Energy needs for economic development just like those for metabolic growth
Intuitively we all understand that there is a fairly strict relationship between economic activity and energy consumption. When we think of the amount of reduction in that consumption that is necessary to try to get some control over greenhouse emissions and how that will constrain economic growth we tend to think of how we can mitigate our own energy use with as little pain as possible. The fact is, however, that outside of the developed world huge increases in energy usage will be necessary to raise their great numbers of people out of poverty. We would like to think that we can somehow achieve this while at the same time drastically reducing fossil fuel use, but on sober reflection it’s hard to see how that can be done.
Researchers at the University of New Mexico studied the relationship between energy consumption and economic activity in this regard. The paper, James H. Brown, “Energy and the Limits of Economic Growth” is published in the January issue of Bioscience (61 Bioscience 19) and is available as a pdf file from AIBS or at JSTOR (behind paywall). Using data from the International Energy Agency and the World Resources Institute, they establish the statistical relationships between energy use and economic activity for 220 nations over 24 years. They do this by calculating the per capita energy usage (including human biological metabolism) for each country and plot it against the per capita GDP of the country (for each year from 1980-2003). A regression through the mean GDP, produces a line (which accounts for 76% of the variation) with a slope of 0.76 (y-axis being per capita energy consumption in watts and x-axis being per capita GDP in constant $US), which “indicates that the rate of per capita energy consumption associated with greater economic activity increases less rapidly than GDP itself.” (The graph is Figure 1 of the article.)
The authors find it interesting that this slope (0.76) is nearly the same (0.75) as the value of the exponent for the scaling of metabolic rate with body mass in animals. They do not believe that this is a coincidence. Societies, they believe, like animals, have metabolisms that must burn fuel to sustain themselves and grow. They believe that the relationship (as they have quanitified it) between economic growth and energy consumption is causal, although other factors must come into play to account for the variation in countries. (One thing I noticed is that for countries that rely on animal power the metabolic imput of the animals does not seem to have been included. Whether this is significant or not I have no idea. In addition, higher energy consumption might be required in countries that have more difficult terrain for transportation than islands or areas with navigable rivers. Again I don’t know how significant these difference are. The authors themselves allow that energy use in colder climates is greater than warmer ones. There are undoubtedly many such variables.)
The authors take the relationship further. Instead of depending entirely on GDP they analyze quality-of-life factors. These include measures of nutrition, education, health care, resource use, technology, and innovation. They find the same relationship with energy consumption. The authors say this is not surprising since it “takes money and energy to train engineers, MDs, and PhDs; to produce vaccines, drugs, and medical equipment; and to construct and maintain road, rail, airplane, cell phone, and Internet networks, hospitals and research centers, parks and conservation areas, and modern buildings and cities.”
They also show how ecological degradation follows in lock-step with economic development. There is a relationship between the increase of socially desirable goods and services and the increased consumption of energy and other natural resources which are both related to the increased environmental impacts “that now include climate change, pollution, altered biogeochemical cycles, and reduced biodiversity.”
If the relationship between energy consumption and economic growth holds, then there are serious implications for future growth. To simply raise the current population to the standard of living presently enjoyed in the United States now would require “a nearly fivefold increase in the rate of energy consumption, from 17 to 77 terawatts (1 terawatt = 1012 watts).” If population increases to the projected level of 9.5 billion in 2050, then an increase of 16 times current world energy use would be required. And even if that increased population were raised only to the very modest level of current per capita Chinese GDP, then still 2.5 times current energy consumption will be necessary.
The solution must lie in one or more of the following three options: increased energy supply, acceptance of decreased GDP (current for developed countries or expected for developing countries) or population decline. Each of the options its beset with problems. The first is limited by technical feasibility (currently very limited) and the latter two are unlikely to occur without some form of political compulsion.
It’s beginning to look like a Malthusian world after all.