Aside from blaming over-population, a second mainstream response to the ecological crisis is to claim that science and technology will save the planet. From this perspective, rather than focusing on reducing consumption or population, what primarily needs to happen is for scientific or technological advancements to make the production of commodities more efficient; that is, to make commodities progressively less dependent on material resources, a process often referred to as ‘decoupling’ (or ‘dematerialization’). By way of decoupling, the ecological impacts of economic activity can decrease, in theory, even as the economy grows, meaning that per capita incomes can grow indefinitely while remaining within ecological limits – or so the argument goes.
In assessing the validity of this argument it is imperative to distinguish between ‘relative’ and ‘absolute’ decoupling. Relative decoupling refers to a decline in the ecological impact per unit of economic output. Absolute decoupling refers to a decline in the ecological impact of total economic output. While relative decoupling may occur, making each commodity less ecologically intensive, if the total consumption of commodities increases then there may be no absolute decoupling; indeed, the absolute ecological impact of total economic activity may increase. Since the scientific research cited in an earlier post showed that the global economy already exceeds the planet’s sustainable carrying capacity, it is clear that absolute decoupling is what is urgently needed. It is also clear, however, that absolute decoupling is not occurring.
Consider, for example, the energy intensity per unit of global economic output, where the evidence of relative decoupling is quite clear. Tim Jackson reports that the amount of energy needed to produce each unit of the world’s economic output has fallen more or less continuously in recent decades, with the global energy intensity per unit now 33 per cent lower on average than it was in 1970. Unsurprisingly, this improved energy efficiency is also leading to relative decoupling in terms of carbon emissions intensities. The global carbon intensity per unit of economic output declined by almost a quarter from just over 1 kilogram of carbon dioxide per US dollar in 1980 to 770 grams of carbon dioxide per US dollar in 2006.
However, despite declining energy and carbon intensities, Jackson shows that carbon dioxide emissions from fossil fuels have increased 80 per cent since 1970. ‘Emissions today,’ he adds, ‘are almost 40% higher than they were in 1990 – the Kyoto base year – and since the year 2000 they have been growing at 3% per year.’ Without entering into the intricacies of the emissions literature, the present point is simply that despite significant relative decoupling of energy and carbon intensities, absolute levels of carbon emissions are rising significantly.
Peter Victor arrived at essentially the same conclusion when he reviewed studies of decoupling with respect to the total material resource requirements of Germany, the Netherlands, United States, and Japan – some of the most technologically advanced nations on the planet. He reports that although a modest degree of decoupling occurred from 1975-1993, the decoupling was insufficient to prevent the total use of resources increasing during this period. He explains that ‘[t]his is because the rate of increase in GDP in each of the four countries was greater than the rate of decrease in material intensity.’ Globally the message is essentially the same:
Comparing 2002 with 1980 about 25 per cent less natural resources (measured in physical units) were used to produce one dollar of GDP. This relative decoupling of economic growth and resource use was insufficient to prevent the total quantity of resource extraction increasing, which it did by 36 per cent.
In this context reference must be made to the related matter of the Environmental Kuznets Curve (EKC) hypothesis. This hypothesis holds that the relationship between per capita GDP and environmental impact is represented by an inverted U-shaped curve, implying that environmental impact grows during low levels of per capita GDP, levels off at mid-level per capita GDP, and at high levels of per capita GDP environmental quality improves. In essence, the reasoning beneath the hypothesis is as follows: (1) that wealthy countries have the financial luxury of worrying about environmental issues where poor countries must focus solely on providing for basic needs, irrespective of environmental impact; and (2) that as countries get richer their consumption habits tend to shift from ‘goods’ to ‘services’ – representing a shift from ‘industrial’ societies to ‘post-industrial’ or ‘information’ societies – which is claimed to have environmental benefits (due to decoupling). This hypothesis is used to argue that there are no environmental limits to growth in per capita income – that growth is ultimately good for the environment, even if at first it seems bad.
A comprehensive review of the literature on EKC hypothesis is beyond the scope of this post, but in broad terms its empirical status can be expressed as follows. Some studies have shown that where the environmental damage is generated and suffered within a nation (or within adjacent and cooperating nations) the EKC hypothesis can indeed be valid. These limited circumstances can include wastewater discharge, sulphur dioxide emissions, and carbon monoxide emissions. On the other hand, when the environmental problems cross national boundaries, most studies conclude that the EKC does not hold. Most importantly, several studies have come to the conclusion that the EKC does not hold for carbon dioxide, arguably the greatest environmental problem. Furthermore, a 2009 study by Holm and Englund has done much to debunk the widely held belief that a movement toward a ‘service’ or ‘post-industrial’ economy leads to reduced environmental impacts. In a review of the evidence on this matter, they conclude that despite growth of the service sector during the last decades in the world’s wealthier countries, overall resource consumption has increased (which confirms Victor’s assessment above). In another review of the data and methodologies used to estimate the EKC hypothesis, David Stern concludes that ‘the statistical analysis on which the environmental Kuznets curve is based is not robust. There is little evidence for a common inverted U-shaped pathway that countries follow as their incomes rise.’ It is wrong, therefore, to assume that economies can ‘grow their way out’ of the environmental crisis.
The message of this post is not that decoupling through techno-efficiency improvements is unnecessary – far from it. Decoupling has an absolutely vital role to play in the attainment of a sustainable society. But the evidence shows that despite many examples of relative decoupling, growth in overall economic output and consumption has meant that absolute impacts on the environment are still increasing. It is fanciful, therefore, and arguably irresponsible, to claim that technology, science, efficiency, and decoupling are capable of solving the ecological crisis, when they are, at best, a partial solution. In order to achieve the absolute decoupling needed to achieve ecological sustainability, what is needed is a fundamental reassessment of current consumption habits.
In short, simpler lifestyles of reduced consumption are a necessary part of any transition to a sustainable society. In this transition, the Voluntary Simplicity Movement is leading the way.
 As Mark Sagoff puts it, ‘Nature need not limit economic growth… as long as knowledge increases and the sun shines.’ Mark Sagoff, ‘Carrying Capacity and Ecological Economics’ (1995) 45 Bioscience 610, 614. See also, Bjorn Lomborg, The Skeptical Environmentalist: Measuring the Real State of the World (2001); Indur Goklany, The Improving State of the World: Why We’re Living Longer, Healthier, More Comfortable Lives on a Cleaner Planet (2007); Julian Simon and Herman Kahn, The Resourceful Earth: A Response to Global 2000 (1984).
 See Tim Jackson, Prosperity with Growth: Economics for a Finite Planet (2009).
 See, e.g., Norman Myers and Julian Simon, Scarcity or Abundance?: A Debate on the Environment (1st ed, 1994).
 In what follows I draw upon more comprehensive discussions and literature reviews in Jackson, Prosperity without Growth, above n 2; Peter Victor, Managing without Growth: Slower by Design, not Disaster (2008).
 Jackson, Prosperity with Growth, above n 2, 69.
 Ibid 171.
 Ibid. See also, United Nations Development Program, ‘Human Development Report’ (2007/8) (noting that ‘efficiency gains have failed to prevent large aggregate increases in emissions’); Stephen Purdey, Economic Growth, International Relations, and the Environment: The Growth Paradigm (2010) 136-7 (reviewing evidence that carbon emissions per capita show a clear tendency to increase with income). See also, Blake Alcott, ‘Jevons’ Paradox’ (2005) 54(1) Ecological Economics 9.
 Victor, above n 4, 55.
 Ibid 55-6.
 For the first explicit statement of this hypothesis, see Gene Grossman and Alan Kruger, ‘Environmental Impacts of a NAFTA Agreement’ (1991) (National Bureau of Economic Research Working Paper, 3914).
 See Wilfred Beckerman, A Poverty of Reason: Sustainable Development and Economic Growth (2002).
 As Beckerman puts it, ‘although economic growth usually leads to environmental degradation in the early stages of the process, in the end the best – and probably the only – way to attain decent environment in most countries is to become rich.’ Wilfred Beckerman, ‘Economic Growth and the Environment: Whose Growth? Whose Environment?’ (1992) 20(4) World Development 481, 482. See also, Lomborg, above n 1.
 For a recent discussion and review, see David Stern, ‘Between Estimates of the Emissions-Income Elasticity’ (2010) 69(11) Ecological Economics 2173.
 See Soumyananda Dinda, ‘Environmental Kuznets Curve Hypothesis: A Survey’ (2004) 49(4) Ecological Economics 431.
 But see Stern, above n 16, disputing the case for sulphur.
 Jie He and Patrick Richard, ‘Environmental Kuznets Curve for CO2 in Canada’ (2009) 69(5) Ecological Economics 1083; Robert Ayres, ‘Economic Growth: Politically Necessary but not Environmentally Friendly’ (1995) 15(2) Ecological Economics 97 (stating that ‘the regularity [of the EKC] only holds for a relatively small subset of environmental problems’ and that any general proposition that economic growth is good for the environment is ‘false and pernicious nonsense’).
 Michael Common and Sigrid Stagl, Ecological Economics: An Introduction (2005) 249.
 Stig-Olof Holm and Göran Englund, ‘Increased Ecoefficiency and Gross Rebound Effect: Evidence from USA and Six European countries 1960-2002’ (2009) 68(3) Ecological Economics 879.
 Ibid. See also, Philip Lawn, ‘Goods and Services and the Dematerialisation Fallacy: Implications for Sustainable Development Indicators and Policy’ (2001) 2 International Journal of Services Technology and Management 363.
 David Stern, ‘The Rise and Fall of the Environmental Kuznets Curve’ (2004) 32(8) World Development 1419, 1435.
 Stern, ‘Between Estimates of the Emissions-Income Elasticity,’ above n 16.
 See, e.g., William McDonough and Michael Braungart, Cradle to Cradle: Remaking the Way we Make Things (2009).