Earth’s climate has unequivocally been altered by anthropogenic activity, and consequences including wildfire, drought, flooding, heatwaves, severe storms are already affecting livelihoods globally. To capture possible future climates, the Intergovernmental Panel on Climate Change (IPCC) has produced a suite of Shared Socioeconomic pathway scenarios that consider the complex positive and negative feedback between climate, policy, atmospheric physics, socio-economic and political decisions, and provide estimates of future conditions. Though these resources are the most suitable and realistic set of input data for the representation of future climate systems, there are inconsistencies among design practitioners and some scientists on the implementation of these scenarios in a modelling context and the interpretation of simulation output. One such misinterpretation of climate scenario data is presented: an evaluation of the long-term thermal regime within a mine-waste rock pile after mine closure. A simple 2D hillslope comprising mine-waste rock and soil cover in a permafrost region is considered using thermal (no seepage). Given the current lack of regulatory guidance on the implementation of future climate simulations, a comparison of current methods is made to highlight the potential risks of current practices. These practices include using both IPCC climate forecasting tools AR5 and AR6, methods that average scenarios rather than evaluating the uncertainty of a scenario and evaluate time periods beyond 100 years. Guidance is provided on climate scenario selection best practices for the thermal evaluation of mine rock piles in permafrost regions, and potential impacts arising from the improper use of a scenario are identified.