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Background: Information about airborne pollen concentrations is required by a range of end users, particularly from the health sector who use both observations and forecasts to diagnose and treat allergic patients. Manual methods are the standard for such measurements but, despite the range of pollen taxa that can be identified, these techniques suffer from a range of drawbacks. This includes being available at low temporal resolution (usually daily averages) and with a delay (usually 3–9 days from the measurement). Recent technological developments have made possible automatic pollen measurements, which are available at high temporal resolution and in real time, although currently only scattered in a few locations across Europe. Materials & Methods: To promote the development of an extensive network across Europe and to ensure that this network will respond to end user needs, a stakeholder workshop was organised under the auspices of the EUMETNET AutoPollen Programme. Participants discussed requirements for the groups they represented, ranging from the need for information at various spatial scales, at high temporal resolution, and for targeted services to be developed. Results: The provision of real‐time information is likely to lead to a notable decrease in the direct and indirect health costs associated with allergy in Europe, currently estimated between €50–150 billion/year.1 Discussion & Conclusion: A European measurement network to meet end user requirements would thus more than pay for itself in terms of potential annual savings and provide significant impetus to research across a range of disciplines from climate science and public health to agriculture and environmental management. [ABSTRACT FROM AUTHOR]

In this study, we assess the skill of a stochastic weather generator (SWG) to forecast precipitation in several cities in western Europe. The SWG is based on a random sampling of analogs of the geopotential height at 500 hPa (Z500). The SWG is evaluated for two reanalyses (NCEP and ERA5). We simulate 100-member ensemble forecasts on a daily time increment. We evaluate the performance of SWG with forecast skill scores and we compare it to ECMWF forecasts. Results show significant positive skill score (continuous rank probability skill score and correlation) compared with persistence and climatology forecasts for lead times of 5 and 10 d for different areas in Europe. We find that the low predictability episodes of our model are related to specific weather regimes, depending on the European region. Comparing the SWG forecasts to ECMWF forecasts, we find that the SWG shows a good performance for 5 d. This performance varies from one region to another. This paper is a proof of concept for a stochastic regional ensemble precipitation forecast. Its parameters (e.g., region for analogs) must be tuned for each region in order to optimize its performance. [ABSTRACT FROM AUTHOR]

In this paper we present daily mean wind speed as a new variable in the publicly accessible E‐OBS gridded datasets. Each of the variables in the E‐OBS dataset is provided at a spatial resolution of 0.1° × 0.1° and 0.25° × 0.25°. The variable "daily mean wind speed" starts from 1980 and is updated every month. The main method that we apply is the use of adaptive covariate selection to model the monthly mean wind speed as a function of covariates, like altitude, distance to coast and surface roughness. Then, we use Gaussian process regression to interpolate the daily anomalies from the station locations to the grid locations. In addition, we develop ensemble dispersion improvement auto‐tune (EDIT) to improve the reliability of the local ensemble spread. In order to communicate the methodological uncertainty in the resulting dataset, the E‐OBS wind speed grid is provided as a 20‐member ensemble of random realizations. As part of a preliminary analysis, we investigate the hypothesized wind speed stilling effect in recent decades. Indeed, we do find a small yet significant wind speed stilling effect in the E‐OBS dataset. [ABSTRACT FROM AUTHOR]

Many countries have some kind of energy-system transformation either planned or ongoing for various reasons, such as to curb carbon emissions or to compensate for the phasing out of nuclear energy. One important component of these transformations is the overall reduction in energy demand. It is generally acknowledged that the domestic sector represents a large share of total energy consumption in many countries. Increased energy efficiency is one factor that reduces energy demand, but behavioral approaches (known as “sufficiency”) and their respective interventions also play important roles. In this paper, we address citizens’ heterogeneity regarding both their current behaviors and their willingness to realize their sufficiency potentials—that is, to reduce their energy consumption through behavioral change. We collaborated with three Swiss cities for this study. A survey conducted in the three cities yielded thematic sets of energy-consumption behavior that various groups of participants rated differently. Using this data, we identified four groups of participants with different patterns of both current behaviors and sufficiency potentials. The paper discusses intervention types and addresses citizens’ heterogeneity and behaviors from a city-based perspective. [ABSTRACT FROM AUTHOR]

Recently, much attention has been devoted to better understand the internal modes of variability of the climate system. This is particularly important in mid-latitude regions like the North-Atlantic, which is characterized by a large natural variability and is intrinsically difficult to predict. A suitable framework for studying the modes of variability of the atmospheric circulation is to look for recurrent patterns, commonly referred to as Weather Regimes. Each regime is characterized by a specific large-scale atmospheric circulation pattern, thus influencing regional weather and extremes over Europe. The focus of the present paper is the study of the Euro-Atlantic wintertime Weather Regimes in the climate models participating to the PRIMAVERA project. We analyse here the set of coupled historical simulations (hist-1950), which have been performed both at standard and increased resolution, following the HighresMIP protocol. The models' performance in reproducing the observed Weather Regimes is assessed in terms of different metrics, focussing on systematic biases and on the impact of resolution. We also analyse the connection of the Weather Regimes with the Jet Stream latitude and blocking frequency over the North-Atlantic sector. We find that—for most models—the regime patterns are better represented in the higher resolution version, for all regimes but the NAO-. On the other side, no clear impact of resolution is seen on the regime frequency of occurrence and persistence. Also, for most models, the regimes tend to be more tightly clustered in the increased resolution simulations, more closely resembling the observed ones. However, the horizontal resolution is not the only factor determining the model performance, and we find some evidence that biases in the SSTs and mean geopotential field might also play a role. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to introduce the official statement of the Fifth European Conference on Health-Promoting Schools. Design/methodology/approach: The Fifth European Conference on Health-Promoting Schools was held on 20–22 November 2019 in Moscow, Russian Federation, with over 450 participants from 40 countries. A writing group was established to prepare a draft version of the statement before the conference. On the basis of an online and offline feedback process, the opinions of the participants were collected during the conference and included in the finalisation of the statement. Findings: The final conference statement comprises six thematic categories (values and principles; environment, climate and health; schools as part of the wider community; non-communicable diseases (NCDs); evidence base; and digital media), with a total of 23 recommendations and calls for action. Originality/value: The recommendations and calls for action reflect current challenges for Health Promoting Schools in Europe. They are addressed to all actors in governmental, non-governmental and other organisations at international, national and regional levels involved in health promotion in schools and are to be applied for the further development of the concept. [ABSTRACT FROM AUTHOR]

How climate change will unfold in the years to come is a central topic in today's environmental debate, in particular at the regional level. While projections using large ensembles of global climate models consistently indicate a future decrease in summer precipitation over southern Europe and an increase over northern Europe, individual models substantially modulate these distinct signals of change in precipitation. So far model improvements and higher resolution from regional downscaling have not been seen as able to resolve these disagreements. In this paper we assess whether 2 decades of investments in large ensembles of downscaling experiments with regional climate model simulations for Europe have contributed to a more robust model assessment of the future climate at a range of geographical scales. We study climate change projections of European seasonal temperature and precipitation using an ensemble-suite comprised by all readily available pan-European regional model projections for the twenty-first-century, representing increasing model resolution from ~ 50 to ~ 12 km grid distance, as well as lateral boundary and sea surface temperature conditions from a variety of global model simulations. Employing a simple scaling with global mean temperature change we identify emerging robust signals of future seasonal temperature and precipitation changes also found to resemble current observed trends, where these are judged to be statistically significant. [ABSTRACT FROM AUTHOR]

Foresters from many countries are seeking for tree species or provenances able to cope with expected climate change. While it becomes clear that some temperate tree species will increasingly suffer from climate warming, the fate of the ecologically and economically important silver fir (Abies alba Mill.) remains uncertain and debated because the ecological requirements of this species, as well as its resilience to drought, are still unclear. On the one hand, paleoecological studies reveal that this species was widely distributed under much warmer climate, suggesting a high potential to cope with ongoing and future climate warming. On the other hand, species distribution models generally predict a strong decline of its climatic suitability in the future. This paper aims to clarify the potential of this species to thrive in central and western Europe under predicted climate warming by reviewing the knowledge gained from different fields. Based on insight from different fields, we argue that silver fir has a great potential to thrive under warmer conditions in western and central Europe provided sufficient rainfall, as forecasted by climate models for most regions by 2100. For instance, dendroecological studies demonstrate that silver fir is more resistant and resilient to drought compared to co-occurring species such as Norway spruce, European beech and larch. The most prominent obstacle for increasing the proportion of fir in mixed forests nowadays is ungulate browsing that often prevents its upgrowth. [ABSTRACT FROM AUTHOR]

This paper investigates how former hunter-gatherers living along the southern North Sea coast in NW Europe adapted to long-term and short-term climatic and environmental changes at the beginning of the Holocene. It is argued that contemporaneous hunter-gatherers repeatedly changed their hunting equipment in response to changing climate and environment, not just for functional reasons but mainly driven by socio-territorial considerations. Based on a Bayesian analysis of 122 critically selected radiocarbon dates a broad chronological correlation is demonstrated between rapid changes in the design and technology of stone projectiles and short but abrupt cooling events, occurring at 10.3, 9.3 and 8.2 ka cal BP. Combined with the rapid sea level rises and increased wildfires these climatic events probably impacted the lifeways of hunter-gatherers in such a way that they increasingly faced resource stress and competition, forcing them to invest in the symbolic defense of their social territories. [ABSTRACT FROM AUTHOR]

Cities are major drivers of environmental change at all scales and are especially at risk from the ensuing effects, which include poor air quality, flooding and heat waves. Typically, these issues are studied on a city-by-city basis owing to the spatial complexity of built landscapes, local topography and emission patterns. However, to ensure knowledge sharing and to integrate local-scale processes with regional and global scale modelling initiatives, there is a pressing need for a world-wide database on cities that is suited for environmental studies. In this paper we present a European database that has a particular focus on characterising urbanised landscapes. It has been derived using tools and techniques developed as part of the World Urban Database and Access Portal Tools (WUDAPT) project, which has the goal of acquiring and disseminating climate-relevant information on cities worldwide. The European map is the first major step toward creating a global database on cities that can be integrated with existing topographic and natural land-cover databases to support modelling initiatives. [ABSTRACT FROM AUTHOR]

Timely forecasts of the onset or possible evolution of droughts are an important contribution to mitigate their manifold negative effects. In this paper we therefore analyse and compare the performance of the first month of the probabilistic extended range forecast and of the seasonal forecast from the European Centre for Medium-range Weather Forecasts (ECMWF) in predicting droughts over the European continent. The Standardized Precipitation Index (SPI- 1) is used to quantify the onset or likely evolution of ongoing droughts for the next month. It can be shown that on average the extended range forecast has greater skill than the seasonal forecast, whilst both outperform climatology. No significant spatial or temporal patterns can be observed, but the scores are improved when focussing on large-scale droughts. In a second step we then analyse several different methods to convert the probabilistic forecasts of SPI into a Boolean drought warning. It can be demonstrated that methodologies which convert low percentiles of the forecasted SPI cumulative distribution function into warnings are superior in comparison with alternatives such as the mean or the median of the ensemble. The paper demonstrates that up to 40% of droughts are correctly forecasted one month in advance. Nevertheless, during false alarms or misses, we did not find significant differences in the distribution of the ensemble members that would allow for a quantitative assessment of the uncertainty. [ABSTRACT FROM AUTHOR]

Background: Physical inactivity is a major public health concern, exacerbated in countries with a (sub)tropical climate. The built environment can facilitate physical activity; however, current evidence is mainly from North American and European countries with activity-friendly climate conditions. This study explored associations between built environment features and physical activity in global tropical or subtropical dry or desert climate regions. Methods: A systematic review of four major databases (Web of Science, Scopus, PubMed, and SportDISCUS) was performed. To be included, studies had to investigate associations between perceived or objective built environment characteristics and adult's physical activity and had to be conducted in a location with (sub)tropical climate. Each investigated association was reported as one case and results were synthesized based upon perceived and objectively assessed environment characteristics as well as Western and non-Western countries. Study quality was evaluated using a tool designed for assessing studies on built environment and physical activity. Results: Eighty-four articles from 50 studies in 13 countries with a total of 2546 built environment-physical activity associations were included. Design (connectivity, walking/cycling infrastructure), desirability (aesthetics, safety), and destination accessibility were the built environment characteristics most frequently associated with physical activity across the domains active transport, recreational physical activity, total walking and cycling, and moderate-to-vigorous physical activity, particularly if multiple attributes were present at the same time. Very few studies assessed built environment attributes specifically relevant to physical activity in (sub)tropical climates. Most studies were conducted in Western countries, with results being largely comparable with non-Western countries. Findings were largely generalizable across gender and age groups. Results from natural experiments indicated that relocating to an activity-friendly neighborhood impacted sub-groups differently. Conclusions: Built environment attributes, including destination accessibility, connectivity, walking and cycling infrastructure, safety, and aesthetics, are positively associated with physical activity in locations with (sub)tropical climate. However, few studies focus on built environment attributes specifically relevant in a hot climate, such as shade or indoor recreation options. Further, there is limited evidence from non-Western countries, where most of the urban population lives in (sub)tropical climates. Policy makers should focus on implementing activity-friendly environment attributes to create sustainable and climate-resilient cities. [ABSTRACT FROM AUTHOR]

The acquisition and dissemination of essential information for understanding global biogeochemical interactions between the atmosphere and ecosystems and how climate–ecosystem feedback loops may change atmospheric composition in the future comprise a fundamental prerequisite for societal resilience in the face of climate change. In particular, the detection of trends and seasonality in the abundance of greenhouse gases and short-lived climate-active atmospheric constituents is an important aspect of climate science. Therefore, easy and fast access to reliable, long-term, and high-quality observational environmental data is recognised as fundamental to research and the development of environmental forecasting and assessment services. In our opinion article, we discuss the potential role that environmental research infrastructures in Europe (ENVRI RIs) can play in the context of an integrated global observation system. In particular, we focus on the role of the atmosphere-centred research infrastructures ACTRIS (Aerosol, Clouds and Trace Gases Research Infrastructure), IAGOS (In-service Aircraft for a Global Observing System), and ICOS (Integrated Carbon Observation System), also referred to as ATMO-RIs, with their capabilities for standardised collection and provision of long-term and high-quality observational data, complemented by rich metadata. The ATMO-RIs provide data through open access and offer data interoperability across different research fields including all fields of environmental sciences and beyond. As a result of these capabilities in data collection and provision, we elaborate on the novel research opportunities in atmospheric sciences which arise from the combination of open-access and interoperable observational data, tools, and technologies offered by data-intensive science and the emerging collaboration platform ENVRI-Hub, hosted by the European Open Science Cloud (EOSC). [ABSTRACT FROM AUTHOR]

Atmospheric waveguides have been linked to amplified atmospheric Rossby waves and therefore to extreme weather events in the mid-latitudes. Waveguides have often been calculated on zonal-mean data, and/or on timescales of a month or longer. Here, I develop an objective algorithm to detect barotropic waveguides, and create a dataset of time- and spatially-varying waveguides in both summer and winter for both the Northern and Southern Hemisphere (NH/SH), including a metric of waveguide depth. In this dataset, waveguides for waves of zonal wavenumber 5 exist in the extra-tropics on more than 40 % of days across many longitudes, with the frequency of occurrence reducing for higher zonal wavenumbers. Waveguides tend to be more frequent, and deeper, in summer than in winter, and more frequent in the NH than the SH. Composites of days with high spatial mean waveguide depth over particular regions show a double jet structure associated with strong waveguide occurrence, consistent with previous research. Significant positive correlations exist between waveguide depth and the presence/strength of quasi-stationary waves. In the SH these correlations are strong across much of the mid-latitudes in both seasons, whilst in the NH significant correlations are found only over the Atlantic, Europe and Asia during NH summer, with the strongest correlations over the Atlantic and western Europe, a region notable for its strong positive trend in extreme heat temperature events in recent decades. [ABSTRACT FROM AUTHOR]

Large hail (greater than 2 cm in diameter) can cause devastating damage to crops and property and can even cause loss of life. Because hail reports are often collected by individual countries, constructing a Europe-wide large-hail climatology has been challenging to date. However, the European Severe Storm Laboratory's European Severe Weather Database provides the only pan-European dataset for severe convective-storm reports. The database is comprised of 62 053 large-hail reports from 40 CE to September 2020, yet its characteristics have not been evaluated. Thus, the purpose of this study is to evaluate hail reports from this database for constructing a climatology of large hail. For the period 2000–2020, large-hail reports are most prominent in June, whereas large-hail days are most common in July. Large hail is mostly reported between 13:00–19:00 local time, a consistent pattern since 2010. The intensity, as measured by maximum hail size, shows decreasing frequency with increasing hailstone diameter and little change over the 20-year period. The quality of reports by country varies, with the most complete reporting being from central European countries. Thus, results suggest that despite its short record, many indications point to the dataset representing some reliable aspects of the European large-hail climatology, albeit with some limitations. [ABSTRACT FROM AUTHOR]

Heterogeneous radiative forcing in mid-latitudes, such as that exerted by aerosols, has been found to affect the Arctic climate, though the mechanisms remain debated. In this study, we leverage Deep Learning (DL) techniques to explore the complex response of the Arctic climate system to local radiative forcing over Europe. We conducted sensitivity experiments using the Max Planck Institute Earth System Model (MPI-ESM1.2) coupled with atmosphere-ocean–land surface components. Utilizing a DL-based clustering method, we classify atmospheric circulation patterns in a lower-dimensional space, focusing on Poleward Moist Static Energy Transport (PMSET) as our primary parameter. We developed a novel method to analyze the circulation patterns' contributions to various climatic parameter anomalies. Our findings indicate that the negative forcing over Europe alters existing circulation patterns and their occurrence frequency without introducing new ones. Specifically, we identify changes in a circulation pattern with a high-pressure system over Scandinavia as a key driver for reduced Sea Ice Concentration (SIC) in the Barents-Kara Sea during autumn. This circulation pattern also influences middle atmospheric dynamics, although its contribution is relatively minor compared to other circulation patterns that resemble the phases of the North Atlantic Oscillation (NAO). Our multidimensional approach combines DL algorithms and human expertise to offer a novel analytical tool that could have broader applications in climate science. [ABSTRACT FROM AUTHOR]

The present paper evaluates the alteration of certain night-time climate indices namely warm nights (Tmin > 17 °C) and tropical nights (Tmin ≥20 °C) during the 21st century in the city of Szeged. This examination was performed within the framework of a project founded by International Visegrad Fund, where the change of more climate indices were examined in several Central European cities. In this study the MUKLIMO_3 microclimatic model was used, which ensured the modelling of the local scale processes in the examined area. In the model for the land use we applied the Local Climate Zone (LCZ) system. In order to analyze longer periods the cuboid method was applied, which is a dynamical-statistical downscaling technique. We calculated the indices for 1981-2010 based on measurements and for 2021-2050 and 2071-2100 from the EURO-CORDEX datasets. In this study we present the results of Representative Concentration Pathways (RCP) scenarios namely RCP 4.5 and RCP 8.5. Our results show that highest values appear in the city centre and the number of the days clearly increases in the 21st century especially according to scenario RCP 8.5. The values depend on the built-up types and there are more days towards to the densely built-up LCZs. Moreover, considering the relative changes of the zones, larger values appear in sparsely built-up zones and natural surfaces. [ABSTRACT FROM AUTHOR]

Climate change impacts are already happening through the world, and it is now clear that there is the need for an adaptive response from global institutions down to the local level. Reducing vulnerability to cope with climate variability might be more challenging in tropical countries than in North America or Europe. The ten papers of this special issue were presented during the Adaptclim conference that was held by the Sinergia Project, the CLARIS LPB project, and the GeoData Institute in Asunción, Paraguay, in 2010. All papers, except one regarding the Brahmaputra Basin in South Asia, present studies from South America. These studies are first contextualized geographically and then are related one to another by a simplified vulnerability concept linking climate stress to sensitivity and adaptive capacity of natural and human systems. One half of the papers focus on actual or future climate change and the present-day causes of the vulnerability of natural and agrosystems. Droughts are and will be the main source of stress for agriculture in South America. Increasing fragmentation of forest of the center of this continent is aggravating their vulnerability to dry spells. Another half of the studies of this special issue deal with the adaptive capacity human populations to system perturbations produced or enhanced by climate change. The studies point out inclusion of traditional knowledge and involvement of local actors in their own vulnerability assessment to increase adaptive capacity. These elements of climate justice, giving voice to those less responsible for carbon emissions but bearing their most severe consequences, allow the particular needs of a community to be considered and can direct adaptation policy toward preserving or rebuilding their specific capabilities under threat from climate change. The special issue also made clear that a basin analysis of the climate change problem could provide information, results, and methods more readily of use for the local population and decision makers. [ABSTRACT FROM AUTHOR]

This paper presents a novel data set of regional climate model simulations over Europe that significantly improves our ability to detect changes in weather extremes under low and moderate levels of global warming. The data set provides a unique and physically consistent data set, as it is derived from a large ensemble of regional climate model simulations. These simulations were driven by two global climate models from the international HAPPI consortium. The set consists of 100 × 10-year simulations and 25 × 10-year simulations, respectively. These large ensembles allow for regional climate change and weather extremes to be investigated with an improved signal-to-noise ratio compared to previous climate simulations. The changes in four climate indices for temperature targets of 1.5 °C and 2.0 °C global warming are quantified: number of days per year with daily mean near-surface apparent temperature of > 28 °C (ATG28); the yearly maximum 5-day sum of precipitation (RX5day); the daily precipitation intensity of the 50-yr return period (RI50yr); and the annual Consecutive Dry Days (CDD). This work shows that even for a small signal in projected global mean temperature, changes of extreme temperature and precipitation indices can be robustly estimated. For temperature related indices changes in percentiles can also be estimated with high confidence. Such data can form the basis for tailor-made climate information that can aid adaptive measures at a policy-relevant scales, indicating potential impacts at low levels of global warming at steps of 0.5 °C. [ABSTRACT FROM AUTHOR]

Hailstorms represent one of the major sources of damage and insurance loss to residential, commercial, and agricultural assets in several parts of Central Europe. However, there is little knowledge of hail risk across Europe beyond local historical damage reports due to the relative rarity of severe hail events and the lack of uniform detection methods. Here we present a new stochastic catalog of hailstorms for Europe. It is based on satellite observations of overshooting cloud tops (OT) that indicate very strong convective updrafts and hail reports from the European Severe Weather Database (ESWD). Historic hail events are defined based on OT detections from satellite infrared brightness temperatures between 2004 and 2011 for the warm seasons (April-September). The satellite-based historical event properties are complemented by hailstone observations from ESWD to stochastically simulate more than 1 million individual events with an event footprint resolution of 10 km. The final hail event catalog presented in this paper is the first one with a spatial event distribution that is based on a single homogeneous observation source over Europe. Areas of high hail probability or hail risk are found over Central and Southern Europe, including mountainous regions such as the Alps or the Pyrenees. Another region of relatively high hail risk is present over central Eastern Europe. [ABSTRACT FROM AUTHOR]

Cities are gaining prominence committing to respond to the threat of climate change, e.g., by developing local climate plans or strategies. However, little is known regarding the approaches and processes of plan development and implementation, or the success and effectiveness of proposed measures. Mainstreaming is regarded as one approach associated with (implementation) success, but the extent of integration of local climate policies and plans in ongoing sectoral and/or development planning is unclear. This paper analyses 885 cities across the 28 European countries to create a first reference baseline on the degree of climate mainstreaming in local climate plans. This will help to compare the benefits of mainstreaming versus dedicated climate plans, looking at policy effectiveness and ultimately delivery of much needed climate change efforts at the city level. All core cities of the European Urban Audit sample were analyzed, and their local climate plans classified as dedicated or mainstreamed in other local policy initiatives. It was found that the degree of mainstreaming is low for mitigation (9% of reviewed cities; 12% of the identified plans) and somewhat higher for adaptation (10% of cities; 29% of plans). In particular horizontal mainstreaming is a major effort for local authorities; an effort that does not necessarily pay off in terms of success of action implementation. This study concludes that climate change issues in local municipalities are best tackled by either, developing a dedicated local climate plan in parallel to a mainstreamed plan or by subsequently developing first the dedicated and later a mainstreaming plan (joint or subsequent "dual track approach"). Cities that currently provide dedicated local climate plans (66% of cities for mitigation; 26% of cities for adaptation) may follow-up with a mainstreaming approach. This promises effective implementation of tangible climate actions as well as subsequent diffusion of climate issues into other local sector policies. The development of only broad sustainability or resilience strategies is seen as critical. • Trends in mainstreaming climate change issues were analyzed for 885 cities EU-28. • EU cities provide numerous local mitigation (#664) and/or adaptation (#321) plans. • Mainstreaming was investigated as vertical and horizontal approach. • 9% of cities have mainstreamed mitigation LCP; 12% of mitigation LCPs mainstreamed. • 10% of cities have mainstreamed adaptation LCP; 29% of adaptation LCPs mainstreamed. [ABSTRACT FROM AUTHOR]

Abstract The field of quantitative palaeoclimatology has made significant progress in the past decades. However, this progress has been spatially heterogeneous and strong discrepancies – both in terms of quality and density – exist between Europe and North America and the rest of the world. The need to balance this distribution of quantified records has never been stronger, and improving our understanding of past global climate is urgent in order to better evaluate and employ the predictions of climate models. In this paper, it is argued that this gap can be reduced by applying the climate reconstruction method CREST (Climate REconstruction SofTware) calibrated using the open-access GBIF (Global Biodiversity Information Facility) database, which contains hundreds of thousands modern distributions of numerous bio-indicator proxies (e.g. pollen, chironomids, foraminifers, etc.). Using the taxonomical diversity of the GBIF database, CREST can be used to reconstruct various climate and/or environmental parameters from assemblage variety of different records. Independent from the usual reconstruction techniques using surface samples for calibration, the CREST/GBIF framework can also be used as an independent tool that can be easily and efficiently applied (1) to complete the global coverage of climate reconstructions, as exemplified with a precipitation reconstruction from Lake Van, Turkey, (2) to revisit existing data sets to obtain new quantitative reconstructions, and (3) to evaluate and/or refine reconstructions based on other methods. The application of this tool promises to foster advances in our understanding of the past climate variability of the Earth system at a global scale. Highlights • A new, globally applicable probabilistic tool to quantitively reconstruct past climates. • The calibration dataset contains the distributions of multiple palaeoclimatic bio-indicators. • Understudied regions can now be explored using the CREST/GBIF framework. • A dedicated software exists to facilitate the use of the CREST/GBIF framework. [ABSTRACT FROM AUTHOR]

Lightning is one of the leading causes of weather-related fatalities worldwide and also has a strong impact on atmospheric chemistry (i.e., NOx production). Lightning can also lead to power system breakdowns, ignite forest fires, damage wind turbine and lead to perturbation of transportation, in particular to aviation. Thus, knowing when, where lightning strike and which atmospheric environments are more frequently associated with lightning is important. Furthermore, given the increase in the population density in recent decades (i.e., more people are exposed to lightning) and the increased urbanization (i.e., cities are getting larger and thus are more exposed to lightning) is essential to understand the spatial and temporal distribution of storm producing lightning and their environments in the current climate and their changes in the past and coming decades. To address these issues, in this study we analyze the changes in the number of days with atmospheric conditions leading to lightning over southeastern Europe. Here we consider the non-inductive charging mechanism as the main mechanism for cloud electrification. We search for ingredients supporting for this cloud electrification mechanism using a series of parameters (e.g., convective available potential energy, total precipitable water, heights of various isotherms) obtained from vertical profiles collected from radiosonde sites over southeastern Europe (e.g., Romania, Hungary, Bulgaria). This paper will present the changes between 1980 and 2018 in the number of days with condition supporting the occurrence of lightning in urban areas from southeastern Europe. [ABSTRACT FROM AUTHOR]

This paper starts from the observation that development projects that create various forms of environmental injustice in Europe are an integral part of the process of biospheric expulsions, that is of pushing out groups from adequate land, water or air, as described by Saskia Sassen (2014). Apart from the environmental, socio-economic and health-impacts of ecologically destructive projects, there is an added dimension of concern that has been less obvious in the past, but tends to become increasingly pronounced in a warming world. Is it possible that accumulating environmental inequalities and forms of injustice can create new and "unnatural" vulnerabilities to the projected climate change impacts? The fi rst question that we tackle is whether environmental justice confl icts in Europe tend to take place disproportionately in climate hotspot areas, which are geographic spaces with above-average social sensitivity, potential vulnerability, potential social impact, potential environmental impacts or response capacity (ESPON, 2011). The second question concerns the distribution of diff erent characteristics of projects and of their associated confl icts in climate hotspot vs. non-hotspot areas. The fi nal goal is to establish, at a preliminary level, the emergence of a climate edge in Europe, a spatial confi guration in which vulnerability to climate change impacts is shaped by processes of biospheric expulsion, as postulated at a general level by Sassen. For the analysis, the most current data on environmental justice confl icts (444) from the Environmental Justice Atlas and ESPON climate impact projections, mapped on the Climate Adapt platform, are used. The expected result is to provide a preliminary description of the postulated climate edge. [ABSTRACT FROM AUTHOR]

BACKGROUND: Heat is a significant cause of mortality, but impact patterns are heterogenous. Previous studies assessing such heterogeneity focused exclusively on risk rather than heat-attributable mortality burdens and assume predictors are independent. OBJECTIVES: We assessed how four interrelated regional-level sociodemographic predictors—education, life expectancy, the ratio of older to younger people (aging index), and relative income—influence heterogeneity in heat-attributable mortality burdens in Europe and then derived insights into adaptation strategies. METHODS: We extracted four outcomes from a temperature–mortality study covering 16 European countries: the rate of increase in mortality risk at moderate and extreme temperatures (moderate and extreme slope, respectively), the minimum mortality temperature percentile (MMTP), and the underlying mortality rate. We used structural equation modeling with country-level random effects to quantify the direct and indirect influences of the predictors on the outcomes. RESULTS: Higher levels of education were directly associated with lower heat-related mortality at moderate and extreme temperatures via lower slopes and higher MMTPs. A one standard deviation increase in education was associated with a -0.46 ± 0.14, -0.41 ± 0.12, and 0.41 ± 0.12 standard deviation ( ± standard error) change in the moderate slope, extreme slope, and MMTP, respectively. However, education had mixed indirect influences via associations with life expectancy, the aging index, and relative income. Higher life expectancy had mixed relations with heat-related mortality, being associated with higher risk at moderate temperatures (0.33 ± 0.11 for the moderate slope; -0.19 ± 0.097 for the MMTP) but lower underlying mortality rates (-0.72 ± 0.097). A higher aging index was associated with higher burdens through higher risk at extreme temperatures (0.13 ± 0.072 for the extreme slope) and higher underlying mortality rates (0.93 ± 0.055). Relative income had relatively small, mixed influences. DISCUSSION: Our novel approach provided insights into actions for reducing the health impacts of heat. First, the results show the interrelations between possible vulnerability-generating mechanisms and suggest future research directions. Second, the findings point to the need for a dual approach to adaptation, with actions that explicitly target heat exposure reduction and actions focused explicitly on the root causes of vulnerability. For the latter, the climate crisis may be leveraged to accelerate ongoing general public health programs. [ABSTRACT FROM AUTHOR]

Acquiring and distributing essential information for understanding global biogeochemical interactions between the atmosphere and ecosystems, and how climate-ecosystem feedback loops may change atmospheric composition in the future is a fundamental pre-requisite for societal resilience in view of climate change. Particularly, the detection of trends and periodicity in the presence of greenhouse gases and short-lived climate-active atmospheric constituents is an important aspect of climate science. Thus, the availability of an easy and fast access to reliable, long-term, and high-quality environmental data is recognized as fundamental for research and for developing environmental prediction and assessment services. In our Opinion Article, we develop the role environmental research infrastructures in Europe (ENVRI RIs) and particularly the atmosphere-centred research infrastructures ACTRIS, IAGOS and ICOS can assume with their capacities for standardised acquisition and reporting of long-term and high-quality observational data, complemented by rich metadata, for the provision of data by open access, and for data interoperability across different research fields including all fields of environmental sciences and beyond. Resulting from these capacities in data collection and provision, we elaborate on the novel research opportunities in atmospheric sciences which evolve from the combination of open-access and interoperable observational data, tools and technologies offered by data-intensive science, and the emerging service ecosystem of the collaboration platform ENVRI-Hub, hosted by the European Open Science Cloud. [ABSTRACT FROM AUTHOR]

Classifications by self‐organizing maps (SOMs) have been used to study links between extreme weather events and atmospheric circulation. However, SOMs may often provide a too generalized image of circulation, which is too coarse to properly resolve meteorological extremes. Several approaches have been used to circumvent this limitation, including an increase in the number of nodes and/or relaxation of the stress on topological ordering of nodes, through adjusting the neighbourhood radius. Here, we (1) test whether weighting of training fields based on extremity of their circulation could lead to SOMs that would better represent circulation extremes without impairing the topological ordering of nodes, and (2) we investigate whether Sammon maps (SM), which have so far been limited to validation of SOMs in climatology, could provide a viable alternative to SOMs in studying weather extremes. We show that removing a certain percentage of circulation fields closest to the climatological mean has a greater effect on the representation of circulation extremes than more than doubling the SOM array size. Additionally, this step allows for decreasing the neighbourhood radius, the parameter responsible for topological ordering, which would not otherwise be possible without impairing the topology of the map. The SOMs are compared with two newly developed methods that discretize SMs based on arbitrarily chosen and distribution‐based bins. We demonstrate the usefulness of both methods in climate model validation and show that both methods are able to capture circulation variability in its extremes in more detail than the SOMs. The distribution‐based method does not suffer from sample‐size issues and outperforms all other classifications in extracting ERA5 patterns leading to extreme temperature minima over central Europe. Our results suggest that classifications based on SM could be a viable alternative to SOMs when SOMs lack the ability to discriminate circulation outliers leading to temperature extremes. [ABSTRACT FROM AUTHOR]

Background: Catalonia (in the north east of the Iberian Peninsula) is among the most prospected territories in Europe, from the ethnobotanical point of view. The aim of the present paper is to undertake a global analysis in the area considered, including plants, plant life forms, and ethnobotanical data within a physiographic and geographic framework. Methods: Data from 21 ethnobotanical prospection areas in Catalonia were collected, analyzed, and compared, with the focus on plant life forms and geographic divisions. Results: A total of 824 taxa constitute the Catalan ethnoflora, and 316 of them are shared by the six physiographic zones recognized in Catalonia. When three major geographic areas are considered (Pyrenean, inland, and littoral), 394 taxa have been reported in only one out of the three areas. Concerning life forms, phanerophytes and chamaephytes together, i.e., those taxa present all through the year, are the most cited (37.12%). Conclusions: This first study constitutes a new approach to ethnobotanical data analysis. The results show the particular importance of plants with a large distribution area and plants with available biomass throughout the year. Apart from this, other kind of plants, e.g., those present in only one territory, are of interest for its originality and sometimes for the local significance. [ABSTRACT FROM AUTHOR]

Large hail (greater than 2 cm in diameter) can cause devastating damage to crops and property, and can even cause loss of life. Because hail reports are often collected by individual countries, constructing a European-wide large-hail climatology has been challenging to date. However, the European Severe Storm Laboratory's European Severe Weather Database provides the only pan-European dataset for severe convective storms. The database is comprised of 62,053 large-hail reports from 40 C.E. to September 2020, yet its characteristics have not been evaluated. Thus, the purpose of this study is to evaluate this database for the purposes of constructing a climatology of large hail. For the period 2000–2020, large-hail reports are most prominent in June, whereas large-hail days are most common in July. Large hail is mostly reported between 1300–1900 local time, a consistent pattern since 2010. The intensity, as measured by maximum hail size, shows decreasing frequency with increasing hailstone diameter, and no change over the 20-year period. The quality of reports by country varies, with the most complete reporting being from central European countries. These results suggest that despite its short record, many indications are that the dataset represents some reliable aspects of European large-hail climatology, albeit with some limitations. [ABSTRACT FROM AUTHOR]

During the last few decades, unheated attic spaces (so-called "cold attics") have been one of the most moisture-problematic spaces in the building practices of Europe and North America. Problems with such spaces are usually associated with condensation, frost formation, and mould growth on the lower surfaces of the roof deck. To solve these problems, a number of qualitative studies were performed. Although these studies revealed many important pieces of information, some of them are seemingly not in accordance with one another. Therefore, there has not yet been presented cold attic design which is suitable (especially moisture-safe) for the whole target region. The aim of this paper is to determine whether such a design can be determined or state the reasons why it is not possible. Based on a review of published studies, 38 cold attic designs were selected for detailed analysis. Their comparative parameters were established, quantified, and compared. The moisture-safeness of each design was evaluated using an original approach, and the designs were sorted into groups based on their similarities. Despite many uncertainties, it was found that the criteria for moisture-safe cold attic design in the target region can likely be stated. [ABSTRACT FROM AUTHOR]

The North Atlantic Oscillation (NAO), a basic variability mode in the Northern Hemisphere, undergoes changes in its temporal and spatial characteristics, with significant implications on European climate. In this paper, different NAO flavors are distinguished for winter in simulations of a Coupled Atmosphere-Ocean GCM, using Self-Organizing Maps, a topology preserving clustering algorithm. These flavors refer to various sub-forms of the NAO pattern, reflecting the range of positions occupied by its action centers, the Icelandic Low and the Azores High. After having defined the NAO flavors, composites of winter temperature and precipitation over Europe are created for each one of them. The results reveal significant differences between NAO flavors in terms of their effects on the European climate. Generally, the eastwardly shifted NAO patterns induce a stronger than average influence on European temperatures. In contrast, the effects of NAO flavors on European precipitation anomalies are less coherent, with various areas responding differently. These results confirm that not only the temporal, but also the spatial variability of NAO is important in regulating European climate. [ABSTRACT FROM AUTHOR]

Climate services have emerged as a research and operational field in recent years. This development has been underpinned and supported by significant research, funding and agenda‐setting efforts such as the Global Framework for Climate Services internationally and the Roadmap for Climate Services and the Copernicus Climate Change Service in Europe. The fast pace at which this field is developing raises a number of key challenges that need to be critically examined and addressed to ensure the future development and sustainability of climate services in Europe. This opinion piece highlights a number of challenges currently threatening the viability of climate services including the complexity of the concept of climate services; the complex landscape of complementary research and development areas relevant to climate services; existing rights to freely access and use climate services; current limitations to funding structures and mechanisms and how that impacts on the development of climate services; the emphasis on co‐production as a precondition to climate services development; and the limited role of the social sciences in the research and operational field of climate services. Effectively addressing these challenges will require a commitment from the scientific and practitioner communities to engage in critical and reflective debates around the future conceptualization and operationalization of climate services in Europe. This paper aims to provide critical input to stimulate a necessary and overdue debate around the sustainability and future of climate services in Europe. This article is categorized under: Social Status of Climate Change Knowledge > Knowledge and Practice [ABSTRACT FROM AUTHOR]

This study investigates present and future European heat wave magnitudes, represented by the Heat Wave Magnitude Index-daily (HWMId), for regional climate models (RCMs) and the driving global climate models (GCMs) over Europe. A subset of the large EURO-CORDEX ensemble is employed to study sources of uncertainties related to the choice of GCMs, RCMs, and their combinations. We initially compare the evaluation runs of the RCMs driven by ERA-interim reanalysis to E-OBS (observation-based estimates), finding that the RCMs can capture most of the observed spatial and temporal features of HWMId. With their higher resolution compared to GCMs, RCMs can reveal spatial features of HWMId associated with small-scale processes (e.g., orographic effects); moreover, RCMs represent large-scale features of HWMId satisfactorily (e.g., by reproducing the general pattern revealed by E-OBS with high values at western coastal regions and low values at the eastern part). Our results indicate a clear added value of the RCMs compared to the driving GCMs. Forced with the emission scenario RCP8.5, all the GCM and RCM simulations consistently project a rise in HWMId at an exponential rate. However, the climate change signals projected by the GCMs are generally attenuated when downscaled by the RCMs, with the spatial pattern also altered. The uncertainty in a simulated future change of heat wave magnitudes following global warming can be attributed almost equally to the difference in model physics (as represented by different RCMs) and to the driving data associated with different GCMs. Regarding the uncertainty associated with RCM choice, a major factor is the different representation of the orographic effects. No consistent spatial pattern in the ensemble spread associated with different GCMs is observed between the RCMs, suggesting GCM uncertainties are transformed by RCMs in a complex manner due to the nonlinear nature of model dynamics and physics. In summary, our results support the use of dynamical downscaling for deriving regional climate realization regarding heat wave magnitudes. [ABSTRACT FROM AUTHOR]

One of the principal features of climate is its spatial variability. Long distance travels are an essential part of life in contemporary societies. In 2012 tourism arrivals reached 1 billion people at the global scale. In a short time one can move to extremely different climatic conditions and one's organism is under great pressure of atmospheric stimuli which can be very different from those experienced at home. Spatial differences in climate stimuli need various adaptation strategies in humans. The paper considers adaptation strain in tourists from seven central and northern European cities travelling to the Mediterranean regions of Barcelona, Rome and Athens for the period 1991-2000. The Adaptation Strain Index (ASI) was applied for this purpose. Seasonal and spatial patterns of bioclimatic contrasts are considered. Summer was the season with greatest spatially differentiated adaptation strain, but in winter the need for adaptation was the highest. [ABSTRACT FROM AUTHOR]

Knowledge of fog and low stratus (FLS) cloud patterns and life cycles is important for traffic safety, for the production of solar energy and for the analysis of cloud processes in the climate system. While meteorological stations provide information on FLS, a data set describing FLS formation and dissipation times on large spatial and temporal scales does not yet exist. In this study, we use logistic regression to extract FLS formation and dissipation times from a satellite‐based 10‐year FLS data set covering central Europe. The resulting data set is the first to provide a geographic perspective on FLS formation and dissipation at a continental scale. The patterns found show a clear dependency of FLS formation and dissipation times on topography. In mountainous areas, FLS forms in the night and dissipates in the morning. In river valleys, the typical FLS life cycle shifts to formation after sunrise and dissipation in the afternoon. Seasonal patterns of FLS formation and dissipation show similar FLS formation and dissipation times in winter and autumn, and in spring and summer, with longer events in the former two seasons. [ABSTRACT FROM AUTHOR]

In this study, drought events over a large area of the Northern Hemisphere, including continental Europe, Ireland, the United Kingdom, and the Mediterranean basin, were analyzed using the Standardized Precipitation Index (SPI) at various times scales (3, 6, 12, and 24 months). To this purpose, the Global Precipitation Climatology Centre (GPCC) Full Data Monthly Product Version 2018 data set, with spatial resolutions of 0.5° longitude/latitude and for the period 1951–2016, has been used. First, the temporal evolution of the percentage of grid points, falling within the severe and extreme drought categories, has been evaluated. Then, a trend analysis has been performed at a seasonal scale, considering the autumn-winter and the spring-summer periods, and at an annual scale. The results of this paper highlight that the Mediterranean basin and North Africa are the most consistently vulnerable areas showing a general reduction in SPI values especially for the long time scale. [ABSTRACT FROM AUTHOR]

The main purpose of the analysis is to characterize the location of extratropical lows relative to the jet streaks over Europe and the North Atlantic. Algorithms are presented for jet streak detection and cyclone positioning relative to jet streaks. All time steps in the tracked cyclone lifetime together as well as cyclogenesis, maximum deepening and cyclolysis stages separately are examined. The analysis includes strong jet streaks (>50 ms−1) detected in 300 hPa wind fields in the winter period (1958–2002). The location of cyclones in the jet streak‐associated coordinate system is determined. The cyclone positions, situated near jet streak (<1,300 km), are depicted in the circular distribution diagrams and counted within 15° intervals and jet streak quadrants. The distribution of low‐pressure systems at the cyclogenesis and maximum deepening stages resembles the four‐quadrant model of upper‐level divergence: modal intervals are situated in the Left Front (LF) (primary mode: 45–60°) and the Right Rear (RR) (secondary mode: 195–210°) quadrants. Significant changes in cyclone counts at the LF‐LR and LR‐RR boundaries are likely to be a response to the divergence field aloft. Bimodality is distinctly pronounced in the case of cyclogenesis events and maximum deepening phases. The cyclolysis sites are unimodally distributed with maximum frequency in the Left Rear (LR) quadrant. The modal intervals of cyclogenesis and maximum deepening samples deviate towards the LF‐LR and RR‐LR boundary lines from the bisectors of the LF and RR quadrants, respectively. Such angular displacement is congruent with the shift of divergence‐convergence meridional dipoles in the entrance and exit region towards the cyclonic side of the jet stream. The incipient and maximum deepening stages of cyclones are located within the divergent quadrants in almost 80% of cases (of those near jet streaks). Nearly 60% of the cyclolysis events are situated in the convergent quadrants. [ABSTRACT FROM AUTHOR]

This study presents the monthly 10‐m wind speed climatology, decadal variability and possible trends in the North Atlantic and Europe from ERA5 reanalysis from 1979 to 2018 and investigates the physical reasons for the decadal variability. Additionally, temporal time series are examined in three locations: the central North Atlantic, Finland and Iberian Peninsula. The 40‐year mean and the 98th percentile wind speeds emphasize a distinct land‐sea contrast and a seasonal variation with the strongest winds over the ocean and during winter. The strongest winds and the highest variability are associated with the storm tracks and local wind phenomena such as the mistral. The extremeness of the winds is examined with an extreme wind factor (the 98th percentile divided by mean wind speeds) which in all months is higher in southern Europe than in northern Europe. Mostly no linear trends in 10‐m wind speeds are identified in the three locations but large annual and decadal variability is evident. The decadal 10‐m wind speeds were stronger than average in the 1990s in northern Europe and in the 1980s and 2010s in southern Europe. These decadal changes were largely explained by the positioning of the jet stream and storm tracks and the strength of the north–south pressure gradient in the North Atlantic. The 10‐m winds have a positive correlation with the North Atlantic Oscillation in the central North Atlantic and Finland on annual scales and during cold season months and a negative correlation in Iberian Peninsula mostly from July to March. The Atlantic Multi‐decadal Oscillation has a moderate negative correlation with the winds in the central North Atlantic but no correlation in Finland and Iberian Peninsula. Overall, our results emphasize that while linear trends in wind speeds may show a general long‐term trend, more information on the changes is obtained by analysing long‐term variability. [ABSTRACT FROM AUTHOR]

In this study we investigate convective environments and their corresponding climatological features over Europe and the United States. For this purpose, National Lightning Detection Network (NLDN) and Arrival Time Difference long-range lightning detection network (ATDnet) data, ERA5 hybrid-sigma levels, and severe weather reports from the European Severe WeatherDatabase (ESWD) and Storm PredictionCenter (SPC) StormDatawere combined on a commongrid of 0.258 and 1-h steps over the period 1979-2018. The severity of convective hazards increases with increasing instability andwind shear(WMAXSHEAR), but climatological aspects of these features differ over both domains. Environments over theUnited States are characterized by higher moisture, CAPE, CIN, wind shear, andmidtropospheric lapse rates. Conversely, 0-3-km CAPE and low-level lapse rates are higher over Europe. From the climatological perspective severe thunderstorm environments (hours) are around 3-4 times more frequent over the United States with peaks across the Great Plains,Midwest, and Southeast. Over Europe severe environments are the most common over the south with local maxima in northern Italy. Despite having lower CAPE (tail distribution of 3000-4000 J kg-1 compared to 6000-8000 J kg-1 over theUnited States), thunderstorms over Europe have a higher probability for convective initiation given a favorable environment. Conversely, the lowest probability for initiation is observed over the Great Plains, but, once a thunderstorm develops, the probability that it will become severe is much higher compared to Europe. Prime conditions for severe thunderstorms over the United States are between April and June, typically from 1200 to 2200 central standard time (CST), while across Europe favorable environments are observed from June to August, usually between 1400 and -100 UTC. [ABSTRACT FROM AUTHOR]

Many climate extremes, including heatwaves and heavy precipitation events, are projected to worsen under climate change, with important impacts for society. Future projections required for adaptation are often based on climate model simulations. Given finite resources, trade-offs must be made concerning model resolution, ensemble size, and level of model complexity. Here we focus on the resolution component. A given resolution can be achieved over a region using either global climate models (GCMs) or at lower cost using regional climate models (RCMs) that dynamically downscale coarser GCMs. Both approaches to increasing resolution may better capture small-scale processes and features (downscaling effect), but increased GCM resolution may also improve the representation of the large-scale atmospheric circulation (upscaling effect). The size of this upscaling effect is therefore important for deciding modelling strategies. Here we evaluate the benefits of increased model resolution for both global and regional climate models for simulating temperature, precipitation, and wind extremes over Europe at resolutions that could currently be realistically used for coordinated sets of climate projections at the pan-European scale. First we examine the benefits of regional downscaling by comparing EURO-CORDEX simulations at 12.5 and 50 km resolution to their coarser CMIP5 driving simulations. Secondly, we compare global-scale HadGEM3-A simulations at three resolutions (130, 60, and 25 km). Finally, we separate out resolution-dependent differences for HadGEM3-A into downscaling and upscaling components using a circulation analogue technique. Results suggest limited benefits of increased resolution for heatwaves, except in reducing hot biases over mountainous regions. Precipitation extremes are sensitive to resolution, particularly over complex orography, with larger totals and heavier tails of the distribution at higher resolution, particularly in the CORDEX vs. CMIP5 analysis. CMIP5 models underestimate precipitation extremes, whilst CORDEX simulations overestimate compared to E-OBS, particularly at 12.5 km, but results are sensitive to the observational dataset used, with the MESAN reanalysis giving higher totals and heavier tails than E-OBS. Wind extremes are somewhat stronger and heavier tailed at higher resolution, except in coastal regions where large coastal grid boxes spread strong ocean winds further over land. The circulation analogue analysis suggests that differences with resolution for the HadGEM3-A GCM are primarily due to downscaling effects. [ABSTRACT FROM AUTHOR]

In this study, we evaluate a set of high-resolution (25–50 km horizontal grid spacing) global climate models (GCMs) from the High-Resolution Model Intercomparison Project (HighResMIP), developed as part of the EU-funded PRIMAVERA (Process-based climate simulation: Advances in high resolution modelling and European climate risk assessment) project, and from the EURO-CORDEX (Coordinated Regional Climate Downscaling Experiment) regional climate models (RCMs) (12–50 km horizontal grid spacing) over a European domain. It is the first time that an assessment of regional climate information using ensembles of both GCMs and RCMs at similar horizontal resolutions has been possible. The focus of the evaluation is on the distribution of daily precipitation at a 50 km scale under current climate conditions. Both the GCM and RCM ensembles are evaluated against high-quality gridded observations in terms of spatial resolution and station density. We show that both ensembles outperform GCMs from the 5th Coupled Model Intercomparison Project (CMIP5), which cannot capture the regional-scale precipitation distribution properly because of their coarse resolutions. PRIMAVERA GCMs generally simulate precipitation distributions within the range of EURO-CORDEX RCMs. Both ensembles perform better in summer and autumn in most European regions but tend to overestimate precipitation in winter and spring. PRIMAVERA shows improvements in the latter by reducing moderate-precipitation rate biases over central and western Europe. The spatial distribution of mean precipitation is also improved in PRIMAVERA. Finally, heavy precipitation simulated by PRIMAVERA agrees better with observations in most regions and seasons, while CORDEX overestimates precipitation extremes. However, uncertainty exists in the observations due to a potential undercatch error, especially during heavy-precipitation events. The analyses also confirm previous findings that, although the spatial representation of precipitation is improved, the effect of increasing resolution from 50 to 12 km horizontal grid spacing in EURO-CORDEX daily precipitation distributions is, in comparison, small in most regions and seasons outside mountainous regions and coastal regions. Our results show that both high-resolution GCMs and CORDEX RCMs provide adequate information to end users at a 50 km scale. [ABSTRACT FROM AUTHOR]

This article analyses Climate Public Private Partnerships in the light of EU climate law and includes an economic perspective to explain the objectives and efficiency behind Climate Public Private Partnerships. Climate Public Private Partnerships are regulated by EU public procurement law for which reason the legal cross field between EU climate law and EU public procurement law is analysed to evaluate how EU law supports Climate Public Private Partnerships. Furthermore, the article includes game theory as an instrument to assess Climate Public Private Partnerships under EU law. The article concludes that EU law does not include the sufficient legal support to provide efficient Climate Public Private Partnerships as a tool to reach Europe's climate goals. [ABSTRACT FROM AUTHOR]

Climate warming has substantially advanced spring leaf flushing, but winter chilling and photoperiod co‐determine the leaf flushing process in ways that vary among species. As a result, the interspecific differences in spring phenology (IDSP) are expected to change with climate warming, which may, in turn, induce negative or positive ecological consequences. However, the temporal change of IDSP at large spatiotemporal scales remains unclear. In this study, we analyzed long‐term in‐situ observations (1951–2016) of six, coexisting temperate tree species from 305 sites across Central Europe and found that phenological ranking did not change when comparing the rapidly warming period 1984–2016 to the marginally warming period 1951–1983. However, the advance of leaf flushing was significantly larger in early‐flushing species EFS (6.7 ± 0.3 days) than in late‐flushing species LFS (5.9 ± 0.2 days) between the two periods, indicating extended IDSP. This IDSP extension could not be explained by differences in temperature sensitivity between EFS and LFS; however, climatic warming‐induced heat accumulation effects on leaf flushing, which were linked to a greater heat requirement and higher photoperiod sensitivity in LFS, drove the shifts in IDSP. Continued climate warming is expected to further extend IDSP across temperate trees, with associated implications for ecosystem function. [ABSTRACT FROM AUTHOR]

At regional to local scales internal variability is expected to be a dominant source of uncertainty in analyzing precipitation extremes and mean precipitation even far into the 21st century. A debated topic is whether a faster increase in subdaily precipitation extremes can be expected. Here we analyzed seasonal maximum precipitation in various time steps (3 hr, days, and 5 days) from a high‐resolution 50‐member large‐ensemble (CRCM5‐LE) and compared them to changes in mean precipitation over Europe. Our results show that the magnitude of change in extreme precipitation varies for season and duration. Subdaily extremes increase at higher rates than daily extremes and show higher scaling with temperature. Northern Europe shows widespread scaling above Clausius‐Clapeyron of subdaily extremes in all seasons and for daily extremes in winter/spring. Scaling above Clausius‐Clapeyron is also visible over Eastern Europe in winter/spring. For most regions and seasons the forced response emerges from the internal variability by midcentury. Plain Language Summary: The knowledge on how and why the intensity and frequency of extremes changes is critical to a resilient society. Our adaptive measures that are currently in place are based on observed extremes of the past. We know that observations are only one realization of a chaotic system and that the climate system is altered by natural variations, and anthropogenic contributions. Since we can only measure one realization of the world, we need climate models to investigate the influence of natural variability and anthropogenic factors. In this study we focus on the contribution of natural variability and the detection of regional patterns of changes in extreme precipitation. We used regional climate simulations, driven by multiple runs of global climate simulations under the same emission scenario, but with slight changes at the start of the simulation to imitate the butterfly effect of the climate system and simulate natural variability. We have found that natural variability plays a dominant role in the first half of the 21st century. But we have also found that subdaily extreme precipitation is increasing at a higher rate than daily extremes and that some of this change can be attributed to the warming of the atmosphere. Key Points: Subdaily extreme precipitation intensifies faster than daily extremes and mean precipitationOn regional scales internal variability remains a dominant source of uncertainty until the end of the 21st centuryWidespread scaling rates of subdaily extremes above Clausius‐Clapeyron over Northern and Eastern Europe [ABSTRACT FROM AUTHOR]

For the first time, we analyze 2.2 km UK Met Office Unified Model convection-permitting model (CPM) projections for a pan-European domain. These new simulations represent a major increase in domain size, allowing us to examine the benefits of CPMs across a range of European climates. We find a change to the seasonality of extreme precipitation with warming. In particular, there is a relatively muted response for summer, which contrasts with much larger increases in autumn and winter. This flattens the hourly extreme precipitation seasonal cycle across Northern Europe which has a summer peak in the present climate. Over the Western Mediterranean, where autumn is the main extreme precipitation season, there is a regional increase in hourly extreme precipitation frequency, but local changes for lower precipitation thresholds are often insignificant. For mean precipitation, decreases are projected across Europe in summer, smaller decreases in autumn, and increases in winter; comparable changes are seen in the driving general circulation model (GCM) simulations. The winter mean increase is accompanied by a large decrease of winter mean snowfall. Comparing the driving GCM projections with the CPM ones, the CPMs show a robust enhanced intensification of precipitation extremes at the convection-permitting scale compared to coarser resolution climate model projections across various European regions for summer and autumn. [ABSTRACT FROM AUTHOR]

We perform simulations with the WRF regional climate model at 12 and 3 km grid resolution for the current and future climates over Central Europe and evaluate their added value with a focus on the daily cycle and frequency distribution of rainfall and the relation between extreme precipitation and air temperature. First, a 9 year period of ERA-Interim driven simulations is evaluated against observations; then global climate model runs (MPI-ESM-LR RCP4.5 scenario) are downscaled and analyzed for three 12-year periods: a control, a mid-of-century and an end-of-century projection. The higher resolution simulations reproduce both the diurnal cycle and the hourly intensity distribution of precipitation more realistically compared to the 12 km simulation. Moreover, the observed increase of the temperature–extreme precipitation scaling from the Clausius–Clapeyron (C–C) scaling rate of ~ 7% K−1 to a super-adiabatic scaling rate for temperatures above 11 °C is reproduced only by the 3 km simulation. The drop of the scaling rates at high temperatures under moisture limited conditions differs between sub-regions. For both future scenario time spans both simulations suggest a slight decrease in mean summer precipitation and an increase in hourly heavy and extreme precipitation. This increase is stronger in the 3 km runs. Temperature–extreme precipitation scaling curves in the future climate are projected to shift along the 7% K−1 trajectory to higher peak extreme precipitation values at higher temperatures. The curves keep their typical shape of C–C scaling followed by super-adiabatic scaling and a drop-off at higher temperatures due to moisture limitation. [ABSTRACT FROM AUTHOR]

Precipitation is a crucial variable for hydro-meteorological applications. Unfortunately, rain gauge measurements are sparse and unevenly distributed, which substantially hampers the use of in situ precipitation data in many regions of the world. The increasing availability of high-resolution gridded precipitation products presents a valuable alternative, especially over poorly gauged regions. This study examines the usefulness of current state-of-the-art precipitation data sets in hydrological modeling. For this purpose, we force a conceptual hydrological model with multiple precipitation data sets in >200 European catchments to obtain runoff and evapotranspiration. We consider a wide range of precipitation products, which are generated via (1) the interpolation of gauge measurements (E-OBS and Global Precipitation Climatology Centre (GPCC) V.2018), (2) data assimilation into reanalysis models (ERA-Interim, ERA5, and Climate Forecast System Reanalysis – CFSR), and (3) a combination of multiple sources (Multi-Source Weighted-Ensemble Precipitation; MSWEP V2). Evaluation is done at the daily and monthly timescales during the period of 1984–2007. We find that simulated runoff values are highly dependent on the accuracy of precipitation inputs; in contrast, simulated evapotranspiration is generally much less influenced in our comparatively wet study region. We also find that the impact of precipitation uncertainty on simulated runoff increases towards wetter regions, while the opposite is observed in the case of evapotranspiration. Finally, we perform an indirect performance evaluation of the precipitation data sets by comparing the runoff simulations with streamflow observations. Thereby, E-OBS yields the particularly strong agreement, while ERA5, GPCC V.2018, and MSWEP V2 show good performances. We further reveal climate-dependent performance variations of the considered data sets, which can be used to guide their future development. The overall best agreement is achieved when using an ensemble mean generated from all the individual products. In summary, our findings highlight a climate-dependent propagation of precipitation uncertainty through the water cycle; while runoff is strongly impacted in comparatively wet regions, such as central Europe, there are increasing implications for evapotranspiration in drier regions. [ABSTRACT FROM AUTHOR]