Whether or not you agree with climate change, we all prefer to breathe cleaner air. Fossil fuels burn carbon based materials producing gas and particulates that are emitted into the air. These gases include carbon dioxide, carbon monoxide, sulphur dioxide, nitrogen oxides, heavy metals (including lead and uranium) and fly ash and are released into the atmosphere.
The graph below illustrates the findings of a World Nuclear Association (WNA) report that reviewed over twenty studies of greenhouse gas emissions from electricity generation. The report concludes that the third party studies clearly show that greenhouse gas emissions from all forms of fossil fuel generation are an order of magnitude higher than those from nuclear energy and renewables.
The studies chosen used a range of assumptions, however they all took the approach of studying the full lifecycle emissions from all the generation types, not only those emissions directly associated with generation.
Further information on uranium supply can be found here: http://world-nuclear.org/World-Nuclear-Association/Publications/Reports/Lifecycle-GHG-Emissions-of-Electricity-Generation/