Modern humans have rapidly changed the conditions that were prevalent during their emergence as a species some 200,000 years ago. For tens of thousands of years humans lived within the constraints of their bioregions and made adaptive adjustments to climatic and biophysical changes. Within the last 10,000 years, humans have successfully colonised nearly every type of ecosystem and bioregion on the planet.
The main source of energy available to humans within this evolutionary context was ‘people power’, the energy gained from the food hunted and gathered within given bioregions. The effort needed to gather essential nutrients for life roughly equalled the energy gained from such enterprise. As a consequence, human ecology lived within the thermodynamic constraints of place and human health in all of its dimensions was an expression of such limitations (Boyden, 1999).
However, as human cultural, agricultural and technological evolution proceeded, the ability to leapfrog the limitations of place grew exponentially. Surpluses in food production, and later, virtually every form of productive capacity, has been associated with a number of problems with the human-nature relationship. Homo sapiens has moved from a local patch disturbing species (Rees, 2000) to a species that now disturbs not only the biosphere, but also the global atmosphere. The human health impacts of such a transition have been well-documented (McKewon, 1988; Boyden, 1999; McMichael, 2001). The so-called ‘diseases of affluence’ such as heart disease, obesity, hypertension, diabetes and some forms of cancer have emerged within a post scarcity society (Hetzel and McMichael, 1987). Overriding all of this is global warming and climate change where potentially irreversible, catastrophic impacts are possible for ecosystem and human health (physical and mental) at a planetary scale (Aron and Patz, 2001; McMichael, 2001; Albrecht, et al 2007).
Ecological Footprint Analysis
Ecological Footprint Analysis (EFA) has been developed as a relatively new tool to assess the impact and sustainability of humans on planet earth (Wackernagel and Rees, 1996; Lenzen and Murray, 2001; WWF Living Planet Report, Global Footprint Network). EFA differs from other measures of human impacts in that it offers a comparative insight into aggregate resource consumption and waste production at a number of different scales. By converting all forms of resource consumption and waste assimilation into a universal unit of biologically productive land (hectares per person) needed to produce those resource and waste assimilation services, meaningful comparisons can be made between the resource intensity of lifestyles worldwide.
What is interesting about EFA is that, in general, it shows that people in rich countries (also those with high per capita use of fossil fuels), generally have the largest Ecological Footprint (EF). This information, combined with other data generated on the health problems of humans, gives us some compelling information about just how intimately the ecological footprint, health status, lifestyle and sustainability are connected. Using publicly available data from the WWF in their Living Planet Report 2010 and the World Health Organisation data on obesity it is possible to see more clearly this connection.
I have put into Table 1 (below) data on some of the largest and smallest national per person ecological footprints in the world and their corresponding rates of obesity for females. The ecological footprint for Nauru has not been calculated. The measure of obesity is body mass index (BMI) where, according to the WHO as the weight in kilograms divided by the square of the height in metres (kg/m2 ). A BMI over 25 kg/m2 is defined as overweight, and a BMI of over 30 kg/m2 as obese (http://www.who.int/mediacentre/factsheets/fs311/en/ ).
Table 1 also shows how an estimate of a ‘fair earth share’ of available resources can be illustrated. Current best estimates are that given the amount of biologically productive land available on this earth, plus the land needed to assimilate wastes such as carbon dioxide, there is approximately two hectares of land per person if all 7.0 billion people on earth were to have an equal share of biologically productive and useful land. The data also show that a number of countries have ecological footprints near 10 hectares per person which translates into approximately 3-4 planets worth of biologically productive land if universalised.
A Heavy Footprint and Health
While I do not wish to argue that there is a simple causal relationship between per person EF and obesity levels expressed as BMI, it is clear that countries with a high EF generally also have a high percentage of people with a BMI defined by the WHO as obese. The converse is also immediately obvious in countries with a very small EF. People in the Pacific Island nations defy this trend in that they have, in, for example, Nauru , about 80% of the female population clinically defined as obese, yet traditionally they had a national ecological footprint that was hardly measurable. However, studies undertaken on obesity in the Pacific suggest that rather than caused primarily by genes or a traditional cultural preference for largeness, clinically defined obesity is a new problem connected to the importation and consumption of high fat and energy dense food, increased use of technology, abandonment of food production and with all of the above, decreased physical activity (Obesity in the Pacific [PDF]).
When the major components of the ecological footprint are broken down it is clear that one of the largest segments is that contributed by food inputs and outputs. The net result of populations (or segments of populations) that over consume food and nutrition while at the same time reducing their physical activity levels is increasing obesity (with attendant chronic disease), an ever increasing ecological footprint and non-sustainability.
Reducing our ecological footprint is vital for planetary and human health. The cheap (until Peak Oil) and freely available energy in a fossil fuel based economy is now, ironically embodied in humans in the form of obesity. In effect, humans are eating fossil hydrocarbon energy and converting their ‘high-hydrocarb’ diet to body fat.
The connections between a high-hydrocarb diet, obesity and climate change may not seem immediately obvious; however, they both produce unfortunate consequences for the health of people and the planet.
Aron, J., and Patz, J. (eds) (2001) Ecosystem Change and Public Health: A Global Perspective, Baltimore, The Johns Hopkins Press.
Albrecht, G. (2005). Solastalgia: A new concept in human health and identity. PAN: Philosophy Activism Nature (3), 41-55.
Albrecht, G, Sartore, G et. al. (2007) Solastalgia: The distress caused by environmental change, Australasian Psychiatry. Vol. 15, Special Supplement, pp. 95-98.
Boyden, S. (1987) Western Civilization in Biological Perspective: Patterns in Biohistory, New York, Oxford University Press.
Hetzel, B., and McMichael, T. (1987) The LS Factor: Lifestyle and Health, Ringwood, Penguin.
Lenzen, M., and Murray, S. (2001). A modified ecological footprint method and its application to Australia. Ecological Economics 37(2): 229-255.
Living Planet Report 2010 (WWF). http://wwf.panda.org/about_our_earth/all_publications/living_planet_report/ (accessed May 9 2011)
McKeown, T. (1988) The Origins of Human Disease, Oxford, Basil Blackwell.
McMichael, T. (2001) Human frontiers, environments and disease, Cambridge, Cambridge University Press.
Obesity in the Pacific http://www.wpro.who.int/publications/pub_9822039255.htm (accessed May 9 2011)
Rees, W. (2000) Patch Disturbance, Ecofootprints, and Biological Integrity: Revisiting the Limits to Growth (or Why Industrial Society Is Inherently Unsustainable) in Pimental, D. et al Ecological Integrity: Integrating Environment, Conservation, and Health, Washington, D.C. Island Press, pp. 139 – 156.
Wackernagel, M and Rees, W (1996) Our Ecological Footprint, Gabriola Island, New Society Publishers.
WHO 2010 https://apps.who.int/infobase/Comparisons.aspx/ (accessed May 9 2011)