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George Porter

Earth was created about four and a half billion years ago as a fragment of the Sun breaking away and setting itself in orbit. It was the Sun's solar energy that caused life to develop. The human race, endowed with intelligence and dexterity is a relatively recent arrival.

The global natural ecosystem, or the biosphere, provides the goods and services on which all life depends. The human economy is, therefore, a subsidiary system of the economy of the biosphere. As such, it is properly referred to as the human economic sub-system.

The global ecosystem has evolved over a period of millions of years into a complex of independent, but closely related components maintained in a state of delicate balance.

The human economy, being dependent on the biosphere for the resource flows which provide the energy for human activity, must be recognised as the controlling force for human operations. The natural economy of the biosphere sets physical limits to the level of human demands on natural resources.

In a sustainable world, the critical factor is the scale of the human economy in relation to that of the global ecosystem or biosphere. Population times average per capita resource use is the total flow through the human sub-system, which is returned to the ecosystem as waste. A sustainable economy is one in which:

  1. the total throughput of renewable resources is no greater than the net primary production of the ecosystem, and
  2. The total extraction of non-renewable resources is no faster than the rate at which alternative resources can be discovered.

There are categories of natural resources, non-renewable and renewable. Non-renewables are those found in the Earth's crust or lithosphere, which contains minerals, fossil fuel and gas fields and heat. These resources are non-renewable. Once used and discarded, they are lost forever to the oceans and atmosphere. They are a once off capital resource. In theory, in a sustainable society, non-renewable resources would not be mined unless recycled, or mined only if substitutes became available through renewable sources such as solar energy. It is vital therefore, to use non-renewable resources prudently and in accordance with international agreements for their equitable allocation. This is not happening now. Instead, it's an all out race to extract scarce minerals and fossil fuels with no regard to the future. The human economy considers them as "free gifts".

Renewable resources are those created by solar energy captured by plant life through the chemical process of photosynthesis. The total amount of plant and animal life created by photosynthesis - the standing-forests, grasslands, fresh water and animal and plant life is the total biomass. Biomass less respiration (plants) is the net primary production (NPP), and is limited by the capacity of existing biomass to absorb the sun's energy. The total amount of NPP estimated to be created each year, varies from 150 to 224 billion tonnes. This amount will fluctuate according to the health of the biosphere.

It would be logical, therefore, for the human race to feel a deep concern for the efficient maintenance of the biosphere. Its presence on Earth has, in fact, been marked in recent years by serious exploitation and on-going damage to critically important ecosystems, though only in the last half century has evidence of serious consequences of this damage and dislocation been observed and studied.

The reversion of grasslands to deserts, of rainforests to pasture, and conversion of productive land to urban and highway use, reduces potential biomass production. Results of research carried out at Stanford University, published in 1987 by Vitousek et al indicates that humans have destroyed outright 12 per cent of this terrestrial net primary productivity and, at the time of the study, now eight years old, humans were co-opting or using an additional 27 per cent for its own use. Thus one species - Homo Sapiens - has appropriated close to 40 per cent of the terrestrial food supply, leaving only 60 per cent for the millions of other plants and animals, and for the additional billions of human numbers yet to come. This is without taking account of diminished capacity for ecosystem damage. On the basis of these figures, the per global capita consumption of biomass resources averages 12 tonnes per person based on UNDP figures for income distribution for 1992, and depicted in the wineglass diagram. On this basis:

  • The top 20% that get 85% of GNP use 51 billion tonnes.
  • The middle 60% that get 13.6% of GNP use 8.16 billion tonnes.
  • The bottom 20% that get 1.4% of GNP use 0.84 billion tonnes.

On a per capita basis:

  • The top 20% use 46.2 tonnes each.
  • The middle 60% use 8.16 tonnes each.
  • The bottom 20% use 0.84 tonnes each.

If biomass allocation was on an equal basis:

  • The top 20% would have to reduce consumption to about 25% or by 75%.
  • The middle group would need to receive three times as much, and the third group 12 times.

However, as consumption is already above sustainable levels, the human economy needs to be reduced in volume, so increasing the degree by which the top 20 per cent must reduce their consumption. Even then no provision is made for future population numbers.

Food supply is a critical factor. The study Why Sustained Economic Growth is not Possible - a Study based on the World Food Situation by PIRM on the world food supply, which brings together findings of leading world scientists and analysts, endorses this view. Even the maintenance of current world food production, will require a major international effort to increase efficiencies and move to equitable distribution.

It is clear from such studies that humans are already making unsustainable demands on natural systems. Consider the following:

  • Earth's capacity to produce biomass is being eroded by human actions.
  • Human population is expected to at least double within 50 years, on the assumption of a continuing resource flow capable of meeting demands.
  • Other forms of life and their environments also depend on maintaining biomass production.
  • Most humans are living below satisfactory levels of consumption, and many are living in absolute poverty. Countries of the South have ambitions to attain higher standards which must be supported.
  • Ozone depletion and climate change underscore the danger of overstepping Earth's ability to absorb human waste products.
  • At present, 37% of the human population live in low lying coastal zones where net primary production is high and which offer opportunities to reverse the negative flow of nutrients from the land to the sea. These numbers will, on present trends, increase to 4.2 billion or 70 per cent of world population over the next few years. The coastal zones are highly productive and are essential as fish spawning grounds and rich food producing areas. They are also under threat from sea level rise through global warming.
  • The increasing loss of tropical rainforest, now approaching 20 million hectares a year, and the burning of grasslands, the greatest source of CO2 causing global warming, are compounding the problem to critical proportions.
  • World food production is close to its physical limits and cannot cope much longer with further increases in human numbers. A scenario which assumes continuation of current production practices, will show decreasing potential for food production.
  • The loss of productive soil represents a continuing loss of essential elements necessary for soil fertility. Current rates of soil loss are estimated to be at least 10 times the possible rate of soil creation by natural processes.
  • Increasing quantities of toxic chemical infiltrating into the environment are destroying natural fertility and polluting water supplies and ecosystems, further threatening life support functions.

Latest estimates of loss of natural capital per annum are:

  • Human wastes lost to the seas, oceans and other large water bodies: 21 billion tonnes
  • Loss of soils through erosion to the oceans and other water bodies 8 billion tonnes
  • Loss of carbon and other nutrients to the seas and the atmosphere 7 billion tonnes.

These figures represent a loss of natural capital that is largely irrecoverable. Loss of natural capital is reducing the capacity of the natural economy to provide goods (productive capacity) and services (air, water and land) for the maintenance of the human and animal populations.

The capacity of Earth to support humans is determined not just by basic food requirements, but also by our levels of consumption of a whole range of resources; by the volume of waste generated; by the use of technologies; and our capacity to deal with threats and disasters.

By failing to understand the functioning of the economy of nature, the human race is proving to be an unworthy guardian of its natural inheritance. Destruction or damage to the base of the natural economy means that the human economy will suffer accordingly. The human sub-system can exist as a healthy and sustainable system only if the economy on which it depends is equally healthy and sustainable.

Resources that are available to humans are controlled by the two scientific laws of thermodynamics, and the limitations these laws place on human economic production. It is necessary to understand these laws in order to understand the operation of the economy of the biosphere.

The first law is simple enough. It is that the total quantity of matter is fixed. Matter, or energy, can neither be created nor destroyed, only modified.

Note: While this statement is true in respect to terrestrial resources it takes no account of free energy considered to be available in space.

The second law of thermodynamics is more difficult to comprehend, but understanding it is equally essential. It is also called the entropy law, and states that matter, or stored energy, has a tendency to break down during the production process, with a resulting loss of energy. For example, a piece of coal when burnt, produces heat. This heat, or energy, is emitted to the atmosphere mainly as CO2 leaving behind embers which will quickly dissipate. High entropy is a strong tendency to lose energy, while low entropy is a tendency to retain energy.

The total amount of solar energy that can be captured by the global ecosystems is 0.05 per cent. In addition to energy captured by photosynthesis, solar energy can be captured for direct human use by various forms of technology. Use of solar energy should be maximised to release more biomass for other human use.

In general terms, economic policy should be to increase productivity of natural capital rather than increase the productivity of man-made capital and its accumulation, as is currently the case.

Despite warnings by scientists and analysts of excessive drawdown of natural resources, the global economy is set to grow substantially to meet increasing human demands. The World Bank predicts 400 per cent growth of the world economy, while the Brundtland Report "Our Common Future" referred to the need for growth of the world economy by 500 per cent to meet the needs of future population numbers. Sustained economic growth, though a contradiction in terms, is the official policy of the United Nations, world governments, corporations and financial and trade institutions and business generally.

Instead, governments and major private corporations, despite warnings and despite the 1992 Earth Summit, are moving at maximum speed to increase consumption. The cry for sustained economic growth is heard everywhere - in every country.

To compound the problem further, grave damage to natural resources and human and animal health is caused by widespread use of chemicals and chemical-based products. Large quantities of toxic substances are being released continuously into the atmosphere, seas, water supplies and the land, where they continue to accumulate. Chemical pollution and damage is a serious long-term problem with serious social and financial costs. Chemicals harmful to human health continue to be applied to food crops as pesticides, herbicides, fungicides and fertilisers.

Recently released findings of research studies in the US, reveal a new threat from low dosage, low level human ingestion of toxic chemicals which remain in the human body tissues and are transferred to the next generation. These may not show up for 40 years. This is of special concern, since exposure to this form of poisoning is almost universal.

Another serious long-term threat from toxic chemicals in the environment is their effect on natural soil fertility. Top soil is a vital capital assset as is pure water and clean air. The world's primary forests and their bio-diversity are equally precious. Since all natural elements that make up the biosphere are, in their natural state, in balance, the disruption of any one part can cause system dysfunction and eventual collapse.

The issue is not merely to care for the environment, but rather to use available natural capital and energy flows within naturally imposed limited.

Equally important is to shift the emphasis from man-made capital accumulation to natural capital preservation and rehabilitation of damaged ecosystems, particularly soil and forest, air and water.

Scientific research and development of technology must in future be directed to increasing the productivity of natural capital, rather than to increase productivity of labour and economic capital at the expense of natural resources.

The function of the UN regarding sustainability and global resource management is to provide an overview, and a full understanding of the actions required at all levels for the necessary action to be taken, and in particular to facilitate action at local and national levels.

Society must cease to look upon "progress" as something desirable. "Eternal Progress" is a nonsensical myth. What must be implemented is not a "steadily expanding economy", but a zero growth economy, a stable economy. Economic growth is not only unnecessary but ruinous.

Aleksandr I. Solzhenitsyn (1974)

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