Future overheating risk in prisons in England and Wales using the UK climate projections

High temperatures, leading to overheating, impact the welfare of prisoners, staff and visitors in prisons in England and Wales. Quantifying current and future overheating risk can inform adaptation decision making and prioritisation of investment. In this study, a set of measurements of temperatures inside and outside six prisons, a magistrates court and an approved premises were used to establish a simple relationship between indoor and outdoor temperatures. This relationship is combined with an ensemble of climate projections and an open-source risk assessment framework, CLIMADA, to estimate the change in risk of indoor overheating. This framework supports a spatially consistent assessment of risk, enabling risk to be compared between sites. The expected number of days each prison cell or non-cell overheats is assessed for the recent past and global warming levels of 2°C and 4°C above the preindustrial era. The results indicate a large increase in risk of overheating in cells in the prisons and magistrates court, especially under 4°C of warming. The highest increases are seen in older prisons, where overheating could occur between 100 and 120 days per year if the climate warms to 4°C above pre-industrial. The overheating risk in other areas within the prisons is much smaller but still increases under a warming climate. These results show that retrofitting solutions will increasingly be needed to minimise overheating of the existing prison stock as our climate continues to warm, and that consideration of overheating needs to be incorporated into the design of new prisons.