences of the wealthy) to oversized vehicles, environmentally damaging and wasteful food, leisure patterns and work patterns involving driving and flying47. This implies reducing expenditure and wealth along ‘sustainable consumption corridors’, i.e. minimum and maximum consumption standards48,49 (Fig. 2). On the technological side, reducing the need for consumption can be facilitated by changes such as increasing lifespans of goods, telecommunication instead of physical travel, sharing and repairing instead of buying new, and house retrofitting43.
However, the other two pillars of shift and improve are still vital to achieve the socio-ecological transformation46. Consumption patterns still need to be shifted away from resource and carbon-intensive goods and services, e.g. mobility from cars and airplanes to public buses and trains, biking or walking, heating from oil heating to heat pumps, nutrition—where possible—from animal to seasonal plant-based products43,46. In some cases this includes a shift from high- to low-tech (with many low-tech alternatives being less energy intense than high-tech equivalents, e.g. clothes line vs. dryer) and from global to local47. In parallel, also the resource and carbon intensity of consumption needs to be decreased, e.g. by expanding renewable energy, electrifying cars and public transport and increasing energy and material efficiency43,46.
The avoid-shift-improve framework, coherently applied with a dominant avoid and strong shift, implies the adoption of less affluent, simpler and sufficiency-oriented lifestyles to address overconsumption—consuming better but less46,47,49,50. This also includes addressing socially unsustainable underconsumption in impoverished communities in both less affluent and affluent countries, where enough and better is needed to achieve a more equal distribution of wealth and guarantee a minimum level of prosperity to overcome poverty48,49. Thus, establishing a floor-and-ceiling strategy of sustainable consumption corridors is necessary48,49 (Fig. 2).
It is well established that at least in the affluent countries a persistent, deep and widespread reduction of consumption and production would reduce economic growth as measured by gross domestic product (GDP)51,52. Estimates of the needed reduction of resource and energy use in affluent countries, resulting in a concomitant decrease in GDP of similar magnitude, range from 40 to 90%53,54. Bottom-up studies, such as from Rao et al.55 show that decent living standards could be maintained in India, Brazil and South Africa with around 90% less per-capita energy use than currently consumed in affluent countries. Trainer56, for Australia, and Lockyer57, for the USA, find similar possible reductions. In current capitalist economies such reduction pathways would imply widespread economic recession with a cascade of currently socially detrimental effects, such as a collapse of the stock market, unemployment, firm bankruptcies and lack of credit50,58. The question then becomes how such a reduction in consumption and production can be made socially sustainable, safeguarding human needs and social function50,59 However, to address this question, we first need to understand the various growth imperatives of capitalist social and economic systems and the role of the super-affluent segments of society60.
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“Scientists’ warning on affluence” Nature Communications 19 June 2020
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