Challenges of scale in assessing the risks of climate change for heritage.

Heritage is a living process-our legacy from the past, including social and ecological systems, within which we live today and pass on to future generations. Assessing climate change risks is essential for understanding how hazards, exposure, vulnerability, and responses interact to produce impacts for heritage. These interactions operate across diverse spatial and temporal scales. Current approaches to risk assessment evaluate the scales of climate data, heritage processes, and governance decisions implicitly, leading to misalignments that limit how effectively risks are identified, interpreted, and managed. Here we show that these misalignments arise when observational, measurement, and operational scales diverge. The observational scale defines the boundary and timeframe of a risk assessment. The measurement scale concerns the resolutions of data used, from global climate models to site-level monitoring. The operational scale represents those of underlying processes, from short-term flooding to multi-decadal maintenance and knowledge transmission. When these scales diverge, mismatches obscure how climate change risks are understood and managed. These mismatches reveal not only technical challenges but also deeper divides between knowledge systems, institutional actions, and governance structures. A scale-aware approach can help translate risk assessments into effective actions, aligning data, processes, and responsibilities.