The observational study covered approximately 55,300 square kilometers spanning 11 cities and jurisdictions in the Pearl River Delta, from dense metropolitan districts around the estuary to forested mountains in the north and west. Its authors said the region provides a pronounced setting for studying heat–carbon coupling because cool, densely vegetated mountain forests border subtropical urban landscapes where summer daytime land surface temperatures frequently exceed 35 °C and can surpass 40 °C in extreme heat-island cores. The analysis used 4,158 spatially representative samples retained after quality control, covering urban cores, suburban transition zones, agricultural plains and peripheral ecological areas. Because the design was confined to one summer and paired with annual productivity data, it estimates regional associations and apparent thresholds rather than demonstrating how carbon storage changes over time.

To assemble the evidence, the team processed several datasets through Google Earth Engine. Summer 2023 land surface temperature and vegetation greenness came from MODIS products at 1-kilometer resolution, while net primary productivity was represented by the 500-meter annual MODIS product. ERA5-Land supplied mean 2-meter air temperature and monthly precipitation for June through August, and a 30-meter digital elevation model provided elevation and slope. Sampling combined 3,000 random points, 1,500 systematically spaced points and 500 denser observations in urban–rural transition zones, where temperature, vegetation and land cover changed rapidly. The strategy was designed to avoid concentrating the analysis in either the hottest city centers or the cooler forest belt. Values were extracted at each sample location at their native resolutions after coordinate harmonization, rather than being unnecessarily resampled.

The analytical framework combined four methods. Geographically weighted regression generated local coefficients describing how six environmental predictors varied in their relationships with productivity across space. Those local sensitivities were supplied to an enhanced XGBoost model, allowing gradient-boosted decision trees to represent nonlinear patterns and interactions while remaining spatially informed. SHAP, or SHapley Additive exPlanations, attributed model predictions to individual variables and traced the influence of temperature across its range. A Q10 respiration model then converted productivity estimates into a carbon budget by comparing net primary productivity with estimated soil heterotrophic respiration. Spatial block cross-validation was used to reduce the inflated performance that can arise when spatially autocorrelated neighboring samples are divided randomly between training and test data.

Land surface temperature emerged as the most influential feature in the enhanced model and had a strong negative Pearson correlation with net primary productivity, with a coefficient of −0.68. Vegetation greenness, represented by the normalized difference vegetation index, had a strong positive association with productivity at 0.72, while 2-meter air temperature was negatively correlated with productivity at −0.59. Surface temperature was itself negatively associated with greenness at −0.72, and greenness was positively associated with productivity at 0.72. Elevation was positively related to productivity at 0.56 and negatively related to surface temperature at −0.63. By contrast, precipitation had little association with productivity, with a correlation of −0.05. These are statistical relationships, not proof that any single variable directly caused the observed differences, but together they describe a coherent spatial pattern of hot, sparsely vegetated surfaces and lower modeled carbon fixation.

Machine-learning interpretation located the onset of accelerated productivity decline at approximately 27.1–28.1 °C. At lower temperatures, the SHAP contribution of surface temperature was positive or close to zero, whereas it became increasingly negative as conditions heated. A separate analysis of the distribution of respiration-constrained net ecosystem productivity identified a transition interval of roughly 28.93–29.93 °C. That interval also concerns an onset location, but it was calculated from carbon-budget estimates rather than from the SHAP analysis of productivity. The third value, an estimated source–sink switch of 32.05 °C, came from the central Q10 = 2.0 respiration scenario, under which mean net primary productivity fell below estimated soil respiration as surface temperature approached 32 °C. The switch moved earlier with Q10 = 2.5 and later with Q10 = 1.5, showing how the respiration parameter introduces uncertainty into the estimate.

Geographically weighted coefficients showed that thermal sensitivity was far from uniform. About 76% of the study area had negative local temperature coefficients. In the hottest urban cores around the Pearl River estuary and the Shenzhen–Dongguan corridor, mean land surface temperature exceeded 36 °C, the mean local coefficient was approximately −0.182 and mean net primary productivity was 0.32 kgC/m²/yr. Suburban areas with temperatures of 28–36 °C had intermediate coefficients of roughly −0.08 to −0.12. In the cooler northern mountains, where land surface temperature was generally below 28 °C, mean net primary productivity reached 1.21 kgC/m²/yr and the local temperature coefficient was slightly positive, about +0.043. The negative temperature sensitivity in urban cores was reported as 4.2 times greater than in peripheral forested ecological zones, a difference obscured by spatially uniform analyses.

Carbon-budget classification estimated that 93.6% of sampled locations, or 3,892 sites, remained carbon sinks, while 6.4%, or 266 locations, were estimated to be carbon sources. Among the sinks, 1,886 were classified as strong sinks, 1,359 as sinks and 647 as weak sinks. Strong sinks formed a largely continuous belt through the northern mountainous forest and western agricultural–forestry zones. Most of the 266 source locations were weak sources, with only three classified as strong sources in the extreme urban heat-island cores of Shenzhen Bao’an, southern Dongguan and inner Guangzhou. The spatial model therefore depicts a pronounced regional gradient rather than a uniform outcome: sink capacity weakened toward the urbanized estuary, while substantial modeled carbon uptake remained in the vegetated mountainous periphery.

Vegetation appeared to buffer, but not eliminate, the association between heat and productivity loss. At the same surface temperature, locations with normalized difference vegetation index values below 0.3 had SHAP values approximately 2.5 times more negative than those with values above 0.6. The enhanced model also slightly outperformed standard XGBoost: mean test R² increased from 0.6179 to 0.6318, an improvement of about 2.2%, with the largest gains in folds containing many urban–rural transition samples. The result supports the value of representing spatial heterogeneity, but the study has important limitations. Annual productivity does not resolve the timing of summer heat effects; the Q10 parameter may vary with soil moisture and local conditions; a single season cannot reveal whether the apparent thresholds persist under acclimatization or carryover effects; and MODIS resolution can blur small urban refuges and fine-scale forest structure. The findings are best understood as a regional risk map and a basis for further monitoring, not as a universal physical tipping point or direct proof that heat caused the observed carbon losses.

Subject of Research: Spatial modeling of summer heat effects on carbon-sink stability across the Greater Bay Area

Article Title: Apparent thermal thresholds of carbon sink weakening in the Guangdong–Hong Kong–Macao Greater Bay Area revealed by remote sensing and spatial machine learning

Article References: Li, C., Yu, H., Sun, B., Wu, J., Wang, H., & Hong, T. (2026). Apparent thermal thresholds of carbon sink weakening in the Guangdong–Hong Kong–Macao Greater Bay Area revealed by remote sensing and spatial machine learning. Frontiers in Forests and Global Change, 9, 1996868. https://doi.org/10.3389/ffgc.2026.1996868

Image Credits: AI Generated

DOI: 10.3389/ffgc.2026.1996868

Keywords: carbon sinks, extreme heat, land surface temperature, net primary productivity, remote sensing, spatial machine learning, urban heat island, forest carbon, Greater Bay Area, soil respiration, Apparent, thermal

The research harnessed eBird, the Cornell Lab of Ornithology’s vast citizen-science platform, to compare bird communities inside roughly 452 cities with the communities in their surrounding areas. Because eBird records are contributed by volunteers rather than trained survey crews, the authors had to confront the well-known statistical pitfalls of opportunistic data: uneven sampling effort, observer crowding around popular hotspots, and the tendency of birders to chase rare species. The team applied rigorous filtering and coverage-based rarefaction techniques, standardizing their estimates of species richness so that a heavily birded park in Miami could be compared fairly with a sparsely visited suburb in Saskatchewan. They drew city boundaries from United States and Canadian census products, overlaid climate data from the CHELSA database, and used WorldPop population layers and MODIS satellite vegetation indices to characterize the human footprint of each urban area.

The headline result concerns winter. In the surrounding wildlands of North America, native bird species richness climbs dramatically from the Arctic toward the tropics, and this gradient is at its steepest during winter—the season when cold stress, food scarcity, and snow cover ruthlessly sort out which species can survive at high latitudes. Inside cities, however, the researchers found that this winter gradient is significantly flattened. Northern cities hold more native bird species in winter than their latitude alone would predict, while the diversity advantage of southern cities is somewhat diminished. In effect, urban environments act as insulating refuges that partially decouple bird diversity from the climatic tyranny of latitude.

The mechanisms behind this decoupling are physically intuitive. Cities generate urban heat islands: paved surfaces absorb solar radiation, buildings trap heat, and waste heat from human activity warms the surrounding air, often raising winter temperatures by several degrees relative to nearby countryside. Add to this the artificial food subsidies that city birds exploit—bird feeders, ornamental fruiting shrubs, landfills, and discarded food—and the urban landscape becomes a thermal and caloric lifeline precisely when natural environments are most punishing. Previous work, including a 2016 study on homogenizing effects of cities on North American winter bird diversity, hinted at this pattern; the new research confirms it at continental scale with far richer data.

Season matters enormously to this story. During the breeding season, when birds fan out across the continent to nest, the latitudinal gradient inside and outside cities looks far more similar, and the urban flattening effect largely disappears. This makes ecological sense: in summer, the climatic constraints that cities buffer are relaxed, and the negative consequences of urban living—habitat loss, window collisions, cats, noise, and light pollution—dominate instead. It is only when the continent freezes that the city’s hidden warmth reveals its full influence on the geography of bird diversity.

Even more striking is what happens when the researchers split their analysis by native status. Non-native bird species—species introduced by human transport and established outside their ancestral ranges—showed weak or no latitudinal gradient in any season. Their distributions are shaped not by deep evolutionary and climatic processes but by the geography of human commerce: ports, pet trade routes, horticultural practices, and the accidental corridors of global trade. This finding reinforces a growing recognition in biogeography that the Anthropocene has produced two essentially different avifaunas sharing the same map: one governed by dispersal limitation, climate, and millions of years of evolutionary history, and another governed by shipping schedules and human preferences.

The study also probed the interaction between human population density and temperature, and uncovered a surprising reversal. Across most conditions, denser human populations reduce native bird richness—the familiar litany of urban harms: habitat destruction, disturbance, and simplified vegetation. But when conditions turn cold, this negative effect weakens and can even reverse, with denser urban areas supporting richer native bird communities than expected. The likely explanation lies in the coupling of human density with heat and food provisioning. Where winters are brutal, more people means more feeders, more heat, more evergreen ornamental plantings, and more microclimatic shelter—a concentrated dose of exactly the resources that winter birds need most.

Methodologically, the team leaned on structural equation modeling to disentangle the direct and indirect pathways linking latitude, climate, human density, vegetation, and bird richness. This approach allowed them to ask not merely whether cities alter diversity patterns, but through which causal channels: does urbanization act on birds primarily by changing temperature, by changing vegetation, or by changing the number of humans generating resources? The models pointed to temperature as a central mediator, with urban climate modification emerging as a key mechanism by which cities rewrite the biogeographic script written by latitude alone.

The implications stretch well beyond academic biogeography. As climate change warms the planet and urban land expands relentlessly—projections suggest cities will absorb enormous swaths of additional land by mid-century—the interaction between climate and urbanization will increasingly shape which species persist where. Conservation planning has traditionally treated the latitudinal gradient as a stable backdrop against which local actions play out. This study suggests that backdrop itself is malleable. Cities, often written off as biodiversity deserts, can under certain seasonal conditions act as refugia, and the authors explicitly call for leveraging these positive effects in conservation strategy—designing winter bird-friendly cities with native vegetation, reduced collisions, and sustained green corridors.

There is also a quieter lesson about the scientific enterprise itself. Seventeen million observations, each one contributed by an ordinary person with binoculars and a smartphone, made this continental-scale discovery possible. No traditional survey network could have assembled comparable coverage across hundreds of cities and their surrounding landscapes in three seasons. The study stands as both a warning—that humanity’s footprint has grown powerful enough to bend ecology’s oldest pattern—and an invitation, showing that the same sprawling human networks reshaping the natural world can also help us understand it, one bird at a time.

Subject of Research: How urbanization alters the latitudinal diversity gradient of birds across North American cities

Article Title: Cities alter the latitudinal diversity gradient of birds in North America

Article References: Xie, Y., Chen, X., Burger, J. R., Hurlbert, A. H., & Feng, X. (2026). Cities alter the latitudinal diversity gradient of birds in North America. Nature Cities. https://doi.org/10.1038/s44284-026-00529-6

Image Credits: AI Generated

DOI: 10.1038/s44284-026-00529-6

Keywords: urban ecology, biodiversity, latitudinal diversity gradient, birds, eBird, citizen science, urban heat island, biogeography, native species, non-native species, winter ecology, North America

The study, led by researchers analyzing nearly four decades of weather station records, satellite imagery and ocean indices, set out to answer a deceptively simple question: when a local climate shifts, how much of that shift belongs to the planet’s natural cycles, and how much belongs to us? To do this, the team contrasted two twenty-year windows, using a single weather station in central Tepic with continuous data from 1980 to 2018 and only 2.6 percent missing readings. They standardized monthly temperature and precipitation anomalies and correlated them with the multivariate El Niño index, a composite measure built from sea-level pressure, winds, sea surface temperature and cloudiness over the tropical Pacific. They then layered on a Bayesian network analysis, a probabilistic technique that estimates the chance of a climatic outcome given an ENSO phase, even when no strict cause-and-effect relationship exists.

The temperature signal was unambiguous. Average temperature climbed from 21.9 degrees Celsius in the historical period to 22.9 degrees in the recent one. Maximum temperatures rose by about 0.8 degrees, but the most dramatic change came at night: minimum temperatures jumped by roughly 1.3 degrees, and during the autumn and winter months of October through January, the increase exceeded 2 degrees. Rising nighttime minimums are a classic fingerprint of urbanization, because asphalt and concrete absorb heat all day and release it slowly after dark. They are also among the most dangerous manifestations of warming for human health, depriving bodies of the overnight recovery window during heat waves and straining the cardiovascular systems of the elderly and children.

Precipitation told a more turbulent story. The annual total barely moved, hovering near 1,130 to 1,160 millimeters across both periods, but the seasonal rhythm shifted sharply. Summer rainfall declined by between 2 and 6 percent, while autumn and winter rains surged by 13 to 20 percent. That combination, drier summers and wetter autumns, is a recipe for both water stress and flooding, and Tepic is poorly equipped for the latter. The city’s drainage infrastructure is more than fifty years old, its natural watercourses have been obstructed by construction, and buildings have spread into flood-prone zones. The researchers warn that increasingly intense autumn storms will overwhelm sewers and urban rivers, a problem they trace directly to decades of unplanned growth.

The ENSO analysis revealed something unexpected: the Pacific’s grip on Tepic’s climate is not static, and it is moving in opposite directions for temperature and rain. El Niño’s influence on temperature variation doubled, from 10 percent in the historical period to 20 percent in the recent one, with warm Niño events now reliably associated with temperature increases and cool Niña events with decreases. The correlation between the ocean index and minimum temperature flipped entirely, from an inverse relationship of minus 10 percent to a positive one of 19 percent. In winter and spring months, the probability that a Niño event would raise minimum temperatures leapt from 8 percent historically to 34 percent in the current period. Meanwhile, ENSO’s influence on precipitation weakened, falling from 17 percent to 8 percent, yet the anomalies it produces grew more extreme, with the amplitude of wet and dry swings widening in the recent record.

Those shifting probabilities matter for forecasting. During summer El Niño events, the probability of reduced rainfall doubled from 10 percent to 20 percent, and the phenomenon’s seasonal footprint contracted from July through September to June through August, heightening the risk of drought precisely when crops and reservoirs need water most. In winter, Niña events now carry a 33 percent probability of precipitation decrease, up from 24 percent, threatening the severe droughts that historically struck between March and May. On the wet side, autumn El Niño events still bring torrential rains, though with diminished probability, 14 percent versus 31 percent historically. The Bayesian analysis also showed anomaly ranges stretching from severely dry to extremely wet conditions, a sign that when ENSO does act on Tepic’s rain, it acts harder.

To measure the human hand directly, the team turned to satellites. They processed thermal infrared imagery from Landsat 5, 7 and 8 for March of 1986, 2000 and 2018, converting raw radiance into surface temperature through standard brightness-temperature transformations calibrated across the different sensors. The picture that emerged was of a city cooking itself. In 1986, surface temperatures across Tepic ranged from 20.1 to 36.9 degrees Celsius. By 2000 the maximum had climbed to 43.9 degrees, and by 2018 it reached 45.3 degrees, roughly 8 degrees hotter than the historical ceiling. The heat island itself, defined as the zone of very high surface temperatures, covered 9.2 percent of the city in 1986, shrank in relative terms to 6.8 percent in 2000 and 6.1 percent in 2018, but in absolute area it exploded: the 2018 footprint amounted to 345.5 hectares against 217.1 hectares in 2000, a 62.8 percent expansion.

The geography of that expansion tells its own story. In 2000 the heat island was concentrated in the historic center. By 2018, scorching zones had appeared in the southeast, precisely where the city’s fastest growth occurred. The urban footprint doubled between the mid-1980s and 2015, and grew another 43.6 percent between 2000 and 2018 alone, much of it at the expense of the forests surrounding the city, including the Sierra de San Juan, a state-level biosphere reserve that supplies critical ecosystem services. The region lost about 30 percent of its adjacent forest cover over the study period. Vegetation absorbs thermal radiation and releases moisture, creating a microclimate buffer against planetary-scale phenomena; strip it away, the researchers argue, and the city loses its natural shield, leaving local temperatures more exposed to swings driven by the Pacific.

That loss of buffering may explain the study’s most provocative finding: the apparent link between heat island growth and ENSO’s doubled influence on temperature. The relationship remains descriptive rather than statistically proven, and the authors are careful to say so. They relied on a single weather station, made only three satellite observations across four decades, and could not perform a formal statistical correlation of heat island area against climate variability. They call for annual monitoring, in-situ temperature measurements of different urban surfaces, an inventory of green spaces, and the inclusion of future climate scenarios. They also suggest examining other ocean-atmosphere drivers, from the Pacific Decadal Oscillation to the North American monsoon and hurricanes, that could be shaping Tepic’s climate alongside ENSO.

Even with those caveats, the implications reach far beyond one mid-sized Mexican city. Tepic’s population of nearly half a million in its metropolitan area, hosting over 40 percent of the state of Nayarit’s people, makes it a template for hundreds of cities across the developing world where urban sprawl is outpacing planning. The consequences documented here, higher electricity demand and greenhouse emissions, water stress, intensified heat waves, flooding from aging drainage, and risks to public health ranging from viral disease to psychological strain, are the standard costs of unplanned growth. The researchers’ prescription is blunt: expand meteorological monitoring networks, invest in climate action research, and treat urban planning as an essential instrument for building climate-resilient cities. As global temperatures rise and the Pacific keeps oscillating, the cities that protect their forests and green space, the study suggests, will be the ones best armored against both.

Subject of Research: The influence of ENSO and the urban heat island on temperature and precipitation variation in Tepic, western Mexico

Article Title: Influence of ENSO and the urban heat island on climate variation in a growing city of the western Mexico

Article References: Nájera González, O., Nájera González, A., Marceleño Flores, S., & Flores Vilchez, F. (2024). Influence of ENSO and the urban heat island on climate variation in a growing city of the western Mexico. One Ecosystem, 9, Article e125302. https://doi.org/10.3897/oneeco.9.e125302

Image Credits: AI Generated

DOI: 10.3897/oneeco.9.e125302

Keywords: ENSO, El Niño, urban heat island, climate change, Tepic, Mexico, urbanization, deforestation, Landsat, precipitation, Bayesian networks, urban planning

Urban green spaces play a crucial role in mitigating the urban heat island effect, providing shade, improving air quality, and supporting pollinators and other wildlife. But their effectiveness depends heavily on the plants themselves. When temperatures soar, heat-sensitive species can suffer leaf chlorosis, reduced photosynthesis, membrane destabilization, and even death. The review, led by Patricia Duarte de Oliveira Paiva and colleagues at the Federal University of Lavras in Brazil, systematically searched Scopus and Web of Science for studies published between 2016 and 2026, ultimately identifying 25 studies that met strict eligibility criteria. Of these, 21 were rated as high methodological quality, providing a robust evidence base for understanding how ornamental species respond to elevated temperatures.

The review found that heat tolerance in ornamental plants is not the product of a single mechanism but rather the coordinated integration of multiple strategies operating across scales—from visible morphological adjustments to invisible molecular cascades. Heat-tolerant genotypes consistently maintain photosynthetic pigments, membrane stability, and carbon assimilation, while susceptible ones exhibit chlorosis, reduced biomass, and impaired photosynthetic performance. The authors emphasize that thermotolerance depends on the intensity, duration, and frequency of heat exposure, as well as on species- and genotype-specific traits.

At the physiological level, plants deploy a range of cooling and protective strategies. Stomatal regulation helps reduce leaf temperature through transpiration, while some species exhibit paraheliotropism—reorienting leaves vertically to minimize direct solar radiation. Anatomical traits also matter: studies of urban tree species found that evergreens maintained superior water status and lower leaf temperatures during natural heatwaves compared with deciduous species, and that leaf thickness and spongy tissue thickness correlated positively with heat tolerance. In Rhododendron, the heat-tolerant cultivar ‘Lan Yin’ preserved chloroplast integrity and xylem structure, while the sensitive cultivar ‘Liu Qiu Hong’ suffered plasmolysis and chloroplast damage.

Underlying these visible responses is a sophisticated molecular machinery. When temperatures rise, plants activate heat shock transcription factors (HSFs) that bind to heat shock elements in the promoters of heat shock protein (HSP) genes. These molecular chaperones—classified into families such as HSP100, HSP90, HSP70, HSP60, and small HSPs—stabilize and refold denatured proteins, preventing aggregation and facilitating the degradation of irreversibly damaged proteins. In tall fescue (Festuca arundinacea), the small heat shock protein FaHSP17.8-CII was shown to enhance thermotolerance by preserving photosystem II stability and reinforcing heat stress memory. In roses, the transcription factor RhHsfA7 positively regulates heat tolerance by activating heat-responsive genes and enhancing antioxidant capacity.

Calcium signaling plays a central role in heat perception. Heat stress induces a rapid influx of calcium ions through membrane-associated channels, activating calmodulins and calcium-dependent protein kinases (CDPKs) that modulate downstream responses, including the regulation of reactive oxygen species (ROS) homeostasis and abscisic acid (ABA) production. ABA, in turn, promotes stomatal closure to conserve water and activates the expression of heat-responsive genes. Other hormones, including salicylic acid, jasmonates, and brassinosteroids, also participate in the heat stress response, though their roles vary depending on species, tissue, and stress intensity.

Reactive oxygen species occupy a dual role in heat stress biology: they act as signaling molecules that trigger protective responses, but excessive accumulation leads to oxidative damage to lipids, proteins, and DNA. The balance between ROS production and scavenging is a major determinant of thermotolerance. Tolerant plants synthesize antioxidant enzymes—including superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase—as well as non-enzymatic antioxidants such as ascorbate and glutathione. In Rhododendron, the heat-tolerant cultivar ‘Gommer Waterer’ maintained membrane integrity under prolonged heat stress by increasing glutathione peroxidase and glutathione S-transferase activities, while the sensitive cultivar exhibited weaker antioxidant responses and reduced glutathione recycling.

Exogenous compounds offer promising tools for enhancing thermotolerance. Melatonin application alleviated heat stress in tall fescue by promoting growth, protecting photosynthetic pigments, and enhancing antioxidant defenses, while in roses it boosted heat tolerance through modulation of the RhCOMT1 gene. Spermidine, a polyamine, improved heat tolerance in tall fescue by reducing ROS accumulation and maintaining cell membrane stability. Trehalose application and overexpression of the trehalose-6-phosphate synthase gene enhanced heat tolerance in roses by preserving photosynthetic stability and mitigating oxidative damage. However, the authors caution that most of these results were obtained under controlled conditions, and validation in real urban environments remains limited.

Epigenetic mechanisms add another layer of complexity. Heat stress can induce DNA demethylation of heat-responsive genes, histone modifications, and the action of noncoding RNAs, enabling plants to establish a form of stress memory. This ‘thermomemory’ allows plants to respond more rapidly and robustly to recurrent heat events, and in some cases can be transmitted across generations, providing progeny with enhanced resilience to ancestral stress. In tall fescue, transcriptional memory of FaHSP17.8-CII was associated with reduced ROS accumulation and sustained photosystem II activity after heat stress, illustrating how epigenetic regulation translates into physiological protection.

The review highlights significant gaps in current knowledge. Most available studies have focused on a small number of species—particularly tall fescue, a turfgrass frequently used in heat stress research—leaving the responses of many ornamental species used in urban landscapes poorly characterized. Moreover, few studies have examined plant responses under natural urban conditions, where plants face combined stresses including heat, drought, and poor soils. Expanding comparative studies across a wider range of species will be essential for identifying reliable thermotolerance markers that can support breeding programs and the selection of climate-resilient genotypes. Ultimately, the authors argue, integrating these advances into urban landscape planning will contribute to greener, cooler, and more sustainable cities capable of withstanding the heat challenges of the coming decades.

Subject of Research: Physiological and molecular mechanisms of heat stress tolerance in urban ornamental plants

Article Title: Physiological and molecular responses of urban ornamental plants to heat stress

Article References: Paiva, P. D. D. O., Magalhães, H. S., & Paiva, R. (2026). Physiological and molecular responses of urban ornamental plants to heat stress. Frontiers in Horticulture, 5, Article 1923332. https://doi.org/10.3389/fhort.2026.1923332

Image Credits: AI Generated

DOI: 10.3389/fhort.2026.1923332

Keywords: heat stress, ornamental plants, urban green infrastructure, thermotolerance, heat shock proteins, reactive oxygen species, antioxidant defense, epigenetics, climate change, plant hormones, photosystem II, urban heat island

The review, led by Elisa Y. M. Ang of the Singapore Institute of Technology together with Aminu Yusuf of Istanbul University-Cerrahpasa and colleagues, is unusual in that it unites two research streams that are typically treated in isolation: personal cooling devices that chill the skin directly, and large-scale alternatives to the vapor-compression systems that dominate buildings. Database searches reveal an exponential increase in publications on human cooling technology, reflecting a rapidly growing field driven by climate realities. Even with dramatic emissions cuts, climate scientists widely agree that dangerous levels of heat and humidity are likely to become more common, making sustainable cooling a survival issue rather than a luxury.

Conventional air conditioning is an especially wasteful way to keep people comfortable. Because cooling is delivered to entire rooms, up to 70 percent of the energy can be wasted on empty space rather than human bodies. Personal cooling devices, or PCDs, promise to sidestep this inefficiency by targeting the skin itself, and they can also provide relief where air conditioners cannot follow, from construction sites and sports fields to outdoor medical settings. Yet the technology remains immature. To ground their assessment, the authors conducted a medium-scale market and user survey in which 56 participants evaluated three commercial products: a fan-based vest, a flow thermoelectric vest, and an ice-packed vest.

The thermoelectric vest, which exploits the Peltier effect to produce solid-state, tunable cooling, received the highest overall satisfaction rating at 3.93 out of 5. By contrast, the ice-packed vest was repeatedly described as heavy and uncomfortable because of condensation buildup, while the fan vest offered limited cooling and raised safety concerns about exposed blades. Even the best-performing device suffered from roughly three hours of battery life, high production costs, and added weight, which is a serious drawback for outdoor or industrial workers who need continuous cooling across a full shift. The authors caution that their survey was limited in sample size and trial duration, so the findings should not be overgeneralized, but the conclusion aligns with prior evaluations: no commercial personal cooling device is yet adequate as a stand-alone replacement for space cooling.

On the passive side of the field, however, remarkable progress is emerging from materials science. Phase change materials such as paraffin waxes and hydrated salts absorb body heat as they melt, sustaining cooling for up to two hours in optimized vests, though low thermal conductivity, leakage, and long recharge times remain obstacles. Evaporative approaches, which exploit water’s high latent heat, struggle in humid climates and leave wearers wet. The most striking advances come from radiative cooling textiles. Human skin, with an emissivity above 0.95, radiates heat in the mid-infrared range of 7 to 14 micrometers, and engineered fabrics can amplify this pathway. One bioinspired metafabric with a dual-gradient Janus design achieves 99.4 percent solar reflectance and 0.94 mid-infrared emittance, delivering a 17.8 degrees Celsius skin temperature reduction under intense sunlight while wicking sweat at a rate of just 0.5 milliliters per hour.

Smart fabrics are also learning to adapt. A sandwich-structured nanofibrous textile reported in 2025 combines a cooling side with 97.9 percent solar reflectance and a heating side made of carbon nanotubes absorbing 88.4 percent of sunlight; flipping the fabric switches between modes. Other designs draw inspiration from the Namib Desert beetle, using circular and triangular patterns to transport sweat continuously and reducing skin temperature by 1.3 degrees Celsius compared with cotton. Thermochromic fabrics that reflect sunlight and reverse moisture transport under hot conditions point toward garments that respond dynamically to the environment rather than offering static regulation. Meanwhile, thermoelectric garments are being rebuilt for the body: multi-stage coolers, flexible heatsinks made from hydrogel and nickel foam, and paraffin-graphene composites have demonstrated sustained on-skin cooling of 7 to 11 degrees Celsius, though the underlying bismuth telluride materials are nearing their efficiency limits and new compounds such as n-type PbS are being explored.

Because personal devices cannot yet replace whole-building cooling, the review devotes equal attention to the supply side. Here the verdict is sobering: quantitative comparisons of fourteen space-cooling technologies found vapor-compression still superior in coefficient of performance, exergetic efficiency, and power density, and it retains the highest overall sustainability score when scalability and maturity are counted. The realistic near-term path is therefore greener refrigerants, including flammable hydrocarbons like R290 and R600, alongside emerging cycles that must close the efficiency gap. Solid-state options include magnetocaloric cooling, which exploits temperature changes in gadolinium-family alloys under varying magnetic fields; electrocaloric cooling, based on dielectric materials responding to electric fields; and elastocaloric cooling, in which shape-memory alloys like nickel-titanium release and absorb latent heat under mechanical stress. All are refrigerant-free but remain limited by material costs, fatigue, and modest temperature spans.

Among the more promising newcomers, membrane heat pumps stand out. Identified by the U.S. Department of Energy in 2014 as one of the top three technologies for high energy savings, they separate moisture from air across water-vapor-selective membranes, avoiding the heavy condensation penalty of conventional systems and using only water as the working medium. Thermodynamic models suggest a potential coefficient of performance between 10 and 40, though prototypes currently achieve less than 3 due to vacuum pump inefficiencies, and even a 10 percent drop in water vapor rejection pushes performance below 3. Radiant cooling, which chills occupants directly through temperature-controlled surfaces rather than conditioning air, has demonstrated energy savings up to 50 percent and is already installed in landmark buildings such as the Pearl River Tower in Guangzhou, though condensation in humid climates remains the central engineering challenge.

Complementary, city-scale strategies multiply these gains. District cooling systems, proven in the Gulf Cooperation Council region where air conditioning consumes up to 70 percent of Saudi household electricity, achieve coefficients of performance of 4 to 6 and cut energy use by 30 to 50 percent through load sharing, and fifth-generation networks with bidirectional heat exchange can save up to 40 percent of electricity. Snow storage in Sweden, Norway, and Japan offers free seasonal cooling, while cool roofs stay 28 to 33 degrees Celsius cooler than traditional surfaces and green infrastructure intercepts 70 to 90 percent of incoming solar radiation through canopy shade, with building energy savings of 20 to 80 percent. In Singapore’s Cool Canyon experiments, cool surfaces cut sensible heat release by 30 percent and lowered afternoon air temperature by up to 2 degrees.

The review’s integrated perspective carries clear implications. For engineers, hybrid strategies combining localized and space-based cooling can deliver meaningful savings without sacrificing comfort. For manufacturers, the priorities are durability, flexibility, and heat rejection in wearables, whose performance is still measured by standards designed for uniform indoor environments and which often overestimate real-world cooling. For policymakers, the authors argue, localized cooling needs its own tailored standards, alternative technologies belong in energy codes, and district-scale low-carbon infrastructure deserves targeted incentives. Achieving this will require broader field trials, standardized evaluation metrics, and life-cycle assessments to bridge the gap between laboratory demonstrations and deployable, climate-resilient cooling.

Subject of Research: Alternative personal and space cooling technologies for sustainable thermal comfort

Article Title: Human cooling solutions: alternatives to conventional cooling solutions

Article References: Ang, E. Y. M., Yusuf, A., Soh, C. B., & Wang, P. C. (2026). Human cooling solutions: alternatives to conventional cooling solutions. Frontiers in Thermal Engineering, 6, Article 1602847. https://doi.org/10.3389/fther.2026.1602847

Image Credits: AI Generated

DOI: 10.3389/fther.2026.1602847

Keywords: human cooling, personal cooling devices, radiative cooling, thermoelectric cooling, vapor compression, solid-state cooling, membrane heat pumps, district cooling, urban heat island, phase change materials, cooling fabrics, thermal comfort

The stakes could hardly be higher. By 2030, the World Bank estimates that nearly 90 percent of South Asia’s population will be exposed to extreme heat, and a quarter will face severe flooding risks, with Bangladesh flagged as among the most endangered nations. The consequences reach far beyond a missed lecture. Research across 29 tropical countries has shown that early-life exposure to extreme temperatures and erratic precipitation measurably reduces the total years of schooling a child completes, meaning that today’s classroom discomforts can calcify into lifelong educational deficits.

The researchers chose Jagannath University deliberately. Old Dhaka, or Puran Dhaka, is a four-century-old district of narrow roads, wholesale markets, and historic buildings packed at a density of roughly 100,000 people per square kilometer, according to the Bangladesh Bureau of Statistics. Decades of breakneck urbanization have consumed green spaces and wetlands, converted floodplains into residential blocks, and disrupted natural drainage. The result is a classic urban heat island: heatwaves here are stronger and longer-lasting than in surrounding rural areas, and waterlogging routinely paralyzes streets, damages infrastructure, and degrades living conditions. Students commuting through this environment absorb the climate’s shocks twice over, first on the road and again in the lecture hall.

Methodologically, the study is a model of qualitative rigor. The team conducted 38 semi-structured, in-depth interviews with students aged 18 to 26, supplemented by two focus group discussions split by gender and five key informant interviews with three faculty advisors, a librarian, and an assistant proctor. Interviews ran 45 to 60 minutes and were translated into Bangla so participants could speak naturally, then transcribed, translated back, and analyzed using Braun and Clarke’s six-phase reflexive thematic analysis. Purposive sampling ensured representation across faculties, years of study, gender, religion, residence type, and socioeconomic background. The analysis was anchored in three theoretical pillars: Bronfenbrenner’s Ecological Systems Theory, which situates learning within nested layers of environment; Lazarus and Folkman’s Stress and Coping Theory, which explains why identical stressors produce different outcomes; and Fredricks’ three-part model of student engagement spanning behavioral, emotional, and cognitive dimensions.

Five themes emerged, and the first is striking in its simplicity: students understand climate change not as an abstract scientific concept but as a lived, bodily experience. One sociology student described winters that are no longer cold, extreme heat, unexpected rainfall, and pollution from brick kilns and filled-in rivers as evidence that climate change is ‘no longer a distant issue but something that is affecting our everyday lives.’ A zoology student who moved from a village to Old Dhaka reported that the heat felt far more intense in the city and that the predictable rhythm of seasons had dissolved. A business student put it bluntly: walking to an 8:30 a.m. class in intense heat leaves him physically exhausted, and climbing to the seventh floor feels harder than it once did.

The second and third themes trace how that lived experience becomes an academic handicap. Extreme heat pushes classes online, but load-shedding and unstable mobile networks then sabotage the digital fallback, so students miss examination topics discussed during chaotic online sessions and cannot reliably recover the material. A fine arts student watched sudden rain destroy fieldwork at Bahadur Shah Park, stretching a two-day project into six or seven. A computer science student reported sitting in overcrowded, humid classrooms where the 50-minute lecture becomes an exercise in endurance: the heat crushes concentration, interest in learning falls, and examination performance follows. Study habits collapse in parallel. A botany student said that heat in his hostel has destroyed the regular study routine he maintained through school, admitting he once sat final examinations underprepared simply because he could not study in the heat. Long commuters describe arriving home too exhausted to study on weekdays, pushing all learning into holidays and stacking pressure onto examination periods.

Engagement itself shows the strain across all three of Fredricks’ dimensions. Behaviorally, waterlogged roads cause lateness and missed attendance, and rain keeps group members from reaching campus for collaborative presentations. Emotionally, students report watching the clock during afternoon lectures, counting down to release from unbearable rooms. A faculty advisor confirmed the pattern, noting that students on back benches without fan access struggle to concentrate and sometimes ask teachers to cancel or shorten classes. Cognitively, the erosion is perhaps most alarming. One philosophy student living on the top floor of a communal mess said the motivation she had during her school-leaving examinations is simply no longer reachable; another student reported that he once studied three to four hours at a stretch but now cannot sustain focus for even 40 to 50 minutes.

The physical and psychological toll threads through every account. A student who wears hijab described how heat triggers severe headaches that developed into migraine, at times so severe she returns to her room in tears. Others report dehydration, heat rash, and skin infections from wading through dirty floodwater. Female students in crowded buses describe sweating, dizziness, and arriving too unwell to concentrate. Sleep is the invisible casualty: a social work student said outages and ambient heat keep him awake until three or four in the morning before 9 a.m. classes, leaving him irritable, dozing through lectures, and performing so poorly on examinations that he feels depressed about his future. In one female dormitory, eight students share a room and two share a single bed, a suffocating arrangement that breeds irritability precisely when examination pressure peaks. The study echoes broader evidence, including findings that Bangladeshi students in disaster-prone regions experience stress that forces survival above study, and that rising classroom temperatures internationally reduce attention and cognitive function.

Yet students are not passive. They carry umbrellas everywhere, share cold drinks that they know are unhealthy, shower two or three times daily, switch off lights to shave a degree off room temperature, and treat sunscreen as a reluctantly absorbed financial burden. Academically, they migrate to the central library, where the librarian reports morning queues during hot weather and seats too scarce to meet demand, and they restructure their days around the climate itself, one computer science student studying immediately after the dawn prayer because morning temperatures are the only tolerable ones. These strategies echo coping patterns documented in Spain, Indonesia, and India, and consistent with evidence that structured schedules and time management are effective problem-focused responses. But the authors stress the obvious: individual improvisation cannot substitute for structural protection. Their recommendations range from improved ventilation, drainage, green space, and reliable electricity on campus to flexible schedules, hybrid learning models, counseling services, climate adaptation committees, and national policy alignment with the Sustainable Development Goals on education, sustainable cities, and climate action.

The study’s limitations are honestly stated: a single institution, a purposive rather than statistically representative sample, and reliance on self-reported experience. But its core insight travels well beyond Old Dhaka. Climate change is not merely damaging infrastructure or agriculture; it is quietly taxing cognition, sleep, motivation, and attendance among the very cohort that South Asia’s future depends upon. As one respondent reflected, seasons are no longer behaving normally, and the balance nature once held is slipping. If universities and policymakers do not build climate-resilient learning environments soon, the region risks raising a generation whose potential was measured not in grades, but in degrees Celsius.

Subject of Research: The effects of climate change on university students' study habits, academic engagement, and coping strategies in climate-vulnerable urban Bangladesh

Article Title: A qualitative exploration of climate change effects on study habits and academic engagement of Jagannath University students

Article References: Bhattacharjee, M., Sheikh, M. K., Sarker, S. S., & Akter, S. (2026). A qualitative exploration of climate change effects on study habits and academic engagement of Jagannath University students. Environmental Challenges, 25, Article 101689. https://doi.org/10.1016/j.envc.2026.101689

Image Credits: AI Generated

DOI: 10.1016/j.envc.2026.101689

Keywords: climate change, higher education, Bangladesh, Old Dhaka, heat stress, academic engagement, study habits, waterlogging, student mental health, qualitative research, urban heat island, climate adaptation

The study comes at a pivotal moment. Italy’s National Recovery and Resilience Plan has earmarked funding for an urban forestry program described as unique in Europe, targeting the country’s 14 metropolitan cities and 1,268 municipalities, an area covering 15.47 percent of the national territory. By 2026, at least 4.5 million trees and shrubs are expected to be planted across roughly 4,500 hectares, with 3.5 million of those individuals destined for designated final areas. The program operates under the Urban and Peri-Urban Forestry Plan and a ministerial decree built on the principle of planting the right tree in the right place, following biogeographical and ecological criteria standardized at the national level. Globally, the urgency is clear: the UN’s International Resource Panel projects that 2.5 billion people will move into cities by 2050, driving resource consumption up by as much as 125 percent, while cities already account for over 70 percent of greenhouse gas emissions and more than 60 percent of energy use.

To map what is actually happening on the ground, the research team combined a comprehensive bibliographic and documentary review with an analysis of municipal planning documents, technical reports, project plans, online documentation and gray literature. They then verified and expanded the documentary record through direct field observations conducted in August and September 2025, census-ing the plant species used in each intervention. All recorded species were classified by botanical family, chorological type, biological form and native or alien status in Italy, following current national checklists. The team compiled the geographic distribution of the projects using QGIS software, producing the first complete overview of urban forestry activity across the region.

The results show a striking geographic imbalance. Of the 40 interventions identified, the Metropolitan City of Bari accounts for 25 initiatives, far outpacing Lecce with six, Foggia and Taranto with three each, Brindisi with two and Barletta-Andria-Trani with just one. The researchers attribute this concentration to the priorities of densely populated metropolitan areas, the availability of financial resources partly supported by national recovery funds, and the growing integration of urban planning with climate adaptation policies. The scale of ambition in Bari is remarkable: the Terre dell’Alta Murgia and Dalla Murgia all’Adriatico projects alone cover 220 hectares with 220,000 trees, while smaller sites such as Parco Rossani, at just 0.03 hectares, pack in 200 trees and 1,000 shrubs. The 14-hectare Parco della Rinascita, rising on a former industrial site, will host 2,000 trees and 50,000 shrubs.

Beyond the metropolitan capital, the survey documented a network of smaller interventions across the region. In Ruvo di Puglia, a Green Lane project combines 214 trees with 2,400 shrubs; Modugno’s ASI Urban Park received 3,000 trees on a single hectare; and the former Marrasca landfill in Noci was transformed with 3,584 plantings of downy oak, Trojan oak, field maple and Mediterranean shrubs. In Lecce province, peri-urban afforestation at Minervino and Nardò reached a combined 11,000 individuals, dominated by holm oak, kermes oak, stone pine and carob. Taranto’s projects, including the Paolo VI district and the Archaeological Park of the Magna-Greek Walls, total roughly 5,500 individuals, while Foggia’s urban and industrial forests, part of a corporate partnership, planted up to 1,650 trees including holm oak, manna ash and wild pear.

The species census recorded 55 tree and shrub taxa, and the family-level breakdown tells a story of deliberate ecological choice. The Fagaceae, the oak family, dominate with 11 taxa, followed by Rosaceae with six, and the Lamiaceae and Oleaceae with four each. Within Fagaceae, the genus Quercus stands out with eight taxa, reflecting both the ecological versatility of oaks across different soil and climate conditions and their deep cultural significance in the Apulian landscape, where they are a defining element of the traditional forest scenery. Other frequently planted natives include carob, nettle tree, field maple, manna ash, Aleppo pine, myrtle, mastic tree, strawberry tree and Mediterranean buckthorn, all species shaped by millennia of adaptation to drought, heat and poor calcareous soils.

Chorological analysis confirmed a strong native-first strategy: 44 of the 55 recorded taxa are native to Italy, with just six naturalized aliens, three casual aliens, two invasive aliens and two cryptogenic species. The researchers argue this preference carries multiple advantages. Native species generally require less maintenance and irrigation while supporting key ecosystem services such as microclimate regulation, stormwater management, carbon sequestration and mitigation of the urban heat island effect. They also bolster urban biodiversity by providing habitat and food for fauna and by creating ecological corridors linking city green spaces to the surrounding natural landscape, and greater botanical heterogeneity itself enhances ecosystem resilience against environmental stressors, disease and climate change.

The standout case study is the Poggiofranco district in Bari, which the authors present as a model of advanced ecological design. Implemented in February 2024 on about 1.2 hectares of calcareous soil, the project brought together the University of Bari’s Department of Soil, Plant and Food Sciences, the municipal administration, the Campanale forest nursery and the Alberitalia Foundation. All 1,400 plantings were one- to two-year-old natives grown from certified seeds collected in Apulian regional forests, a measure intended to guarantee locally adapted genotypes. The seedlings were arranged in an irregular curvilinear pattern with four meters between rows and 1.5 meters within rows, deliberately mimicking natural forest structure. Five tree species and four shrub species were selected for drought tolerance and consistency with the area’s potential natural vegetation, specifically the Cyclamino hederifolii–Quercetum ilicis plant association of the dry thermo-Mediterranean zone. Holm oak led the planting with 400 individuals, while four other species received 180 each and three, including cork oak, were limited to 60.

Perhaps the most socially resonant finding is how many projects target degraded or abandoned land: the former Fibronit industrial site in Bari, the former Marrasca landfill in Noci, and several peripheral and industrial zones across the region. The survey frames urban reforestation as a tool of environmental and social regeneration, converting neglected, sometimes contaminated spaces into accessible, multifunctional public areas that raise urban quality of life and strengthen social cohesion, with thematic parks, green memorials and pedestrian pathways woven into local planning.

Yet the study also sounds a note of caution. Despite the strong native emphasis, the presence of naturalized or potentially invasive taxa such as paper mulberry and London plane highlights the need for continuous monitoring and adaptive management to prevent harmful impacts on urban biodiversity. The authors conclude that Apulia’s experience offers a replicable model for other Mediterranean regions, but only if future planning deepens interdisciplinary collaboration among ecologists, urban planners and policymakers so that species selection, planting design and long-term management remain consistent with local ecological conditions and the escalating realities of climate change.

Subject of Research: Urban forestation projects and native tree species selection in Apulia, southern Italy

Article Title: Urban forestation in Apulia (southern Italy): An overview

Article References: Pardi, R., Cirlincione, F., Di Gristina, E., Venturella, G., & Gargano, M. L. (2026). Urban forestation in Apulia (southern Italy): An overview. Italian Botanist, 21, 139-157. https://doi.org/10.3897/italianbotanist.21.181254

Image Credits: AI Generated

DOI: 10.3897/italianbotanist.21.181254

Keywords: urban forestry, Apulia, native species, reforestation, Mediterranean ecosystems, Quercus, biodiversity, urban heat island, ecosystem services, Bari, climate resilience, invasive species

The study’s author, Samuel Ikendi of the University of California’s Division of Agriculture and Natural Resources and the Merced Earth Institute, positions universities as proxies for evaluating what he calls Green Squares: central open softscape nodes that bring together ecological, social, symbolic, and institutional functions. Synthesizing architectural phenomenology, environmental psychology, and chrono-urbanism, the research uses the 15-Minute Campus framework as an interpretive temporal lens. Rather than treating proximity as a cold geometric distance, the framework shifts the analytical gaze to the fluid rhythms of daily life, recognizing that proximity is fundamentally an embodied experience structured by pedestrian routines, shifting user patterns, and institutional paces unfolding across the same landscape over time.

Methodologically, the inquiry is unusual. It spans an 18-year biographical continuum from 2008 to 2026 across three distinct campus design eras: the 19th-century agrarian park layout of Iowa State University in Ames, the 20th-century post-colonial urban hilltop of Makerere University in Kampala, and the 21st-century master-planned grid of UC Merced in California’s Central Valley. The researcher served as the primary analytical instrument, logging physical features into a four-tier qualitative matrix that separated observational notes on infrastructure and text, methodological notes, theoretical notes mapping elements to the spirit of place, and reflexive observer’s comments. Two-cycle thematic coding processed 184 individual raw text statements and landscape features captured across 64 pedestrian walkthrough traverses, with negative case analysis deliberately cataloging spatial friction, sensory shock, and design failures to prevent celebratory bias.

The empirical analysis reveals how built layouts function across five themes. First, historical anchors bind institutional identity. At Iowa State, the straight Curtiss–Beardshear axis connects the agricultural college to central administration along a non-motorable corridor, anchored by a central flagpole with a Class of 1876 bronze plaque and the historic Cooperative Extension plaque marking the 1906 birthplace of county agricultural extension work. At Makerere, the white-and-blue Main Administration Building, traditionally called the Ivory Tower, was meticulously reconstructed after a devastating 2020 fire gutted the historic structure, restoring its 1941 architectural form. At Merced, a founding chancellor plaque at the edge of the Carol Tomlinson-Keasey Quadrangle anchors institutional legitimacy directly into a landscape that was open pasture land only decades ago.

Second, processional rituals translate structural forms into what the study terms kinetic devotion. The 110-foot brick Campanile at Iowa State, housing a 50-bell carillon whose bells were added incrementally from 1899 to 1967, organizes graduation choreography around a bronze-and-walnut academic mace sculpted to mirror the tower’s geometry. Campus lore holds that a student officially becomes an Iowa Stater when kissed under the Campanile as the carillon tolls midnight, a tradition called campaniling that transforms the daytime thoroughfare into an intimate peer-bonding site. At Merced, the 40-foot stainless steel Beginnings arches bookend a student’s experience: incoming students march southwest across Scholars Bridge through the arches during Orientation’s Journey Inward, and seniors execute a retrograde processional through the same arches at Commencement’s Journey Outward.

Third, environmental markers operate as living policy texts. A single ‘Triumph’ Elm near Curtiss Hall at Iowa State carries a timeline plaque recognizing partnerships between the university and seven tribal colleges across Nebraska, South Dakota, and North Dakota, materializing structural equity through botanical form. At Makerere, the asymmetrical Makerere@100 monument features a ten-sided concrete foundation base, each side inscribed with a plaque documenting one decade of history from the 1922 technical college through the persecution-era 1970s to the modern collegiate transition, while an active meteorological station near Freedom Square materializes the central square as a living laboratory. At Merced, Toloma Grove, dedicated in 2010 with seven California valley oak saplings and indigenous flora, carries a plaque acknowledging the Miwuk and Yokuts peoples, establishing an indigenous land acknowledgment from the young campus’s inception.

Fourth, human-scale philanthropic rest stops humanize these squares. At Iowa State, concrete benches donated by the Class of 1916 and granite benches installed by the Class of 1910 beneath pine groves display past student custody on the lawn. At Makerere, the recovery of the fire-gutted administration building was heavily supported by localized alumni donor networks through a ‘Buy-a-Brick’ initiative with engraved recognition plaques, making intergenerational stewardship legible on the grass. At Merced, the massive Sierra granite Peterson Stone, inscribed for a regional philanthropic family who funded foundational initiatives when the campus lacked a donor network, serves as a sun-warmed informal bench that democratizes the modern plaza. Fifth, spatial containment dynamics emotionally heighten each square: at Makerere, student strikes mobilized on Freedom Square with the chant ‘Eh, Makerere Oyee!’ echoing off the Main Library and administration facades, forcing executives to walk down onto the grass to negotiate, while at Merced the Kolligian Library and the Science and Engineering arcade frame the quadrangle with floodlit safety perimeters.

The study is careful about its qualitative boundaries. It deployed no microclimatic instrumentation, no surface temperature sensors, no canopy closure measurements, and no student surveys, so all assertions about climate resilience and student psychology are positioned as literature-informed interpretations rather than measured outcomes. The research explicitly notes that the three landscape types possess different baseline conditions, such as canopy density and surface albedo, that alter their real-world biophysical performances. The mature interlocking canopy at Iowa State and Makerere blocks direct solar radiation, whereas Merced’s wide concrete panels create intense summer exposure due to elevated albedo and a lack of mature tree cover, generating localized thermal stress that only native microclimatic sanctuaries like Toloma Grove can relieve. The Fairfield Canal, with its waterfowl and open water, introduces biophilic vitality that softens hardscape glare during extreme midday heat.

The implications scale outward. The study argues that place-identity forged within micro-level nodes potentially extrapolates through campustown interface zones to intersect with municipal civic cores, exemplified by the 2024 municipal annexation that legally integrated Merced’s 1,140-acre campus grid into the city limits. The findings suggest open softscape midpoints function as adaptive chronotopes, localized timespaces where institutional history, cyclic rituals, and spontaneous daily cadences entangle and synchronize, supporting context-sensitive cooling, public inclusion, and temporal planning under the New Urban Agenda and Sustainable Development Goal 11. City planners are urged to establish strict softscape mandates protecting central lawns from densification.

Perhaps the most provocative recommendation concerns orientation rhetoric. The study critiques the top-heavy blindness of traditional welcome speeches, which almost exclusively direct attention upward toward monumental landmarks like the Campanile, the Makerere administration tower, or the soaring Beginnings arches. An over-emphasis on intimidating monolithic architecture is interpreted as potentially reinforcing displacement, imposter syndrome, and alienation among first-generation and low-income scholars. The author proposes Place-Based Contextual Orientation: administrators should rewrite orientation scripts to de-center architectural elitism and elevate human-scale micro-monuments flanking the same squares, from the tribal-college Triumph Elm at Iowa State to the Peterson Stone at Merced and the alumni-funded brick repairs at Makerere, so that a student’s daily fast-paced pathways are physically supported by the collective timeline of regional families, bridging historical town–gown divisions and helping diverse cohorts feel a deep, unshakeable sense of place.

Subject of Research: Urban Planning & Sustainable Cities

Article Title: Reading the midcampus core matters: autoethnographic reflexivity of ‘Green Squares’ as temporally integrated 15-Minute Campus nodes for student belonging, town–gown integration, and climate resilience

Article References: Ikendi, S. (2026). Reading the midcampus core matters: autoethnographic reflexivity of ‘Green Squares’ as temporally integrated 15-Minute Campus nodes for student belonging, town–gown integration, and climate resilience. Frontiers in Sustainable Cities, 8, Article 1962466. https://doi.org/10.3389/frsc.2026.1962466

Image Credits: AI Generated

DOI: 10.3389/frsc.2026.1962466

Keywords: 15-Minute Campus, chrono-urbanism, campus green space, student belonging, town-gown integration, urban heat island, climate resilience, autoethnography, place-identity, sustainable cities, Reading, midcampus

Scientists led by Carla de Souza Farias of Brazil’s National Institute for Amazonian Research set out to answer a deceptively simple question: does the mere presence of a city in the central Amazon induce more extreme precipitation? Previous work on Manaus had examined single storm events, leaving open whether the urban effect was a one-off curiosity or a robust, repeatable pattern. To settle the matter, the team assembled a decade of observations from 2010 to 2020 and identified 45 extreme precipitation events that appeared in two independent datasets: the IMERG satellite rainfall product and the ERA5 atmospheric reanalysis produced by the European Centre for Medium-Range Weather Forecasts.

The screening was deliberately strict. Of the roughly 177 extreme events flagged by IMERG and 176 by ERA5, only 45 were coincident in both products. This filtering matters because satellite grids and reanalyses often disagree on the exact timing and location of localized convective storms in the Amazon, and the researchers wanted simulations initialized with physically consistent conditions. Extreme days were defined as those exceeding the 97.5th percentile of daily rainfall, and the events clustered in the rainy season from November to May, with February and June showing the highest monthly counts.

For each of the 45 events, the team ran paired simulations with the Weather Research and Forecasting model, or WRF, coupled to the Single Layer Urban Canopy Model. In the urban experiment, Manaus was represented with three district classes: industrial and commercial zones, low-intensity residential areas, and high-intensity residential neighborhoods, with parameters tuned using local street widths, roof dimensions, and census-based population density. In the control experiment, the entire urban footprint was replaced with forest. Ninety simulations in total, each 60 hours long, allowed the researchers to compare the same storms over the same 427 square kilometers with and without the city.

The verdict was striking. In 65 percent of the events, total accumulated rainfall was higher with the city present, and in the urban center the average increase reached 16.8 percent. Hourly rainfall intensity told an even sharper story: about 79.2 percent of hourly values in the urban run exceeded those of the forested control, and the maximum hourly precipitation intensity rose by up to 50 percent. The urban scenario also produced longer-lived storms, with the 90th percentile of event duration reaching 19 hours compared with 16.6 hours without the city, suggesting that urban forcing helps sustain convection once it begins.

The mechanism unfolds in three linked steps. First, the city heats up. Asphalt, concrete, and other high-thermal-inertia materials raised the simulated surface temperature by as much as 2.9 degrees Celsius at midday relative to the forested scenario, with air temperature at two meters rising by about 0.6 to 0.7 degrees Celsius. This warming acts as a thermal trigger: the anomalous surface heating peaks around noon, and the largest precipitation intensification follows in the afternoon between 14:00 and 17:00 local time, exactly the window in which the urban heat island of Manaus has been observed to peak in field measurements.

Second, the heated boundary layer drives the atmosphere upward. The researchers found a statistically significant positive correlation between the precipitation difference and vertical wind speed at the 800 hectopascal level, in the middle troposphere, with a correlation coefficient of 0.39 and a p-value of 0.008. Stronger updrafts over the city lift warm, unstable air toward the level where deep convective clouds form. Third, and perhaps most surprising given the setting, the city imports its own moisture. Although near-surface humidity was actually lower over the urban area than over the forest, because trees pump water into the air through evapotranspiration, specific humidity at 800 hectopascals showed a significant positive correlation with the precipitation increase. The interpretation is that urban heating and the rough, friction-generating canopy converge moist air laterally from the surrounding forest and rivers, drawing it into the urban core where it fuels towering convective cells.

The spatial fingerprint of this process is unmistakable. When the domain was divided into nine geographic sectors, the central quadrant coinciding with the urban area recorded the highest accumulated rainfall, 1,136.1 millimeters across the 45 events, and captured the maximum in 11 cases, or 24.4 percent of the total. The southwest sector followed with 1,101.3 millimeters and nine events, consistent with the prevailing northeast-to-southwest flow that advects storms initiated over the city downwind. In the forested control run, by contrast, the precipitation maxima shifted to the peripheral southeast and east sectors, and the central sector dropped to 972.6 millimeters with only five winning cases. In effect, the city traps and concentrates rainfall that would otherwise be distributed over forest and rivers.

The findings place Manaus within a growing global picture. A 2024 analysis of more than 1,000 cities found that over 60 percent of urban areas act as so-called urban wet islands, where precipitation exceeds that of surrounding rural areas, a phenomenon that has roughly doubled in magnitude over the past two decades. Yet the Amazonian case is distinctive because of its setting: the city sits between the Negro and Solimões rivers, embedded in an atmosphere so humid that near-surface specific humidity exceeds 18 grams per kilogram even during extremes. That abundance of moisture means the urban heat island does not dry out storms, as it can in arid cities such as Phoenix, but instead supercharges them, converting a modest thermal anomaly into a deep convective engine fed by the surrounding rainforest.

The practical implications are sobering. Manaus already suffers recurring flash floods and landslides, aggravated by rapid and often unplanned growth on highly impermeable ground. If urbanization reliably intensifies the heaviest rainfall by double-digit percentages, then the city’s own expansion is compounding its flood risk at precisely the moment climate change is loading the atmosphere with more water vapor. The authors note that their controlled experiments deliberately excluded anthropogenic heat emissions and urban aerosols, both of which could add further complexity, and they call for multi-layer canopy models and coupled chemistry simulations in future work. For now, the message for Amazonian cities is clear: as the forest gives way to pavement, the storms above it grow heavier, and the water that falls has nowhere to go but the streets.

Subject of Research: Urbanization effects on extreme precipitation in the central Amazon city of Manaus

Article Title: Does the urban presence of a city in the central Amazon induce more extreme precipitation?

Article References: de Souza Farias, C., Candido, L. A., de Melo Monte, M. J., Buscioli Capistrano, V., Andreoli, R. V., Holanda Hall, D., de Jesus Machado, J., & Quaresmas Dias-Júnior, C. (2026). Does the urban presence of a city in the central Amazon induce more extreme precipitation?. Theoretical and Applied Climatology, 157(11), Article 722. https://doi.org/10.1007/s00704-026-06646-5

Image Credits: AI Generated

DOI: 10.1007/s00704-026-06646-5

Keywords: Manaus, Amazon, extreme precipitation, urban heat island, WRF model, convection, urbanization, flooding, tropical meteorology, moisture convergence, land-use change, climate modeling

The work, published in the journal Results in Chemistry by A.M. Metha and S. Sumathi, addresses a persistent dilemma in pigment chemistry. Traditional dark pigments, including many iron oxide and chromium-based compounds, absorb broadly across both the visible and near-infrared regions, converting absorbed sunlight into surface heat. This contributes to the urban heat island effect, in which cities become substantially warmer than their surroundings because of heat-absorbing construction materials, and it drives up the energy demand for air conditioning. Many classic pigments also carry a toxic burden, relying on cadmium, selenium, chromium, or lead, all of which pose risks to human health and the environment. A benign pigment that combines strong color with high near-infrared reflectance has therefore become a prized target in materials research.

The Indian team chose strontium molybdate, SrMoO4, as the host lattice, and the choice is chemically shrewd. The compound adopts the tetragonal scheelite structure, an arrangement in which isolated tetrahedral molybdate groups sit among strontium ions. Its wide band gap of about 4.2 electronvolts means the material itself is essentially colorless and nearly transparent to visible light, and its low intrinsic absorption in the near-infrared makes it an excellent reflector in that band. Because of its forgiving framework, foreign ions can be slipped into the lattice without destroying the structure, which is precisely what doping experiments require. Previous studies had already exploited this versatility, producing yellow pigments with cerium doping and luminescent materials with europium, dysprosium, and terbium.

To generate color, the researchers turned to iron, a proven chromophore for warm tones. They synthesized a complete series of compounds with the formula Sr1-xFexMoO4, where the iron fraction ranged from zero to half of the strontium content, using a hydrothermal method that is remarkably gentle by pigment standards. Aqueous solutions of strontium nitrate, ferric nitrate, and ammonium molybdate were mixed, the pH was adjusted to neutral with ammonia, and the mixture was sealed in a Teflon-lined autoclave at 180 degrees Celsius for fifteen hours. Conventional reddish-brown pigments often require calcination at 600 to 1200 degrees Celsius or beyond, so a low-temperature, water-based route carries both energy and cost advantages for industrial scale-up.

Structural analysis confirmed the doping strategy worked cleanly. Powder X-ray diffraction showed that every composition, from pure SrMoO4 through the highest iron loading, crystallized in the single tetragonal scheelite phase with no secondary impurities, and Rietveld refinement verified that the lattice remained intact with high goodness-of-fit values. Interestingly, the lattice parameters increased slightly with iron content rather than contracting, even though iron ions are much smaller than strontium. The authors attribute this to local structural relaxation, a mixed iron valence state, and charge-compensation effects within the crystal. Fourier-transform infrared spectroscopy supported the same conclusion, showing the characteristic molybdate vibrations but no separate iron oxide signals, which would have indicated undissolved impurity phases.

Where the chemistry gets truly interesting is in the electronic structure. X-ray photoelectron spectroscopy of the optimal composition, Sr0.8Fe0.2MoO4, revealed a mixed-valence world at the surface: iron present as both Fe2+ and Fe3+, and molybdenum coexisting as Mo5+ and Mo6+. This charge redistribution, together with iron-induced oxygen vacancies, introduces new energy levels inside the wide band gap of the host. The result is dramatic in the optical data. The undoped compound absorbs only in the ultraviolet, through a ligand-to-metal charge-transfer transition within the molybdate tetrahedra, and its band gap of 4.22 electronvolts falls steadily to 1.87 electronvolts at the highest iron loading. The new absorption channels include oxygen-to-iron charge transfer, iron d-d transitions, and intervalence charge transfer between neighboring iron ions, all of which soak up visible light and paint the powder in warm brown tones.

Color measurements in the CIE Lab* system traced this evolution quantitatively. The pure compound is nearly white, with a lightness value of 93.67. Iron doping drags the lightness down to about 45 at the highest loading while pushing the red and yellow coordinates positive, and the hue angle slides from 63.6 to 44.5 degrees, crossing into the 40-to-60-degree window that defines true reddish-brown shades. Crucially, the near-infrared solar reflectance, calculated against the ASTM G173-03 standard solar spectrum, stayed impressively high: 82.4 percent for the undoped host, 70.0 percent at ten percent iron, and 69.8 percent at the optimal twenty percent loading, only falling to 58.4 percent at the heaviest doping. That trade-off between color intensity and reflectance is the central challenge of cool pigment design, and the molybdate framework held the line better than most alternatives.

The comparison with published reddish-brown pigments makes this performance striking. Lanthanum ferrite and related orthoferrite pigments, typically fired at 1200 degrees Celsius, manage reflectances of only 33 to 43 percent. Bismuth ferrite variants reach about 52 percent, iron-substituted yttrium aluminate 45 percent, and cerium-praseodymium oxide 58 percent. The iron-doped strontium molybdate made here at 180 degrees Celsius beats them all, delivering comparable color with 60 to 70 percent reflectance. The authors credit the molybdate lattice itself, which retains its near-infrared reflectivity even after iron is introduced, effectively decoupling the visible coloration from the thermal performance.

Real-world testing put the numbers to work. In a laboratory setup, metal sheets coated with a PVDF-based paint containing the Sr0.8Fe0.2MoO4 pigment were irradiated with a 250-watt infrared lamp thirty centimeters away. The bare sheet climbed from 31.8 to a scorching 62.3 degrees Celsius within ten minutes, while the coated sheet peaked at 57.1 degrees, and the coated surface stayed roughly 3.6 degrees cooler on average over an hour of continuous irradiation. Under genuine outdoor sunlight on the Vellore campus in early September, with ambient temperatures near 37 degrees and solar irradiance approaching 1000 watts per square meter, the pigment-coated sheet ran about 4 to 5 degrees cooler than bare metal, and a version layered over a white titanium dioxide base coat performed best of all, reaching 45.2 degrees when the bare surface hit 61.2 degrees. Commercial iron oxide paint, by contrast, provided only about half that benefit.

The pigment also passed the durability gauntlet that determines whether a laboratory curiosity can become a commercial coating. Thermogravimetric analysis showed only about 6 percent weight loss up to 800 degrees Celsius, with the crystal structure surviving intact, and exposure to dilute hydrochloric acid, nitric acid, and sodium hydroxide produced total color differences between 1.84 and 4.96, all within the accepted threshold of 5 for chemical resistance. Taken together, the results sketch a coherent recipe for the next generation of cool coatings: a benign, iron-based chromophore locked inside a highly reflective molybdate framework, manufactured at low temperature, and capable of shaving several degrees off the surfaces that bake under the sun. For a warming world covered in dark roofs, that modest temperature difference, multiplied across entire cities, could translate into meaningful savings in cooling energy and a measurable dent in the urban heat island effect.

Subject of Research: Iron-doped SrMoO4 near-infrared reflective cool pigments for energy-efficient coatings

Article Title: Design of reddish-brown iron-doped SrMoO 4 pigments with high NIR reflectance for cool coating applications

Article References: Metha, A., & Sumathi, S. (2026). Design of reddish-brown iron-doped SrMoO4 pigments with high NIR reflectance for cool coating applications. Results in Chemistry, 31, Article 103958. https://doi.org/10.1016/j.rechem.2026.103958

Image Credits: AI Generated

DOI: 10.1016/j.rechem.2026.103958

Keywords: cool pigments, near-infrared reflectance, strontium molybdate, iron doping, urban heat island, scheelite structure, hydrothermal synthesis, passive cooling, inorganic pigments, band gap engineering, thermal management, PVDF coatings