Search Results (36)

This study quantifies the spatiotemporal evolution of non-communicable disease (NCD) mortality risk associated with temperature extremes in the Metropolitan Area of the Valley of Mexico (MAVM) from 2000 to 2019. Using a Bayesian risk assessment framework, we analyzed 747,131 deaths to evaluate the impact of extreme temperature indices (Tn90p, Tn10p, TNn, Tx90p, Tx10p, TXx, DTR) across demographic and geographic dimensions. Results reveal a significant intensification of mortality risk, particularly for circulatory and metabolic diseases after 2005 and 2014. Risk expansion analysis identified 16 cases of robust relative risk (RR) intensification, predominantly among elderly populations. Females and males aged 65+ with metabolic diseases exhibited the highest thermal vulnerability. Our analysis further indicates a systematic shift in mortality risk toward higher nocturnal temperatures and reduced diurnal variability, suggesting a transition from cold-related stress to persistent nighttime heat exposure. Spatial Bayesian modeling shows a progressive homogenization of environmental risk across the metropolitan area, with high-risk thermal profiles expanding from the urban core toward peripheral municipalities, reducing the extent of previously lower-risk zones. Notably, the number of municipalities in the highest risk category for females aged 65+ with metabolic diseases increased by 550%, while for males of the same age, the expansion reached 163%. These findings indicate that vulnerability in megacities is a dynamic process driven by nocturnal warming and thermal instability. They highlight the urgent need to integrate climate-sensitive planning strategies—such as the identification and preservation of climatic refuge zones—into urban development policies, alongside continuous monitoring of temperature-related health risks. Full article

Global warming has significantly intensified the risks of summer heatwaves, making outdoor thermal comfort during extreme heat periods a critical research focus. Under centralized rural village reconstruction policies, traditional settlements are being replaced by regularized modern communities characterized by new materials and standardized layouts. However, the impact of these morphological transitions on the micro-scale thermal environment remains under-researched, with a notable lack of comparative perspectives between traditional organic and modern standardized typologies. This study identifies six representative zones based on spatial configuration. By integrating UAV photogrammetry (Pix4Dmapper v4.5), AutoCAD 2019, and QGIS (v3.22), morphological characteristics were quantified, followed by microclimate simulations using ENVI-met v5.9. The results reveal that while peak daytime Physiological Equivalent Temperature (PET) in the standardized zones (49.2–51.8 °C) is slightly lower than in traditional zones (53.5–55.2 °C), a phenomenon of thermal homogenization emerges in the former. Specifically, values in standardized zones are highly concentrated around the median (53.5 °C), contributing to a significant upward trend in the minimum PET values, with nearly all sampling points exceeding 47.0 °C. Quantitative analysis identifies green coverage and perviousness as primary cooling drivers, while spatial openness and imperviousness promote thermal homogenization. In contrast, traditional zones retain critical cool refuges due to their spatial heterogeneity. This research provides an empirical foundation and quantitative reference for understanding the thermal performance differences across different rural spatial typologies. The findings offer insights for planners to optimize street layouts and shading strategies, ultimately mitigating heat stress and fostering climate-resilient modern countryside development. Full article

Nighttime temperatures in the Afro-alpine zone (>2050 m) of Kahuzi-Biega National Park frequently fall below 5 °C. However, the thermal advantages provided by night nests of Grauer’s gorilla, Gorilla beringei graueri along this elevation gradient have yet to be quantified. From 3 January to 7 January 2025, 80 night nests were located along the Mt. Kahuzi–Biega ridge (2000–2650 m above sea level); 66 with complete data were analyzed. Nest-interior and ambient temperatures were measured using calibrated mercury thermometers, while canopy openness was assessed through sky-facing photographs analyzed with ImageJ. Canopy openness ranged from 18% at 2050 m (dense bamboo) to 83% at 2625 m (open ericaceous scrub), with a mean of 50.5 ± 18.8%. The interiors of the nests consistently exhibited warmer temperatures than the humid ambient air, with a mean temperature difference of 2.03 ± 0.37 °C, ranging from 1.39 to 2.68 °C. Linear mixed-model analysis (n = 66) indicated a significant reduction in thermal buffering correlated with increasing elevation (β = −7.4 × 10⁻⁴ °C m⁻¹, 95% CI −8.9 × 10⁻⁴ to −5.9 × 10⁻⁴, p < 0.001) and greater canopy openness (β = −0.020 °C per %, p < 0.001); fog density and precipitation from the previous night did not exhibit a significant effect. The model explained 78% of the variance in ΔT (marginal R²). Over a 650 m Afro-alpine gradient, Grauer’s gorillas create a 2.0 °C thermal refuge, which decreases by approximately 30% near the summit. This study represents the first quantitative evidence that canopy density can mitigate the elevation penalty for any African great ape. Canopy retention is the only terrestrial mechanism that can mitigate accelerated warming at high altitudes, which is occurring at a rate of +0.45 °C per decade. Without canopy retention, national conservation strategies for the Democratic Republic of Congo must allocate funds for extended energy subsidies at elevations exceeding 2500 m. Full article

Urban areas face rising risks from extreme heat due to climate change, intensifying thermal stress and exacerbating social inequalities. Urban climate refuges—cool, accessible indoor and outdoor public spaces that maintain their ordinary functions—are increasingly adopted as a local adaptation measure to protect vulnerable populations during heat events. This study aims to develop and test a SWOT–CAME analytical framework to evaluate and compare the maturity, equity, and implementation logic of urban climate refuge networks in three European cities with contrasting climates and governance traditions: Barcelona, Amsterdam, and Copenhagen. A qualitative multiple-case design is combined with a transparent indicator set (coverage, accessibility, and typology mix) derived from official municipal sources and planning documents. Results show differentiated pathways: Barcelona represents an institutionalized network model; Amsterdam illustrates an emerging coordinated public-health approach; and Copenhagen reflects an ecosystem-based orientation where green–blue infrastructure provides substantial passive cooling capacity but requires clearer heat-specific operational protocols. The discussion highlights the need for hybrid adaptation strategies that combine nature-based solutions with operational governance and targeted support for vulnerable groups. The paper concludes with a transferable framework for cities seeking to integrate climate refuges into resilience and climate-justice agendas. Full article

As coal mining operations extend deeper underground, the importance of refuge chambers as temporary shelters for miners grows given the heightened risk of accidents. The severe geothermal conditions in deep mines present significant challenges to temperature regulation within these chambers, potentially subjecting miners to hazardous heat exposure. The utilization of phase change plates (PCPs) presents a promising approach to improving temperature regulation performance. To systematically investigate the enhancement effects of nano-graphite particles (NGPs) and fin structures on the thermal performance of phase change materials (PCMs), this study conducted thermophysical property tests and temperature-controlled melting experiments to analyze the influence of varying NGP concentrations on the thermal characteristics of PCMs, while observing their melting behavior. Four PCP models were designed: base PCM, PCM with NGPs, plate fin, and pin fin. Based on the enthalpy-porosity method, numerical simulations were performed to systematically evaluate the melting kinetics and temperature regulation performance of each design under extended operation conditions. The findings indicate that while NGP doping markedly increases the thermal conductivity and peak melting temperature of the PCM, it also results in a reduction in latent heat capacity. The NGP-enhanced No. 25 paraffin wax (RT25) PCP reduced the surface temperature by 1.02 °C compared to the base material. During extended operation, the NGP-based model outperformed others, maintaining effective temperature regulation for 149.8 h, 13 h longer than the base PCM and exceeding the standard requirement by 53.8 h. This underscores its notable advantages in thermal management. These advancements offer a valuable reference for the utilization of PCP in refuge chambers, thereby augmenting their temperature regulation capabilities. Full article

Small urban parks are the dominant form of green spaces in most Japanese cities and hold great potential for heat stress mitigation. However, most research has focused on large urban parks, leaving a knowledge gap in how small parks can be designed to mitigate heat. Given that small parks are primarily used for rest, we focused on resting areas and assessed their thermal conditions in three typical small parks in Kyoto, Japan. We then examined how the spatial arrangements of park elements influenced thermal conditions. Results revealed that nearly half of the resting areas were uncomfortable, underscoring the urgent need for spatial design improvements. Linear mixed-effects models showed that while shade elements, such as tree canopies and roofs, most effectively enhanced thermal perception, their effectiveness was distance- and orientation-dependent. We also found a critical mismatch between green ground and shade elements that adversely affected thermal conditions. Our findings highlight that strategic spatial design, particularly the thoughtful placement of shade elements and resting areas, is the key to providing thermal comfort in small urban parks. This study provides evidence that small parks can act as urban heat spots if poorly designed, but with appropriate design they can become cool refuges. Full article

Coral reefs are increasingly impacted by marine heatwaves and global warming, with the 2023–2024 El Niño–Southern Oscillation (ENSO) event causing unprecedented thermal stress across the Eastern Tropical Pacific. This study assessed the effects of this event on coral reefs in the Gulf of Papagayo, Costa Rica. Sea surface temperatures exceeded the bleaching threshold for seven months, reaching a record 10.2 Degree Heating Weeks—twice the levels recorded during the 1997–1998 ENSO. Benthic and fish community surveys revealed severe coral mortality, particularly in Pocillopora-dominated reefs, with some sites losing over 90% of live coral cover. Resilience varied across sites, likely influenced by factors such as local water circulation, coral genetic diversity, symbiont type, and heterotrophic capacity. Reefs with higher genetic diversity and thermally tolerant Durusdinium symbionts showed partial recovery. Seasonal upwelling appeared to buffer thermal stress in some areas, potentially acting as a natural climate refuge. Bleaching also impacted reef fish communities, with a notable decline in invertebrate-feeding species on degraded reefs. These findings highlight the interplay between prolonged thermal stress, coral biology, and local oceanographic processes in shaping reef resilience. Identifying and protecting such climate refugia will be critical for coral conservation under future climate change scenarios. Full article

Amphibians face a global conservation crisis, driven largely by habitat degradation. Effective and practical strategies for habitat restoration are urgently needed, particularly for Critically Endangered species in human-impacted ecosystems. Telmatobius philippii is a species classified as Critically Endangered by the IUCN. Its habitat is restricted to a few thermal springs in the Ascotán salt flat in Chile. A significant portion of one of these springs, V11, dried up in 2005 due to industrial groundwater withdrawals, leading to the loss of natural refuges and population decline. As part of a recovery plan for this spring we implemented a habitat improvement program by installing artificial refuges (clay tiles, bricks, and rock piles) and monitored their use over a two-year period. The results indicated that the refuges, particularly the clay tiles, were utilized by T. philippii at all life stages (larvae, juveniles, and adults). Refuge occupancy increased over time, reaching 75% by the end of the study, and the presence of eggs and early-stage larvae confirmed successful breeding associated with the artificial structures. This demonstrates the positive effect of artificial refuges as a practical tool for the recovery of Telmatobius populations. To our knowledge, this study provides the first documented case of successful habitat enhancement for this threatened group of high Andean amphibians, offering a replicable strategy for conservation in fragile ecosystems. Full article

There is increasing interest in the role of parks as potential cool refuges in the age of climate change. Such potential refuges result from the Park Cool Island (PCI) effect, reflecting the temperature differential between the park and surrounding urban areas. However, this study of different park typologies in Perth, Australia, illustrates that while surface temperatures are 10–15 °C lower in parks during summer afternoons (much less than at other times), air temperatures are generally no different from the adjacent streetscape for the smaller parks. Only the largest park in the study had 1–2 °C lower morning and mid-afternoon air temperature differentials. The study illustrates that while the PCI is a real phenomenon, the magnitude in terms of air temperature is small, and it is of less relevance to the conditions felt by humans in average summer daytime conditions than the direct effects of solar radiation. Many studies have assessed the PCI effect, an indicator that has shown a wide range across different studies and measurement techniques. However, this novel paper utilises satellite remote-sensed land surface temperatures, on-ground measurements of surface temperatures, air temperatures, and humidity, as well as modelling using the microclimatic simulation software ENVI-met version 5.0. A reliance on land surface temperature, which in isolation has a marginal correlation with human experience of thermal comfort, has led some researchers to overstate the PCI effect and its influence on adjoining urban areas. The research reported in this paper illustrates that it is the shade provided by the canopy in parks, rather than parks themselves, that provides meaningful thermal comfort benefits. Accordingly, adaptation to increasing temperatures requires the creation of a continuous canopy, ideally over parks, streetscapes, and private lots in an interconnected network. Full article

This study assesses the projected impacts of climate change on hydrological processes in the Gersprenz catchment, a representative low mountain range basin in central Germany, under the RCP8.5 scenario. Using the SWAT+ model and a bias-corrected climate projection ensemble, it simulates the temporal and spatial dynamics of water availability, discharge and water temperature through 2100. The results indicate a substantial reduction in seasonal discharge, with summer minima decreasing by 85% and autumn minima decreasing by 38% compared to the baseline. Rising air temperatures drive substantial warming, with maximum summer water temperatures projected to exceed 28 °C, increasing thermal stress on aquatic ecosystems. Spatial analysis reveals strong variability: Southern subcatchments, located in the upstream part of the catchment, face severe water deficits, while groundwater-fed springs provide localized thermal refuges but with limited buffering capacity. Northern regions generally show higher resilience, with exceptions. The findings highlight the fine-scale sensitivity of hydrological processes to climate change, shaped by catchment characteristics and amplified by natural seasonal variations. This study presents a framework for identifying spatio-temporal hotspots of water scarcity at the subcatchment scale, providing a basis for spatially targeted adaptation strategies to mitigate the impacts of climate change on regional water resources and ecosystems. Full article

Connectivity is crucial for species conservation, but most assessments define connectivity solely in terms of protected or natural areas and land covers without regard for the underlying thermal environment. As climate change accelerates, it is becoming increasingly important to not only assess land use and land cover changes (LULCC) but also how surface temperatures are evolving and creating more fragmented thermal refuges over time. This research investigates how the surface thermal environment has changed over time in Phoenix, Arizona, USA, a desert city in the southwestern United States, and how the spatial patterns of cooler refuges within the heat landscape, or “heatscape,” may be affecting wildlife habitat availability alongside LULCC. We quantify the structural and functional connectivity of thermal refuges using a suite of connectivity metrics from landscape ecology to demonstrate how the spatial distribution and configuration of these critical areas has changed over the last 35 years and what the implications are for the many wildlife species living in this desert environment. Results show that thermal refuge patches have been shrinking and becoming more fragmented over the past 35 years, with connectivity also declining over the same period. A key inflection point was identified in 2000, when the probability that cooler refuges patches were connected dropped to nearly zero, and it has remained at that low level ever since. These shifts in connectivity are tightly coupled with LULCC in the study area, particularly the loss of irrigated agriculture as it has been replaced by residential and other developed land uses over time. Decreasing water security in the region also threatens to reduce the availability of cooler patches and, simultaneously, the connectivity of those refuges. Introducing cooler patches through engineered materials or artificial shade may help offset some of the losses from irrigated lands. The findings offer a perspective for conservation research with implications for advancing a more formal thermal landscape ecology for understanding and improving the relationship between spatial thermal patterns and ecological processes. Full article

Thermal refuges in streams are essential for the survival of coldwater fish species such as Redband trout (Oncorhynchus mykiss) in landscapes with stressful or lethal stream temperatures. We utilized an uncrewed aerial system (UAS) mounted with thermal and natural color sensors to conduct hourly flights over a 24 h period in the desert stream Little Jacks Creek during late summer when temperatures were near seasonal maximums and streamflow was near seasonal minimums. We used fine-resolution imagery to map stream temperatures and characterize how our thermal sensor exhibits variability across a diel period in an environment where thermal sensor viability had not yet been assessed. Thermal imagery from 3 out of 24 flights showed no significant differences when compared to true water temperatures from in-stream temperature loggers, which appeared to be highly dependent on atmospheric conditions. The thermal imagery (range of $9.17$ to $21.04 °$C) consistently underestimated HOBO logger stream temperatures (range of $13.6$ to $17.1 °$C) during cooler, nighttime flights and overestimated temperatures during hotter, afternoon hours, resulting in a global RMSE of 2.12 $°$C. Between-flight RMSE values ranged from 0.53$°$C to 4.00$°$C, within the error range of the thermal sensor. The thermal data support existing findings of optimal hours for flying UAS thermal surveys and showed specific patterns in TIR sensor accuracy that were dependent on the time of flight. This study yields valuable lessons for future stream temperature data collection in environments with highly variable temperatures, aiding in the calibration of thermal sensors on UAS missions. Furthermore, our results provide insights into environmental stressors such as increased stream temperatures, which is vital for conservation efforts for organisms that rely on coldwater refuges within desert streams. Full article

Phase change thermal energy storage (PCTES) technology has garnered significant attention in addressing thermal management challenges in building HVAC systems. However, the cooling performance of PCTES systems in humid scenarios remains unexplored, which is crucial in subtropical regions, high-humidity underground areas, and densely populated spaces. Taking the mine refuge chamber (MRC) as an example, this study focuses on a passive temperature and humidity control system by employing cold storage phase change plates (PCPs) for 96 h. First, an improved and simplified full-scale numerical model including PCPs and MRC parts is established. Then, the model is validated through the experimental results and solved using a numerical method. Finally, the influence of various factors within the system is investigated and an optimization method involving batch operation is proposed. The results indicate that (1) within 40 h, the use of cold storage PCPs leads to an indoor temperature reduction of 4.8 °C and a 7% decrease in relative humidity; (2) the PCPs show asynchronous states in sensible and latent heat transfer rates; (3) for every 50 additional PCPs, the average indoor temperature increases by 0.6 °C and the relative humidity decreases by 1.5%; (4) implementing batch operation of PCPs ensures that the indoor Heat Index drops by 10 °C, which is vital for human survival. The findings will play a crucial role in the global expansion and application (including geographical and functional aspects) of phase change thermal storage technology. Full article

Thermal refuges are becoming increasingly influential for dictating the population status and spatial distribution of cold-water stenotherm salmonids in the mid- to southern extent of their range. The global climate is predicted to continue to warm, and therefore, the overall thermal suitability of freshwater habitats for stream salmonids is predicted to decline in concert. However, stream and river thermal heterogeneity will offer considerable resiliency for these populations. Thermal refuges are formed by many physical processes; common natural refuges include cold tributary plumes, groundwater springs, alcoves, and hyporheic upwellings. However, many anthropogenically formed refuges (such as stratified reservoirs or cold-water tailrace outflows) also exist in hydropower-regulated rivers. The significance of these refuges to stream salmonids depends on their size and temperature differential, but also other habitat characteristics such as their depth, flow velocity, Froude number, and many biotic factors within the refuges. Modern technologies such as drone-mounted thermal infrared cameras and other remote sensing techniques allow for the efficient identification of such refuges, and inexpensive options include the identification of refuges during ice cover using orthophotographs. Behavioural thermoregulation, i.e., salmonids aggregating in cold-water refuges, can be either facultative or obligate and the timing of these events is governed by life stage, species, and population-specific physiologically regulated cumulative thresholds that are inherently related to the recent thermal history, or hysteresis, of each individual. Salmonids appear to have an excellent spatial cognition for locating and relocating cold-water refuges, and their spatial distribution is largely affected by the availability of the cold-water refuges during the warm-water period in many thermally stressed rivers. Gregarious behaviour is the norm for salmonid fishes within the thermal refuges; however, the size/microhabitat hierarchy appears to dictate the within-refuge distribution at the micro-scale. There continues to be a great impetus for protecting—and in carefully determined cases creating—cold-water refuges in the future. A thorough understanding of what a “goldilocks” refuge is for various salmonids and their different life stages will be imperative as cold-water restoration is gaining popularity. Finally, disentangling the roles of the climate-induced and landscape activity-induced warming potential of fluvial freshwater will be important to ensure continued environmentally responsible landscape activities in future waterscapes. Full article

The migratory life history of anadromous salmonids requires successful migration between nursery, feeding, and spawning habitats. Smolting is the major transformation anadromous salmonids undergo before migration to feeding areas. It prepares juvenile fish for downstream migration and their entry to seawater. We reviewed the effects of climate change on smolt ecology from the growth of juveniles in fresh water to early post-smolts in the sea to identify the potential effects of climate change on migratory salmonid populations during this period in their life history. The focus was especially on Atlantic salmon. The shift in suitable thermal conditions caused by climate change results in Atlantic salmon expanding their range northward, while at the southern edge of their distribution, populations struggle with high temperatures and occasional droughts. Climatic conditions, particularly warmer temperatures, affect growth during the freshwater river phase. Better growth in northern latitudes leads to earlier smolting. Thermal refuges, the areas of cooler water in the river, are important for salmonids impacted by climate change. Restoring and maintaining connectivity and a suitably diverse mosaic habitat in rivers are important for survival and growth throughout the range. The start of the smolt migration has shifted earlier as a response to rising water temperatures, which has led to concerns about a mismatch with optimal conditions for post-smolts in the sea, decreasing their survival. A wide smolt window allowing all migrating phenotypes from early to late migrants’ safe access to the sea is important in changing environmental conditions. This is also true for regulated rivers, where flow regulation practices cause selection pressures on migrating salmonid phenotypes. The freshwater life history also affects marine survival, and better collaboration across life stages and habitats is necessary among researchers and managers to boost smolt production in rivers. Proactive measures are recommended against population declines, including sustainable land use in the catchment, maintaining a diverse mosaic of habitats for salmonids, restoring flow and connectivity, and conserving key habitats. Full article