Concern about climate warming is a strong driving force for reduced fossil fuel consumption. European leaders want to reduce greenhouse gas releases to nearly zero by 2050 and extend the electrification of final energy use as much as possible. Nuclear energy should be a primary choice in this perspective. Unfortunately, hostility towards nuclear energy persists despite past successful achievements. The arguments of deniers are based on economic viability, risks of accidents and long-lived nuclear wastes. None of these arguments—partially justified for today’s light-water technology—is a showstopper in the long term. Technologies have something in common with the living world: they are in constant evolution. The process is slow, taking almost a century to produce disruptive changes. Starting in 1950, nuclear technology should be very different in 2050 as a result of current R&D. Factory-made modules with reduced power sizes known as SMR (Small Modular Reactors), will address some of the economic and safety concerns. Emergent technologies dubbed Generation-IV will considerably enlarge the applications towards water desalination, high temperature heat and naval propulsion. Adoption of different reactor coolant fluids (helium gas, liquid heavy metals or molten salts) instead of water should reduce the safety concerns. Combining specific choices of reactor fuels with adequate neutron spectra might contribute to the elimination of long-lived nuclear wastes. Ignoring the intricacies of technology change and persisting blindly in today’s hostile attitude can lead to environmentally detrimental choices.