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Research finds population, consumption drive global climate change

By Jessica Knoblauch

A new study by an MSU researcher and his colleagues pinpoints causes of a recent finding by a working group of the Inter-Governmental Panel on Climate Change that global climate warming is due to human activities.

Principal factors affecting climate change are human population growth and consumption, according to research by Environmental Science and Policy Program Director Thomas Dietz and his colleagues Eugene A. Rosa of Washington State University and Richard York of the University of Oregon. While these two environmental stressors have long been thought to be primary drivers of environmental impact, a lack of extensive testing and contradictory arguments regarding the impact of consumption left the extent of their influence in question.

Their findings suggest their impact is so great that they may outpace any potential environmental benefits from industrial modernization and improving technologies. Urbanization, economic structure, age of population and other analyzed factors have little effect, according to their research, published in an article titled, “Driving the human ecological footprint,” in the February issue of Frontiers in Ecology and the Environment.

Dietz and his colleagues created a program called STIRPAT (Stochastic Impacts by Regression on Population, Affluence, and Technology) to examine various greenhouse gases and the ecological footprint of nations. The model demonstrates there are factors creating dramatic inequities in the amount of resource consumption and waste emissions among nations. While population is a major influence on the environment in all nations, the detrimental environmental impacts are most pronounced in nations where the population is most affluent.

The findings challenge a number of theories that suggest improved technological efficiency and a decline in resource requirements of modernizing nations will inevitably lead to environmental sustainability. Instead, the study suggests that growth in population and affluence will increase the stresses humanity places on the environment. Dietz noted that, “We can compensate for this by reducing our ecological intensity – producing more human well being with less environmental impact. If we reduce intensity by about 2 percent a year, we can hold impact constant, globally. But we cannot be complacent – it will take a major effort to improve our efficiency by 2 percent and an even greater effort to reduce our impact.”

For more information on STIRPAT, visit the Web at www.stirpat.org/