Search Results (95)

Charcoal rot, caused by Macrophomina phaseolina, is an increasingly important constraint in soybean, particularly under hot and dry conditions. While heat and drought are known to favor disease development, short early-season cold spells—common in temperate regions—may predispose soybean to subsequent infection, yet this interaction remains poorly quantified. It was evaluated whether transient chilling increases charcoal rot severity and whether cultivar-specific differences modulate this predisposition. Nine commercial cultivars spanning MG 00, 0, and 0–I were grown in a controlled walk-in chamber under either optimal conditions (control) or a three-day cold spell initiated at the first fully expanded trifoliate (20–23 days after sowing, DAS). Standardized cut-stem inoculation was performed at 26 DAS, and stem lesion length was recorded every 3–4 days across five assessments at 3, 7, 10, 14, and 21 DPI. Two-way ANOVA (treatment, genotype, treatment × genotype) with Tukey’s HSD tested effects. Cold stress significantly increased lesion lengths at all assessments, with the strongest divergence at the earliest measurement. Genotype and treatment × genotype were also significant, revealing differential responses among cultivars; notably, one line (G9) showed consistently small treatment-induced increases. These results indicate that brief early-season cold exposure can predispose soybean to more severe charcoal rot, with the magnitude dependent on genotype and timing. Incorporating cold-stress predisposition into screening and breeding should enhance resilience under increasing climate variability. Full article

Late spring frosts and transient cold spells constrain tomato productivity. This study presents a comparative analysis of the chilling response of two Solanum lycopersicum cultivars, MoneyMaker (MM) and Micro-Tom (MT), and the wild relative S. lycopersicoides. The assessment integrated physiological parameters, such as electrolyte leakage and PSII efficiency, expression levels of CBF1–3 genes (via qPCR), and fatty acid composition dynamics of membrane lipids (via gas-liquid chromatography-mass spectrometry). The results revealed distinct response strategies. S. lycopersicoides exhibited comprehensive tolerance and was coordinated across biological levels. Its key mechanisms include superior membrane integrity, sustained PSII photochemical efficiency, stable upregulation of CBF genes (with predominant CBF3 induction), and consistently high α-linolenic acid content. This integration prevented membrane damage and sustained photosynthesis. Conversely, the MM cultivar displayed high sensitivity, characterized by transient CBF1 upregulation, an absence of adaptive lipid remodelling, rapid membrane damage, and severe photoinhibition, explaining its poor recovery. The MT genotype demonstrated an intermediate phenotype, featuring delayed but persistent CBF activation, and the partial lipid profile shifted toward the wild-type pattern, indicating a partial adaptive capacity for membrane adjustment. These findings establish S. lycopersicoides as a vital genetic resource for breeding cold-tolerant tomatoes, while MT provides a model for studying adaptation mechanisms in cultivated varieties. Full article

Climate change is increasing the frequency of extreme weather events, posing critical challenges for the resilience of specialized transportation services (STSs) that provide essential mobility for people with disabilities. In the South Korean context, heatwaves, cold spells, and heavy rainfall are particularly relevant because they directly affect health risks, trip demand, and operational reliability, making them central stressors for evaluating STS resilience in Busan. This study examines STS resilience in Busan, South Korea, focusing on three weather stressors: heatwaves, cold spells, and heavy rainfall. Large-scale operational data from the STSs of Busan were analyzed using the 4R (robustness, rapidity, redundancy, and resourcefulness) framework to classify daily service performance into distinct profiles. The analysis revealed that heatwaves coincided with reduced trip demand and shorter waiting times, yet this apparent stability reflected demand suppression rather than genuine robustness. Heavy rainfall produced the most severe disruptions, with longer and more variable waiting times that exacerbated inequities across users. Cold spells were associated with rapid recovery and the preservation of critical trips, although the small number of cases limits broader interpretation. These findings indicate that resilience in STSs is not uniform but event-specific, offering policy insights for strengthening operational stability and promoting equity in accessible transport. Full article

The daily maximum and minimum temperatures measured by the HNMS’s stations from 1960 to 2022, are used to compute percentile-based indices capturing the percentage of days below or above the 10th and 90th percentile, respectively (TN10p, TX10p, TN90p, TX90p), and event duration indicators (WSDI and CSDI). The climate extremes indices are evaluated assuming two different reference periods (1961–1990 and 1991–2020), and trend analysis is performed using the Mann–Kendall test. The results show a significant increase in the frequency of the warm days and nights. The magnitude and perceived timing of trends depend on the baseline chosen. Using the warmer 1991–2020 reference period dampens the upward trends in warm–extreme indices and amplifies the downward trends in cold extremes. Full article

Exposure to extreme temperature events (ETEs) and ambient fine particulate matter (PM_2.5) has been linked to an increased risk of pneumonia mortality, but their interactive effects remain largely unknown. We investigated 50,196 pneumonia deaths from 2015 to 2022 in Jiangsu province, China, with a time-stratified case-crossover design. An individual-level exposure to heat wave, cold spell, and PM_2.5 was assessed at each subject’s residential address using validated grid datasets. Conditional logistic regression models integrated with a distributed lag nonlinear model were used to quantitatively estimate both independent and interactive effects. With different ETE definitions, the cumulative odds ratio (OR) of pneumonia mortality associated with heat wave and cold spell ranged from 1.22 (95% confidence interval [CI]: 1.14, 1.31) to 1.60 (1.40, 1.81), and from 1.08 (1.002, 1.17) to 1.18 (1.01, 1.38), respectively, while the OR for PM_2.5 ranged from 1.013 (1.006, 1.021) to 1.016 (1.009, 1.024). We observed a synergistic effect (relative excess risk due to interaction [RERI] ranging from 0.40 [0.06, 0.76] to 1.16 [0.41, 2.09]) of co-exposure to heat wave and PM_2.5, as well as an antagonistic effect (RERI ranging from −0.20 [−0.40, −0.03] to −1.02 [−1.78, −0.38]) of co-exposure to cold spell and PM_2.5 on pneumonia mortality. It was estimated that up to 6.49% of pneumonia deaths were attributable to heat wave and PM_2.5 exposures. We found that heat wave and cold spell interacted oppositely with PM_2.5 to increase the odds of pneumonia mortality, highlighting the needs to reduce co-exposures to heat wave and PM_2.5. Full article

Extreme sea surface temperature (SST) events, such as marine heatwaves (MHWs) and marine cold spells (MCSs), severely affect warm water coral reefs. However, further study is required on their historical and future spatiotemporal patterns, driving mechanisms, and impacts in coral reef regions. This study analyzed the spatiotemporal patterns in MHWs/MCSs for the periods 1982–2022 and 2023–2070 using ten indices based on OISSTv2.1 and CMIP6 data, respectively, identified key MHW drivers via four machine learning methods (Random Forest, Extreme Gradient Boosting, Light Gradient Boosting Machine, and categorical boosting) and SHAP values (Shapley Additive Explanations), and then examined their relationship with coral coverage across ten global marine regions. Our results revealed that (1) MHWs are not only increasing in their average intensity but also becoming more extreme, while MCSs have declined. More MHW days are observed in regions like the Red Sea, the Persian Gulf, and the South Pacific Islands, with increases of up to 28 days per decade. (2) Higher-latitude coral reefs are experiencing more severe MHWs than equatorial regions, with up to 1.24 times more MHW days, emphasizing the urgent need to protect coral refuges. (3) MHWs are projected to occur nearly year-round by 2070 under scenario SSP5–8.5. The area ratio of MHWs to MCSs is expected to rise sharply from 2040 onward, reaching approximately 100-fold under the SSP2–4.5 scenario and 196-fold under the SSP5–8.5 scenario, particularly in the Marshall Islands and Caribbean Sea regions. (4) The coefficient of variation (CV) of annual temperature, annual ocean heat content, and monthly temperature were the top three factors driving MHW intensity. We emphasize that future MHW predictions should focus more on the CV of forecasting indicators rather than just the climate means. (5) Coral coverage exhibited post-mortality processes following MHWs, showing a strong negative correlation (r = −0.54, p < 0.01) with MHWs while demonstrating a significant positive correlation (r = 0.6, p < 0.01) with MCSs. Our research underscores the sustained efforts to protect and restore coral reefs amid escalating climate-induced stressors. Full article

Sustainable Development Reserves are organized units in the Amazon that are essential for the proper use and sustainable management of the region’s natural resources and for the livelihoods and economy of the local communities. This study aims to provide a climatic characterization of the Madeira River Sustainable Development Reserve (MSDR), offering scientific support to efforts to assess the feasibility of implementing adaptation measures to increase the resilience of isolated Amazon communities in the face of extreme climate events. Significant statistical analyses based on time series of observational and reanalysis climate data were employed to obtain a detailed diagnosis of local climate variability. The results show that monthly mean two-meter temperatures vary from 26.5 °C in February, the coolest month, to 28 °C in August, the warmest month. Monthly precipitation averages approximately 250 mm during the rainy season, from December until May. July and August are the driest months, August and September are the warmest months, and September and October are the months with the lowest river level. Cold spells were identified in July, and warm spells were identified between July and September, making this period critical for public health. Heavy precipitation events detected by the R80, Rx1day, and Rx5days indices show an increasing trend in frequency and intensity in recent years. The analyses indicated that the MSDR has no potential for wind-energy generation; however, photovoltaic energy production is viable throughout the year. Regarding the two major commercial crops and their resilience to thermal stress, the region presents suitable conditions for açaí palm cultivation, but Brazil nut production may be adversely affected by extreme drought and heat events. The results of this study may support research on adaptation strategies that includethe preservation of local traditions and natural resources to ensure sustainable development. Full article

Marine heatwaves (MHWs) and Marine cold spells (MCSs) are oceanic events characterized by prolonged periods of anomalously warm or cold sea surface temperatures, which pose significant ecological and socio-economic threats on a global scale. These extreme temperature events exhibit an asymmetric trend under ongoing climate change in recent decades: MHWs have increased markedly in both frequency and intensity, whereas MCSs have shown an overall decline. Among the potential drivers, mesoscale eddies play a critical role in modulating sea surface temperature anomalies (SSTAs). Anticyclonic eddies (AEs) promote downwelling, generating positive SSTAs that potentially favor MHWs, while cyclonic eddies (CEs) enhance upwelling and negative anomalies that are potentially related to MCSs. In this paper, we investigate the relationship between mesoscale eddies and MHWs/MCSs using global satellite-derived datasets from 2010 to 2019. By analyzing the spatial overlap and intensity correlation between eddies and MHWs/MCSs, it is found that 12.2% of MHWs are accompanied by AEs, and 13.4% of MCSs by CEs, with a high degree of spatial containment where approximately 90.2% of MHW events are found within the mean eddy contour of AEs, and about 93.1% of MCS events fall inside the mean eddy contour of CEs. Stronger eddies tend to be associated with more intense MHWs/MCSs. This study provides new insights into the role of mesoscale eddies in regulating extreme oceanic temperature events, offering valuable information for future predictions in the context of climate change. Full article

A severe cold air outbreak hit the US and parts of Canada in January 2019, leaving behind many casualties where at least 21 people died as a consequence. According to Insurance Business America, the event cost the US about 1 billion dollars. In the Midwest, surface temperatures dipped to the lowest on record in decades, reaching −32 °C in Chicago, Illinois, and down to −48 °C wind chill temperature in Cotton and Dakota, Minnesota, giving rise to broad media attention. A zonal wavenumber 1–3 planetary wave forcing caused a sudden stratospheric warming, with a displacement followed by a split of the polar vortex at the beginning of 2019. The common downward progression of the stratospheric anomalies stalled at the tropopause and, thus, they did not reach tropospheric levels. Instead, the stratospheric trough, developing in a barotropic fashion around 70° W, turned the usually baroclinic structure of the Aleutian high quasi-barotropic. In response, upward propagating waves over the North Pacific were reflected at its lower stratospheric, eastward tilting edge toward North America. Channeled by a dipole structure of positive and negative eddy geopotential height anomalies, the waves converged at the center of the latter and thereby strengthened the circulation anomalies responsible for the severely cold surface temperatures in most of the Midwest and Northeast US. Full article

Thermal comfort is not a luxury; rather, a lack of it is a matter of life and death, particularly for vulnerable people, such as older people. This work systematically reviews and analyses the thermal comfort of older people and their health and mortality as it relates to exposure to extreme temperatures, and suggests acceptable thermal conditions and the related energy use of buildings. A total of 69 out of 198 papers were found on older people and these were analysed in detail. This was followed by an analysis of the UN and UK governments’ open access data. This work highlights the disparity regarding the definition of age for older people and encourages the use of the term ”older people”, rather than ”elderly”, which can be an offensive piece of terminology. The UK findings suggest a significant relationship between cold (below 5 °C) outdoor air temperatures and mortality in older people, particularly for those who are over 85 years old. In the UK, thermal conditions can lead to up to 175 deaths per degree temperature change up to two weeks after a cold spell or an overly hot period. The indoor comfort temperature of older people varies between 22.5 and 27 °C in natural ventilation mode. However, some studies found 18 °C to be comfortable in winter time, a finding which could lead to a significant energy saving in relation to space heating. Current gaps in and the recommended future direction of research include topics such as gender differences in terms of thermal comfort and during menopause; thermal comfort conditions, adaptive behaviours and naturally ventilated buildings; thermal conditions when sleeping and energy use as it relates to space heating or cooling for older people. Full article

Regular meteorological observations in Padua started in 1725 and have continued unbroken up to the present, making the series one of the longest in the world. Daily mean temperatures and precipitation amounts have recently been homogenized for the entire 1725–2024 period, making it possible to add new measurements without further work. Starting from the temperature series, the trends of cold and warm spells are investigated in this paper. The ongoing warming that started in the 1970s is extensively analyzed on the basis of the variability of the mean values and a magnitude index that captures both the duration and intensity of a spell and by investigating the frequency of extreme events by means of Intensity–Duration–Frequency curves. The periods with the greatest deviation from the climatological average are analyzed in detail: February 1740 and April 1755, the months with the largest negative and positive temperature anomalies, respectively, in the 300-year-long series. Moreover, the analysis of snow occurrences extracted from the original logs, together with the pressure observations from the long series of London and Uppsala, made it possible to evaluate the most typical synoptic situations leading to snow events in Padua for the whole period. Full article

Arctic Alaska is warming at twice the rate of the rest of the nation, severely impacting infrastructure built on permafrost. As winters warm, the effectiveness of thermosyphons used to stabilize foundations diminishes, increasing the risk of infrastructure failure. Because thermosyphons operate with the highest efficiency during winter cold snaps, studying the variation trends and patterns of winter cold snaps in Alaska is particularly important. To address this issue, this study analyzes the historical temperature data of four selected locations in Subarctic and Arctic Alaska, including Bethel, Fairbanks, Nome, and Utqiagvik. The winter cold snap is defined as a period when the average daily temperature drops below a specific site’s mean winter air temperature. The frequency, duration, and intensity of the winter cold snaps are computed to reveal their trends. The results indicate that the mean annual air temperature (MAAT) shows a warming trend, accompanied by sudden warming after 1975 for all study sites. The long-term average monthly air temperature also indicates that the most significant warming occurs in the winter months from December to March. While the frequencies of winter cold snaps remain relatively unchanged, the mean intensity and duration of cold snaps show a declining trend. Most importantly, the most intense cold snap during which the thermosyphons are the most effective is becoming much milder over time for all study sites. This study focuses specifically on the impact of changes in winter cold spells on thermosyphon effectiveness while acknowledging the complexity of other influencing factors, such as temperature differences, design features, coolant properties, and additional climatic parameters (e.g., wind speed, precipitation, and humidity). The data for this study were obtained from the NOAA NCEI website. The findings of this study can serve as a valuable reference for the retrofit or design of foundations and for decision making in selecting appropriate foundation stabilizing measures to ensure the long-term stability and resilience of infrastructure in permafrost regions. Moreover, the insights gained from this research on freeze–thaw dynamics, which are also relevant to black soils, align with the journal’s focus on sustainable soil utilization and infrastructure resilience. Full article

Recent studies have revealed a rise in extreme heat events worldwide, while extreme cold has reduced. It is highly likely that human-induced climate forcing will double the risk of exceptionally severe heat waves by the end of the century. Although extreme heat is expected to have more significant socioeconomic impacts than cold extremes, the latter contributes to a wide range of adverse effects on the environment, various economic sectors and human health. The present research aims to evaluate the contemporary spatio-temporal variations of extreme cold events in Southeastern Europe through the intensity–duration cold spell model developed for quantitative assessment of cold weather in Bulgaria. We defined and analyzed the suitability of three indicators, based on minimum temperature thresholds, for evaluating the severity of extreme cold in the period 1961–2020 across the Köppen–Geiger climate zones, using daily temperature data from 70 selected meteorological stations. All indicators show a statistically significant decreasing trend for the Cfb and Dfb climate zones. The proposed intensity–duration model demonstrated good spatio-temporal conformity with the Excess Cold Factor (ECF) severity index in classifying and estimating the severity of extreme cold events on a yearly basis. Full article

As a type of green stormwater infrastructure (GSI), stormwater parks play a crucial role in mitigating urban heat and managing stormwater, especially in subtropical monsoon climates where high temperatures and rainfall coincide. The benefits of microclimate improvement are associated with the specific surface types of stormwater parks. However, research on how different surfaces affect the microclimates of stormwater parks remains limited. This study utilized an unmanned aerial vehicle to investigate the surface temperature characteristics of blue–green–gray underlying surfaces within a stormwater park and employed multiple linear regression to analyze their impact on the microclimate. The results indicated that (1) blue underlying surfaces functioned as a stable cold source in dry periods but warmed quickly after rainfall. (2) Green surfaces consistently provided a cooling effect on the microclimate, with cooling intensity intricately related to vegetation structure. Specifically, the cooling effects of arbor–shrub–grass and arbor–shrub combinations were greater than those of other plant configurations. (3) The warming effect of gray underlying surfaces was affected by weather conditions and permeability, with pervious concrete exhibiting lower surface temperatures than impervious pavements during dry spells, although this difference diminished significantly after rain. These findings provide scientific evidence and design guidance for enhancing the sustainability of microclimates. Full article

The late spring cold spell severely affects the growth of litchi flower buds. Melatonin, as a signaling molecule, can enhance the plant’s ability to resist abiotic stress by regulating multiple physiological processes. However, there are few studies on the function of melatonin in litchi under cold stress. In the present study, 100 μM of melatonin was selected based on the ABA content in litchi seedlings. To identify genes potentially involved in melatonin and cold stress conditions in litchi, four RNA-seq libraries of litchi leaves under melatonin and cold conditions were constructed. In total, 6.4–8.5 Gb of trimmed bases were generated in each library. Thirty-five genes were randomly selected for qRT-PCR analysis. The results showed a strong positive correlation between the data from qRT-PCR and RNA-seq. A total of 4590 differentially expressed genes (DEGs) were identified in the treatment of melatonin (1845) and melatonin in cold condition (2745). The expression of several genes belonging to starch and sucrose metabolism, plant hormones (auxin, ABA), MAPK, and alpha-linolenic acid metabolism pathways were differentially expressed. The enhanced carbohydrate metabolism might lead to litchi seedlings treated with melatonin to produce more metabolic energy. Abscisic acid can improve cold tolerance. Collectively, our results reveal that pretreatment with melatonin (100 μM) protects litchi seedlings from cold stress through plant hormones and carbohydrate metabolism and provides potential genes for future research. Full article