Older people are higher contributors to mortality excess and most sensitive to environmental influences, e.g. temperature. As the population ages, variability in temperature is liable to impact a large proportion of life insurance or pension policies in a portfolio. Climate change is projected to significantly affect future mean temperatures. Moreover, future changes in mean temperature are estimated to vary across different regions of the United Kingdom. Accordingly, the present paper investigates the potential impact of future mean temperature changes on older-age mortality in England & Wales and Scotland. The corresponding effect on older-age mortality differences between England & Wales and Scotland is also investigated.