In recent years, we have heard statements indicating that it is possible to decouple GDP growth from energy growth. I have been looking at the relationship between world GDP and world energy use and am becoming increasingly skeptical that such a decoupling is really possible.
Prior to 2000, world real GDP (based on USDA Economic Research Institute data) was indeed growing faster than energy use, as measured by BP Statistical Data. Between 1980 and 2000, world real GDP growth averaged a little under 3% per year, and world energy growth averaged a little under 2% per year, so GDP growth increased about 1% more per year than energy use. Since 2000, energy use has grown approximately as fast as world real GDP–increases for both have averaged about 2.5% per year growth. This is not what we have been told to expect.
Why should this “efficiency gain” go away after 2000? Many economists are concerned about energy intensity of GDP and like to publicize the fact that for their country, GDP is rising faster than energy consumption. These indications can be deceiving, however. It is easy to reduce the energy intensity of GDP for an individual country by moving the more energy-intensive manufacturing to a country with higher energy intensity of GDP.
What happens when this shell game is over? In total, is the growth in world GDP any less energy intense? The answer since 2000 seems to be “No”.
It seems to me that at least part of the issue is declining energy return on energy invested (EROI)–we are using an increasing share of energy consumption just to extract and process the energy we use–for example, in “fracking” and in deep water drilling. This higher energy cost is acting to offset efficiency gains. But there are other issues as well, which I will discuss in this post.
If GDP growth and energy use are closely tied, it will be even more difficult to meet CO2 emission goals than most have expected. Without huge efficiency savings, a reduction in emissions (say, 80% by 2050) is likely to require a similar percentage reduction in world GDP. Because of the huge disparity in real GDP between the developed nations and the developing nations, the majority of this GDP reduction would likely need to come from developed nations. It is difficult to see this happening without economic collapse.