A potential clash of ideologies is identified between the climate change agenda and the conservation of the historic built environment. Whilst the conservation of both the natural environment and our built heritage should ideally be mutually beneficial, the lack of a robust policy framework within the planning system is proving to be highly problematic. The study examines how the historic built environment in Wales can contribute towards the national target of achieving a carbon neutral society within a generation through policy reform within the planning system. A brief history of the building conservation movement is provided, along with a description of how it has evolved. Climate change and its implications for the planning system are also examined. A hypothesis is also included in the study, which suggests that the current planning policy framework is insufficiently equipped to aid the historic built environment in adequately contributing towards the target of achieving a carbon neutral society within a generation. The analytical section draws upon the evidence base of the study, which is in the form of primary data such as surveys and secondary data such as previously published statistics. The findings of the study are identified and analysed in order to reach robust conclusions, which in turn lead onto a series of recommendations on how the planning policy framework for the historic built environment in Wales can be modified to become more effective in making significant reductions in carbon emissions over the next generation. The duration of the study period is from 1st January 2010 to 31st December 2014. All literature, data and other information included in this thesis, and subsequent analysis and conclusions, are considered to be up-to-date at the study’s ‘cut-off’ date of 31st December 2014. The Viva Voce for the study took place on 7th October 2015. Subsequently, changes have been made to the thesis that refer to information released after the original 31th December 2014 cut-off date.