As he put it, climate change is an inevitable outcome of the massive rise of the global middle class in the twentieth century and beginning of the twenty-first, which was good news for all concerned. Yes, we are paying the piper now in terms of over-use of resources and over-saturation of our ecologies with waste, but that is not something to feel guilty about.
Rather these effects are the outcome of a binge of development that has produced a lot of global well-being. As well, King sees the global population stabilizing with ongoing development, with the implication that if we can rebound from our recent excesses during the twentieth-first century, we should be able to plateau comfortably for the longer term.
King sees the necessary corrective as a more efficient use of natural resources (including water, food, and energy) to comfortable sustain an enlarged middle class, which he defines in keeping with the Brookings Institute as inclusive of people who spend from $10-$100 a day. We should be planning for an ongoing middle class that can live long and safe lives, though not in the wasteful manner in which we have been accustomed. Driving SUVs in the city and eating large quantities of meat are activities King singles out as problematically inefficient.
By contrast, our challenge is to innovate processes that will permit large number of people to live comfortably, spreading what we have further. King takes for an example the massive amounts of energy that are lost when various fuels are converted to electricity, which is comparable to the Energy Return on Energy Invested (EROI) metric. We might derive from King that the best energy forms for the twenty-first century might be those that will maximize the return on energy invested in a process with energy output. As John Morgan tweeted to me, "You can’t sustain a complex society on a low EROEI energy source."
According to figures from 2010 first published in the Annals of the New York Academy of Science and co-authored by Charles Hall, the inventor of the metric, the highest EROI energy formats--those that give the most energy back for the energy put in--are hydro-electric power and coal. Fossil fuels overall have high EROIs--with the exception of bitumen, which is virtually at the bottom of the scale and should be decisively cleared off the slate given its additionally high externalities (costs to uninvolved parties). Coal likewise has a high social cost that eliminates it as an optimal energy form for the twenty-first century. Hydro, meanwhile, faces declining capacity due to global climate change.*
We clearly need to look further down the list for plausible green** energy sources for the twenty-first century. Biofuels have the very lowest EROIs and should as such be eliminated from consideration, no matter their profile as renewable energy. Solar is likewise a relatively inefficient form of energy production according to this metric, as has been expanded upon in a recent publication by Hall. Wind is better. Nuclear energy has an EROI as high as natural gas when using a diffusion enrichment processes and a potential for much higher EROI than any fossil fuel when fast reactor or thorium processes are used.*** The externalities of nuclear have recently been analyzed by a neutral risk analyst as low, with the admission that controversy persists.
There are other ways of looking at the problem of meeting energy needs--including the return on investment in financial terms (ROI) and the question of how to reduce demand. As well, different decisions about energy will be warranted in different locations and circumstances, though I submit that EROI stands as a valuable formula in making them. From it we may derive that--barring paradigm-shifting advances in existing or novel energy sources--wind and nuclear will most efficiently fuel the requirements of a large global middle class during the upcoming century.****
*It has been pointed out to me that there are new developments coming in smaller hydro stations.
**In a course that involves correcting from the overuse of carbon fuels I have chosen to focus on low-carbon energies, though moderately carbon-dioxide emitting natural gas will surely remain central to the energy mix for some time and has the benefit of a moderate EROI, apparently even with fracking.
***An article in Scientific American by Mason Inman notably suggested that the EROI from nuclear was lower than previously estimated, but it has been highly disputed (see the addendum on EROI that was published online and particularly its comment section).
****Wow. A new paper published in Energy in 2013 is even more decisive on the differentials between EROIs and comes to a different conclusion. "Nuclear, hydro, coal, and natural gas power systems (in this order) are one order of magnitude more effective than photovoltaics and wind power."