Climate change, as revealed by gradual changes in temperature, precipitation, atmospheric moisture, and wind intensity, as well as sea level rise and changes in the occurrence of extreme events, is already affecting cultural heritage sites. Accordingly, there is a rapidly increasing body of research reporting on the impacts of climatic stressors on cultural heritage and on the assessment of climate change impacts on cultural heritage assets. This review synthesizes the international literature on climate change impacts on tangible cultural heritage by developing hazard‐impact diagrams focusing on the impacts of gradual changes in climate on: (1) the cultural heritage exposed to the outside environment, (2) the interiors of historical buildings and their collections, and (3) a third diagram associated with climate change and the impacts due to sudden changes in the natural physical environment (e.g., storm surges, floods and landslides, wildfire) in addition to sea level rise, permafrost thawing, desertification and changes in the properties of the oceans. These diagrams, which depict the relationships between various stressors and their impacts on cultural heritage, will allow other researchers, stakeholders, and potentially decision makers to determine the potential impacts of climate change on a specific cultural heritage asset without a separate examination of the literature. This review thus provides the current state‐of‐the‐art on the impacts of climate change on the tangible, built heritage, that is, monuments, archeological sites, historical buildings, as well as their interiors and the collections they hold, highlights the limitations of previous research, and provides recommendations for further studies. This article is categorized under: Assessing Impacts of Climate Change > Evaluating Future Impacts of Climate Change

Most monuments and buildings in the Maltese Islands are constructed of the local Globigerina Limestone. Today, this Globigerina Limestone shows considerable damage in many buildings, particularly through alveolar weathering, which is frequently very intense. Owing to Malta's marine environment, salt crystallization in the stone's pore spaces has been recognized as the main weathering process responsible for the deterioration of the country's monuments. In order to obtain more information on the fabric-dependent weathering processes of Globigerina Limestone, detailed analyses were carried out. Globigerina Limestone samples obtained from stone types with two different known qualities were characterized according to petrographical, geochemical and physical properties. These included porosity, pore radii distribution and tensile strength, as well as water and humidity transport properties. Investigations by means of salt crystallization tests on quarry samples of both stone types reinforced the idea that the extent of salt weathering depends on salt type and concentration and pore-space properties. Visible weathering damage was recorded and evaluated for a representative monument (the Church of Santa Marija Ta' Cwerra in Siggiewi) by means of a monument mapping method, which was carried out twice over a period of 9 years (1995 and 2004). The identified weathering forms were also correlated with a previously developed weathering model for Globigerina Limestone. According to the results of the mapping, salt analyses carried out on samples from the church and salt-loading tests on quarry samples, there exists a significant correlation between visible damage and salt load. The zoning of weathering damage is obviously related to different salt concentrations. The zone with severe weathering damage is characterized by a high concentration of halite. Consequently, salt weathering represents the main damage process for the Globigerina Limestone of Malta.

The Globigerina Limestone occurs as two types of building stone: the resistant ‘franka’ and the easily weathering ‘soll’. Research on both fresh and weathered samples has led to an understanding of the main differences in these two types of stone. The causes and mechanisms of deterioration have also been established. ‘Franka’ and ‘soll’ differ in geochemical and mineralogical composition and in physical properties. The ‘soll’ is richer in the non-carbonate fraction, which occludes some of the pore space, resulting in a lower overall porosity and a higher proportion of small pores. The ambient local environment, heavily loaded with sea salt, particularly sodium chloride and sulphates, readily induces deterioration in ‘soll’, whereas ‘franka’ tends to resist better in this aggressive environment. The weathering process of Globigerina Limestone in general has been explained as a sequence of steps, from the formation of a thick and compact superficial crust, to the loss of this crust, to the initiation of alveolar weathering. Understanding the deterioration mechanisms of Globigerina Limestone permits criteria for proper conservation treatment to be established.

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