Background Climate Research Articles

Assessing CMIP Models’ Ability to Detect Observed Surface Warming Signals Related to Climate Change

Abstract Assessing if CMIP models can detect observed climate change signals is crucial for evaluating their realism and strengthening confidence in future projections. These signals can only be compared once distinguishable from the background climate “noise.” Built for impact studies but not detection purpose, the time of emergence (ToE) estimates when this occurs using a fixed signal-to-noise ratio. To more accurately assess models’ ability to reproduce observed climate change signals, we introduce the time of detection (ToD), which employs a statistical significance test of the nonlinear trend, accounting for the time series length. ToD and ToE are computed for sea surface temperature (SST) and relative SST (RSST) across four observational and 69 CMIP5/6 historical and shared socioeconomic pathways 5–8.5 (SSP5–8.5) scenario datasets. ToD precedes ToE and is less sensitive to the chosen threshold. While already detectable in most of the tropics, SST warming in the equatorial Pacific is detectable in ∼90% of models but only one out of four observational datasets, due to a stronger modeled warming. Because RSST signals are weaker than SST signals, they do not emerge anywhere but are detectable in two regions. The enhanced warming in the western Indian Ocean, detected in ∼45% of models, is not robust in observations when excluding pre-1960 dubious data. Conversely, the subdued southeast Pacific warming detected in observations and ∼80% of models is robust and consistent with a poleward extension of the Southern Hemisphere Hadley cell. The ToD’s ability to detect subtle signals allows for assessing the realism of the CMIP warming pattern in this region. Significance Statement Recent studies emphasize the importance of the climate change warming pattern and its apparent discrepancy between climate models and observations in the equatorial Pacific. We argue that our newly proposed time of detection (ToD) is better suited than the well-known time of emergence (ToE) for investigating where modeled and observed warming patterns can be confidently compared. In agreement with previous studies, our analysis indicates model–observations disagreement over the equatorial Pacific. Using ToD instead of ToE allows for detecting a robust subdued warming (i.e., weaker than the tropical average) in the southeast Pacific and therefore confirms the realism of the CMIP warming pattern in this region.

A scaling law for predicting urban trees canopy cooling efficiency

Urban heat mitigation is a pressing concern for cities. Intense urban heat poses a threat to human health and urban sustainability. Tree planting is one of the most widely employed nature-based heat mitigation methods worldwide. Therefore, city policy makers require knowledge of how much temperature will be reduced by increasing urban tree canopy (UTC). Cooling efficiency (CE), which was been proposed to quantify the magnitude of temperature reduction associated with a 1% increase in UTC, has been primarily investigated at smaller scales previously. However, such small-scale results cannot be used to develop policy at the whole-city scale. This study developed a method that reveals the scaling relations of CE so as to predict its effects at the city scale. CE was found to follow the form of a power law as spatial scale increased from the small analytical units through intermediate size units up to the extent of a whole city. The power law form appeared consistently across cities with different climate backgrounds during summer daylight hours. Furthermore, the power law form was robust within cities under different summer weather conditions. The power-law scaling approach can thus be used to predict CE at the whole-city scale, providing a useful tool for managers to set UTC goals to mitigate extreme urban heat.

Late-Holocene hydroclimatic change and its effect on human activity at Xiada Co on the western Tibetan Plateau

The scarcity of paleoclimate records in the western Tibetan Plateau (TP) hinders our understanding of how environmental evolution affects past human population, agriculture, and animal husbandry. Here, we utilized a range of materials to investigate the impact of climate change on human activities in the Xiada Co basin on the western TP during the Late-Holocene. We presented a continuous compound-specific hydrogen isotope record of sedimentary leaf waxes (δ2Hwax) from a sediment core of Xiada Co, and compared it to XRF core-scanning elements, brGDGT-based mean annual air temperature (MAAT) record, and fecal stanol-based human population proxy record from the same sediment core, as well as archeological evidence from the TP. The δ2Hwax exhibited a sustained increasing trend during the period from 4700 to 900 cal yr BP, followed by a generalized decrease in δ2Hwax values during 900–0 cal yr BP. The multi-proxy analysis of Xiada Co sediments revealed that the δ2Hwax values mainly reflect changes in the ISM precipitation, and are also influenced to some extent by glacier meltwater. Furthermore, a warm and humid climate condition was conducive to human habitation. Appropriate adaptation strategies, such as the herding of cold-tolerant and dry-tolerant sheep and the cultivation of barley in the western TP, led to a surge in population density during 3400–2900 cal yr BP, despite the slightly deteriorated climate background. This study confirmed the importance of choosing the right adaptive strategies to cope with climate change for human survival and development on the Tibetan Plateau.

How was the impact of heatwaves on daily hospital admissions in Portugal (2000-2018)?

Abstract Background Climate change has increased the frequency, intensity, and duration of heatwaves, posing a serious threat to public health. While the link between high temperatures and premature mortality has been extensively studied, the comprehensive quantification of heatwave impacts on morbidity remains understudied. Methods We assessed the relationship between heatwaves and daily hospital admissions at a county level in Portugal, considering all major diagnostic categories and age groups, over a 19-year period from 2000 to 2018. Our nationwide study included a comprehensive geospatial analysis, integrating over 12 million hospital admission records with heatwave events indexed by the Excess Heat Factor (EHF), covering all 278 mainland counties. To estimate the impact of heatwaves on hospital admissions, we applied negative binomial regression models at both national and county levels. Results A statistically significant overall 18·9% increase in daily hospital admissions was found during heatwave days (IRR=1·189, 95% CI: 1·179-1·198). This impact affected all age groups, with pediatric ages being the most affected (21·7%), followed by the working-age (19·7%) and elderly individuals (17·2%). All 25 Major Disease Diagnostic Categories experienced significant increases, particularly Burns (34·3%), Multiple Significant Trauma (26·8%), and Infectious and Parasitic Diseases (25·4%). Notable rises were also observed in Endocrine, Nutritional, and Metabolic (25·1%), Mental (23%), Respiratory (22·4%), and Circulatory (15·8%) diseases. Conclusions Our results provide statistically significant evidence of the association between heatwaves and increased hospitalizations across all age groups and for all major causes of disease. This is the first study to estimate the full extent of heatwaves’ impact on hospitalizations using the EHF index over a comprehensive 19-year period, encompassing an entire country, and spanning 25 disease categories during multiple heatwave events. Key messages • There is a clear association between heatwaves and increased hospital admissions across all age groups and Major Diagnostic Categories. • Our data offer crucial information to guide policymakers in effectively and efficiently allocating resources to address the profound healthcare consequences resulting from climate change.

Exploring Climate Health Risks and Adaptations among Vulnerable Populations in Israel’s Negev Desert

Abstract Background Climate change represents the paramount challenge to global health, disproportionately impacting particular vulnerable individuals and communities. By identifying and elucidating disparities in health-related climate risks among these groups, we can facilitate the development of appropriate and equitable climate adaptation strategies. This research identified climate-related risks, health perceptions and needs, and behaviors among Jewish and Bedouin populations in the Negev Desert, a region highly susceptible to climate change, located at the intersection of geographical and social marginality. Methods Ten focus groups (n = 69) among vulnerable Jewish and Bedouin residents were conducted and systematically analyzed to identify disparities in health-related climate risks and behaviors. Vulnerabilities were defined based on income, age, health status, living environment, and outdoor activities. Results The findings highlight both shared and distinct difficulties and barriers vulnerable Jewish and Bedouin Negev residents face in the context of climate-related health risks. Key themes that emerged address: a) the direct and indirect impacts of climate-related events on health and well-being; b) the exacerbation of climate-related health risks by existing vulnerabilities and systemic barriers; c) the pivotal role of community resources in coping strategies; and d) lack of trust in the state and its institutions which underpin climate-related experiences. Conclusions The complexity of coping with climate change encompasses individual, community, and national/institutional levels. Vulnerable populations’ experiences with climate change are impacted by factors such as poverty, social marginality, violence, and barriers to accessing healthcare and other services, and is not a standalone phenomenon. Therefore, climate change adaptation and mitigation cannot be distinguished from other challenges impacting the health and well-being of populations. Key messages • Climate adaptation efforts must integrate with broader social and health strategies to effectively support vulnerable groups. • Community resources and trust in institutions are crucial for vulnerable populations facing climate change impacts.

Climate change and health topics in pre-university education in Kosovo: A Content Analysis

Abstract Background Climate health literacy (CHL), recommended and recognized as vital for the global response to climate change and impacts on health, lacks comprehensive studies on its integration into primary and secondary school curricula. In Kosovo, where numerous environmental issues already exist and are expected to worsen due to climate change, the resulting health outcomes pose significant challenges. Moreover, the low environmental knowledge among youth further adds to the complexity of addressing these issues. This study addresses this gap by focusing on understanding and enhancing the inclusion of climate change and health topics in pre-university education. Methods A content analysis was conducted on: (1) core curricula, (2) subject curricula, and (3) textbooks for pre-university education (grades 0-12) in Kosovo. The outcomes of the content analysis were then juxtaposed with the CHL framework to identify alignment and gaps. Results We found that curricula in Grades 0-5, contained one topic on climate change and health topic out of 638 (0.16%) topics documented; however, textbooks did not elucidate this focus. Grades 6-9 had 2 out of 701 (0.28%) and the relevant textbook revealed that various environmental and health topics are covered, but that they lack exploration of the interrelatedness between environmental pollution, climate change, and health. Grades 9-12 had the highest integration with 4 out of 745 (0.54%). Textbook analysis of these grades revealed a more in-depth coverage of climate change and health linkages. In total, seven topics out of a pool of over 2000 topics encompassed learning outcomes related to climate and health in Kosovo’s pre-university education. Conclusions The current efforts to integrate climate change and health into Kosovo’s curriculum fails to meet the recommendations for achieving CHL levels. Localized and context relevant additions are needed to fulfil CHL among students in Kosovo and other countries interested in improving CHL. Key messages • This case serves as a testing ground for a framework assessing climate health literacy within curricula. The results identify gaps and areas of improvement, which inform the implications to attain CHL. • Results reveal shortcomings in the incorporation of climate change and health topics in schools, underscoring the necessity for tailored strategies to foster CHL among students.

Review of national climate change risk assessment methods for impacts on health and health systems in WHO European Region

Abstract Background Climate change poses significant risks to health and health systems. The European Union climate adaptation strategy sets out the pathway to become climate resilient by 2050 and supports the development of adaptation strategies across all levels of governance. Whilst many European countries have published climate change risk assessments (CCRA), it is unclear to what extent health outcomes have been quantified or prioritised. There is a need to improve methods for CCRA methods to support decision making on adaptation and better quantify future impacts on health. The aim of this study is to review the methods used in national CCRAs for impacts on health and health systems in the WHO European region. Methods National and European level CCRAs were identified from national government websites and European document databases e.g. Climate-ADAPT. The most recently published CCRA from each country was included. Data extracted from CCRAs included climate scenarios used, modelling data, outcomes, types of evidence evaluated, stakeholder involvement, health information, methods for prioritization of adaptation options and urgency scoring. Data extracted from each document was grouped by climate risk or outcome. Results Nearly all WHO EURO countries have conducted a formal assessment of climate risks and over half specifically include risks to health. All countries assessed the urgency to adapt to heat and flooding however, less than half consider the health related risks related to disrupted water supply and quality as well as impacts on food supply and security. The key reported health outcomes identified across countries were mortality, infectious disease, chronic diseases and mental health. Conclusions There is varying progress in the quantification and prioritization of health risks from climate change across Europe. To support better public health decision-making, CCRAs should integrate sub-national and local information for targeted adaptation action.

Public perceptions of the health impacts of climate change: a survey study in Greece

Abstract Background Climate change is the biggest global health threat of the 21st century. Despite the tremendous challenges, many people remain unaware of the human health implications of climate change. People perceptions about the health harms of climate change can increase public support for the action needed to reduce climate change. The aim of this study was to examine the public perception of climate change as a human health issue in Greece. Methods A population survey study was conducted from October to December 2023 in the municipalities of Messini and Alexandroupoli, Greece, following proportional quota sampling. A questionnaire was developed and included measures about the socio-demographic background of participants, their understanding of key facts about climate change and their views about climate change thread to human health. Results 406 individuals with a mean age 37.7 (sd = 14.8) participated in the study. Participants understood that climate change is happening (93.6%) and 54% of them think climate change is mostly or entirely caused by human activities, whereas 38% think it is caused equally by human activities and natural causes, and about 8% think climate change is mostly or entirely caused by natural causes. A majority of participants reported that climate change has adversely affected the health of people in various way, either a moderate amount or a great deal, including physical or mental harm from forest fires (90%), physical or mental harm from storms and floods (87%), heat-related illnesses (82%), illness due to reduced outdoor air quality (70%) and loss of housing for residents displaced by extreme weather events (70%). Conclusions Participants viewed climate change as an important cause of health harm, however they partially understood that climate change is caused by humans. Public health authorities should educate the public and policymakers about the climate change and advocate for policies to address the human health challenges of climate change. Key messages • Public health authorities should educate the public and policymakers about the climate change problem and its impact to human health. • Providing people with information about the health harms of climate change can increase public support for the actions needed to reduce emissions.

Environmental impact analysis of ajmaline challenge protocols: a comparative assessment of carbon footprint reduction in Brugada Syndrome diagnosis

Abstract Background Climate change is an urgent public health crisis that significantly impacts disease development and health outcomes. The 2022 Lancet Countdown Report revealed that healthcare contributes with 5.2% of global emissions, prompting a call for environmentally conscious approaches. In this context, we explored the environmental impact of different ajmaline challenge protocols, aiming to contribute to a more sustainable medical landscape. Purpose This study aims to compare the carbon footprint of two ajmaline challenge protocols commonly used in diagnosing Brugada syndrome, an inherited cardiac disorder associated with sudden cardiac death. Methods We performed a retrospective and observational analysis of adult patients (pts) who underwent ajmaline testing between March 2020 and June 2023 in two hospitals. In Group A (infusion protocol), 1mg/kg of ajmaline diluted in 50 mL of 5% glucose solution was infused in 10 minutes, up to the target dose, until a positive result or termination criteria ensued. In Group B (bolus protocol), 10 mg of ajmaline were administered every 2 minutes, again up to the target dose of 1mg/kg (maximum of 100 mg) or test interruption was indicated. Greenhouse gas emissions resulting from material processing were estimated based on life cycle analyses of each product's composition. Material consumption, waste production, and direct measurement of weights were considered. Results A total of 101 pts were included, 49 pts in group A with a mean age of 47.3±14.3 years old and 52 patients in group B with a mean age of 43.9±16.6 years-old. No complications were observed in either group. Test performance was not evaluated, since both protocols have been previously validated. Group A, utilizing the infusion method, exhibited a higher environmental impact, producing 18.19 kg CO2eq, compared to 6.23 kg CO2eq (p<0.001) in Group B (bolus protocol). Group B not only demonstrated a 66% reduction in CO2eq emissions but also used significantly less plastic (16g vs 102g per test) and glass (1.58 kg vs 1,79Kg), emphasizing its environmental superiority. Conclusions Shifting from infusion to bolus in ajmaline challenge protocols results in a substantial reduction in carbon footprint. Our findings emphasize the potential impact of adopting more dematerialized approaches in cardiac testing, urging healthcare professionals to embrace sustainable practices. Despite the study's limited sample size, the global adoption of such environmentally friendly strategies promises significant positive effects on healthcare's environmental footprint.

A questionnaire to assess ecoanxiety and its sociodemographic determinants among Italian adolescents

Abstract Background Climate change poses serious challenges to Public Health, including mental health impacts. In Italy, few studies investigated the rise of eco-anxiety, especially among adolescents, who are the main group affected by this feeling. Specific measurement tools for this population are needed to fill this gap. The aim is to adapt the Italian version of the Climate Change Anxiety Scale (CCAS) to adolescents, and pair it with a socioeconomic and demographic questionnaire (SDQ) to assess determinants. Methods The Italian CCAS was modified for adolescents through a process involving a literature review, expert discussions, and a pretest. This adapted version (a-CCAS) was tested with individuals aged 14-18 years old, maintaining an ideal ratio of 10 respondents per item. Extant psychometric scales were utilized to assess its validity. The SDQ was developed from results of a systematic review of known associations between socioeconomic and demographic factors and eco-anxiety in youth, and expert discussions, and validated by piloting the SDQ with another sample of adolescents. Internal consistency of the a-CCAS and SDQ was assessed by Cronbach’s alpha (Cα). Results The a-CCAS kept most of its original content, comprising 13 items and 2 subscales: cognitive and functional impairment. Pilot respondents were 162; Cα coefficient was >0.7 for both subscales. Convergent and concurrent validity showed positive correlations with the extant scales. The SDQ comprised 12 items in 3 domains: family, social and political-environmental determinants. Respondents were 47 and Cα coefficient was >0.7. Conclusions The a-CCAS and SDQ are valid tools for assessing baseline eco-anxiety and its determinants in Italian adolescents and can contribute to Public Health efforts to reduce the climate-related mental health burden, by measuring the impact of specific educational interventions about climate change targeted at the young. This questionnaire was created as part of the PRIN P2022JJ3LB project. Key messages • These results contribute to filling an evidence gap on eco-anxiety and its socioeconomic and demographic determinants among Italian adolescents by providing researchers with a valid measurement tool. • This tool holds promise for assessing the impact of psychologically-informed educational interventions about climate change and adaptive coping strategies on adolescents’ eco-anxiety levels.

Heat-related risk in outdoor workers in the context of climate change: a systematic review

Abstract Background Climate change is one of the paramount challenges in the current global health setting. From an occupational health perspective, outdoor workers are amongst the most vulnerable populations to climate change and heat-related risk. A systematic review was performed, aiming to assess heat-related health outcomes in outdoor workers. Methods The research query was structured using the Population, Intervention, Comparison and Outcome (PICO) model, and including synonyms and Medical Subject Headings (MeSH) terms for the following keywords: “outdoor workers”, “climate change”, and “occupational risk”. The systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statements, screening three databases (PubMed, Web of Science, and Scopus). Results After duplicate removal and title and abstract screening, the final screening by full-text resulted in 10 included studies. The included studies were performed mostly on construction (included in 5 studies, 50.0%) and agriculture (in 5 studies, 50.0%) workers. Eight studies (80.0%) had a majority of male workers, while one (10.0%) had a majority of female workers, and one study (10.0%) did not report on the gender ratio. Four of the included studies (40.0%) reported a high prevalence of heat-related symptoms, ranging from 64.0% to 90.3% of workers. Three studies (30.0%) showcased a prevalence of heat-related symptoms in less than 50% of workers (ranging from 11.6% to 47.5%). Three studies (30.0%) evaluated odds ratio, highlighting an increased odds ratio of heat-related symptoms in outdoor workers. Conclusions This systematic review highlights heat-related stress in outdoor workers as an important occupational risk. Mitigation and prevention strategies should be developed and implemented at a company, national, and supra-national level, to ensure the safety and wellbeing of outdoor workers worldwide. Key messages • A systematic review was performed to assess risks related to climate change in outdoor workers. Heat-related symptoms were reported with a high prevalence, ranging from 64.0% to 90.3% of workers. • Mitigation and prevention strategies should be developed and implemented at a company, national, and supra-national level, to ensure the safety and wellbeing of outdoor workers worldwide.

Short-term effects of ambient temperature variability on myocardial infarction hospitalizations in Sweden: A nationwide case-crossover study

Abstract Background Climate change threatens human health and general welfare via multiple dimensions. However, the short-term effect of temperature variability, a crucial aspect of climate change, on myocardial infarction (MI) remains largely unexplored. Purpose We aimed to assess the short-term effects of temperature variability on MI hospitalizations within the nationwide SWEDEHEART registry. Methods This population-based nationwide study involved 228,897 MI patients from the SWEDEHEART registry in Sweden from 2005 to 2019. High-resolution (1 km × 1 km) daily mean ambient temperature was estimated using a spatiotemporal machine learning methodology and assigned to patients’ home addresses. Temperature variability was calculated as the difference between the same-day (as the MI event) ambient temperature and the average temperature recorded over the preceding seven days. Specifically, an upward temperature shift represents a rise in the current day’s temperature relative to the seven-day average, while a downward temperature shift indicates a corresponding decrease. A time-stratified case-crossover design incorporating a conditional logistic regression model with distributed lag non-linear model was applied to estimate the association between ambient temperature variability and total MI, ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI). Moreover, we assessed potential effect modification by sex and medication intake. The results were expressed as odds ratio (OR, with their 95% confidence intervals [CIs]) per 1°C increase in temperature variability. Results Our study found that a 1°C increase in upward temperature shift was significantly associated with increased risks for total MI, STEMI, and NSTEMI (OR [95% CI]: 1.010 [1.006-1.015], 1.014 [1.006-1.022], and 1.009 [1.004-1.014], respectively). Furthermore, a 1°C greater in downward temperature shift was significantly associated with decreased risks for total MI and NSTEMI (OR [95% CI]: 0.995 [0.991-0.999], and 0.993 [0.988-0.998], respectively). Moreover, we found that males and patients who were on any heart medication, particularly digitalis, were at a higher risk of MI associated with exposure to higher upward temperature shifts compared to females and their counterparts not taking these medications. Conclusions This nationwide case-crossover study provides novel evidence that short-term exposure to increasing upward temperature shift is associated with an increased risk of MI hospitalization. Our finding highlights the cardiovascular health threats posed by upward temperature shifts, which are anticipated to increase in frequency and intensity due to climate change.

Highly inhomogeneous interactions between background climate and urban warming across typical local climate zones in heatwave and non-heatwave days

Abstract Urban heat island (UHI) in conjunction with heatwave (HW) leads to exacerbation of thermal stress in urban areas. Prior research on UHI and HW has predominantly concentrated on examining the thermal conditions at the surface and near-surface, with few investigations extending to the radiative and dynamical interactions of UHI and HW, particularly with a focus on the inhomogeneities across local climate zones (LCZs). Here, we analyse the temperature disparity between HW and non-HW conditions across LCZs in the Sydney area by quantifying the contributions of individual radiative and dynamical processes using the coupled surface-atmosphere climate feedback-response analysis method (CFRAM). Three moist HW events in 2017, 2019, and 2020 are simulated using the Weather Research and Forecasting (WRF) model coupled with the single-layer urban canopy model (SLUCM). It is found that the maximum surface and 900 hPa temperature difference between HW and non-HW days may reach up to 10 K, with the increased net solar radiation during HWs being comparable to the typical level of anthropogenic heat flux in urban areas. It is also found that the reduction of clouds, the presence of vapour, and the increase of sensible heat contribute to the warming effect to various degrees, with the contribution of clouds being the most dominant. Conversely, the generation of dry convection and the increase of latent heat flux lead to cooling effects, with the latter being more dominant and capable of causing up to 10 K surface temperature difference between LCZ1 (compact high-rise) and LCZ9 (sparsely built). The differences in the contributions of climate feedback processes across different LCZs become more evident during more severe and humid HWs. These findings underscore the necessity of implementing LCZ-tailored heat mitigation strategies.

Cooling benefits from urban planting depend on local background canopy cover: A continental cross-city comparison

Numerous studies have shown that the cooling efficiency (CE) of urban trees varies by cities with different climate backgrounds, and recent research further indicated that there may be large within-city variations in CE. However, how such within-city variations differ across cities, and their relations to the local percent of urban tree canopy (Ptree) remain poorly understood. This study aims to fill this gap based on a comparison study across 118 cities with different biomes and climates in the continental USA. We used the tree canopy layer of the National Land Cover Dataset (NLCD) 2011 to measure urban tree canopy (UTC), and calculated land surface temperature (LST) based on Landsat thermal bands. We found: 1) CE had larger within-city and cross-city spatial variations in cities located in arid and semi-arid biomes. 2) CE was related to Ptree in nonlinear ways in >90 % of the study cities. In most cities (approximately 70 %), CE had an L-shaped relationship with Ptree, showing that CE first declined quickly with the increase of Ptree, but then gradually dropped in a slower way or became relatively stable after Ptree reached a certain threshold. 3) While there was no significant difference in the types of CE-Ptree relationship among biomes and climates, the threshold of Ptree in CE-Ptree nonlinear ways was smaller in arid cities. The results of this threshold linking cooling benefits and current UTC can serve as a useful tool to prioritize locations for urban planting to maximize cooling benefits.

Effects of Extreme Climatic Events on the Autumn Phenology in Northern China Are Related to Vegetation Types and Background Climates

The increased intensity and frequency of extreme climate events (ECEs) have significantly impacted vegetation phenology, further profoundly affecting the structure and functioning of terrestrial ecosystems. However, the mechanisms by which ECEs affect the end of the growing season (EOS), a crucial phenological phase, remain unclear. In this study, we first evaluated the temporal variations in the EOS anomalies in Northern China (NC) based on the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) from 2001 to 2018. We then used event coincidence analysis (ECA) to assess the susceptibility of EOS to four ECEs (i.e., extreme heat, extreme cold, extreme wet and extreme dry events). Finally, we examined the dependence of the response of EOS to ECEs on background climate conditions. Our results indicated a slight decrease in the proportion of areas experiencing extreme heat and dry events (1.10% and 0.66% per year, respectively) and a slight increase in the proportion of areas experiencing extreme wet events (0.77% per year) during the preseason period. Additionally, EOS exhibited a delaying trend at a rate of 0.25 days/a during the study period. The susceptibility of EOS to ECEs was closely related to local hydrothermal conditions, with higher susceptibility to extreme dry and extreme hot events in drier and warmer areas and higher susceptibility to extreme cold and extreme wet events in wetter regions. Grasslands, in contrast to forests, were more sensitive to extreme dry, hot and cold events due to their weaker resistance to water deficits and cold stress. This study sheds light on how phenology responds to ECEs across various ecosystems and hydrothermal conditions. Our results could also provide a valuable guide for ecosystem management in arid regions.

Winter snowpack loss increases warm-season compound hot-dry extremes

Ongoing warming intensifies snowpack extremes, posing significant hydroclimatic risks to socio-ecological systems. However, the relation between snowpack extremes and subsequent compound hydroclimatic extremes remains unclear. Here, we investigated the impact of snowpack extremes on warm-season compound hydroclimatic extremes in the Northern Hemisphere using multisource datasets from 1980 to 2022. We found widespread increases in deficient, short, and deficient-short snowpack extremes, triggering more compound hot-dry extremes within a month after snowpack disappearance (mean coincidence rate over 0.6, p < 0.05). The impact of compound snowpack extremes exceeded that of individual snowpack extremes in both areas (over 10%) and coincidence rates (over 0.2). Meanwhile, increased intensity, rather than frequency, of snowpack extremes drove mainly the occurrence of compound hydroclimatic extremes. Furthermore, background climate factors, followed by vegetation, topography, and soil, affected relations between snowpack and compound hydroclimatic extremes. These findings will deepen our understanding of the emerging consecutive extremes and improve their predictability.

Regionalization, Decomposition, and Information Mining for Precipitation: A Novel Framework Based on Multivariate SOM Clustering and Multiscale Features

Abstract Precipitation regionalization, serving as a foundation for extrapolating information from gauged to ungauged sites, contributes to a comprehensive understanding of the spatial distribution of precipitation. However, existing studies have focused mainly on precipitation, neglecting the influence of climate background and meteorological circulation. Moreover, there is a lack of specialized analysis of regionalization results. This study proposes a novel approach to precipitation regionalization that considers covariates in the circulation field and periodic features. The method utilizes Barnett–Preisendorfer canonical correlation analysis coupled with principal component analysis (BPCCA) to select covariates and multivariate self-organizing map (SOM) clustering for preliminary regionalization. Wavelet decomposition is further used for regional feature analysis. The methodology is empirically applied to analyze summer precipitation in Shanxi Province, identifying homogeneous regions characterized by diverse spatiotemporal distributions. The results successfully identified 12 distinct regions of precipitation, effectively capturing the influence of topographic and atmospheric factors. According to the periodic and trend characteristics of each region at different time scales, we merged the division results on the three frequencies and six regions were ultimately differentiated. Specifically, a decreasing trend was observed in the southern and southeastern parts of Shanxi, as well as in the western part of the Lüliang Mountains. They had a significant 4-yr period mode, and the decreasing trend was more significant in the southern region. In contrast, northern Shanxi showed no trend and a significant 8-yr period mode. This proposed method presents an effective strategy for enhancing precipitation regionalization and extracting valuable information from the circulation field and multiple frequencies.

No such thing as waste in primary food sector.

The European Union (EU) circular economy action plan aims to double its use of recycled material by 2030. We argue that waste-centric approach to resources may have adverse consequences to this ambition. The aim of the work was to find out the factors limiting or promoting the use of waste from primary food sector in countries with the same cultural background and similar climate in Estonia, Latvia, Lithuania and Norway. Biomass from the primary food production sector is of good quality and excellent to use, but its use may be limited if given waste status. From numerous management decision trigger clusters, which may affect valorisation of the biomass, we focus on technology and policy. Our semi-structured interviews addressed the analysis and management of waste or by-products and explored the end-of-waste and alternative mechanisms that allowed the biomass to be valorised. However, the interviews revealed that none of the companies regard anything becoming waste, but as raw material or production left-over. Any obstacles hypothesised turned out not to be acknowledged by companies at all. This appears to be a very good example of the use of resources, but the approach is haphazard and may conflict with official understanding and waste reporting requirements. Definition of waste is the same in the EU, and arbitrary treatment can be misleading. There is a need for better management of the material flow to ensure effective biomass circulation avoiding its becoming waste. We recommend that this be addressed by introducing environmental, social, governance and a self-control system.

Exploring maladaptive patterns of small-scale green roofs through evaluation in a capacity of heat mitigation: A case study in seoul

Climate change leads to more frequent and intense heat waves, exposing urban populations to extreme heat conditions and significant health risks. Many cities are adopting Nature-based Solutions (NbS) to mitigate urban heat, with green roofs emerging as a widely recognized NbS. Although numerous green roof projects are implemented on a small scale, research on the effectiveness of small-scale green roofs on an urban scale is limited, making it challenging to identify the critical factors for both maladaptation and success. Therefore, we assessed the cooling potential of 18 small-scale green roofs in Seoul, Republic of Korea. This comparative study that adopted a multi-site approach examined the cooling capacity of green roofs to reduce surface temperature and identified characteristics of effective and ineffective green roofs. We utilized a developed difference-in-differences method to improve causal inference, effectively isolating the effects of individual green roofs from background climate change. The multi-site comparative approach and more robust causal inference methods improved our understanding of the effects of small-scale green roofs. The findings of this study indicate that three out of 18 green roofs were statistically significant maladaptation cases with an increase in LST. This evidence can help an urban planner reduce ineffectiveness and enhance effective adaptation practices. Our proposed method is expected to support government projects, especially those with limited budgets, in efficiently managing urban heat and reducing trial and error.

Large-Scale Climate Modes Drive Low-Frequency Regional Arctic Sea Ice Variability

Abstract Summer Arctic sea ice is declining rapidly but with superimposed variability on multiple time scales that introduces large uncertainties in projections of future sea ice loss. To better understand what drives at least part of this variability, we show how a simple linear model can link dominant modes of climate variability to low-frequency regional Arctic sea ice concentration (SIC) anomalies. Focusing on September, we find skillful projections from global climate models (GCMs) from phase 6 of the Coupled Model Intercomparison Project (CMIP6) at lead times of 4–20 years, with up to 60% of observed low-frequency variability explained at a 5-yr lead time. The dominant driver of low-frequency SIC variability is the interdecadal Pacific oscillation (IPO) which is positively correlated with SIC anomalies in all regions up to a lead time of 15 years but with large uncertainty between GCMs and internal variability realization. The Niño-3.4 index and Atlantic multidecadal oscillation have better agreement between GCMs of being positively and negatively related, respectively, with low-frequency SIC anomalies for at least 10-yr lead times. The large variations between GCMs and between members within large ensembles indicate the diverse simulation of teleconnections between the tropics and Arctic sea ice and the dependence on the initial climate state. Further, the influence of the Niño-3.4 index was found to be sensitive to the background climate. Our results suggest that, based on the 2022 phases of dominant climate variability modes, enhanced loss of sea ice area across the Arctic is likely during the next decade. Significance Statement The purpose of this study is to better understand the drivers of low-frequency variability of Arctic sea ice. Teasing out the complicated relationships within the climate system takes a large number of examples. Here, we use 42 of the latest generation of global climate models to construct a simple linear model based on dominant named climate features to predict regional low-frequency sea ice anomalies at a lead time of 2–20 years. In 2022, these modes of variability happen to be in the phases most conducive to low Arctic sea ice concentration anomalies. Given the context of the longer-term trend of sea ice loss due to global warming, our results suggest accelerated Arctic sea ice loss in the next decade.