In a recent paper , Pushker Kharecha and James Hansen presented calculations that the use of nuclear power has already prevented almost two million deaths:
“Because nuclear power is an abundant, low-carbon source of base-load power, it could make a large contribution to mitigation of global climate change and air pollution. Using historical production data, we calculate that global nuclear power has prevented an average of 1.84 million air pollution-related deaths and 64 gigatonnes of CO2-equivalent (GtCO2-eq) greenhouse gas (GHG) emissions that would have resulted from fossil fuel burning. On the basis of global projection data that take into account the effects of the Fukushima accident, we find that nuclear power could additionally prevent an average of 420,000-7.04 million deaths and 80–240 GtCO2-eq emissions due to fossil fuels by midcentury, depending on which fuel it replaces.”
“In Germany, which has announced plans to shut down all reactors by 2022, we calculate that nuclear power has prevented an average of over 117,000 deaths from 1971-2009.”
 Kharecha, P.A., and J.E. Hansen, 2013: “Prevented mortality and greenhouse gas emissions from historical and projected nuclear power,” Environ. Sci. Technol., 47, 4889-4895, doi:10.1021/es3051197.
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