The global problem
The 1992 Rio ‘Earth Summit’ expressed concern that:
The global objective and strategy
The global objective was explicitly identified at the 1992 ‘Earth Summit’ – sustainable development. The Rio Declaration identifies the fundamental aim as:
What is the international community doing to identify ‘new analytical and predictive tools’, and develop a methodology for global, regional and national ecological audits? Research in this area goes back some way, but recent work holds new promise. Three concepts in particular – ‘earthshare’, ‘ecological footprint’, and ‘sustainability deficit’ – can be used to help humanity understand the nature and severity of the problem and how to measure the damage being wrought by each nation-state.
Earthshare
The ‘earthshare’ is the amount of land every human has if the ecologically productive land on earth is divided evenly. On a finite planet, an increased global population will have less productive land area per capita. The natural asset base of Earth needs to be appreciated objectively. Of the planet’s total surface of 51 billion hectares, only 7.4 billion hectares, some 15%, is ecologically available land. With the increase in the global population, the individual human ‘earthshare’ has dwindled, from 5.5 hectares per person in 1900 to less than one-third of that by 2000. If an individual’s present earthshare were a circular island, it would have a diameter of 138 metres. One-sixth of the island would be arable land, the rest pasture, forest and wilderness, and built-up area.
Ecological footprint
The ecological footprint of a specified population is the area of ecologically-productive land and water required, on a continuous basis with prevailing technology, to provide all the energy and material resources consumed and absorb all the wastes discharged by that population. The size of the ecological footprint is not fixed, but is dependent on money income, prevailing values, other sociocultural factors, and the state of technology.
The ‘earthshare’ is the amount of land every human has if the ecologically productive land on earth is divided evenly. A rough assessment of the four major human requirements shows that current appropriations of natural resources and services already exceeds Earth’s long-term carrying capacity. Agriculture already occupies 4.8 billion hectares (3.3 billion hectares of pasture and 1.5 billion hectares of cropland). Sustainable production of current roundwood harvest, including firewood, would require a productive forest area of 1.7 billion hectares. To sequester the excess CO2 released by fossil fuel combustion, a further 3.1 billion hectares of carbon-sink land would need to be set aside. This totals 9.6 billion hectares some 30% above what is available today, and 10% above all potential land.
Thus there is evidence that humanity’s Ecological Footprint already exceeds global carrying capacity. The ‘global footprint’ has been estimated today at 2.8 hectares per capita – 35% above the average earthshare of 2.1 hectares. That is to say, the draw-down on the planet’s natural resources exceeds the sustainability level by one-third.
Sustainability deficit
The ‘sustainability deficit’ or ‘ecological deficit’ is a measure of overshoot. It estimates the difference between an area’s ecological capacity and its actual ‘footprint’. It therefore reveals the extent to which that area is dependent on extra-territorial productive capacity through trade or appropriated natural flows. The ‘global ecological deficit’, unlike ‘national ecological deficits’, cannot be subsidized through trade and draw-down from other surplus countries. It depends instead on the liquidation of natural capital stock. It cannot be spatial, imposing the burden on other areas at a single point in time. It can only be temporal, imposing the burden on future generations.
The current generation, then, is drawing down on Earth’s natural resource base at an unprecedented rate. If this continues, today’s inhabitants of Earth will leave a degraded planet for future generations – possibly to an irretrievable degree. Without a concerted effort today to reduce material throughput, the generations of the twenty-first century will be left to satisfy their needs from a much-diminished stock of natural capital. As the authors of the concept put it, there is now “solid evidence that the human enterprise already far exceeds the long-term biophysical carrying capacity of the planet. People today are living on the biophysical heritage of their children.”
The Brundtland Report argued for “more rapid economic growth in both industrial and developing countries”, and suggested that a “five-to-ten-fold increase in world industrial output can be anticipated by the time world population stabilises some time in the next century”. It has been contended, however, that to accommodate this sustainably, on present technology, would require six to twelve additional planets. To accommodate it on Earth alone would require a heightened level of technology that that can do the same with six to twelve times less energy and material.
What is required is an appreciation of the relationship between an optimal global population, or range thereof, that can be sustained by the planet in terms of development and consumption.
Global Population Sustainable Development Sustainable Consumption