Edited by M. Granger Morgan, Carnegie Mellon University, Pittsburgh, PA, and approved June 11, 2015 (received for review November 27, 2014)
The current carbonization of the global energy system poses a severe challenge for efforts to reduce carbon emissions. Here we show that the increase in the carbon intensity of energy production is caused mainly by the increased use of coal, not only in China and India but also across a broad range of developing countries, especially poor, fast-growing countries mainly in Asia. The (relatively) low coal prices are an important reason countries choose coal to satisfy their energy needs. This result underlines the importance of cheaply available energy for economic growth and suggests that viable alternatives to cheap coal will be required to ensure the participation of developing countries in global climate change mitigation.
Coal was central to the industrial revolution, but in the 20th century it increasingly was superseded by oil and gas. However, in recent years coal again has become the predominant source of global carbon emissions. We show that this trend of rapidly increasing coal-based emissions is not restricted to a few individual countries such as China. Rather, we are witnessing a global renaissance of coal majorly driven by poor, fast-growing countries that increasingly rely on coal to satisfy their growing energy demand. The low price of coal relative to gas and oil has played an important role in accelerating coal consumption since the end of the 1990s. In this article, we show that in the increasingly integrated global coal market the availability of a domestic coal resource does not have a statistically significant impact on the use of coal and related emissions. These findings have important implications for climate change mitigation: If future economic growth of poor countries is fueled mainly by coal, ambitious mitigation targets very likely will become infeasible. Building new coal power plant capacities will lead to lock-in effects for the next few decades. If that lock-in is to be avoided, international climate policy must find ways to offer viable alternatives to coal for developing countries.
Author contributions: J.C.S., O.E., and M.J. designed research; J.C.S., O.E., and M.J. performed research; J.C.S. and M.J. analyzed data; and J.C.S. and M.J. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1422722112/-/DCSupplemental.
