This session welcomes new research addressing the challenge of extreme heat and its impacts, with studies focusing on the Global South particularly welcome. Suitable contributions may: (i) assess the definitions and indicators typically used to describe extreme heat stress conditions and human habitability limits, (ii) quantify the drivers and underlying processes of extreme heat in observations and/or models; (iii) quantify historical climate trends and projections (iv) examine the challenges of monitoring and predicting extreme heat on all temporal scales; (v) assess vulnerability and exposure to extreme heat associated with diverse socio-economic impacts; (vi) focus on societal response and adaptation to extreme heat in a warming climate, including heat-health early warning systems and anticipatory action, adaptation and management solutions; (vii) introduce transdisciplinary research frameworks for assessing impacts on human health, economic productivity, and the environment.
We encourage submissions from a broad range of disciplines including environmental and climate sciences, climate impact studies, global and occupational health and epidemiology.
As temperatures rise with ongoing anthropogenic climate change, extreme heat events are becoming more frequent and are starting to occur outside of the expected heat season. Unusually early or late extreme heat events can create outsized impacts as individuals may be less acclimated to intense heat or unready to employ cooling strategies. Here we characterize the historical baseline seasonality of extreme heat around the globe and quantify how this seasonality is shifting over time. We define heat seasons as the three months with the highest historical fraction of extreme heat events during a baseline period in the 1980s. We find that in this baseline period, the extreme heat season is distinct from meteorological summer throughout much of the world, but captures a high fraction of the total annual observed extreme heat days. This is true even in low latitudes where the amplitude of temperature seasonality is low. Heat seasons are also expanding asymmetrically: some regions now experience a higher fraction of extreme heat events in the months following the heat season, while others experience a higher fraction preceding the heat season. At most locations around the globe, this observed asymmetrical lengthening of the extreme heat season is not explained by annual mean warming shifting up preexisting seasonal mean temperatures. Regional trends in seasonal mean temperature and humidity underscore that additional local dynamics are altering extreme heat drivers differentially during the two shoulder seasons. These results highlight the need for heat alert systems to focus on new times of year and prompt further study of compound events where extreme heat seasons are encroaching on the peak seasons for hazards such as wildfire or hurricanes.
How to cite: Ivanovich, C., Cook, B., and McDermid, S.: Global Extreme Heat Seasons Are Lengthening Asymmetrically, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7630, https://doi.org/10.5194/egusphere-egu26-7630, 2026.
The probability of record heat is increasing under climate warming; however, the factors controlling spatial and temporal variations in the probability of record breaking heat have not been systematically investigated. Here, we use large ensemble seasonal hindcast data for 1980-2024 to quantify how the probability of breaking records for the climatologically warmest month has evolved across different regions. We isolate the roles of the evolving record margin, background climate change, and climate variability in shaping the probability of breaking the current record. An observed record-breaking event reduces the likelihood of further records under a stationary climate, with larger record margins associated with larger decreases in record probability. Global warming has increased record probability; however, this effect varies significantly at regional scales with largest increases in Arabian Peninsula and smaller increases in Parts of Russia and Central Asia. El Nino events increase the probability of record warmth across the tropics by around 5% compared with during La Nina. The results demonstrate that the probability of record warm months is controlled by a combination of regional factors, including the evolution of existing records and externally forced warming, leading to a heterogenous distribution of current risk.
How to cite: Li, Z., Maycock, A., Birch, C., and Zhang, Y.: Likelihood of record breaking heat controlled by current record margin and spatial pattern of warming , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14834, https://doi.org/10.5194/egusphere-egu26-14834, 2026.
Background: Extreme temperatures are a key indicator of climate change, and the frequency and intensity of deadly heatwaves are projected to rise. Heat already poses a major public health threat, with over a billion people exposed globally, and yet Africa is warming faster than the global average. Tropical countries such as Uganda are expected to experience hotter conditions and growing cooling needs. However, extreme heat remains under-studied in tropical climates, especially in Africa. Although there is no single universal definition of heatwaves, current evidence generally identifies heatwaves as periods of unusually high temperatures relative to local climates.
Objective: This study aims to assess the spatio-temporal characteristics of heatwaves in Uganda and their trends.
Methods: We analyzed daily temperature data from 31 meteorological stations across Uganda over a 34-year period to assess national and regional trends. Heat extremes were characterized using three complementary heatwave metrics: the 90th percentile of maximum temperature (TX90), the Heat Index (HI), and the Excess Heat Factor (EHF). To describe temperature extremes and warming rates, the mean Tmax was calculated per year, month, and zone. The hottest and coolest years and months were identified by their respective Tmax values, while trends in monthly mean Tmax were estimated using linear regression. The slopes were expressed as °C per decade, and the months with the fastest warming and cooling rates were reported alongside their corresponding p-values. Stations were classified according to the ten climatological zones and zonal aggregation was performed to summarize station-level heatwave metrics into broader climatic regions, thereby capturing spatial patterns while reducing sensitivity to local variability.
Results: Uganda has warmed by an average of 1.7°C over the past three decades. February consistently emerges as the hottest month, while July and November are generally the coolest, with some regional variation. The year 2016 was the hottest on record, with the highest mean maximum temperature of 30.35°C recorded in northern Uganda. Across all stations, the proportion of days classified as heatwave days increased significantly, rising by an average of 0.2 percentage points per year between 1990 and 2023.
Heatwave characteristics exhibit strong spatial and temporal variability. Annual heatwave prevalence at individual stations ranges from years with no heatwaves to years exceeding 20–30%, with notable peaks in 1998, 2003, 2010, and 2023. The annual average number of heatwave events fluctuates widely, from 0 to more than 15 events per year at some stations. After 2015, more stations experienced frequent and intense episodes, indicating a clear intensification of heatwaves. Seasonally, heatwaves occur most often from June to August, with additional clusters in February –April and October–November. Sparse heatwave prevalence in the 1990s contrasts sharply with the dense occurrence of heatwave days in recent years.
Conclusion: Uganda is experiencing significant warming and a marked increase in both the frequency and intensity of heatwaves. This multi-metric characterization provides a robust foundation for understanding heat risk in a tropical African context, informs the design of heat-related policies and early warning systems, and offers a methodological framework applicable to other countries assessing evolving heatwave hazards.
How to cite: Amuron, I., Sseviiri, H., de Perez, E. C., Aalst, M. V., Kiswendsida, G., Orach, C. G., and Blandford, J.: Characterizing Heat Extremes in Uganda: A Multi-Metric analysis of Heatwave Trends, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5946, https://doi.org/10.5194/egusphere-egu26-5946, 2026.
High temperatures and heatwaves are among the most significant climate extremes, with well-documented effects on human health, including increased mortality rates. Heatwave impacts may arise from a single extreme variable, such as air temperature, or from compound conditions in which multiple variables jointly contribute to heat stress without all being individually extreme. In humid tropical regions, the co-occurrence of high temperature and humidity substantially amplifies physiological heat stress. India is a major global heatwave hotspot, particularly during the pre-monsoon season.
In this study, we identify and characterize compound heatwave events over Kerala, India, using a multi-variable framework that integrates air temperature and Wet-Bulb Globe Temperature (WBGT) a humidity-sensitive indicator of physiological heat stress. Heatwaves are classified into dry and humid categories based on percentile-based thresholds and the duration of event. Dry heatwaves are defined using the 90th percentile and a minimum three-day duration of daily maximum air temperature from the India Meteorological Department, while humid heatwaves are identified using the 90th percentile and three-day persistence of WBGT.
Our results indicate that compound heatwave events are increasingly frequent over Kerala, with heat stress intensifying as atmospheric humidity increases. These compound heatwaves impose a substantially higher heat stress burden than dry heatwaves, highlighting the limitations of temperature-only indices and highlighting the importance of incorporating humidity-sensitive metrics for improved heatwave monitoring, early warning, and risk assessment in humid tropical regions.
How to cite: Anoop, P. and Resmi, S.: Identification and Characterization of Compound Heatwaves in Kerala a Humid Tropical Region of India., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16426, https://doi.org/10.5194/egusphere-egu26-16426, 2026.
Heatwaves are intensifying across the Middle East with distinct daytime and nighttime impacts. We quantify the climatology and trends of daytime, nighttime, and compound heatwaves using station observations for 2005 to 2025, and evaluate four AI-weather models for near-surface air temperature during a recent high-impact episode (Zittis et al., 2025).
Daytime heatwaves recur from the eastern Mediterranean through northern Iraq and Iran into Anatolia during warm seasons, whereas nighttime and compound events cluster along the southern Red Sea and Arabian Gulf coasts. Trends show significant summer and autumn increases across all classes (daytime: +4.09 and +6.09; nighttime: +4.13 and +6.22; compound: +3.42 and +2.40 per year), a winter increase led by nighttime events, and a spring increase in both nighttime and compound events, consistent with asymmetric diurnal warming, strong land–atmosphere coupling over arid interiors, and coastal humidity that limits nocturnal cooling.
A case study of 10 to 27 June 2024 documents record-breaking daytime anomalies over the northern Middle East and persistent nocturnal warmth along maritime margins, with peak impacts around 17 June in the Mecca region. ERA-5 diagnostics indicate a quasi-stationary Rossby wavetrain, an anomalous ridge over southwest Asia, and an intensified Arabian Heat Low that weakened low-level ventilation and sustained humid coastal nights.
We assess GraphCast, PanguWeather, FourCastNetv2, and Aurora using six-hourly forecasts initialized at 00 UTC on 12 June 2024 and verified against ERA-5 from 12 to 22 June. All capture synoptic timing and multi-day persistence but underestimate daytime peaks and show lead-dependent cold biases. PanguWeather provides the strongest deterministic temperature guidance; GraphCast corroborates synoptic evolution. Operationally, a bias-corrected PanguWeather and GraphCast blend is recommended.
Reference:
Zittis, G., Alberti, T., Almazroui, M. et al. Analysis of the 2024 Hajj heat event and future temperature extremes in Mecca. npj Nat. Hazards 2, 107 (2025). https://doi.org/10.1038/s44304-025-00159-3
How to cite: Nelli, N., Francis, D., Fonseca, R., Hassanzadeh, P., Cherif, C., and Ghedira, H.: The June 2024 Middle East compound heatwave: Dynamical drivers and AI-weather forecast models’ evaluation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3815, https://doi.org/10.5194/egusphere-egu26-3815, 2026.
Summer seasons have warmed rapidly over western Europe increasing the number of hot days and severe heat waves. Notably, heat extremes have intensified more than the seasonal average temperatures as a result of the widening of daily temperature distributions and the heterogeneous warming of the season with the already warmer late summer warming more than early summer.
Here we show that the above described changes are even more pronounced for extremely warm seasons amplifying their heat impacts. We compare summer seasons with return periods of 100 years in current climate to similarly rare seasons in pre-industrial climate. We obtain a sufficient number of simulated hot seasons by applying a rare event algorithm that efficiently simulates a hot summer ensemble by iteratively and systematically discontinuing ensemble members that are cold and cloning trajectories that are warm. We use the fully coupled Community Earth System Model (CESM2).
In pre-industrial climate, warm weather in early summer is required to dry out soils allowing temperatures to rise in the second half of summer. In current climate, soils tend to be drier in summer and therefore the requirement of warm weather in early summer is less strict. As a result, in current climate 100-year summers, the accumulation of heat in late summer is more pronounced leading to longer lasting and more intense heat waves. We also show that this difference in the heat characteristics of similarly rare summer seasons goes beyond the climatological widening of the daily temperature distribution and the change in the seasonal cycle.
How to cite: Pfleiderer, P., Noyelle, R., and Sippel, S.: Increase in persistence and intensity of heat waves in hot summers due to the intensification of the seasonal cycle, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17599, https://doi.org/10.5194/egusphere-egu26-17599, 2026.
Understanding the sources of uncertainty in future climate extremes is crucial for effective regional adaptation strategies. This study uses simulations from 26 global climate models to investigate projections of summer maximum temperature (TXx) across four southern South America regions: northern, central-eastern, and southern areas, and central Argentina. A storyline approach is applied to examine how different climate drivers interact to shape TXx changes by the late 21st century (2070–2099).
The storylines are based on changes in key physical drivers, including mid-tropospheric ridging, regional soil moisture, sea surface temperature in Niño 3.4 region and an OLR gradient index that reflects changes in atmospheric stability and the positioning of convective activity over the South Atlantic Ocean. A multi-linear regression framework shows that dominant drivers of projected TXx warming differ across regions. In northern areas, uncertainty is primarily controlled by remote influences, including tropical sea surface temperatures and OLR variations over the subtropical South Atlantic Ocean. Central-eastern areas and central Argentina show a combination of local and remote drivers, whereas southern regions are mostly governed by local factors, such as soil drying and atmospheric blocking. Together, these drivers account for up to 56% of the inter-model spread in regional TXx projections. Nonetheless, their capacity to capture the projected spread in percentile-based indices and regional heatwaves attributes is limited, suggesting that the drivers of heatwave responses vary with the metric.
How to cite: Suli, S., Barriopedro, D., García-Herrera, R., Collazo, S., Squintu, A., and Rusticucci, M.: Storylines of extreme summer temperatures in southern South America, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1753, https://doi.org/10.5194/egusphere-egu26-1753, 2026.
Heat, combined with high levels of humidity, can lead to hyperthermia, i.e. an increase in human body temperature beyond dangerous thresholds. In the most severe cases, it can be deadly, even for young and healthy adults. According to the literature, extreme humid heat over continents is projected to increase markedly at the global scale by the end of the century, particularly over the tropical belt. Yet, the case of small tropical islands is ambiguous because the available studies are based on coarse gridded datasets such as those from global climate models that ignore or distort these islands, calling for dedicated downscaling efforts.
Here, statistically downscaled and bias-corrected model output from CMIP6 using weather station observations from islands across the tropics are used to assess present and future conditions of extreme humid heat. The latter are estimated with the Heat Index (HI) that combines surface temperature and relative humidity.
Similarly to what has been previously shown for continents, the intensity of extreme humid heat events is projected to reach particularly dangerous levels by the end of the century, with higher HI values for islands located closer to the equator. Longer, more common humid heatwaves are also notably projected to increase in frequency, with more pronounced increases equatorward, because of the lower seasonal variability of HI.
Such severe humid heat conditions threaten the lives of millions of small island inhabitants across the tropics, calling for dedicated local adaptation strategies.
How to cite: Bald, L., Belmadani, A., Leroux, M.-D., Pannekoucke, O., Gentric, A., and Qasmi, S.: Small tropical islands also exposed to extreme humid heat by the end of the century, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5401, https://doi.org/10.5194/egusphere-egu26-5401, 2026.
The African Sahel—home to 180 million people—faces escalating risks from the convergence of poverty, food insecurity, political instability, and climate change. While the African Union’s Great Green Wall (GGW) initiative aims to restore 100 million hectares of degraded land to alleviate these challenges, we find that greening coincides with a rapid rise in hazardous humid-heat days (HHDs), threatening human health and livelihoods. Using high-resolution (5 km) datasets from 1983–2016, we map where greening is coinciding with increasing HHDs, and we project 2050 exposure by age cohorts. We find that areas with increased short vegetation experienced a 158% faster rise in HHDs compared to non-greening regions, driven primarily by higher atmospheric moisture rather than air temperature. By 2050, nearly all Sahel residents will experience at least 30 HHDs per year, with children born in the past decade facing the greatest future impacts. Our findings suggest that climate-driven greening may intensify heat-health risks, underscoring the need for GGW and other climate adaptation policies to factor in humid-heat exposure.
How to cite: Tuholske, C., Ivanovich, C., Williams, E., Horton, R., Shukla, S., Funk, C., Andam, K., Kibler, C., Yamba, E., Zimmer, A., and Brooks, N.: Rapidly Increasing Hazardous Humid-Heat Exposure Across Africa’s Great Green Wall, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5992, https://doi.org/10.5194/egusphere-egu26-5992, 2026.
Hot days on tropical land warm faster than the average day, and evidence is growing that this enhanced warming is due to hot days being dry. Mechanisms rooted in tropical atmospheric dynamics and thermodynamics explain how low near-surface air humidity tends to give rise to high surface temperatures. But what makes the air dry in the first place and how the underlying processes may be affected by a changing climate remain open questions, impeding reliable predictions of tropical heat extremes in a warming world.
Here we present a composite moisture budget analysis for hot days on tropical land based on 45 years of daily ERA5 reanalysis data. Using a statistical approach and sampling the hottest day per location and year, we investigate the contributions of horizontal and vertical moisture transports, evapotranspiration, and precipitation to the change in specific humidity during the run-up to hot days.
Preliminary findings based on the vertically-integrated moisture budget indicate that moisture anomalies develop over a characteristic time scale of three to four days prior to the hot day. However, counter to our initial expectations, these anomalies are not generally negative. Only in about half of all cases, the atmosphere undergoes net drying leading up to a hot day. We find that the sign of the moisture anomaly correlates with the background climate as measured by the aridity index: In moist regions, hot days tend to be dry while in arid regions, hot days tend to be moist. In both cases, the anomaly is explained by a regime shift of the horizontal moisture transport, from convergence to divergence in the case of dry anomalies, and from divergence to convergence in the case of moist anomalies.
We discuss the implications of these results for understanding humidity on tropical hot days in a warmer climate.
How to cite: Schmidt, L. and Byrne, M.: What controls humidity on hot days in the tropics?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12018, https://doi.org/10.5194/egusphere-egu26-12018, 2026.
South Asia is a global hotspot of extreme heat and aerosol pollution. Observations and climate projections consistently show an intensification of heat extremes across the region, particularly during the pre-monsoon season when the most deadly heatwaves occur. At the same time, South Asia experiences persistently high aerosol loading due to rapid industrialisation and urbanisation, with sulphate representing the dominant anthropogenic scattering component of the regional aerosol burden. While reductions in aerosol emissions are crucial for improving air quality and public health, changes in aerosol concentrations can also modify extreme heat through direct radiative effects and indirect impacts on clouds and circulation.
Previous observational studies have explored links between aerosols and extreme heat in South Asia, but most rely on direct comparisons of their spatial patterns or long-term trends, providing limited evidence for a causal relationship. Only a few studies have directly examined correlations between aerosol optical depth (AOD) and temperature, often using absolute values that may introduce spurious relationships due to shared seasonality or long-term trends. Moreover, both reanalysis-based and modelling studies rarely distinguish between absorbing and scattering aerosol components, despite their fundamentally different radiative and thermodynamic effects. These limitations hinder a physically interpretable quantification of temperature sensitivity to aerosols.
Here, we combine reanalysis data with CMIP6 experiments to investigate how different aerosol components influence extreme heat in South Asia. Focusing on pre-monsoon daily maximum temperature (Tmax) as a proxy for extreme heat, we find that sulphate aerosols exert a robust cooling effect on extreme heat, particularly over major megacity regions along the Indo-Gangetic Plain. CMIP6 experiments indicate a typical sensitivity of -2 to -6 K per unit sulphate AOD in these densely populated regions, a signal that is broadly consistent in sign with reanalysis-based estimates but more spatially coherent in the model framework. This study provides the first component-specific assessment of aerosol impacts on extreme heat in South Asia.
How to cite: Meng, Y. and Matthews, T.: Aerosol components modulate pre-monsoon extreme heat in South Asia, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15025, https://doi.org/10.5194/egusphere-egu26-15025, 2026.
The vertical structure of heat waves has been an overlooked characteristic until recently. Here we present results of their analysis for Central Europe based on vertical cross-sections of temperature anomalies throughout the troposphere, including links to soil moisture conditions and atmospheric circulation. Heat waves were classified into four types based on the predominant location of positive temperature anomalies: near-surface, lower-tropospheric, upper-tropospheric, and omnipresent, using ERA5 data at multiple pressure levels since 1979. For each heat wave type, we summarize key characteristics, including vertical temperature structure, typical duration, seasonal occurrence within summer, links to atmospheric circulation, and soil moisture preconditioning. We also assess the ability of CORDEX regional climate models to reproduce the characteristics of the individual heat wave types in simulations for the recent climate. Finally, we outline ongoing follow-up studies on topics including sub-daily characteristics of heat waves, off-season events, and a global analysis on the 5° × 5° grid.
How to cite: Lhotka, O., Plavcová, E., Poppová, Z., and Kyselý, J.: Heat wave types in Central Europe: new insights based on vertical structure, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3455, https://doi.org/10.5194/egusphere-egu26-3455, 2026.
Heat stress is an escalating global public health concern, especially as climate change intensifies the frequency, duration, and severity of extreme heat events. Accurate identification of hazardous heat exposure is essential for the development of effective heat-health warning systems (HHWS) and the timely issuance of public alerts.
Traditionally, air temperature (Tair) has been used as the primary metric for triggering heat alerts. However, a growing body of evidence highlights the critical role of humidity in intensifying heat stress and increasing health risks. As a result, integrated heat stress indicators (HSIs)—which incorporate multiple meteorological factors such as temperature, humidity, solar radiation, and wind speed—are gaining attention.
In 2021, Japan updated its national HHWS by replacing Tair with Wet Bulb Globe Temperature (WBGT), a more comprehensive index that accounts for multiple variables. However, the effectiveness of this change, and the broader applicability of various HSIs in predicting heat-related morbidity and mortality remain insufficiently explored.
In this presentation, we synthesize recent research evaluating the performance of multiple HSIs in modeling heat-related health outcomes across Japan and other regions. By comparing various health outcome datasets, we assess how well different HSIs capture population-level vulnerability to heat.
Furthermore, we demonstrate how data-driven techniques can move beyond one-size-fits-all indicators. By leveraging local health datasets, we show how it is possible to fine-tune HSIs to reflect regional population sensitivities, ultimately enhancing the accuracy and effectiveness of heat-health warnings at the local level.
How to cite: Guo, Q. and Kong, Q.: Optimizing Heat Stress Indicators for Protecting Human Health: From Generic Metrics to Localized Solutions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4205, https://doi.org/10.5194/egusphere-egu26-4205, 2026.
The escalation of heat-related health risks due to climate change and population ageing is a growing global concern. However, their independent
contributions to medically certified heatstroke mortality remain insufficiently quantified.
We analysed 28 years (1995–2022) of municipality-level records of medically certified heatstroke deaths (ICD-codes) across 1,831 municipalities and wards in Japan. We fitted hierarchical Bayesian spatiotemporal models incorporating summer temperature anomalies and the municipal share of residents aged ≥65 years.
Heatstroke mortality was higher in warmer summers and in municipalities with older population structures: 42% (RR=1.42, 95% CrI 1.36–1.49) per 0.65°C (1 SD) increase in summer temperature anomalies, and 24% (RR=1.24, 95% CrI 1.18–1.31) per 10-percentage-point increase in the ≥65-year population share. Decomposition of national trends indicated that population ageing progressively increased baseline risk, while large positive temperature anomalies produced additional mortality peaks on this elevated baseline. A sustained upward shift in risk was observed from around 2007 onward. Residual spatial heterogeneity remained after adjustment, with clusters of elevated risk in both urban and rural municipalities.
These findings highlight the need for targeted, place-specific heat-health adaptation as climatic warming and population ageing continue to progress. As a super-aged nation, Japan offers valuable insights into mitigating future heat-related health burdens under ongoing climatic and demographic transitions.
How to cite: Kakinuma, K. and Inoue, N.: Heatstroke mortality under climate and demographic transitions: 28-year spatio-temporal analysis in Japan, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3630, https://doi.org/10.5194/egusphere-egu26-3630, 2026.
Extreme heat is among the deadliest meteorological hazards and poses an increasing threat to human health and socioeconomic systems, including labor productivity.
Here, we present global and regional projections of population exposure to extreme heat stress and associated labor productivity losses across a range of emissions scenarios from the Shared Socioeconomic Pathways (SSPs) and NGFS (Network for Greening the Financial System), which are widely employed in private and financial sector risk assessments.
Robust projections of heat stress impacts require climate data that accurately represent temperature and humidity conditions during the hottest hour of the day, when physiological strain typically peaks. To this end, our analysis builds on a newly derived global dataset of future changes in the Heat Index (HI), a widely used metric of human heat stress integrating the combined effects of temperature and humidity, with enhanced temporal accuracy. Sub-daily relative humidity during the hottest hour is reconstructed from ISIMIP3 daily near-surface specific humidity using a physically and statistically consistent correction framework, enabling a more realistic representation of peak heat stress than standard ISIMIP3 humidity output.
Our results reveal pronounced hotspots of intensifying heat stress and labor productivity losses in densely populated low-latitude regions, including South Asia and West Africa, that are strongly dependent on labor-intensive sectors. In these regions, most projected heat-related productivity losses could be avoided by limiting global warming to 1.5 °C.
How to cite: Langer, R., Schwind, N., Schleussner, C.-F., and Kornhuber, K.: Estimating global labor productivity losses from heat stress under a range of long-term climate scenarios, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14667, https://doi.org/10.5194/egusphere-egu26-14667, 2026.
Heatwaves are driving rapidly increasing cooling demand, placing power systems under growing stress with implications for energy resilience in a changing climate. While recent advances in climate prediction have improved understanding of near-term climate variability, the seasonal-to-multiyear predictability of extreme cooling demand remains insufficiently explored. Here, we assess the prediction skill of heatwaves, cooling degree days (CDDs), and derived categories of cooling demand across Northern Hemisphere hotspots using initialized and uninitialized simulations from the Community Earth System Model version 2 Multiyear Prediction System (CESM2-MP) over the period 1981–2020. We evaluate predictability associated with externally forced signals and internal climate variability, with a focus on summer thermal extremes relevant to cooling demand. We find that externally forced signals provide robust seasonal-to-multiyear predictability of terrestrial heatwaves, enabling skillful forecasts of dry and humid CDDs and associated categories of elevated cooling demand at multi-year lead times. Predictive skill is strongest in regions including the US Southwest, Arabian Peninsula, Central America, and Southeast Asia, where forecasts reliably distinguish between below-normal, elevated, and extreme demand years. Internal climate variability, including ENSO-related signals, contributes additional but more limited predictability at approximately one-year lead time. Our results indicate emerging multi-year predictability of heatwave-driven cooling demand, highlighting the potential for climate-informed approaches to anticipate future demand extremes and support energy-system resilience and adaptation planning.
Key words: terrestrial heatwaves, cooling degree days, cooling demand, predictability, external forcing, CESM2-MP, climate extremes, climate risk, energy resilience, hotspots, urban applications, socio-economic and health impacts.
How to cite: Karwat, A., Lee, J.-Y., Kim, Y.-Y., Yun, J.-E., and Lee, S.-S.: Emerging Multi-year Predictability of Heatwave-Driven Cooling Demand, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16623, https://doi.org/10.5194/egusphere-egu26-16623, 2026.
Introduction: The 2003 European heatwave marked a turning point in the development of heat early warning systems (HEWS), yet little is known about how these systems have evolved once implemented or about the rationale of underlying operational choices. Methods: This study examines the evolution of the Dutch heat warning system from its introduction in 2007 through 2025, operated by the Royal Netherlands Meteorological Institute (KNMI), focusing on changes in warning criteria, operational procedures, and their role in triggering the national heat-health action plan (HHAP). We analysed 18 internal evaluations of major heat events, policy documents, and institutional reflections from system developers and operators to trace the climatic, operational, and institutional drivers of system change. To assess future relevance, we applied the KNMI’23 climate scenarios to evaluate how current warning criteria perform under projected conditions for 2050 and 2100. Results: Results show a transition from a single trigger for the national heat-health action plan, toward a tiered warning system that increasingly integrates expert judgment and societal impact considerations alongside meteorological thresholds, with a fully impact-based Code Red. A key revision in 2021 removed minimum temperature requirements, leaving maximum temperature as the primary trigger. In 2024, the first evaluation of the national HHAP by health authorities, including epidemiological evidence, provides a basis for further development of the warning criteria. Conclusion: The Dutch case highlights how HEWS function as adaptive systems that must continuously balance operational simplicity, impact relevance, and future climate pressures. We conclude by situating these findings within ongoing research and developments, including the development of heat warnings for the tropical island of Bonaire (also under KNMI’s mandate), and introduction of the wet-bulb globe temperature as a complement to traditional heat warnings. These insights are relevant for advancing heat early warning systems in Europe and beyond.
How to cite: Pereira Marghidan, C., Sluijter, R., Blanford, J., Homan, H., Siegmund, P., Hagens, W., and van Aalst, M.: Two decades of operating a heat early warning system: lessons from the Netherlands (2007–2025), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11090, https://doi.org/10.5194/egusphere-egu26-11090, 2026.
As the frequency, duration, and severity of global heatwaves intensify, increasing proportions of urban populations are being exposed to extreme heat risks. Although the health impacts of high temperatures have been extensively documented, the mechanisms linking heat risk perception, experienced impacts, and adaptive behaviors remain insufficiently understood, particularly across different gradients of exposure intensity. Moreover, most cross-sectional studies on heat risk perception overlook the spatial heterogeneity of heat exposure risk, which may lead to biased assessments of residents’ perception levels and adaptive capacity. In this study, spatially explicit heat exposure risk assessments are integrated with household survey data, and structural equation modeling (SEM) is applied to examine the associations among heat exposure risk, residents’ heat risk perception, heat risk impacts, and adaptive behaviors. The results show significant negative associations between heat exposure risk and perception, impact, and adaptation. Residents in high-risk areas tend to have lower levels of heat risk perception, which in turn suppresses adaptive behaviors. Further analyses reveal that socioeconomic factors play moderating roles across different exposure gradients. Age and education are key determinants of heat risk perception, but their effects weaken in high-risk groups. Education significantly affects psychological and physical health impacts and promotes adaptive behaviors, particularly transportation-related protective actions. Income is also positively associated with transportation protective behaviors. These findings highlight the importance of incorporating objective heat exposure risk into studies of heat risk perception and adaptive behaviors. They also underscore the need for differentiated, community-level adaptation strategies to address growing spatial and social inequalities under climate change.
Keywords: Heat exposure risk; Heat risk perception; Adaptive behavior
How to cite: Liu, Q. and Xie, M.: Suppressing the Adaptation Pathway: Negative Effects of Heat Exposure Risk on Perception, Impact, and Behavior, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10075, https://doi.org/10.5194/egusphere-egu26-10075, 2026.
The urban heat island effect, a direct consequence of urbanization, compounded by climate change impacts, poses challenges to population heat stress exposure. Coastal cities, which experience land-sea breezes, are facing additional complexities to address this exposure concern.
This study utilizes the high-resolution Weather Research and Forecasting model coupled with a single-layer Urban Canopy Model to assess the effects of two well-established heat mitigation strategies, i.e., cool roof and urban forestry, on temperature dynamics and population heat stress exposure. Two coastal cities in Western Canada, Vancouver and Victoria, are taken as a testbed. We analyze two climate change scenarios based on the Coupled Model Intercomparison Project Phase 6, covering near- and far-future projections under SSP2-4.5 and SSP5-8.5 pathways.
The results indicate that by the end of the century, the population's exposure to heat stress under SSP5-8.5 will be three times greater than under SSP2-4.5, the urban population growth being the main factor driving increased exposure. Increasing urban vegetation can help reduce urban heat islands and exposure, but planting more trees in already vegetated areas might not yield further cooling benefits and could worsen water management issues during droughts. Conversely, widespread use of reflective roofs or efficient solar panels provides stronger advantages by reducing temperatures both indoors and outdoors, but the extent of their impacts is limited.
This study shows that both heat mitigation strategies are insufficient to counter the projected impacts of climate change on daily temperature extremes, heat-stress days, and population exposure. This emphasizes the crucial necessity of reducing greenhouse gas emissions for lowering population exposure to heat stress rather than betting on climate adaptation strategies.
How to cite: Azargoshasbi, F. and Minet, L.: How effective are adaptation strategies in reducing climate change–induced urban heat stress exposure? A case study of cool roofs and urban forestry in Vancouver and Victoria., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15969, https://doi.org/10.5194/egusphere-egu26-15969, 2026.
Intensifying humid heatwaves (HHWs) across the Indian subcontinent highlight the growing risk of elevated temperatures and increased humidity in urban agglomerates, characterized by dense populations and complex sustainability demand. While conventional Extreme Value Theory (EVT) approaches are commonly used to estimate design events of heat-humidity compound extremes, they are constrained by limited sample sizes and unstable upper tail estimates in data-sparse regions. Recent advances in Metastatistical Extreme Value (MEV) theory demonstrate significant skill improvements for hydroclimatic extremes such as rainfall and flash droughts, but its applicability to compound heat–humidity, i.e., HHWs, remains unexplored for Indian sub-continent, with diverse climate types, primarily dictated by monsoonal circulations. Here, we present the first observational assessment showing the skill of MEV probabilistic framework that can capture the year-to-year variability of the HHW distributions. Using in-situ observations from 54 urban and peri-urban sites across India for over four decades (1980–2025), we develop the MEV-based probabilistic estimates of extreme HHW magnitude, which we compare against the conventional EVT-based distribution. HHW events are identified based on daily observed maximum wet-bulb temperature exceeding the 90th percentile daily variable threshold that persists for two consecutive days or more, while HHW magnitude is estimated as the positive anomaly of daily extreme wet-bulb temperature, exceeding the 90th percentile variable threshold, normalized by its interquartile range. Our results show that MEV consistently outperforms conventional EVT in estimating design events for approximately, 68% of sites, indicating improved representation of moderate to rare HHW events. The uncertainty bounds (indicated by the interquartile range) of the MEV versus EVT design events suggest that MEV offers lower uncertainty, represented by narrower interquartile ranges, compared to conventional EVT across approximately 70% of sites. For example, for a representative site across eastern coastal India, the quantification of the record HHW event during July 2020, with a 64-year return period, is illustrated. The MEV estimated quantile provides error estimates of ~1%, whereas the conventional model underestimates the design events by ~4%, suggesting the MEV model offers improved representation of compound heat and humidity design events, which have implication towards public health and ecosystem sustainability. Our study provides the first application of MEV models to understand the heat-humidity nexus across urban agglomerates of India, and demonstrates its potential to define impact-relevant metrics in a warming climate.
How to cite: Deb, S. and Ganguli, P.: Metastatistical Extreme Value Framework Reveals Robust Improvement in Characterizing Humid Heatwave across Indian Urban Agglomerates, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1445, https://doi.org/10.5194/egusphere-egu26-1445, 2026.
Under the accelerating pace of global warming, extreme heat events are becoming more frequent, intense, and prolonged, posing significant threats to public health and energy security. This study characterizes the evolution and physical mechanisms of "compound extreme heat", defined by the simultaneous occurrence of high ambient temperatures and high humidity, within the complex topographical and urbanized landscape of Taiwan.
By integrating high-resolution observational data with regional climate simulations, we identify the distinct spatiotemporal fingerprints of heatwaves across different geographical regions of the island. Our analysis reveals that the intensification of extreme heat is driven by a synergistic interaction between synoptic-scale circulation and local-scale surface processes. Specifically, the anomalous westward extension and intensification of the Western North Pacific Subtropical High (WNPSH) provide the necessary large-scale subsidence and clear-sky conditions. On a local scale, this is further exacerbated by the Urban Heat Island (UHI) effect and restricted sea-breeze penetration in basin terrains, leading to localized "hotspots" with significantly elevated wet-bulb temperatures.
Furthermore, this research assesses the changing risks associated with these compound events under various CMIP6 warming scenarios. We quantify the drivers of extreme heat through a budget analysis of the surface energy balance and atmospheric moisture, highlighting how land-atmosphere feedbacks amplify heat stress in rapidly growing metropolitan areas. The findings provide critical insights into the physical drivers of subtropical heat extremes and offer a scientific basis for developing region-specific adaptation strategies and early-warning systems for heat-related risks in a warming climate.
How to cite: Juang, J.-Y.: Characterizing the Drivers and Spatiotemporal Evolution of Compound Extreme Heat Events in Subtropical Island Environments: A Multi-Scale Analysis of Taiwan, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11999, https://doi.org/10.5194/egusphere-egu26-11999, 2026.
Recent decades have seen an increase in the frequency and intensity of extreme heat events. Such events have a profound impact on society, as they increase human exposure to heat stress and can negatively affect energy consumption and agriculture. These effects are further amplified in urban environments due to climate change. Belgium, among the most urbanised countries worldwide, has experienced an increasing number of heatwaves in recent years, with several years recording multiple events. However, the future extent and characteristics of heatwaves remain unclear, making it difficult to assess whether current suggested adaptation strategies and heat action plans for today's climate will remain effective under future warming. With this research, we aim to develop a storyline-based selection method to quantify single future heat waves based on the characteristics of past events and thereby enable the identification of relevant case studies for assessing future risks.
With the new Belgian climate projections from the CORDEX.be II project, different global warming levels are being explored (1.5°C, 2°C, 3°C and 4°C), to gain insights into different future extreme events. In this study, we analyse high-resolution data from the regional climate model COSMO-CLM, in which urban areas are explicitly modelled, forced by the global climate model EC-Earth3-Veg (SSP5-8.5), at two horizontal resolutions: 12.5 km (all warming levels) and 2.8 km (2°C and 3°C). By identifying historical extreme events and mapping events with similar characteristics in higher warming levels using different heat metrics, we quantify changes in event duration, temperature characteristics, and intensity relative to the recent past to obtain interesting future cases.
How to cite: Serras, F., Vanderkelen, I., Lampaert, W., and van Lipzig, N.: The next hot thing: Belgian heatwaves in a warming world, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5580, https://doi.org/10.5194/egusphere-egu26-5580, 2026.
With rising global temperatures, extreme heat is expected to become more frequent worldwide. Although less severe compared to other parts of Europe, heat extremes are increasingly affecting countries with relatively cooler climates, such as Norway. The heatwave in July 2025 highlighted Norway's limited preparedness for addressing this kind of risk. It is therefore of interest to investigate the extent to which heat extremes represent an emerging hazard in the country.
Using the recently updated national climate projections for Norway, we analyze both historical and future trends in heat extremes within regions defined by climatologically consistent temperature patterns. These climate projections are dynamically downscaled from global simulations, and bias-adjusted using observational data. To quantify the frequency and intensity of heat extremes at global warming levels, we apply a non-stationary Generalized Extreme Value (GEV) model. This approach offers the advantage of tying the global climate to the local changes in heat extremes. Our analysis focuses on the expected intensities of 100-year heat extremes at different levels of global warming and under different emission scenarios. Specifically, we evaluate projections of daily minimum and maximum temperatures and assess heat events of different durations (e.g., 1-, 3-, 5-, 7-, and 14-day events). This includes examining both daytime heat extremes (high maximum temperatures) and nighttime events (high minimum temperatures). The key research questions driving our study are: (1) Do heat extremes intensities differ at the same global warming levels under different emission scenarios, and (2) at what level of global warming do "severe" heat extremes begin to emerge?
Initial results show that, as expected, all observations and climate models show an increasing trend in the intensity of a 100-yr event with rising global temperatures. However, the rate of increase with global warming level differs markedly between climate models. Furthermore, there is a slight but not systematic difference between climate projections with RCP45 and SSP3-7.0 emission scenarios. Moreover, climate projections generally show a weaker trend compared to observations. The difference becomes more pronounced for longer duration events. Thus, future projections may underestimate the increase in the intensity of heat extremes in Norway.
How to cite: Skålevåg, A. and Ødemark, K.: Future heat extremes in Norway: An emerging hazard?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13604, https://doi.org/10.5194/egusphere-egu26-13604, 2026.
Warm extremes are intensifying in a warming world; however, most heat-related metrics focus on summer heatwaves. Therefore, linear trends often underestimate anomalously warm conditions occurring throughout the year. This limitation hampers our ability to robustly quantify changes in the frequency and severity of warm spells. Here, we assess global and regional changes in year-round warm spells using the Warm Spell Magnitude Index daily (WSMId), a dimensionless and additive metric that integrates warm-spell intensity, duration, and frequency consistently across seasons.
We calculate WSMId with the aid of ERA5 daily maximum temperature data for the period 1980–2024, aggregating warm-spell magnitudes at annual and seasonal time scales to assess long-term changes in the cumulative severity of warm spells. Trend analysis reveals widespread and statistically significant nonlinear intensification of warm spells since 1980, with more than 70 % of global land areas exhibiting a multi-fold increase in annually aggregated warm-spell magnitude.
Spatial patterns indicate especially large relative increases in warm-spell severity in tropical regions, while pronounced intensification is also evident across the mid-latitudes. Comparison with the Warm Spell Duration Index, an index that captures only event duration, confirms the robustness of the detected trends and underscores the enhanced sensitivity of WSMId, which aggregates changes in warm-spell duration and intensity.
Overall, these findings demonstrate that warm spells are not only intensifying but are increasingly compounding across seasons, emphasizing the value of magnitude-based frameworks for assessing escalating thermal stress under climate change.
How to cite: Liakakos, A., Hadjinicolaou, P., Tyrlis, E., and Zittis, G.: A new magnitude-based approach to detect year-round warm spells and their recent intensification, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11101, https://doi.org/10.5194/egusphere-egu26-11101, 2026.
Extratropical continental atmospheres in summertime are close to moist convective neutrality, under which near-surface moist static energy (MSE2m) is tightly constrained by mid-tropospheric saturation moist static energy (MSE500). During moist heat extremes, however, MSE2m often exceeds this moist-convective limit (MSE500), indicating a breakdown of the neutrality assumption. Recent work has attributed this breakdown to the presence of energy inversions in the lower free troposphere during extratropical moist heat extremes.
Here, we advance this understanding by examining the role of dry-air entrainment in modulating moist heat extremes. Building on recent work focused on the tropics, we develop an entrainment-based theoretical framework to diagnose near-surface MSE during extreme moist heat events. We analyse maximum wet-bulb temperature days over land regions between 35°N and 65°N using ERA5 reanalysis data (1991-2020) and CESM2 simulations. Simulations are performed with prescribed sea-surface temperatures and three different entrainment rates: control (entrainment rate=−1 km⁻¹), no-entrainment (0 km⁻¹), and doubled-entrainment (−2 km⁻¹). Our results show that entrainment of dry air intensifies boundary-layer instability (MSE2m – MSE500) during extratropical moist heat extremes. The theoretical framework using entrainment rates diagnosed from the zero-buoyancy plume model successfully explains the breakdown of moist convective neutrality during moist heat extremes. We attribute changes in MSE2m under warming to the combined effects of changes in free-tropospheric MSE, lower-tropospheric saturation deficit, and entrainment strength. This framework improves fundamental understanding of extratropical moist heat extremes and provides a physically-grounded basis for interpreting their future changes.
How to cite: Jha, R. and Byrne, M. P.: Role of dry‑air entrainment in intensifying extratropical moist heat extremes , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5010, https://doi.org/10.5194/egusphere-egu26-5010, 2026.
Humid heat has increased in intensity, frequency, and duration across the world, including in mid-latitude regions not acclimated to it. Wet bulb globe temperature (WBGT) is one of the most representative humid heat metrics in terms of impacts to human health. Here, an established WBGT estimation formula and the high-resolution (9-km) ERA5-Land reanalysis dataset are used to examine summer humid heat trends and drivers across Europe and the Southeast United States. In Europe, both daytime and nighttime WBGT are increasing significantly across nearly the entire domain. Daytime and nighttime trends are of similar magnitude in many areas, with daytime trends largest in western and northern Europe and nighttime trends greatest in eastern and southern Europe. In addition, there are statistically significant and large frequency and duration trends in extreme (90th percentile) WBGT, especially at night near the Mediterranean, where there are approximately three additional extreme nights per decade and extreme event duration is more than one day longer each decade. Unlike in Europe, nighttime WBGT trends in the Southeast United States are larger and more widely statistically significant than daytime trends across most of the region. Like in Europe, there are large increases in the frequency and duration of extremes, particularly at night. For example, regions near the Gulf and in Florida are experiencing nearly three additional extreme summer nights per decade and extreme events are approximately one night longer per decade. A quantification of the importance of WBGT components (temperature, dewpoint, wind speed, solar radiation) shows that dewpoint increases exceed temperature increases and are the primary driver of WBGT trends across the Southeast United States, a region characterized by its hot humid climate and proximity to warm water. However, in the milder and drier climate of Europe, temperature increases are the dominant driver of WBGT changes, with a strong correlation to positive trends in solar radiation. Overall, results suggest that the drivers of humid heat trends depend on regional climate characteristics, which may have broad applications to climate modelling of future humid heat.
How to cite: Milrad, S., Ennis, K., Orletski, K., and Beaty, P.: Climate matters: Differences in trends and drivers of summer humid heat in Europe and the Southeast United States, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1886, https://doi.org/10.5194/egusphere-egu26-1886, 2026.
Heatwaves in the UK are projected to become more frequent and intense due to climate change. While the health risks of extreme heat are well documented, less is known about the effects of compound weather hazards, specifically the co-occurrence of high temperatures and elevated humidity. High humidity can substantially increase heat stress, yet its role in modifying health outcomes in the UK remains underexplored. This study addresses this research gap by investigating how and why humidity varies across UK heatwaves from a meteorological perspective for the first time and quantifying its impact on health. First, we identify historical heatwaves over the past four decades using a spatially extended reanalysis dataset. Second, we stratify these events into more humid and less humid categories and identify the key weather patterns and meteorological drivers leading to humid heatwaves. Third, using daily all-cause mortality and hospital admissions data, we conduct heat episode analyses to assess differential health impacts associated with isolated heatwaves versus those co-occurring with high humidity. Preliminary results suggest that humid heatwaves in the UK have distinct meteorological features which, through compensatory mechanisms, may moderate their impact on health outcomes. On average, more humid heatwaves exhibit higher wet-bulb temperatures and nighttime dry-bulb temperatures, but lower daytime dry-bulb temperatures and downward surface solar radiation, suggesting higher cloud cover. Furthermore, humid heatwave events tend to occur later in the summertime, when populations may be more acclimatised to heat. This work will provide new insights into the drivers of compound humid-heat events and their health implications in the UK, which can help to inform public health preparedness and climate resilience strategies.
How to cite: Reddington, C., Birch, C., Kennedy-Asser, A., Doherty, R., Schurer, A., Sarran, C., Ireland, L., Jackson, L., Simpson, C., and Hajat, S.: Humid heatwaves in the UK: Meteorological drivers and health impacts, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19454, https://doi.org/10.5194/egusphere-egu26-19454, 2026.
Uncompensable heat stress (UHS) occurs when human thermoregulation fails to maintain a stable core temperature, posing severe health risks. While previous studies emphasize humidity’s role in future heat stress, we introduce Critical Temperature Margin (CTM) - the buffer between ambient temperature and critical temperature causing UHS - to quantify heat safety under climate change. The CTM is based on human energy balance equations considering a variety of climate factors and key human physiological limits.
Using ERA5 data (1980-2023) and CMIP6 projections, we quantify future trends in CTM under different radiation environments and classify heat stress by dominant mechanisms: dry heat (sensible heat and radiative components) and moist heat (evaporative component). Our analysis reveals that future UHS changes are primarily driven by increasing dry heat contribution associated with rising temperature and longwave radiation, while humidity effects of rising saturation vapor pressure and declining relative humidity during extreme events largely cancel out. Our key findings show: (1) CTM diminishes by -2.4°C per degree of global warming (-0.8°C locally) on average; (2) increasing prevalence of dry heat dominated regions over past 40 years; (3) outdoor conditions experience more dry heat stress than indoors; (4) sweat evaporation constraints on moist heat stress remain nearly constant, contradicting assumptions that humidity dominates future heat stress.
We also find that human settlements historically avoided thermally challenging regions. However, diminishing CTM threatens millions of world populations, particularly outdoor workers in tropical and subtropical areas who will face similar evaporative cooling capacity but increasing radiative and dry heat loads. Typical moist-heat dominated regions such as India, Sahel, Southeast U.S., East China, Northern Australia will be subject to more than 50% dry heat in outdoor conditions.
These findings clarify the ongoing humidity debate in heat-health research. Our results support targeted mitigation strategies: increased ventilation for moist heat, shade for radiation, and active cooling for dry heat. Our robust projection of the CTM provides critical insights for public health adaptation planning as thermal safety margins continue shrinking globally.
How to cite: Fan, Y. and McColl, K.: Robust Critical Temperature Projections Reveal Diminishing Heat Safety Margins Under Global Warming, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4385, https://doi.org/10.5194/egusphere-egu26-4385, 2026.
Economic expenditure incurred by urban residents to alleviate heat-related discomfort constitutes an observable economic manifestation of their adaptive responses to heat risk. Focusing on the core area within Beijing’s Sixth Ring Road in a megacity context, this study integrates field-based questionnaire surveys with heat exposure data to systematically examine the response characteristics, population heterogeneity, and spatial patterns of residents’ subjective adaptive expenditure under heat conditions. The results indicate that residents’ subjective adaptive expenditure is more strongly associated with subjective heat risk perception than with objective heat exposure risk. A pronounced mismatch exists between objective heat exposure and subjective adaptive expenditure: for every 0.1-unit increase in heat exposure risk, the average monthly subjective adaptive expenditure decreases by 142.99 CNY, while a 1 °C increase in the self-reported temperature threshold triggering adaptive behavior corresponds to an average monthly reduction of 11.70 CNY. The structure of subjective adaptive expenditure shifts from short-term consumption-oriented spending toward maintenance-oriented spending as heat exposure risk increases. Expenditures on protective clothing and equipment, electricity, and adaptive food items are more sensitive to changes in heat exposure risk, whereas health-related expenditures such as disease treatment exhibit relatively high stability. Heat-response patterns among residents display clear clustering characteristics and can be classified into four typical groups: “high exposure–low impact–low expenditure,” “low exposure–high impact–high expenditure,” “medium exposure–medium impact–medium expenditure,” and “low exposure–low impact–low expenditure.” Age, household registration status, and gender emerge as key attributes distinguishing these groups. The total subjective adaptive expenditure of urban residents in Beijing is estimated at approximately 112 million CNY per month, exhibiting a spatial pattern characterized by higher values in central areas and lower values toward the periphery. This study reveals the economic expenditure response associated with adaptive behaviors of urban residents under heat conditions, providing quantitative evidence to support differentiated heat risk management and targeted adaptation policies.
How to cite: Peng, Y., Xie, M., Chen, Y., and Liu, Q.: From Enduring to Adapting Heat Risks: Characteristics of Responses, Group Differences, and Spatial Distribution of Urban Residents' Subjective Expenditures for Heat Adaptation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9978, https://doi.org/10.5194/egusphere-egu26-9978, 2026.
