In the early days of global mass tourism, Gray (1970) suggested that tourist motivations are either driven by “wanderlust” or “sunlust”. The search for warmer climates underpins both and a significant body of work established tourists’ preferences for higher temperatures, sunshine, and less rain (e.g. Falk, 2014; Scott et al., 2016). Theoretical research is validated by most destinations’ tourism statistics that show visitation peaks in summer. However, the increased occurrence of extreme heatwaves is affecting traditional travel patterns, including increasing changes for winter tourism. Prominent examples of heat-related attraction closures (e.g. Acropolis, Athens), event cancellations (e.g. Pitch Music and Arts Festival or Melbourne Open, Australia), and deaths (e.g. Hajj, Mecca) have made headlines around the world.

The Intergovernmental Panel on Climate Change’s Sixth Assessment Report (IPCC, 2022) concluded that human-caused climate change has increased both the frequency and intensity of heatwaves with future warming exacerbating this hazard. Urban environments are particularly exposed due to the heat island effect (Yadav et al., 2023); yet they are heavily frequented by tourists during the hottest months of the year. Tourists are particularly at risk of heat-related illness (HRI) and mortality because they are less familiar with the local conditions, frequently not acclimatized, are physically active during the hottest time of day and may be more difficult to reach with heat warnings (TPCC, 2023). Similarly, tourism workers are affected by extreme heat conditions, raising important questions about how to support vulnerable groups (Rastegar & Becken, 2024). Extreme heat exacerbates justice challenges, as the intersection of vulnerability and climate risks disproportionately burdens those with fewer resources and less capacity to adapt (Parsons et al., 2024). Hence, identifying the types of climate adaptation strategies that can assist in combating extreme heat in just ways is paramount.

This research focuses on changing heat exposure of city tourism. It provides an assessment of future heat risk days and heat exposure for three cities, namely Sydney, Melbourne and Jakarta. Two climate scenarios are examined, including a low emission pathway consistent with achieving the Paris Climate Agreement targets (RCP 2.6) and a high emission pathway representative of where countries fail to achieve current emission reduction policy targets (RCP 8.5). Two critical heat risk thresholds are examined (both using humidex that incorporates daily temperature and relative humidity). The first is the tourist discomfort threshold (>31C), which the majority of international tourists surveyed perceived as unacceptably hot for city tourism (Scott et al., 2016). The second is a dangerous physiological threshold for HRI (>38C), a point between deadly and non-deadly conditions (Mora et al., 2017) and worker productivity is negatively affected (Levi et al., 2018).

The findings show that HRI exposure for tourists and tourism workers is increasing in Sydney and Melbourne and is already at dangerous levels all year in Jakarta. The number of annual heat discomfort days (humidex exceeding 31C) increases from 22 to 25 days in Melbourne and from 45 to 55 days in Sydney between the 1950s and the present (2015–2025) (Figure 1). By the 2050s, heat discomfort days are projected to further increase to 46 in Melbourne and 108 in Sydney in a high emissions scenario (RCP 8.5). The number of days over 38 C could reach 14 and 45 in Melbourne and Sydney, respectively. For Jakarta, the number of days beyond the HRI threshold in 2050 is 365; it is already at 364 days.

Figure 1 Evolving destination heat risk in Melbourne and Sydney.

The findings reveal significant risks from heat; yet very little research has considered differentiated exposures and vulnerabilities by those involved in city tourism, and the wider socio-economic systems they are embedded in (Figure 2). Risk awareness and adaptive capacity to reduce vulnerability are not equally advanced amongst different tourist and worker populations. With a focus on sports events, research highlighted significant health impacts related to heat exposure, although the focus is typically on athletes and not spectators (Mason et al., 2024). As city destinations plan for the future, they will have to consider carefully what adaptation measures need to be put in place to reduce heat-related risks.