Debt overhangs, volatile commodity prices and trade imbalances conspire with demographic change, declining productivity growth in advanced nations and structural change in emerging economies to deliver a variety of adverse conditions for prosperity. Climate change adds a particular twist to this near-perfect storm. Achieving this will require a massive and accelerated transformation in capital markets: a transformation which would be challenging at the best of times, and these are evidently not the best of times.
In short, the question of limits is as relevant now as it ever was. To coincide with the launch of the APPG and to provide a foundation for its work over the next five years, environmental writer Robin Webster and I have put together a short review of the limits debate. We unravel the arguments that have raged for over forty years in its aftermath and explore more recent findings which relate to the original hypothesis. What we found is salutary. Certain other limits to growth — less visible in the report — present equally pressing challenges to modern society.
The result is industrial decline, which forces declines in the service and agricultural sectors. About the year , population peaks and begins to decrease as the death rate is driven upward by lack of food and health services.
But pollution levels soar, depressing land yields and requiring huge investments in agricultural recovery. The population finally declines because of food shortages and negative health effects from pollution. Even a scenario with these features however, results in overshoot and collapse.
The result is rather abrupt decline. If to this scenario one adds reductions in the amount of nonre- newable resources needed per unit of industrial output resource efficiency technology , in combination all these features permit a fairly large and prosperous world, until the bliss starts declining in response to the accumulated cost of the technologies. This technology program comes online too late to avoid a gradual decline in human welfare throughout the century.
But industrial output begins to decline around because the rising expense of protecting the population from starvation, pollution, erosion, and resource shortage cuts into the capital available for growth. Ultimately this simulated world fails to sustain its living standards as technology, social services, and new investment simultaneously become too expensive. One way is to disguise, deny, or confuse the signals. An example would be to buy air conditioners for relief from a warming climate, or to ship toxic wastes for disposal in a distant region.
A second way is to alleviate the pressures from limits by employ- ing technical or economic fixes. For example, reducing the amount of pollution generated per mile of driving or per kilowatt of electricity generated. The third way is to work on the underlying causes, to recognize that the socioeconomic system has overshot its limits, is headed toward collapse, and therefore seek to change the structure of the system.
World3 can be used to test some of the simplest changes that might result from a society that decides to back down from over- shoot and pursue goals more satisfying and sustainable than perpetual material growth. Scenario 7 supposes that after , all couples decide to limit their family size to two children and have access to effective birth control technologies. Because of age structure momentum, the population continues to grow for another generation. But the slower population growth permits industrial output to rise faster, until it is stopped by rising pollution.
Under this scenario, world population peaks at 7. A globally effective, two children policy introduced in reduces the peak population less than 10 percent. But industrial output peaks in and declines. The larger capi- tal plant emits more pollution, which has negative effects on agricul- tural production.
Later on, after , pollution levels are sufficiently high to have negative impacts on life expectancies. What if they set a goal for themselves of an adequate but not excessive standard of living? But pollution increasingly stresses agricultural resources. Per capita food production declines, eventually bringing down life expectancy and population. These changes cause a considerable rise in consumer goods and services per capita in the first decade after the year In fact, they rise higher and faster than they did in the previous run, where industrial growth was not curtailed.
But this economy is not quite stabilized. It has an ecological footprint above the sustainable level, and it is forced into a long decline after The world of Scenario 8 manages to support more than seven billion people at an adequate standard of living for almost 30 years, from to , but during that time the environment and soils steadily deteriorate.
To remain sustainable, the world in this scenario needs to lower its ecological footprint to a level below the carrying capacity of the global environment. Moving in this direction, in another scenario the world seeks stable population and stable industrial output per person, and adds pollution, resource and agricultural technologies starting in In this scenario, population and industrial output are limited as in the previous run, and in addition technologies are added to abate pollution, conserve resources, increase land yield, and protect agri- cultural land.
The resulting society is sustainable: Nearly eight billion people live with high human welfare and a continuously declining ecological footprint. Under this scenario, the world decides on an average family size of two children and sets modest limits for material production, as in the previous scenario.
Further, starting in it begins to develop, invest in, and employ the technologies that increase the efficiency of resource use, decrease pollution emissions per unit of industrial output, control land erosion, and increase land yields until food per capita reaches its desired level.
The society of this scenario manages to begin reducing its total burden on the environment before the year ; from that point the total ecological footprint of humanity is actually declining. The system brings itself down below its limits, avoids an uncontrolled collapse, maintains its standard of living, and holds itself very close to equilibrium. In a final scenario, the sustainability policies of the previous scenario are introduced 20 years earlier, in Under this scenario, population levels off just above six billion instead of eight billion.
Pollution peaks at a much lower level and 20 years sooner, and interferes less with agriculture than it did in the previous scenario. Life expectancy surpasses 80 years and remains high. Life expectancy, food per capita, services per capita, and consumer goods per capita all end up at higher levels than they did in the previous scenario. Two general insights from this effort are valid and relevant.
The final four scenarios also suggest some general conclusions A global transition to a sustainable society is probably possible without reductions in either population or industrial output. A transition to sustainability will require an active decision to reduce the human ecological footprint. There are many choices that can be made about numbers of peo- ple, living standards, technological investment, and allocations among industrial goods, services, food, and other material needs.
The longer the world takes to reduce its ecological footprint and move toward sustainability, the lower the population and material standard that will be ultimately supportable. The higher the targets for population and material standard of living are set, the greater the risk of exceeding and eroding its limits. This means that birthrates roughly equal death rates, and investment rates roughly equal depreciation rates, unless or until technical change and social decisions justify a considered, limited change in the levels of population or capital.
Such a society, with a sustainable ecological footprint, would be almost unimaginably different from the one in which most people now live. Before we can elaborate on what sustainability could be, we need to start with what it need not be. Sustainability does not mean zero growth. Rather, a sustainable society would be interested in qualitative development, not physical expansion.
It would use material growth as a considered tool, not a perpetual mandate. Neither for nor against growth, it would begin to discriminate among kinds of growth and purposes for growth.
It would ask what the growth is for, and who would benefit, and what it would cost, and how long it would last, and whether the growth could be accommodated by the sources and sinks of the earth.
A sustainable society would also not paralyze into permanence the current inequitable patterns of distribution. For both practical and moral reasons, a sustainable society must provide sufficiency and security for all. A sustainable society would not be a society of despon- dency and stagnation, unemployment and bankruptcy that current systems experience when their growth is interrupted.
A sustainable world would also not be a rigid one, with population or production or anything else held pathologically constant. Photograph: Alamy The book Limits to Growth, which predicted our civilisation would probably collapse some time this century, has been criticised as doomsday fantasy since it was published. Limits to Growth was commissioned by a think tank called the Club of Rome. Called World3, this computer model was cutting edge.
The task was very ambitious. The team tracked industrialisation, population, food, use of resources, and pollution. They modelled data up to , then developed a range of scenarios out to , depending on whether humanity took serious action on environmental and resource issues.
So were they right? We decided to check in with those scenarios after 40 years. Dr Graham Turner gathered data from the UN its department of economic and social affairs, Unesco, the food and agriculture organisation, and the UN statistics yearbook. He also checked in with the US national oceanic and atmospheric administration, the BP statistical review , and elsewhere.
That data was plotted alongside the Limits to Growth scenarios. These graphs show real-world data first from the MIT work, then from our research , plotted in a solid line. Solid line: MIT, with new research in bold. Photograph: Supplied As the MIT researchers explained in , under the scenario, growing population and demands for material wealth would lead to more industrial output and pollution.
The graphs show this is indeed happening.When The Limits to Growth was first published in , most economists, along with many industrialists, politicians, and Third World advocates raised their voices in outrage at the suggestion that population growth and material consumption need to be reduced by deliberate means. Another renewable resource is forests, which moderate climate, control floods, and harbor species, from rattan vines to dyes and sources of medicine. As more and more capital goes towards resource extraction, industrial output per capita starts to fall — in the book, from about
A second way is to alleviate the pressures from limits by employ- ing technical or economic fixes. A sustainable world would need rules, laws, standards, bound- aries, social agreements and social constraints, of course, but rules for sustainability would be put into place not to destroy freedoms, but to create freedoms or protect them. Technological advance and the market are reflected in the model in many ways. All the environmental and economic problems discussed in Limits to Growth have been treated at length before.
According to the book, to feed the continued growth in industrial output there must be ever-increasing use of resources.
This means that birthrates roughly equal death rates, and investment rates roughly equal depreciation rates, unless or until technical change and social decisions justify a considered, limited change in the levels of population or capital. All the environmental and economic problems discussed in Limits to Growth have been treated at length before. The result is rather abrupt decline.
Within the last 35 years, the limits, especially of areas with the best soils, have been approached.
The message of is far more real and relevant in The graphs show this is indeed happening. The third way is to work on the underlying causes, to recognize that the socioeconomic system has overshot its limits, is headed toward collapse, and therefore seek to change the structure of the system. An example would be to buy air conditioners for relief from a warming climate, or to ship toxic wastes for disposal in a distant region.
The first stages of decline may already have started. But this economy is not quite stabilized.
In some of the poorest and richest economies, per capita water withdrawals are going down because of environmental problems, rising costs, or scarcity. The three causes of overshoot are always the same, at any scale from personal to planetary. On a global scale, however, they have not yet reduced the vast materials flow through the economy.