Extreme Winter Cold Research Articles

A statistical downscaling prediction model for winter temperature over Xinjiang based on the CFSv2 and sea ice forcing

AbstractBased on a year‐to‐year increment approach, a statistical downscaling model is developed for winter temperature prediction over Xinjiang of northwest China by using the predicted 200‐hPa westerly wind in winter over the Ural Mountains from the Climate Forecast System version 2 (CFSv2) as well as the observed sea ice over the Barents Sea–Laptev Sea in the preceding September. The statistical downscaling hindcasts on the 1983–2018 winter temperature over Xinjiang show that the statistical downscaling method has significantly improved the prediction capability compared with the original CFSv2. Specifically, the temporal correlation coefficients increase from negative to positive in most of Xinjiang, with the values passing the significance test at 90% confidence level at 81% of the stations. The regional averaged root‐mean‐square error reduces by more than 20%. In addition, the anomaly correlation coefficient increases from 0.08 to 0.26, passing the significance test at 95% confidence level. For two typical cases of the extreme cold winter in 2011 and the extreme warm winter in 2016, the spatial distribution characteristics of temperature anomaly are well reproduced, which are generally consistent with the observations. Overall, the statistical downscaling model based on the year‐to‐year increment strategy is a relatively effective method for predicting the winter temperature in Xinjiang.

Pre- and post-oviposition behavioural strategies to protect eggs against extreme winter cold in an insect with maternal care

Depositing eggs in an area with adequate temperature is often crucial for mothers and their offspring, as the eggs are immobile and therefore cannot avoid exposure to sub-optimal temperatures. However, the importance of temperature on oviposition site selection is less clear when mothers can avoid these potential adverse effects by both moving their eggs after oviposition and providing other forms of egg care. In this study, we addressed this question in the European earwig, an insect in which mothers care for the eggs during several months in winter, frequently moving them during this period. We set up 60 females from two random natural populations (as this species often exhibits population-specific life-history traits and behaviours) under controlled thermal gradients, and recorded the temperature at which they built their nests, tested whether they moved their eggs after an experimental temperature change, and measured the effects on egg development and hatching rate. Our results demonstrate that females indeed select oviposition sites according to temperature, and can move their eggs to reach warmer temperatures. We also show that these warmer temperatures are necessary to ensure egg hatching. Although this set of behavioural thermoregulations is present in the two tested populations, we found a population-specific modality of expression. These included the range of temperatures explored before oviposition, temperature selected at oviposition and dynamics of egg transport following a temperature change. Overall, our study sheds light on a new post-oviposition strategy in female insects that overwinter with their eggs for coping with temperature changes. More generally, it also reveals that egg care and/or egg transport do not prevent behavioural thermoregulation via oviposition site selection and highlights the diversity of behaviours that insects can adopt to enhance their tolerance to global climate change.

New insights into maternal egg care in insects: egg transport as an adaptive behavior to extreme temperatures in the European earwig

A recommendation of: Jean-Claude Tourneur, Claire Cole, Jess Vickruck, Simon Dupont, Joel Meunier Pre- and post-oviposition behavioural strategies to protect eggs against extreme winter cold in an insect with maternal care https://doi.org/10.1101/2021.11.23.469705

Energy affordability and trends of mortality in Cyprus

ABSTRACT Energy affordability and climatic variability are associated to human health and this study investigates their impacts on public health for Cyprus, an eastern Mediterranean island afflicted by extreme summer heat and cold winters, especially in the Troodos mountains. Energy poverty indicators are computed through statistical analysis of mortality data and household consumption information, the latter collected through a tailored survey. Results show that almost half of the survey participants spend large proportions of their incomes towards essential energy services. Moreover, ambient temperature is significantly linked to mortality, with a 20-fold higher risk of death in winter and a major shift in mortality noticed around 2013, following a severe financial crisis which exposed rural populations to a higher mortality risk.

Intelligent Reasoning Rules for Home Energy Management (IRRHEM): Algeria Case Study

Algeria is characterized by extreme cold in winter and high heat and humidity in summer. This leads to an increase in the use of electrical appliances, which has a negative impact on electrical energy consumption and its high costs, especially with the high price of electricity in Algeria. In this context, artificial intelligence can help to regulate the daily consumption of electricity, by optimizing the exploitation of natural resources and alerting the individual to avoid energy wasting. This paper proposes a decision-making tool (IRRHEM) for managing electrical energy at smart home. The IRRHEM solution is based on three elements: the use of natural resources, the notification of the inhabitants in case of resources misuse or wasting behavior, and the aggregation of similar activities at same time. Additionally, based on the proposed intelligent reasoning rules, residents’ behavior and activities are represented by OWL (Ontology Web Language) and written and executed through SWRL (Semantic Web Rule Language). Finally, the (IRRHEM) solution is tested in a home located in Algiers city inhabited by a family of four persons. The IRRHEM performance evaluation results are very promising and show a 3.60% rate of energy saving.

Temperature extremes and circulation types in the Czech Republic, 1961–2020

AbstractThis paper presents the characteristics of extreme temperatures in the Czech Republic, as calculated from homogenized series of daily maximum (TMAX) and daily minimum (TMIN) temperatures recorded by 133 climatological stations throughout the territory in the 1961–2020 period. In general, statistically significant increasing linear trends were recognized in series of absolute TMAX, absolute TMIN, numbers of summer days, tropical days, days with tropical nights, heat‐wave, and warm‐anomaly days. Significant decreasing linear trends appeared in series of numbers of frost days, ice days, cold‐wave, and cold‐anomaly days. Objective classification of circulation types demonstrated the importance of anticyclonic types (especially those with warm airflow from the southern quadrant) and an unclassified type in the development of summer hot extremes, while winter cold extremes were linked to cold (north‐)easterly advection. Significant changes in the frequency of certain circulation types emerged, as well as an increasing number of anticyclonic types conducive to hot extremes, a trend that contributed to their more frequent occurrence in recent decades. Existing trends in temperatures were complemented by spatiotemporal analysis of extreme temperatures, the characteristics of extremes and the circulation types in the two “normal” periods of 1961–1990 and 1991–2020. These exhibited significant differences in means and variances. The results obtained are also discussed in a broader context.

Real-time geographic settling of a hybrid zone between the invasive winter moth (Operophtera brumata L.) and the native Bruce spanworm (O. bruceata Hulst).

Hybridization plays an important and underappreciated role in shaping the evolutionary trajectories of species. Following the introduction of a non-native organism to a novel habitat, hybridization with a native congener may affect the probability of establishment of the introduced species. In most documented cases of hybridization between a native and a non-native species, a mosaic hybrid zone is formed, with hybridization occurring heterogeneously across the landscape. In contrast, most naturally occurring hybrid zones are clinal in structure. Here, we report on a long-term microsatellite data set that monitored hybridization between the invasive winter moth, Operophtera brumata (Lepidoptera: Geometridae), and the native Bruce spanworm, O. bruceata, over a 12-year period. Our results document one of the first examples of the real-time formation and geographic settling of a clinal hybrid zone. In addition, by comparing one transect in Massachusetts where extreme winter cold temperatures have been hypothesized to restrict the distribution of winter moth, and one in coastal Connecticut, where winter temperatures are moderated by Long Island Sound, we found that the location of the hybrid zone appeared to be independent of environmental variables and maintained under a tension model wherein the stability of the hybrid zone was constrained by population density, reduced hybrid fitness, and low dispersal rates. Documenting the formation of a contemporary clinal hybrid zone may provide important insights into the factors that shaped other well-established hybrid zones.

Effects of snow manipulation on larch trees in the taiga forest ecosystem in northeastern Siberia

Changes in winter precipitation (snow) may greatly affect vegetation by altering hydrological and biochemical processes. To understand the effects of changing snow cover depth and melt timing on the taiga forest ecosystem, a snow manipulation experiment was conducted in December 2015 at the Spasskaya Pad experimental larch forest in Eastern Siberia, which is characterized by a continental dry climate with extreme cold winters and hot summers. Variables including soil temperature and moisture, oxygen and hydrogen isotope ratios of soil moisture and stem water, foliar nitrogen and carbon contents and their isotopes, phenology, and soil inorganic nitrogen were observed at snow removal (SNOW−), snow addition (SNOW+), and CONTROL plots. After snow manipulation, the soil temperature at the SNOW− plot decreased significantly compared to the CONTROL and SNOW+ plots. At SNOW− plot, snowmelt was earlier and soil temperature was higher than at other plots during spring because of low soil moisture caused by less snowmelt water. Despite the earlier snowmelt and higher soil temperature in the SNOW− plot in the early growing season, needle elongation was delayed. Leaf chemistry also differed between the CONTROL and SNOW− plots. The needle nitrogen content in the SNOW− plot was lower in the middle of July, whereas no difference was observed among the three plots in August. The soil inorganic nitrogen content of each plot corresponded to these results. The amount of soil ammonium was lower in the SNOW− plot than in the other plots at the end of July, however, once production started in August, the amount of soil ammonium in the three plots was comparable. Extremely low soil temperatures in winter and freeze–thaw cycles in spring and dry soil condition in spring and early summer at the SNOW− plot may have influenced the phenology and production of soil inorganic nitrogen.

Long-term series demonstrate small-scale differences in trends within fish assemblages explained by climate variability

Over 30 years (1985–2018) of environmental monitoring data in the Belgian part of the North Sea allowed us to study common and individual species trends within three spatially distinct demersal and benthopelagic fish assemblages in relation to climate-related variability. A combination of multivariate (dynamic factor analysis) and univariate modelling techniques (Trendspotter and Spearman rank correlations) showed that the observed trends in fish densities in two coastal (mud and fine sand) assemblages were best explained by sea surface temperature (SST)-related variables and the Atlantic multidecadal oscillation winter index (AMOwinter). Higher fish densities seem to be linked with extreme cold winters in the year before (e.g. 1985, 1996, 2010), while warmer years may be linked to lower fish densities (fine sand assemblage) a few years later. Trends for the more offshore coarse sand fish assemblage were rather related to the North-Atlantic Oscillation index (NAO) (next to AMOwinter), coupled to the circulation and inflow of warmer saline waters through the English Channel. The temporal decrease in densities in this assemblage may partially reflect climate and subsequent biological regime shifts, as described for the broader North Sea region.At the species level, both positive, negative and varying trends in densities were noted, dependent on the fish assemblage. Overall, densities of most Lusitanean (warm water) species increased over the last decade, positively correlated with most SST-related variables and AMOwinter-values, indicating a northward expansion of their habitat range, which corroborates the findings of other studies. On the contrary, several Boreal (cold water) species were negatively correlated with SST and AMOwinter, with more or less stable trends in density between 1985 and 2000 followed by a decrease in the last decade, potentially explained by a relocation to deeper waters to cope with increasing seawater temperatures. For plaice Pleuronectes platessa, a commercially important species, a linear and significant decrease in length was observed over the 34-year period, most probably related to a combination of climatic influences and fishing induced selection. The current study shows that environmental, climate related drivers are important to explain part of the biological variability and should be taken into account when investigating the direct impact of human activities on the marine, demersal and benthopelagic ecosystem.

Nonlinear changes in cold spell and heat wave arising from Arctic sea-ice loss

Whether Arctic sea-ice loss has significant impacts on climate extremes in mid- and high-latitudes remains uncertain. Here we show the full response of cold and warm extremes under two Arctic sea-ice loss scenarios utilizing a coupled global climate model that permits the air-sea coupling. Our results show that the amount of Arctic sea-ice loss determines the spatial extent and magnitude of the weakening of atmospheric circulation in mid- and high-latitudes of the northern hemisphere, leading to nonlinear changes in cold and warm extremes. A relatively localized and moderate weakening of atmospheric circulation induced by the projected sea-ice loss in the next two decades would contribute to less winter cold extremes over the Northern Hemispheric continents. The risks of winter cold spells would be dramatically reduced as the amount of sea-ice loss is increased to the ice-free state. In contrast, as sea-ice loss increases, the continental regions would have increased risk of heat waves over all mid- and high-latitudes.

Links between atmospheric blocking and North American winter cold spells in two generations of Canadian Earth System Model large ensembles

Due to the significant negative consequences of winter cold extremes, there is need to better understand and simulate the mechanisms driving their occurrence. The impact of atmospheric blocking on winter cold spells over North America is investigated using ERA-Interim and NCEP-DOE-R2 reanalyses for 1981–2010. Initial-condition large-ensembles of two generations of Canadian Earth System Models (CanESM5 and its predecessor, CanESM2) are evaluated in terms of their ability to represent the blocking-cold spell linkage and the associated internal-variability. The reanalysis datasets show that 72 and 58% of cold spells in southern and northern North America coincide with blocking occurring in the high-latitude Pacific-North America. Compared to the two reanalyses, CanESM2 and CanESM5 ensembles underestimate by 19.9 and 14.3% cold spell events coincident with blocking, due to significant under-representation of blocking frequency over the North Pacific (− 47.1 and − 29.0%), whereas biases in cold spell frequency are relatively small (6.6 and − 4.7%). In the reanalyses, regions with statistically significant above-normal cold spell frequency relative to climatology lie on the east and/or south flanks of blocking events, whereas those with below-normal frequency lie along the core or surrounding the blocking. The two ensembles reproduce the observed blocking-cold spell linkage over North America, despite underestimating the magnitude of blocking frequency. The two ensembles also reproduce the physical drivers that underpin the blocking-cold spell linkage. Spatial agreement with the reanalyses is found in the simulated patterns of temperature advection and surface heat flux forcing anomalies during blocking events. While CanESM5 shows an improved representation of the blocking climatology relative to CanESM2, both yield similar results in terms of the blocking-cold spell linkage and associated internal-variability.

Tropicalization of temperate ecosystems in North America: The northward range expansion of tropical organisms in response to warming winter temperatures.

Tropicalization is a term used to describe the transformation of temperate ecosystems by poleward-moving tropical organisms in response to warming temperatures. In North America, decreases in the frequency and intensity of extreme winter cold events are expected to allow the poleward range expansion of many cold-sensitive tropical organisms, sometimes at the expense of temperate organisms. Although ecologists have long noted the critical ecological role of winter cold temperature extremes in tropical-temperate transition zones, the ecological effects of extreme cold events have been understudied, and the influence of warming winter temperatures has too often been left out of climate change vulnerability assessments. Here, we examine the influence of extreme cold events on the northward range limits of a diverse group of tropical organisms, including terrestrial plants, coastal wetland plants, coastal fishes, sea turtles, terrestrial reptiles, amphibians, manatees, and insects. For these organisms, extreme cold events can lead to major physiological damage or landscape-scale mass mortality. Conversely, the absence of extreme cold events can foster population growth, range expansion, and ecological regime shifts. We discuss the effects of warming winters on species and ecosystems in tropical-temperate transition zones. In the 21st century, climate change-induced decreases in the frequency and intensity of extreme cold events are expected to facilitate the poleward range expansion of many tropical species. Our review highlights critical knowledge gaps for advancing understanding of the ecological implications of the tropicalization of temperate ecosystems in North America.

Extreme winter cold-induced osmoregulatory, metabolic, and physiological responses in European seabass (Dicentrarchus labrax) acclimatized at different salinities

Despite climate-change challenges, for most aquaculture species, physiological responses to different salinities during ambient extreme cold events remain unknown. Here, European seabass acclimatized at 3, 6, 12, and 30 PSU were subjected to 20 days of an ambient extreme winter cold event (8 °C), and monitored for growth and physiological performance. Growth performance decreased significantly (p < 0.05) in fish exposed at 3 and 30 PSU compared to 6 and 12 PSU. During cold stress exposure, serum Na+, Cl−, and K+ concentrations were significantly (p < 0.05) increased in fish exposed at 30 PSU. Serum cortisol, glucose, and blood urea nitrogen (BUN) were increased significantly (p < 0.05) in fish exposed at 3 and 30 PSU. In contrast, opposite trends were observed for serum protein, lactate, and triglycerides content during cold exposure. Transaminase activities [glutamic-pyruvate transaminase (GPT), glutamic oxaloacetic transaminase (GOT), lactic acid dehydrogenase (LDH), gamma-glutamyl-transaminase (γGGT)] were significantly higher in fish exposed at 3 and 30 PSU on days 10 and 20. The abundance of heat shock protein 70 (HSP70), tumor necrosis factor-α (TNF-α), cystic fibrosis transmembrane conductance (CFTR) were significantly (p < 0.05) increased in fish exposed at 3 and 30 PSU during cold shock exposure. In contrast, insulin-like growth factor 1 (Igf1) expression was significantly lower in fish exposed at 3 and 30 PSU. Whereas, on day 20, Na+/K+ ATPase α1 and Na+/K+/Cl− cotransporter-1 (NKCC1) were significantly upregulated in fish exposed at 30 PSU, followed by 12, 6, and 3 PSU. Results demonstrated that ambient extreme winter cold events induce metabolic and physiological stress responses and provide a conceivable mechanism by which growth and physiological fitness are limited at cold thermal events. However, during ambient extreme cold (8 °C) exposure, European seabass exhibited better physiological fitness at 12 and 6 PSU water, providing possible insight into future aquaculture management options.

Opposing Trends of Winter Cold Extremes over Eastern Eurasia and North America under Recent Arctic Warming

Under recent Arctic warming, boreal winters have witnessed severe cold surges over both Eurasia and North America, bringing about serious social and economic impacts. Here, we investigated the changes in daily surface air temperature (SAT) variability during the rapid Arctic warming period of 1988/89–2015/16, and found the daily SAT variance, mainly contributed by the sub-seasonal component, shows an increasing and decreasing trend over eastern Eurasia and North America, respectively. Increasing cold extremes (defined as days with daily SAT anomalies below 1.5 standard deviations) dominated the increase of the daily SAT variability over eastern Eurasia, while decreasing cold extremes dominated the decrease of the daily SAT variability over North America. The circulation regime of cold extremes over eastern Eurasia (North America) is characterized by an enhanced high-pressure ridge over the Urals (Alaska) and surface Siberian (Canadian) high. The data analyses and model simulations show the recent strengthening of the high-pressure ridge over the Urals was associated with warming of the Barents–Kara seas in the Arctic region, while the high-pressure ridge over Alaska was influenced by the offset effect of Arctic warming over the East Siberian–Chukchi seas and the Pacific decadal oscillation (PDO)–like sea surface temperature (SST) anomalies over the North Pacific. The transition of the PDO-like SST anomalies from a positive to negative phase cancelled the impact of Arctic warming, reduced the occurrence of extreme cold days, and possibly resulted in the decreasing trend of daily SAT variability in North America. The multi-ensemble simulations of climate models confirmed the regional Arctic warming as the driver of the increasing SAT variance over eastern Eurasia and North America and the overwhelming effect of SST forcing on the decreasing SAT variance over North America. Therefore, the regional response of winter cold extremes at midlatitudes to the Arctic warming could be different due to the distinct impact of decadal SST anomalies.

Field Study on Adaptive Thermal Comfort in Naturally Ventilated Secondary School Buildings in Nepal

Most of the classroom in Nepalese school buildings are thermally less acceptable due to the poor thermal insulation. They are extreme cold in winter and extreme hot in summer season leading for the discomfort in classroom. Thermally uncomfortable classroom causes the negative impact in the academic performance of students. Therefore, there should be serious attention to improve the indoor thermal environment of classroom. There are limited indoor thermal environment studies conducted in Nepalese residential buildings but not at all in school buildings yet.&#x0D; This study investigated the students’ perceptions on thermal comfort inside the classroom of secondary school buildings during the autumn season of 2017 in a temperate climate (Dhading, Kathmandu and Nuwakot districts) of Nepal. 22 classrooms (33 students in average in each class) of 8 school buildings with a total of 818 students aged 12-18 years, 329 (40%) males and 489 (60%) females were participated in the survey. The two simultaneous surveys: questionnaire survey and thermal measurement survey were conducted during the regular lesson periods in each classroom. Students voted at the beginning, in the middle and at the end of the class in minutes’ lecture.&#x0D; About 76% responses were found to be in either of slightly cold, neutral or slightly hot. The results show that the comfort temperature of students was around 28 °C, 26°C and 24°C in Dhading, Kathmandu and Nuwakot districts, respectively. However, the mean comfort temperature and preferred temperature was found to be around 27 °C and 26 °C respectively. The findings of this study may hopefully invoke the awareness of the school building designers, teachers and students to maintain the thermally comfortable school buildings without using mechanical system.

U.S. HOUSEHOLD PREFERENCES FOR CLIMATE AMENITIES: DEMOGRAPHIC ANALYSIS AND ROBUSTNESS TESTING

We estimate how climate amenities influence where households decide to reside in the United States with two main objectives in mind: (i) to produce estimates with sufficient demographic detail to inform demographic population projections for use in climate impact analysis; (ii) to study the robustness of estimates from the existing literature. With respect to the former goal, we find important differences in job-related migration motives by age group and in the overall propensity to migrate among households with children. With respect to the latter aim, our framework shares a common methodological approach with other, recent attempts to recover climate preferences, allowing us to explore the consequences of a number of key assumptions in a systematic manner. Consistent with the existing literature, we find relatively robust estimates of the impact of the frequency of extreme heat days on household location decisions. The impacts of other common measures of climate, including the frequency of extreme cold days, average summer and winter temperatures, annual precipitation, humidity and frequency of sunshine, do not show a strong enough signal in the data to be estimated with precision.

Northern Hemisphere Winter Air Temperature Patterns and Their Associated Atmospheric and Ocean Conditions

AbstractThe Northern Hemisphere (NH) has experienced winter Arctic warming and continental cooling in recent decades, but the dominant patterns in winter surface air temperature (SAT) are not well understood. Here, a self-organizing map (SOM) analysis is performed to identify the leading patterns in winter daily SAT fields from 1979 to 2018, and their associated atmospheric and ocean conditions are also examined. Three distinct winter SAT patterns with two phases of nearly opposite signs and a time scale of 7–12 days are found: one pattern exhibits concurrent SAT anomalies of the same sign over North America (NA) and northern Eurasia, while the other two patterns show SAT anomalies of opposite signs between, respectively, NA and the Bering Sea, and the Kara Sea and East Asia (EA). Winter SAT variations may arise from changes in the SOM frequencies. Specifically, the observed increasing trends of winter cold extremes over NA, central Eurasia, and EA during 1998–2013 can be understood as a result of the increasing occurrences of some specific SAT patterns. These SOMs are closely related to poleward advection of midlatitude warm air and equatorward movements of polar cold airmass. These meridional displacements of cold and warm airmasses cause concurrent anomalies over different regions not only in SAT but also in water vapor and surface downward longwave radiation. Anomalous sea surface temperatures in the tropical Pacific, midlatitude North Pacific, and North Atlantic and anomalous Arctic sea ice concentrations also concur to support and maintain the anomalous atmospheric circulation that causes the SAT anomalies.

Beyond Smoking: Environmental Determinants of Asthma Prevalence in Western Nepal.

Background.Asthma is widely prevalent in Nepal, but the causes are not well known aside from some general associations with ambient air pollution and microbial exposures. Information on the wide-ranging determinants of asthma prevalence among the population at risk can help policy makers to reduce risk.Objective.The present study is a preliminary investigation of the environmental, socioeconomic and behavioral determinants of asthma prevalence in western Nepal.Methods.A survey was conducted among 420 randomly selected households in western Nepal. A cross-sectional analytical study design was employed with the primary data using econometric tools of probit and logistic regression.Results.Environmental variables such as extreme cold winter, deteriorating river water quality and air pollution were associated with an increase in asthma prevalence. However, individual or household characteristics such as advancing age of household head, use of pesticides in the home for the control of pests, piped drinking water with old pipes and lack of participation in awareness programs were associated with an increase in asthma prevalence.Discussion.Among environmental factors, decreasing river water quality, increasing air pollution, and extremely cold winters are more likely to contribute to asthma prevalence. In light of the effects of environmental factors on the prevalence of asthma in Nepal, the high public and private costs of asthma could further impoverish the rural poor.Conclusions.Environmental health policy makers should design adaptation strategies along with additional community programs addressing asthma-instigating factors. Programs to reduce environmental pollution can reduce morbidity due to asthma.Participant Consent.ObtainedEthics Approval.This study was approved by the Ethical Committee of the Nepal Health Research Council.Competing Interests.The authors declare no competing financial interests.

A novel holistic EPC related retrofit approach for residential apartment building renovation in Norway

This paper presents a novel Energy Performance Certification (EPC) related holistic building retrofit approach for a Norwegian apartment block built in 1980s. Based on the pre-combination principles of “Fabric priority”, “Renewable in supplement”, “Avoid complicated installation”, 11 energy retrofit measures (ERMs) were defined and combined into 18 typical retrofit combination packages (COMBs). Targeted simulations with the aim to explore the interconnected and coupled impacts of selected ERMs are performed in a dynamic simulation tool IES Virtual Environment (VE). A novel Energy Limiting Difference (ELD) assessment factor has been defined, which only considers the difference between primary and renewable energy consumption in the extreme cold winter and hot summer months. The post retrofit EPC standard for each COMBs are then linked with these ELD assessment factors respectively. The relationship between ELD assessment factors and the relevant EPC grades for the 18 COMBs is plotted and verified against the obtained EPC results. Without performing the simulation for each month in conventional retrofit approaches, this approach leads to at least 78 % reduced simulation efforts. This ELD-EPC related approach could therefore be used as useful guidelines for similar apartment building retrofits incorporating renewable energy measures in high-density areas in the cold climate region.

Weather extremes and perinatal mortality - Seasonal and ethnic differences in northern Sweden, 1800-1895.

BackgroundMany studies have shown the impact of heat and cold on total and age-specific mortality, but knowledge gaps remain regarding weather vulnerability of very young infants. This study assessed the association of temperature extremes with perinatal mortality (stillbirths and deaths in the first week of life), among two ethnic groups in pre-industrial northern Sweden.MethodsWe used population data of indigenous Sami and non-Sami in selected parishes of northern Sweden, 1800–1895, and monthly temperature data. Multiple logistic regression models were conducted to estimate the association of cold (<10th percentile of temperature) and warmth (>90th percentile) in the month of birth with perinatal mortality, adjusted for cold and warmth in the month prior birth and period, stratified by season and ethnicity.ResultsPerinatal mortality was slightly higher in Sami than in non-Sami (46 vs. 42 / 1000 live and stillbirths), but showed large variations across the region and over time. Both groups saw the highest perinatal mortality in autumn. For Sami, winter was a high-risk time as well, while for non-Sami, seasonality was less distinct. We found an association between exposure to cold and perinatal mortality among winter-born Sami [Odds ratio (OR) 1.91, 95% confidence interval (CI) 1.26–2.92, compared to moderate temperature], while there was little effect of cold or warmth during other seasons. Non-Sami, meanwhile, were affected in summer by warmth (OR 0.20, CI 0.05–0.81), and in autumn by cold (OR 0.39, CI 0.19–0.82).ConclusionsIn this pre-industrial, subarctic setting, the indigenous Sami’s perinatal mortality was influenced by extreme cold in winter, while non-Sami seemed to benefit from high temperature in summer and low temperature in autumn. Climate vulnerability of these two ethnic groups sharing the same environment was shaped by their specific lifestyles and living conditions.