t is true that no one can accurately predict what the combined effect of all the many environmental impacts of human activity will be, but it is certain that our world is changing and that these changes may not all be to our benefit. It is also true that only a small percentage of the world's population, those living in the developed countries, is responsible for most of the resource use and emissions - figures vary but the average mentioned is a ration of 20/80. This realisation has many implications for society. The environmental impacts described above are the result of very specific patterns of development and consumption. These patterns have been marketed so well across the globe that they have become the standard to which everyone from Anchorage to Zanzibar aspire. However, the amazing standard of living achieved in the developed world, and which inspires the dreams of every poor person on the planet, cannot conceivably be replicated for a world population of 10 billion, given our planetary source and sink limits.

This brings is to the question people have been asking since the Club of Rome published their Limits to Growth in the 1970's. How many people can the Earth support? Well, it all depends on the quality of life we want to have. We can in all probability squeeze 200 billion people onto the planet if we want no nature left, if everyone lived in hundred story blocks of flats and if everyone was prepared to subsist on their own waste products. But who wants to live that way? Leaving some ecologically productive space for nature, Table 1 provides some indication of how many people the planet can support at different levels of consumption.

Standard of living Billions of people

Current USA 2 billion

As above with some environmental restrictions 4 billion

Only US and Europe at current, the rest at Mexico's level 6 billion

Everyone at Mexican level 20 billion

Everyone at African level 40 billion

Table 1: Planetary carrying capacity Source: McCLuney, 1999, Audubon Society

Sustainable development is popularly defined as meeting the needs of the present in such a way that we will be able to meet the needs of the future as well. To do this sustainable development requires the promotion of values that encourage consumption standards that are within the bounds of the ecologically possible and to which all could reasonably aspire.i So far there have been two ways of measuring what that level of consumption will be. The one is by measuring our ecological footprint; the other by seeing what a fair share of the world's resources would be for every one.

Our ecological footprint is the sum of those areas (ecologically productive space) we need to sustain the lifestyle of each person. This would be the area of cropland necessary to produce the food we eat, the area of grazing land for producing animal products; the area of forest to produce wood and paper; the area of sea to produce the fish and seafood we consume; the area of land to accommodate housing and infrastructure; and the area of forest necessary to absorb the CO2 from our energy consumption. Table 2 provides the most recent (1997) footprints for a few countries, as well as the current per capita availability of ecologically productive space. From this we can see that our current per capita ecological footprint is about 35 % larger than what is available - we are not only living off our capital, we are already in environmental debt.

Country Footprint in hectares

United States of America 10.3 ha

Sweden 5.9 ha

South Africa 3.2 ha

China 1.2 ha

India 0.8 ha

Bangladesh 0.5 ha

World availability 1.7 ha

World average footprint 2.85 ha

Table 2: Ecological Footprint (1997) Source: World Resources Institute

While we have been doing a lot to decrease our energy consumption at an industry level, this has not had much of an impact on the ecological footprint of most countries, as per capita consumption has increased exponentially. At the same time global availability of cropland has been reduced with 25% over two decades and many of the ocean species that were traditionally part of our diet is in danger of extinction.

Most of our predictions regarding sink and source limits work on current consumption levels, with 20% of the global population using 80% of the resources. The picture would look considerably worse if the remaining 80% of world population begin to live at the same standard. It is estimated that if the population of China's per capita consumption of oil was to match that of the USA, China alone would consume 30% more than the possible current total global oil production. The same would hold for other resources. This is why the Fair Shares concept has been developed.

The Fair Shares concept basically looks at the individual's access to resources - both sink and source. This is calculated on a country-by-country basis as a factor of the national population as a percentage of the global population, the amount of product produced, and the sink capacity or emissions produced, and is based on the premise that the total material input into world economy must be halved. It also includes the idea that we have to reduce our resource consumption not because we will run out of resources, but because of the environmental impact of extracting and using those resources. This gives us an idea of what each person's fair share of the world's productive environmental space is. A special report for the European Union has calculated what the Fair shares concept will mean for the EU's access to some of the most commonly used resources. This is illustrated in Table 3.

Resource Per capita share/year % Reduction required in EU

Total primary energy 60 G Ja 50%

Timber 0.56m2 15%

Cement 80 kg 85%

Iron 36 kg 87%

Aluminium 1.2 kg 90%

Copper 0.75 kg 88%

Lead 0.39kg 83%

Built-up land 0.05ha 3.2%

Agricultural land 0.28ha 30%

Table 3: Environmental Space Fair Shares Source: Hille, 1997 Report to European Environmental Agency

The built environment uses most of the resources that will require a radical reduction in consumption. According to this table, the EU will have to reduce its use of aluminium with 90% as each person is only allowed 1.2 kg of the metal - that is about 32 cool drink cans a year. One of the reasons for this is that annually global aluminium production uses as much energy as the whole of Africa. Its extraction also has severe environmental impacts.

Furthermore, the standard of living enjoyed by the developed world had been achieved at the expense of the developing world and was made possible by an economic system that exploited the poor - both individuals and entire nations. The result is the situation we have now where the eight richest people in the world earn more than the 600 million poorest together, with certain individuals earning more than even affluent countries like New Zealand. The per capita income of Sweden, for example, is equal to the combined per capita income of the 23 poorest African countries, that of the USA to the poorest 35 African countries.

While some enjoy unprecedented wealth and luxury, 2.8 billion people are living in extreme poverty, earning less than US$2 a dayii. One in seven people suffers chronic hunger and 45 000 die of starvation every day. This inequity is felt at both a global level, between developed and developing countries, and at a national level where there is great disparities of wealth within countries.

This is not making for a peaceful society. Since the Second World War over 20 million people have died in armed conflict and 31 million people are annually affected by it. These figures do not include crime-related deaths. Of the 2.3 million people reported as killed by conflict from 1991-2000, over three quarters were from countries with a low Human Development Indexiii. At the heart of most of these conflicts lies the issue of who gets to control and benefit from resources, whether agricultural land, minerals, fossil fuels or water. Many countries are already experiencing problems with illegal immigration and an influx of both political and environmental refugees. If the imbalance of wealth and power is not dealt with, this problem will only become worse in the future.