Human-caused climate change and air pollution remain major global-scale problems and are both due mostly to fossil fuel burning. Mitigation efforts for both of these problems should be undertaken concurrently in order to maximize effectiveness. Such efforts can be accomplished largely with currently available low-carbon and carbon-free alternative energy sources like nuclear power and renewables, as well as energy efficiency improvements.
Cumulative net deaths prevented assuming nuclear power replaces fossil fuels. The top panel (a) shows results for the historical period in our study (1971-2009), with mean values (labeled) and ranges for the baseline historical scenario. The middle (b) and bottom (c) panels show results for the high-end and low-end projections, respectively, of nuclear power supply estimated by the IAEA (ref. 4) for the period 2010-2050.
Error bars reflect the ranges for the fossil fuel mortality factors listed in Table 1 of our paper. The larger columns in panels (b) and (c) reflect the all-coal case and are labeled with their mean values, while the smaller columns reflect the all-gas case; values for the latter are not shown because they are all simply a factor of about 10 lower (reflecting the order-of-magnitude difference between the mortality factors for coal and gas). Countries/regions are arranged in descending order of CO2 emissions in recent years. fsu15="15" countries of the Former Soviet Union and oecd="Organization" for Economic Cooperation and Development.
In a recently published paper (ref. 1), we provide an objective, long-term, quantitative analysis of the effects of nuclear power on human health (mortality) and the environment (climate). Several previous scientific papers have quantified global-scale greenhouse gas (GHG) emissions avoided by nuclear power, but to our knowledge, ours is the first to quantify avoided human deaths as well as avoided GHG emissions on global, regional, and national scales.
The paper demonstrates that without nuclear power, it will be even harder to mitigate human-caused climate change and air pollution. This is fundamentally because historical energy production data reveal that if nuclear power never existed, the energy it supplied almost certainly would have been supplied by fossil fuels instead (overwhelmingly coal), which cause much higher air pollution-related mortality and GHG emissions per unit energy produced (ref. 2).
Using historical electricity production data and mortality and emission factors from the peer-reviewed scientific literature, we found that despite the three major nuclear accidents the world has experienced, nuclear power prevented an average of over 1.8 million net deaths worldwide between 1971-2009 (see Fig. 1). This amounts to at least hundreds and more likely thousands of times more deaths than it caused. An average of 76,000 deaths per year were avoided annually between 2000-2009 (see Fig. 2), with a range of 19,000-300,000 per year.
Likewise, we calculated that nuclear power prevented an average of 64 gigatonnes of CO2-equivalent (GtCO2-eq) net GHG emissions globally between 1971-2009 (see Fig. 3). This is about 15 times more emissions than it caused. It is equivalent to the past 35 years of CO2 emissions from coal burning in the U.S. or 17 years in China (ref. 3) — i.e., historical nuclear energy production has prevented the building of hundreds of large coal-fired power plants.
To compute potential future effects, we started with the projected nuclear energy supply for 2010-2050 from an assessment made by the UN International Atomic Energy Agency that takes into account the effects of the Fukushima accident (ref. 4). We assume that the projected nuclear energy is canceled and replaced entirely by energy from either coal or natural gas. We calculate that this nuclear phaseout scenario leads to an average of 420,000-7 million deaths and 80-240 GtCO2-eq emissions globally (the high-end values reflect the all coal case; see Figs. 1 and 3). This emissions range corresponds to 16-48% of the "allowable" cumulative CO2 emissions between 2012-2050 if the world chooses to aim for a target atmospheric CO2 concentration of 350 ppm by around the end of this century (ref. 5). In other words, projected nuclear power could reduce the CO2 mitigation burden for meeting this target by as much as 16-48%.
