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Soil management strategies involving the application of organic matter (OM) inputs (crop residues, green and livestock manure, slurry, digestate, compost and biochar) can increase soil carbon storage but simultaneously lead to an increase in non‐CO2 greenhouse gas (GHG) emissions such as N2O. Although multiple meta‐analyses have been conducted on the topic of OM input impacts on GHG, none has focused specifically on European arable soils. This study plugs this gap and can assist policymakers in steering European agriculture in a more sustainable direction. The objective of this meta‐analysis was to quantify how OM inputs of different nature and quality, but also the application strategy, can mitigate soil N2O emissions in different pedoclimatic conditions in Europe. We quantitatively synthesised the results of over 50 field experiments conducted in 15 European countries. Diverse arable crops, mainly cereals, were cultivated in monoculture or in crop rotations on mineral soils. Cumulative N2O emissions were monitored during periods of 30–1070 days in treatments, which received OM inputs, alone or in combination with mineral N fertiliser; and in controls fertilised with mineral N. The overall effect of OM inputs had a slight tendency to reduce N2O emissions by 10% (n = 53). With the increasing carbon‐to‐nitrogen ratio of the OM inputs, this mitigation effect became more pronounced. In particular, compost and biochar significantly reduced N2O emissions by 25% (n = 6) and 33% (n = 8) respectively. However, their effect strongly depended on pedoclimatic characteristics. Regarding the other types of OM inputs studied, a slight N2O emission reduction can be achieved by their application alone, without mineral N fertiliser (by 16%, n = 17). In contrast, their co‐application with mineral N fertiliser elevated emissions to some extent compared to the control (by 14%, n = 22). We conclude that amongst the seven OM inputs studied, the application of compost and biochar are the most promising soil management practices, clearly demonstrating N2O emission reduction compared to mineral N fertiliser. In contrast, other OM inputs had a small tendency to mitigate N2O emissions only when applied without mineral N fertiliser. [ABSTRACT FROM AUTHOR]

The voluntary-based initiative Covenant of Mayors (CoM) focused on the active role of local authorities and increased its targets by 2016, through the Sustainable Energy and Climate Action Plans (SECAPs) in terms of GHG reduction from 20% to 40% by 2030. In actual fact, the SECAP, intended as an urban planning tool, has the potential to improve the resilience of the EU Municipalities to climate-change, developing adaptation/mitigation actions and increasing the 'environmental awareness' of the involved actors. From a planning point of view, we affirm that the CoM started a new season of urban planning in Europe that covers the planning demand in the domain of implementing sustainable territorial development objectives. It unlocks the current ineffective planning systems and represents a remarkable practice promoting feasible framework projects for public and private investments. This paper proposes a methodological proposal to exploit this spread of SECAPs in the EU, including the systemic strategic planning approach in the process of SECAP design and ensuring an integrated vision of city development over the list of actions per sector required by the Global CoM procedures. Besides the methodological proposal, a review of the major EU energy policies is provided and relevant Best Practices are presented. [ABSTRACT FROM AUTHOR]

Natural forest expansion (NFE), that is, the establishment of secondary forest on non-forested land through natural succession, has substantially contributed to the widespread expansion of forests in Europe over the last few decades. So far, EU policies have largely neglected the potential of NFE for meeting policy objectives on restoration. Synthesising recent interdisciplinary research, this paper assesses the challenges and opportunities of NFE in view of contributing to European forest and ecosystem restoration. Specifically, we discuss the potential for supporting climate change mitigation and adaptation, biodiversity conservation, and forestry and economic use, summarize the current knowledge about societal perceptions and the policymaking on NFE, and make policy recommendations to better use the potential of NFE. We conclude that NFE has the potential to contribute to the European restoration policy agenda if local contexts and possible trade-offs are properly considered. [ABSTRACT FROM AUTHOR]

The timing of leaf senescence in deciduous trees influences carbon uptake and the resources available for tree growth, defense, and reproduction. Therefore, simulated biosphere‐atmosphere interactions and, eventually, estimates of the biospheric climate change mitigation potential are affected by the accuracy of process‐oriented leaf senescence models. However, current leaf senescence models are likely to suffer from a bias towards the mean (BTM). This may lead to overly flat trends, whereby errors would increase with increasing difference from the average timing of leaf senescence, ultimately distorting model performance and projected future shifts. However, such effects of the BTM on model performance and future shifts have rarely been investigated. We analyzed >17 × 106 past dates and >49 × 106 future shifts of leaf senescence simulated by 21 process‐oriented models that had been calibrated with >45,000 observations from Central Europe for three major European tree species. The surmised effects on model performance and future shifts occurred in all 21 models, revealing strong model‐specific BTM. In general, the models performed only slightly better than a null model that just simulates the average timing of leaf senescence. While standard comparisons of model performance favored models with stronger BTM, future shifts of leaf senescence were smaller when projected by models with weaker BTM. Overall, the future shifts for 2090–2099 relative to 1990–1999 increased by an average of 13–14 days after correcting for the BTM. In conclusion, the BTM substantially affects simulations by state‐of‐the‐art leaf senescence models, which compromises model comparisons and distorts projections of future shifts. Smaller shifts result from flatter trends associated with stronger BTM. Therefore, smaller shifts according to models with weaker BTM illustrate the considerable uncertainty in current leaf senescence projections. It is likely that state‐of‐the‐art projections of future biosphere behavior under global change are distorted by erroneous leaf senescence models. [ABSTRACT FROM AUTHOR]

The forthcoming energy transition driven by the need to reduce CO2 emissions requires large amounts of critical elements to construct renewable energy devices such as car batteries, wind turbines and solar panels. For many elements such as Li, Co, REEs and Ti, the production sources are located in countries with poor social and environmental standards, prone to political destabilization such as military conflicts, or vulnerable to strained relationships with consumer countries. Lately, the volatile geopolitical context has further demonstrated the high dependency of Europe and other developed countries in terms of raw material supply. In addition, there is a debate about the Earth's potential to sustain the transition toward a green society by using conventional resources from mining of terrestrial rocks. As nature conservation and climate mitigation are now priorities for the majority of governments, and since conventional mining on Earth suffers from a growing social resistance, humankind may need to look toward new frontier resources for supplying the mineral needs of the coming decades. Here, we explore the use of extra‐terrestrial resources as a potential source to feed the future supply of critical metals. Extra‐terrestrial mining may be an opportunity for wealth creation and an option for critical metal resource supply when mining on Earth becomes increasingly untenable. We conclude that the potential impacts of extraction and exploitation of space resources, both good and bad, could be societally profound. [ABSTRACT FROM AUTHOR]

Today societies face an unprecedented challenge to limit global warming and restore agricultural soils. Recent studies show that the introduction of cover crops over Europe could result in a cooling impact due to an increase in soil organic carbon stocks, a decrease in the use of fertilizers, and an increase in surface albedo of the croplands. Based on the use of remote sensing data, land cover database, meteorological data, national agricultural statistics, and ground measurements, a generic model was developed to simulate the radiative forcing following the change in surface albedo. This article analyzes the impact of the introduction of cover crops in Europe during the fallow periods. Compared to previous studies, this work discusses: (i) The maximum greening potential in Europe and the associated indirect surface properties changes (ii) for snowfall episodes, and (iii) due to an increase in organic matter. This study shows that the mitigation potential of cover crops through albedo effects could reach 6.74 MtCO2-eq.yr−1 by extending the periods of the introduction of the cover crops to all possible fallow periods. This mitigation could be limited to 5.68 MtCO2-eq.yr−1 if the impact of snowfalls is considered. This would be equivalent to 9.12 gCO2.m−2.yr−1. Finally, this study investigates the feedback loop due to soil darkening with soil organic carbon content increase when cover crops are introduced, considering two scenarios. The first considers the soil organic carbon content increase following repeated incorporation of cover crop biomass into the soil, simulated with the DayCent model. The second, more conceptual and extreme scenario aims at alerting on the possible impact of a combination of carbon farming practices, such as biochar or organic amendments. Our results show that this effect could lead to a loss of 20% of the climate benefit (i.e., 5.39 MtCO2-eq.yr−1). In conclusion, this study shows that cover crops have a strong potential for climate mitigation through direct albedo effects (soil coverage). However, once introduced, cropland should be permanently covered by vegetation or straws in order to avoid this darkening feedback loop effect. [ABSTRACT FROM AUTHOR]

Southeast Europe is considered one of the most vulnerable regions in the context of climate change, and projected future summer warming is expected to exceed global rates significantly. Despite the importance of this problem, there have been few studies that utilized Coupled Model Intercomparison Project Phase 5 (CMIP5) Global Circulation Models (GCMs) and the multi-model ensemble approach to examine extreme heat events on a regional scale. Additionally, the NEX-GDDP dataset, successfully applied in other parts of the world to assess extreme heat, has not yet been utilized for Southeast Europe. This study aims to fill that gap, presenting the time evolution and spatial distribution of extreme heat events in Southeast Europe for the historical period 1950–2005 and for the expected future climate up to the end of the 21st century based on the NEX-GDDP dataset. In order to leverage the strengths of the multi-model ensemble approach, a set of purpose-tailored indicators, such as the annual number of hot days, the maximum number of consecutive hot days, and hot spell duration at different thresholds, is computed by the daily maximum temperature data from all datasets, produced by NEX-GDDP (21 for the historical period and 42 for the future period). The E-OBS dataset is used as a reference for evaluating the NEX-GDDP's capability to simulate the features of the observed historical extreme heat events. The results show that the multi-model ensemble can satisfactorily capture the occurrence of extreme heat events in the historical period, and therefore it is reasonable to assume that the NEX-GDDP dataset has the potential to reproduce such extremes in the projected future. The study provides clear evidence that the persistence and spatial extent of extreme heat will increase significantly. Some indicators that were not relevant for the historical period due to the high-temperature threshold will become helpful in assessing extreme heat in Southeast Europe in the latter part of the century. Thus, under the RCP8.5 scenario, the area-averaged duration of hot spells at 32 °C and 34 °C will increase from near zero in 1976–2005 to 60 and 45 days, respectively, by the end of the century. The indicators used in the study may be helpful for decision-makers to implement climate change mitigation strategies and actions adequately. The findings are consistent with general tendencies in maximum temperatures considered in our previous works but also with the outcomes of recent studies dedicated to the future climate of the region. [ABSTRACT FROM AUTHOR]

Wetlands are a critical component of the landscape for climate mitigation, adaptation, biodiversity, and human health and prosperity. Keeping an eye on wetland vegetation is crucial due to it playing a major role in the planet's carbon cycle and ecosystem management. By measuring the chlorophyll fluorescence (ChF) emitted by plants, we can get a precise understanding of the current state and photosynthetic activity. In this study, we applied the Extreme Gradient Boost (XGBoost) algorithm to map ChF in the Biebrza Valley, which has a unique ecosystem in Europe for peatlands, as well as highly diversified flora and fauna. Our results revealed the advantages of using a set of classifiers derived from EO Sentinel-2 (S-2) satellite image mosaics to accurately map the spatio-temporal distribution of ChF in a terrestrial landscape. The validation proved that the XGBoost algorithm is quite accurate in estimating ChF with a good determination of 0.71 and least bias of 0.012. The precision of chlorophyll fluorescence measurements is reliant upon determining the optimal S-2 satellite overpass time, which is influenced by the developmental stage of the plants at various points during the growing season. Finally, the model performance results indicated that biophysical factors are characterized by greenness- and leaf-pigment-related spectral indices. However, utilizing vegetation indices based on extended periods of remote sensing data that better capture land phenology features can improve the accuracy of mapping chlorophyll fluorescence. [ABSTRACT FROM AUTHOR]

Large‐scale bioenergy plays a key role in climate change mitigation scenarios, but its efficacy is uncertain. This study aims to quantify that uncertainty by contrasting the results of three different types of models under the same mitigation scenario (RCP2.6‐SSP2), consistent with a 2°C temperature target. This analysis focuses on a single bioenergy feedstock, Miscanthus × giganteus, and contrasts projections for its yields and environmental effects from an integrated assessment model (IMAGE), a land surface and dynamic global vegetation model tailored to Miscanthus bioenergy (JULES) and a bioenergy crop model (MiscanFor). Under the present climate, JULES, IMAGE and MiscanFor capture the observed magnitude and variability in Miscanthus yields across Europe; yet in the tropics JULES and IMAGE predict high yields, whereas MiscanFor predicts widespread drought‐related diebacks. 2040–2049 projections show there is a rapid scale up of over 200 Mha bioenergy cropping area in the tropics. Resulting biomass yield ranges from 12 (MiscanFor) to 39 (JULES) Gt dry matter over that decade. Change in soil carbon ranges from +0.7 Pg C (MiscanFor) to −2.8 Pg C (JULES), depending on preceding land cover and soil carbon.2090–99 projections show large‐scale biomass energy with carbon capture and storage (BECCS) is projected in Europe. The models agree that <2°C global warming will increase yields in the higher latitudes, but drought stress in the Mediterranean region could produce low yields (MiscanFor), and significant losses of soil carbon (JULES and IMAGE). These results highlight the uncertainty in rapidly scaling‐up biomass energy supply, especially in dry tropical climates and in regions where future climate change could result in drier conditions. This has important policy implications—because prominently used scenarios to limit warming to 'well below 2°C' (including the one explored here) depend upon its effectiveness. [ABSTRACT FROM AUTHOR]

Over the last decades, the natural disturbance is increasingly putting pressure on European forests. Shifts in disturbance regimes may compromise forest functioning and the continuous provisioning of ecosystem services to society, including their climate change mitigation potential. Although forests are central to many European policies, we lack the long‐term empirical data needed for thoroughly understanding disturbance dynamics, modeling them, and developing adaptive management strategies. Here, we present a unique database of >170,000 records of ground‐based natural disturbance observations in European forests from 1950 to 2019. Reported data confirm a significant increase in forest disturbance in 34 European countries, causing on an average of 43.8 million m3 of disturbed timber volume per year over the 70‐year study period. This value is likely a conservative estimate due to under‐reporting, especially of small‐scale disturbances. We used machine learning techniques for assessing the magnitude of unreported disturbances, which are estimated to be between 8.6 and 18.3 million m3/year. In the last 20 years, disturbances on average accounted for 16% of the mean annual harvest in Europe. Wind was the most important disturbance agent over the study period (46% of total damage), followed by fire (24%) and bark beetles (17%). Bark beetle disturbance doubled its share of the total damage in the last 20 years. Forest disturbances can profoundly impact ecosystem services (e.g., climate change mitigation), affect regional forest resource provisioning and consequently disrupt long‐term management planning objectives and timber markets. We conclude that adaptation to changing disturbance regimes must be placed at the core of the European forest management and policy debate. Furthermore, a coherent and homogeneous monitoring system of natural disturbances is urgently needed in Europe, to better observe and respond to the ongoing changes in forest disturbance regimes. [ABSTRACT FROM AUTHOR]

Soil moisture is central to local climate on land. In situ soil moisture observations are vital for observing vegetation‐relevant root‐zone soil moisture. However, stations included in the International Soil Moisture Network are sparse in regions with strong land‐atmosphere coupling. We apply a machine‐learning‐based procedure for informing future station placement using virtual soil moisture stations in future CMIP6 projections. Stations are placed where the climate is currently most under‐represented. This strategy outperforms random station placement and station placement according to geographical distance. Doubling the current number of stations using this method alleviates the uneven global distribution of stations, increases the skill in the estimation of inter‐annual variability and trends in dry‐season soil moisture, and reduces its differences across climates in future projections. Stations are predominantly placed in tropical climates, especially when optimizing for drying trends. The results can inform future station placement to support climate change mitigation efforts. Plain Language Summary: Water stored in the ground as soil moisture is the main water supply for ecosystems and can influence local weather. Ground observations of soil moisture can measure water in deeper soil layers that roots can access. Many stations are collected in the International Soil Moisture Network database. However, this database mainly contains observation stations from the US and Europe. If we were to put additional stations, we should focus on regions and climates that the current network does not sufficiently cover. Locations in model projections of future climate that currently contain a station ("virtual stations") are used to build a machine‐learning model that predicts soil moisture at locations without stations. We then place new virtual stations where the prediction error of dry‐season soil moisture variability and dry‐season trends is largest. This strategy outperforms randomly placing new stations or placing stations where they are most distant from existing ones. Stations are placed predominantly in the tropics, but prediction improves in all regions. Furthermore, stations are more evenly distributed across the globe, and differences in skill between regions become smaller. This tool can be used to decide where to place future soil moisture stations, which are important for monitoring climate change. Key Points: In situ soil moisture observations are distributed unequally across the globe and sparse in regions with strong land‐atmosphere couplingWe present a machine‐learning based procedure for informing future station placement using virtual soil moisture stationsDoubling the number of stations with this strategy reduces error in soil moisture trends by 0.2–1.4 kg m−2 and reduces global differences [ABSTRACT FROM AUTHOR]

Integrating peatland restoration measures with climate policy is critical for meeting climate targets, but the current policies often fall short of utilizing the large potential that exists. Despite growing private sector interest, few regional voluntary carbon markets for peatlands have emerged worldwide. In this study, we explore three pioneering examples from Europe. From the perspective of social innovation, we aim to provide clarity on how these innovations emerged and developed, which actors drove the innovation process by assuming which roles, and which factors fostered or hindered the development. We do so by mapping the innovation process using Process Net-Map. The results show that all three cases have followed remarkably similar patterns in their innovation processes. Four phases, i.e. preparation, definition, refinement, and up-scaling were identified, as were actors' roles as innovators, promoters, intermediaries, implementers, and knowledge providers. However, the case studies are very different with regard to which actor constellation drove the innovation process: MoorFutures is driven by public and scientific actors, Valuta vor Veen is promoted by civil society actors in consultation with practitioners, and Hiilipörssi shifted from civil society to private actors. The governance modes, that is, actor constellation and their goals, have led to differences in concept, robustness of methodology, mitigation measure, and possibly potential for up-scaling. Our study indicates that the timing of interventions when actors with certain roles stepped in can accelerate the innovation process. Important political, economic, technical, and social factors influencing the innovation process, especially knowledge and trust accumulated between some key actors, are outlined. Private funding for regional voluntary carbon markets (VCMs) can tap the climate mitigation potential from peatlands, which is not currently adequately addressed by governments. Actor constellation drove the innovation process, leading to different concepts, methodologies, and mitigation measures. The timing of interventions by actors, notably providing seed funding, network, expertise and visibility, was critical for success. Building trust for regional VCMs requires not only a robust methodology to calculate emission reductions but also partnership and endorsement. The future development of climate policy on peatlands could be a decisive factor in regional VCMs. [ABSTRACT FROM AUTHOR]

The agriculture sector can contribute to climate change mitigation by reducing its own greenhouse gas (GHG) emissions, sequestering carbon in vegetation and soils, and providing biomass to substitute for fossil fuels and other GHG‐intensive products. The sector also needs to address water, soil, and biodiversity impacts caused by historic and current practices. Emerging EU policies create incentives for cultivation of perennial plants that provide biomass along with environmental benefits. One such option, common in northern Europe, is to include grass in rotations with annual crops to provide biomass while remediating soil organic carbon (SOC) losses and other environmental impacts. Here, we apply a spatially explicit model on >81,000 sub‐watersheds in EU27 + UK (Europe) to explore the effects of widespread deployment of such systems. Based on current accumulated SOC losses in individual sub‐watersheds, the model identifies and quantifies suitable areas for increased grass cultivation and corresponding biomass‐ and protein supply, SOC sequestration, and reductions in nitrogen emissions to water as well as wind and water erosion. The model also provides information about possible flood mitigation. The results indicate a substantial climate mitigation potential, with combined annual GHG savings from soil‐carbon sequestration and displacement of natural gas with biogas from grass‐based biorefineries, equivalent to 13%–48% of current GHG emissions from agriculture in Europe. The environmental co‐benefits are also notable, in some cases exceeding the estimated mitigation needs. Yield increases for annual crops in modified rotations mitigate the displacement effect of increasing grass cultivation. If the grass is used as feedstock in lieu of annual crops, the displacement effect can even be negative, that is, a reduced need for annual crop production elsewhere. Incentivizing widespread deployment will require supportive policy measures as well as new uses of grass biomass, for example, as feedstock for green biorefineries producing protein concentrate, biofuels, and other bio‐based products. [ABSTRACT FROM AUTHOR]

Afforestation is an important mitigation strategy for climate change due to its carbon sequestration potential. Besides this favorable biogeochemical effect on global CO 2 concentrations, afforestation also affects the regional climate by changing the biogeophysical land surface characteristics. In this study, we investigate the effects of an idealized global CO 2 reduction to pre-industrial conditions by a Europe-wide afforestation experiment on the regional longwave radiation balance, starting in the year 1986 on a continent entirely covered with grassland. Results show that the impact of biogeophysical processes on the surface temperatures is much stronger than that of biogeochemical processes. Furthermore, biogeophysically induced changes of the surface temperatures, atmospheric temperatures, and moisture concentrations are as important for the regional longwave radiation balance as the global CO 2 reduction. While the outgoing longwave radiation is increased in winter, it is reduced in summer. In terms of annual total, a Europe-wide afforestation has a regional warming effect despite reduced CO 2 concentrations. Thus, even for an idealized reduction of the global CO 2 concentrations to pre-industrial levels, the European climate response to afforestation would still be dominated by its biogeophysical effects. [ABSTRACT FROM AUTHOR]

This document presents a comprehensive review of research works, regulatory frameworks, technical solutions, and commercial trends related to the integration of shallow geothermal energy (SGE) technologies in modern 5th-generation district heating and cooling (5GDHC) networks. This literature and market analysis is contextualized by the present geopolitical, environmental, and societal scenario in Europe. In this sense, decarbonization of the heating and cooling sector is a crucial piece in the energy transition puzzle to keep global warming below the critical threshold of 1.5 °C by the next century. Moreover, Ukraine war has added urgency to end up with fossil fuel dependency. The most relevant outcome of this literature review is the synergistic relationship between SGE, 5GDHC networks, and urban environments. SGE is most efficiently deployed in urban environments when it is part of a district heating and cooling network, and the modern concept of 5GDHC is the most suitable scenario for it. Since the potential contribution of SGE to the decarbonization of the heating and cooling supply is mostly untapped across Europe, this synergistic effect represents a possible boost. Hybridization with solar photovoltaics and/or storage makes it even more attractive. Outstanding cases are reviewed, challenges for the future are presented, and tools to overcome social reluctance and/or lack of awareness are described, along with a discussion of the stimuli for the deployment of SGE and 5GDHC networks. A particular focus on Mediterranean countries is presented, where SGE systems and DHC networks of any kind show a particularly low deployment compared to the rest of Europe. To this end, the second part of this work evaluates, justifies, and analyzes the possibilities and potentialities of their application in this zone. [ABSTRACT FROM AUTHOR]

Afforestation is an important mitigation strategy to climate change due to its carbon sequestration potential. Besides this positive biogeochemical effect on global CO2 concentrations, afforestation also affects the regional climate by changing the biogeophysical land surface characteristics. In this study, we investigate the effects of an idealized global CO2 reduction to pre-industrial conditions by a Europe wide afforestation experiment on the regional longwave radiation balance, starting in the year 1986 from a continent entirely covered with grassland. Results show that the impact of biogeophysical processes on the surface temperatures is much stronger than of biogechemical processes. Furthermore, biogeophysically induced changes of the surface temperatures, atmospheric temperatures and moisture concentrations are as important for the regional greenhouse effect as the global CO2 reduction. While the greenhouse effect is strengthened in winter, it is weakened in summer. On annual total, a Europe-wide afforestation has a regional warming effect, despite reduced CO2 concentrations. Thus, even for an idealized reduction of the global CO2 concentrations to pre-industrial levels, the European climate response to afforestation would still be dominated by its biogeophysical effects. [ABSTRACT FROM AUTHOR]

How do welfare state policies affect the political support for environmental action of economically vulnerable social groups? Two competing hypotheses can be delineated. On the one hand, a synergy logic would imply that welfare state generosity is associated with higher support for environmental action among economically vulnerable groups due to the insecurity reducing effects of the welfare state. On the other hand, a crowding-out logic would suggest that welfare state generosity is associated with lower support for other policy priorities like environmental action. We test these two hypotheses using 2019 Eurobarometer survey data and country-level indicators of welfare state generosity in 22 European countries. We find that the working class and the elderly are particularly opposed to individual and national environmental action and that the welfare state plays a complex moderating role. Consistent with a synergy logic, welfare state generosity increases pro-environmental behaviour among the working class, but its association with more positive attitudes towards national environmental policies is less strong. Consistent with a crowding-out logic, the elderly appear less likely to behave in environmentally friendly ways if retirement benefits are high. To explore the mechanisms behind this association, we show that the working class who struggle to pay their bills are most opposed to environmental action. Overall, economic insecurities are key obstacles for support of environmental actions and the effects of the welfare state depend both on which social group is concerned and whether individual behaviour versus policy preferences are considered. [ABSTRACT FROM AUTHOR]

Forest models are instrumental for understanding and projecting the impact of climate change on forests. A considerable number of forest models have been developed in the last decades. However, few systematic and comprehensive model comparisons have been performed in Europe that combine an evaluation of modelled carbon and water fluxes and forest structure. We evaluate 13 widely used, state‐of‐the‐art, stand‐scale forest models against field measurements of forest structure and eddy‐covariance data of carbon and water fluxes over multiple decades across an environmental gradient at nine typical European forest stands. We test the models' performance in three dimensions: accuracy of local predictions (agreement of modelled and observed annual data), realism of environmental responses (agreement of modelled and observed responses of daily gross primary productivity to temperature, radiation and vapour pressure deficit) and general applicability (proportion of European tree species covered). We find that multiple models are available that excel according to our three dimensions of model performance. For the accuracy of local predictions, variables related to forest structure have lower random and systematic errors than annual carbon and water flux variables. Moreover, the multi‐model ensemble mean provided overall more realistic daily productivity responses to environmental drivers across all sites than any single individual model. The general applicability of the models is high, as almost all models are currently able to cover Europe's common tree species. We show that forest models complement each other in their response to environmental drivers and that there are several cases in which individual models outperform the model ensemble. Our framework provides a first step to capturing essential differences between forest models that go beyond the most commonly used accuracy of predictions. Overall, this study provides a point of reference for future model work aimed at predicting climate impacts and supporting climate mitigation and adaptation measures in forests. [ABSTRACT FROM AUTHOR]

While the importance of permanent grasslands (PG) for the conservation of high nature value habitats is often acknowledged, their role in most of the main sustainable food system scenarios published in the last few years is less explicit. In the best case, the place of permanent grassland in scenarios and policy agendas is their conservation; in the worst one, they are simply replaced by afforested land or cropland, considered as a better option when the focus is on GHG emissions only. In this paper, we defend the idea that several misinterpretations of the positive and negative impacts of ruminants, the 'natural' users of PG, explain why ruminants are poorly addressed by most scenarios. Based on the findings of an agroecological scenario for Europe—TYFA, standing for Ten Years For Agroecology—in which extensive permanent grassland and ruminants together play a prominent role for biodiversity conservation, nitrogen cycling and climate change mitigation and adaptation, we call for a research agenda that would better inform the specific role of PG in the provision of ecosystem services—and in particular those that depend on nitrogen management. [ABSTRACT FROM AUTHOR]

Substantial amounts of money have been invested in peatland restoration over the last decades to address the current challenges of global changes and to enhance biodiversity. Given the magnitude of financial investments and the pressing societal needs, it is essential that appropriate decisions are made about the restoration techniques employed to avoid negative consequences and to optimise the benefits to human society.Based on the knowledge and expertise that has been developed over recent decades, three approaches to peatland restoration are discussed regarding their implications for climate change, nutrient fluxes and biodiversity: peatland inundation, topsoil removal and slow rewetting.Considered over the long term, for instance tens or hundreds of years, rewetted peatlands have the potential to fulfil multiple restoration goals, including those targeting climate change mitigation, water quality protection and species conservation. In short term, ill‐informed decisions on the approach to peatland restoration can generate negative impacts, for instance on the downstream water quality or radiative forcing gas emissions.Synthesis and application. The restoration of peatlands, and the trajectory that any restorative action may take, is a matter of societal choice; however, it is essential that society understands the broad potential benefits and disadvantages that such restoration may have so that evidence‐based choices can be made. [ABSTRACT FROM AUTHOR]

Recent climate change mitigation strategies rely on the reduction of methane (CH 4) emissions. Carbon and hydrogen isotope ratio (δ13 C CH4 and δ2 H CH4) measurements can be used to distinguish sources and thus to understand the CH 4 budget better. The CH 4 emission estimates by models are sensitive to the isotopic signatures assigned to each source category, so it is important to provide representative estimates of the different CH 4 source isotopic signatures worldwide. We present new measurements of isotope signatures of various, mainly anthropogenic, CH 4 sources in Europe, which represent a substantial contribution to the global dataset of source isotopic measurements from the literature, especially for δ2 H CH4. They improve the definition of δ13 C CH4 from waste sources, and demonstrate the use of δ2 H CH4 for fossil fuel source attribution. We combined our new measurements with the last published database of CH 4 isotopic signatures and with additional literature, and present a new global database. We found that microbial sources are generally well characterised. The large variability in fossil fuel isotopic compositions requires particular care in the choice of weighting criteria for the calculation of a representative global value. The global dataset could be further improved by measurements from African, South American, and Asian countries, and more measurements from pyrogenic sources. We improved the source characterisation of CH 4 emissions using stable isotopes and associated uncertainty, to be used in top-down studies. We emphasise that an appropriate use of the database requires the analysis of specific parameters in relation to source type and the region of interest. The final version of the European CH 4 isotope database coupled with a global inventory of fossil and non-fossil δ13 C CH4 and δ2 H CH4 source signature measurements is available at 10.24416/UU01-YP43IN. [ABSTRACT FROM AUTHOR]

In resisting climate change, to what extent can lifestyle forms of activism be considered to be political? What are their determinants and to what extent do they differ from the determinants of other forms of action? What role do generational factors play? Does the centrality of lifestyle changes for young participants translate into a disaffection towards more traditional forms of action? This article explores the forms of action adopted by participants in two Fridays For Future (FFF) strikes, focusing on the repertoires of action of (young) climate justice protesters. We draw on protest survey data covering the FFF demonstrations held in 15 European countries in March and September 2019. Starting from a sharp generational contrast between the importance given to individual lifestyle changes in addressing the climate emergency, we investigate whether this results in significant generational differences in the choice of the repertoires of action. Challenging the vision of young people as 'disaffected citizens', it is demonstrated that young protesters do not participate less in claim-based action than older cohorts. Furthermore, a process of politicisation can be seen to be unfolding that leads to increased commitment in both lifestyle and political forms of participation – at least among active milieus. [ABSTRACT FROM AUTHOR]

This study investigates the potential of utilizing carbon credits to finance innovative local energy communities in Europe, addressing a significant gap in academic literature. Despite the growing interest in voluntary carbon credits as a mechanism for offsetting carbon emissions, there is limited evidence connecting local energy systems to voluntary carbon markets. The study explores whether carbon credits could serve as a practical tool for funding the development of energy communities, contributing to sustainable energy transitions and climate mitigation strategies. The research employs a comprehensive methodology to assess the quality of carbon credit projects and examines ten innovative energy community projects in Europe. Key findings reveal there is potential for using carbon credits to finance energy community initiatives. However, challenges persist, particularly regarding financing barriers and the volatile nature of carbon markets. The study underscores the importance of policy support in establishing clear standards for voluntary markets and promoting the accessibility of carbon offsets. Furthermore, it suggests potential solutions such as pre-financing agreements and the utilization of carbon market derivatives to enhance project viability. Overall, the study offers insights into the intersection between voluntary carbon markets and local energy initiatives, providing a foundation for further research and policy development in the field of local sustainable development and climate change mitigation. [Display omitted] • Innovative local energy communities in Europe have significant carbon emissions reduction potential. • Carbon credit issuance could financially support the development of local energy initiatives. • Challenges persist in accessing financing and navigating volatile carbon markets. • Policy support is crucial in establishing clear standards for voluntary carbon markets. [ABSTRACT FROM AUTHOR]

Unlocking the full potential of ponds (small water bodies) and pondscapes (network of ponds) as Nature-based Solutions (NbS) is critical pursuit for enhancing ecosystems and societal resilience to climate change and other societal challenges. Despite scattered initiatives for pond/pondscape creation, restoration and management—each considered here a distinct NbS—there is a significant knowledge gap in utilising ponds/pondscapes as effective NbS. We aimed to assess these NbS in terms of their objectives, outcomes, effectiveness, multifunctionality, delivery of potentially conflicting effects, and the implementation process while considering their Nature's Contributions to People (NCPs, i.e., benefits to society). We compiled data on 183 NbS actions implemented across 93 ponds/pondscapes from 24 countries, predominantly from Europe, via a questionnaire distributed to experienced stakeholders implementing NbS in ponds/pondscapes. One single pond/pondscape may imply more than one NbS action. Two-thirds were in rural areas, and one-third in urban settings. Our analysis revealed that Creation of habitat for biodiversity was a primary delivery objective (targeted NCP) in the implementation of most NbS in ponds/pondscapes, often also combined with other NCPs such as Learning and inspiration , Regulation of water quantity , and Physical and psychological experiences , showcasing their intended multifunctionality. Implemented NbS primarily focused on climate change adaptation (especially Regulation of hazards and extreme events , and water quantity) rather than mitigation, with less emphasis on measures like direct greenhouse gas emissions reduction or enhancing carbon sinks. The costs associated with pond's NbS varied significantly depending on factors such as project scope, objectives, location, socio-economic-cultural system, and specific implementation requirements. The creation of ponds/pondscapes often entailed the highest financial investment, much more than their restoration or their management. In conclusion, our study underscores the multifunctionality of ponds/pondscapes and provides insights about their significant potential as cost-effective NbS for enhancing ecosystem and societal resilience to climate change and biodiversity. It underscores the importance of further research to fully understand and measure the diverse range of NbS they offer, particularly in the context of climate change mitigation. Standardised measurements of the NCP provided by these NbS in ponds/pondscapes are essential for validating managers' claims and exploring their role in addressing climate change. Cascading Benefits of Natural-Based Solutions (NbS) in Ponds and Pondscapes: Ponds and pondscapes serve as multifunctional NbS, delivering multiple Nature's Contributions to People (NCPs) to address climate-related challenges and Sustainable Development Goals (SDGs). They regulate the water quantity, mitigating flood risks, and ensuring water availability during droughts. Furthermore, these NbS indirectly support climate change adaptation by preserving microclimates, buffering temperature fluctuations, and providing vital habitats for diverse species, enhancing ecosystem resilience. Simultaneously, these actions offer recreational, cultural, educational, and well-being benefits to local communities impacted by climate change. Despite their potential, the capacity of ponds and pondscapes for climate change mitigation through carbon sequestration and storage remains unknown, requiring further exploration. [Display omitted] • Global study of 183 Nature-based Solutions in ponds/pondscapes in 24 countries. • Pondscapes' Nature-based Solutions are multifunctional and prioritise biodiversity. • Emphasis on climate change adaptation rather than mitigation. • Ponds/pondscapes offer cost-effective Nature-based Solutions. • Need for standardised measures to validate claims and explore climate mitigation. [ABSTRACT FROM AUTHOR]

Biochar (BC) is often proposed as a tool for climate change mitigation, due to the expected long lifetime in the environment. However, BC's stability can vary depending on feedstock type and the presence of labile carbon fractions. In this study, we verify the recent methods with new possible tools for biochar stability assessment on six different biochars derived from commonly available Europe biomass sources. Elemental composition (CHNO), dissolved organic carbon (DOC) and water-soluble carbonates content (WSC), volatile organic compounds (VOCs) composition, and mid-infrared spectra (MIR) were performed to estimate the persistence of biochars. Under similar conditions of pyrolysis, biochar properties can vary depending on a feedstock origin. Less aromatic structure and higher contents of labile carbon fractions (DOCs and WSC) in food waste biochars affected the lower stability, while biochars derived from high lignocellulose materials (straw, wood, and grass) were strongly carbonized, with persistent, aromatic structure. Labile carbon pool content (DOC, WSC) and spectral analysis can be useful tools for biochar stability assessment, giving similar information to the standard molar ratio method. Biochars obtained from agriculture and forestry management biomass should be considered as highly stable in soil and are appropriate for long-term carbon sequestration purposes. [ABSTRACT FROM AUTHOR]

Decarbonizing heating in buildings is a key part of climate change mitigation policies, but deep retrofit is progressing slowly, e.g., at a pace of 0.2%/y of the building stock in Europe. By means of tests in two flats of a multiapartment housing complex recently renovated to very low values of energy needs, this paper explores the role of deep retrofitted buildings in providing energy flexibility services for the occupants/owners/managers and for the energy system. Key to this flexibility increase and capacity savings is the large reduction of energy needs for heating via a high level of external insulation, which allows the thermal capacity of the building mass to act as an energy storage, without the large energy losses presently affecting a large part of the building stock. Due to the limited number of case studies reporting experimental applications in real buildings, this research aims to offer an analysis based on a series of tests and detailed monitoring which show a significant increase in the time interval during which the low-energy-needs building remains in the comfort range, compared to a high-energy-needs building, when active delivery of energy is deactivated during the heating season. Intermittent renewable energy might hence be stored when available, thus enhancing the ability of the energy system to manage inherent variability of some renewable energy sources and/or increasing the share of the self-consumption of locally generated RES energy. Besides, two unplanned heating power outages which have involved the entire building complex allowed us to verify that deep retrofitted buildings are able to maintain thermally safe indoor conditions under extreme events, such as a power outage, for at least 5 days. [ABSTRACT FROM AUTHOR]

Mountain spruce forests in Central Europe decline under storms and bark beetle calamities driven by climate change. A stabilisation by planting rare or missing tree species is expensive and requires funding. A funding policy should mitigate climate change and support biodiversity. The goal of this study was to identify a conversion strategy of even-aged spruce-dominated forest stands to uneven-aged mixed stands with spruce (Picea abies (L.) H.Karst.), beech (Fagus sylvatica L.), and fir (Abies alba Mill.). A simultaneous nonlinear optimisation of the number of planted trees and harvested trees per species and per period schedules stand treatments aiming to maximise the long-term financial outcome. Planting modelling extends a density-dependent stand-level matrix transition model based on diameter classes with an age-class-based model for artificial regeneration. An optimal conversion strategy was applied for five funding policy schemes, each for five initial states representing different stages of age and species composition typical for spruce forest conversion in the mountain zone of the Western Carpathians. Only 50% and higher funding of planting costs for the minor/missing fir and beech species facilitates a substantial increase of their shares in stand volume. Funding decreases the volume failure due to mortality. Funding increases the standing and harvested volume, which mitigates climate change by increasing the carbon sequestration. Funding causes unintended effects on ecosystem services by lowering harvest diameters, decreasing the volume of less profitable beech, and temporarily reducing the stand density aimed at supporting plantings and their diameter increments. [ABSTRACT FROM AUTHOR]

The extensive use of fossil fuels in recent decades is a well-known cause of the climate crisis. Climate action inevitably requires the strategic reorientation of industries that are part of the fossil fuel regime. International oil companies are central to this regime and possess the incumbent's characteristic power and influence to steer this process. However, European international oil companies continue to invest in fossil fuels, even as they acknowledge the climate crisis imperative. Socio-political and economic dynamics can either reinforce the oil regime or pressure firms to take climate action. We aim to comprehensively analyse the dynamics between external socio-political and economic actors' pressures to climate action on the one side, and the industry response on the other, from 2005 to 2019, using Geels Triple Embeddedness Framework. Drawing on a wide range of qualitative and quantitative longitudinal data (e.g. regulations, oil and renewables market trends, companies' investments in oil, renewables, and low-carbon technologies), we characterised the pressures and responses of the different analytical categories and established three phases. The results indicate that policy pressure on the oil regime in this period lacked constancy and comprehensiveness. The Kyoto Protocol ratification produced an initial momentum that prompted some companies to invest in alternative fuels and renewables, but efforts faded after 2010. Societal calls for a transition from fossil fuels and divestments from oil companies have risen since 2017. Recent socio-economic pressures combined with policy pledges for net-zero emissions have prompted all companies to invest beyond fossil fuels. However, efforts are still marginal and additional advancements in climate policy are necessary to foster the renewables market and to promote the phase-out of oil. Key policy insights Europe lacks a comprehensive policy framework to support the fast deployment of available alternative fuels. Policies need to foster the development and adoption of alternatives to petrochemical products, alongside their reduction and recycling. Apart from supporting renewable energy and other alternatives to oil, policies also need to target the phase-out of oil and send a clear signal to companies. [ABSTRACT FROM AUTHOR]

Construction using timber has seen a resurgence in light of global climate mitigation policies. Wood is a renewable resource, and engineered wood products are proving to be competitive against concrete and steel while having several advantages. However, while the renewable nature of wood in construction is a beneficial property for climate mitigation policies, the process of biodegradation introduces a challenge for service life planning. A review of hazard mapping is presented while developing contemporary hazard maps, occurrence maps and projected hazard maps for 2050 using representative concentration pathways (RCP) 2.6 and 8.5. The risk of timber decay is expected to increase in most of Europe as the temperatures rise, with a decrease expected in dryer regions. Termites are likely to experience a range expansion as more areas become suitable, while human activity and an increase in extreme weather events like floods are expected to facilitate dispersion. Marine borer species already present a risk in most European coastal regions; however, the effect of changes in water temperatures are likely to shift the boundaries for individual borer species. Overall, warmer climates are expected to increase the metabolic activity of all of these organisms leading to a general reduction in service life. [ABSTRACT FROM AUTHOR]

Despite the EU's ambitious goals regarding the expansion of marine renewables as a promising climate mitigation and energy security measure, the majority of hydrocarbon exploitation continues occurring offshore with more than 500 oil and gas installations operating in European seas. Given the grave environmental risks these activities pose, the EU has developed secondary rules with implications for the regulation of offshore energy generation. These normative developments have added an extra layer of regional, supra-national regulation of ocean energy production across European seas, which necessarily interacts with the simultaneously applicable rules under regional sea agreements. The article examines the implications of the normative interplay between EU law and regional sea agreements in terms of shaping the environmental regulation of offshore energy production across Europe. In that respect, it explores whether EU law instruments and the EU's sophisticated institutional framework can enhance the rules and standards under the regional sea agreements, in terms both of adding normative content to them and supporting their enforcement. In light of the mutual cross-fertilization between the two applicable regimes, the article equally looks into the normative impact of regional sea conventions on the EU legal framework and its implementation in the context of offshore energy production. [ABSTRACT FROM AUTHOR]

• The nexus between forest-based climate mitigation and health is poorly researched. • This scoping review identified exposure pathways and health co-benefits from forests. • There is potential for synergies between forest management and health benefits. • Interdisciplinary efforts are required for advancement of research and understanding. Climate change is a pressing global challenge with profound implications for human health. Forest-based climate change mitigation strategies, such as afforestation, reforestation, and sustainable forest management, offer promising solutions to mitigate climate change and simultaneously yield substantial co-benefits for human health. The objective of this scoping review was to examine research trends related to the interdisciplinary nexus between forests as carbon sinks and human health co-benefits. We developed a conceptual framework model, supporting the inclusion of exposure pathways, such as recreational opportunities or aesthetic experiences, in the co-benefit context. We used a scoping review methodology to identify the proportion of European research on forest-based mitigation strategies that acknowledge the interconnection between mitigation strategies and human impacts. We also aimed to assess whether synergies and trade-offs between forest-based carbon sink capacity and human co-benefits has been analysed and quantified. From the initial 4,062 records retrieved, 349 reports analysed European forest management principles and factors related to climate change mitigation capacity. Of those, 97 studies acknowledged human co-benefits and 13 studies quantified the impacts on exposure pathways or health co-benefits and were included for full review. Our analysis demonstrates that there is potential for synergies related to optimising carbon sink capacity together with human co-benefits, but there is currently a lack of holistic research approaches assessing these interrelationships. We suggest enhanced interdisciplinary efforts, using for example multideterminant modelling approaches, to advance evidence and understanding of the forest and health nexus in the context of climate change mitigation. [ABSTRACT FROM AUTHOR]

In Europe, increasing the area of legume crops has been identified as a key measure to achieve the objectives set by the European Green Deal and transition toward more sustainable food systems. Although the role of grain legumes in climate change mitigation has been closely examined, little research has focused on how climate change will challenge the development of these crops. This article systematically reviews recent simulation studies to assess the impact of climate change on grain legume performances in Europe and the effect of adaptation strategies. Forty papers using process-based, ecological niche, or statistical models were selected to simulate the response of eight grain legume species to future climate (2020–2100) in Europe. The lack of data on adaptation strategies in Europe was compensated for by enlarging the study area to climatically similar regions. The review highlights a notable imbalance between research about soybean versus other grain legumes, with soybean representing approximately 80% of selected studies. Studies focused on soybean found good agreement, with yield or suitability gains found in northern Europe and a higher probability of yield losses in southern and south-eastern Europe. While a similar spatial pattern may be expected for other grain legumes, the scarcity of data makes this result more uncertain. The review also shows that several adaptation strategies have the potential to mitigate the negative impact of climate change on grain legume performances or enhance its positive impact. The most promising strategies tested include irrigation, change in sowing date, and cultivar choice. In addition, we identify several knowledge gaps that, if addressed, would support legume development in Europe. In particular, key species such as field pea, faba bean, lentil, and chickpea remain blind spots, despite their prominent role in European environmental, agricultural, and nutritional policies. Other knowledge gaps include a lack of accounting for crop response to elevated CO 2 , ozone, and future biotic pressure, and a limited range of adaptation strategies tested and indicators assessed. Implementing multi-criteria analyses that involve stakeholders would help identify relevant inputs and outputs for future simulations. • We review 40 papers assessing grain legume response to climate change in Europe. • Grain legumes other than soybean are blind spots despite their role in policies. • For soybean, yield gains are expected in the north and yield losses in the south. • Adaptation strategies can mitigate the impact of climate change on grain legumes. • We identify several knowledge gaps, including a lack of data on key legume species. [ABSTRACT FROM AUTHOR]

Recent climate change mitigation strategies rely on the reduction of methane (CH4) emissions. δ13CCH4 and δ²HCH4 measurements can be used to distinguish sources and thus to understand the CH4 budget better. The CH4 emission estimates by models are sensitive to the isotopic signatures assigned to each source category, so it is important to provide representative estimates of the different CH4 source isotopic signatures worldwide. We present new measurements of isotope signatures of various, mainly anthropogenic, CH4 sources in Europe, which represent a substantial contribution to the global dataset of source isotopic measurements from the literature, especially for δ²HCH4. They improve the definition of δ13CCH4 from waste sources, and demonstrate the use of δ²HCH4 for fossil fuel source attribution. Results from previous studies were combined in a common database that we updated with our new measurements, as well as with additional literature. We found that microbial sources are generally well characterised. The large variability in fossil fuels isotopic compositions requires particular care in the choice of weighting criteria for the calculation of a representative global value. The global dataset could be further improved by measurements from African, South American and Asian countries, as well as more measurements from pyrogenic sources. The final version of the European methane isotope database coupled with a global inventory of fossil and non-fossil δ13CCH4 and δ²HCH4 source signature measurements, is available at: https://doi.org/10.24416/UU01-4PO56T (Menoud et al., 2021a). [ABSTRACT FROM AUTHOR]

Trees absorb CO 2 and reduce the impact of GHGs. This paper deals about the carbon uptake dynamics produced by the management of unused lands as tool to help the fulfilment of international commitments on atmospheric CO 2. The paper introduces a new perspective of using the unused lands around Municipalities to compensate the carbon emissions of urban contexts, according to the Sustainable Energy Action Plans as answer to climate change, already approved by the most part of Cities in Europe. The model of the carbon dynamics is based on a genetic algorithm which allows to find the sequence of operations on the unused land in space (portions of the land) and time (rotation of cuts and plantations) to ensure the reaching of a given outcome in terms of carbon captured. The algorithm, therefore, behaves as design support of land management, enriching the literature available for the sector. The paper identifies two possible original scenarios of storing carbon referred as " emergency " and " constant rate "; the first produces after fifty years a maximum carbon uptake of the order of 100 tC/ha while the second a maximum uptake rate of the order of 2 tC/(year ha), after an initial start-up period of 40–50 years. • Mathematical model to evaluate tree growth and carbon sink from reforestation. • Optimization model to manage the carbon uptake in different scenarios. • Forest represents an effective way to remove carbon from atmosphere. • Carbon stock per unit of unused areas around cities and urban area. • Climate mitigation tool suitable by municipality in the context of SECAPs. [ABSTRACT FROM AUTHOR]

Solar photovoltaics (PV) plays an essential role in decarbonizing the European energy system. However, climate change affects surface solar radiation and will therefore directly influence future PV power generation. We use scenarios from Phase 6 of the Coupled Model Intercomparison Project (CMIP6) for a mitigation (SSP1-2.6) and a fossil-fuel-dependent (SSP5-8.5) pathway in order to quantify climate risk for solar PV in Europe as simulated by the Global Solar Energy Estimator (GSEE). We find that PV potential increases by around 5 % in the mitigation scenario, suggesting a positive feedback loop between climate change mitigation and PV potential. While increased clear-sky radiation and reduced cloud cover go hand in hand in SSP1-2.6, the effect of a decrease in clear-sky radiation is outweighed by a decrease in cloud cover in SSP5-8.5, resulting in an increase in all-sky radiation. Moreover, we find that the seasonal cycle of PV generation changes in most places, as generation grows more strongly in winter than in summer (SSP1-2.6) or increases in summer and declines in winter (SSP5-8.5). We further analyze climate change impacts on the spatial variability of PV power generation. Similar to the effects anticipated for wind energy, we report an increase in the spatial correlations of daily PV production with large inter-model agreement yet relatively small amplitude, implying that PV power balancing between different regions in continental Europe will become more difficult in the future. Thus, based on the most recent climate simulations, this research supports the notion that climate change will only marginally impact renewable energy potential, while changes in the spatiotemporal generation structure are to be expected and should be included in power system design. [ABSTRACT FROM AUTHOR]

Aim: Forest herbs might be unable to track shifts in habitat suitability due to rapid climate change and habitat fragmentation. In this study, we quantified the role of dispersal limitation and the potential mitigating effect of large‐scale reforestation on the redistribution of the herbaceous forest plant species Primula elatior under climate change. Location: Europe. Methods: High resolution (100 m) landscape‐scale and macro‐climatic variables were combined to predict range‐wide habitat suitability using Maxent. Dispersal limitation was modelled, based on isolation‐by‐resistance (IBR) principles through integration of circuit theory and genomic data, to assess patch accessibility and metapopulation stability under climate change. Large‐scale reforestation was evaluated as a potential mitigating strategy by incorporating a land use change scenario into the distribution and dispersal models. Results: Landscape‐scale variables contributed significantly to the distribution of P. elatior (78.33%) and to the accuracy of our model (AUC = 0.81). Isolation‐by‐resistance (R2cond =.92) was driven by land use (45.5%), distance from rivers (36.4%) and elevation (18.2%). It was estimated that 46.4 ± 13.9% (mean ± SD of climate change scenarios) of the total distribution area would be lost due to climate change by 2050 and an additional 15.6 ± 1.7% (mean ± SD) of the distribution would not be accessible through migration. The median latitude of the patch distribution shifted 183.2 ± 34.8 km (mean ± SD) northwards and 58.1 ± 9.3 km (mean ± SD) to more maritime regions. The patch accessibility was low in these regions and the metapopulation stability decreased considerably in the south of the distribution. Reforestation mitigated 54.1 ± 18.2% (mean ± SD) of the accessible distribution area loss and 49.5 ± 4.2% (mean ± SD) of the decrease in metapopulation stability. Main conclusion: To alleviate the loss of the accessible distribution area of P. elatior under climate change, it will be required to integrate climate mitigation strategies (RCP 2.6), range‐wide afforestation, restoration of ecological connectivity and focused assisted migration to newly available habitat. [ABSTRACT FROM AUTHOR]

Identifying areas that contain species assemblages not found elsewhere in a region is central to conservation planning. 1,2 Species assemblages contain networks of species interactions that underpin species dynamics, 3,4 ecosystem processes, and contributions to people. 5,6,7 Yet the uniqueness of interaction networks in a regional context has rarely been assessed. Here, we estimated the spatial uniqueness of 10,000 terrestrial vertebrate trophic networks across Europe (1,164 species, 50,408 potential interactions 8) based on the amount of similarity between all local networks mapped at a 10 km resolution. Our results revealed more unique networks in the Arctic bioregion, but also in southern Europe and isolated islands. We then contrasted the uniqueness of trophic networks with their vulnerability to human footprint and future climate change and measured their coverage within protected areas. This analysis revealed that unique networks situated in southern Europe were particularly exposed to human footprint and that unique networks in the Arctic might be at risk from future climate change. However, considering interaction networks at the level of trophic groups, rather than species, revealed that the general structure of trophic networks was redundant across the continent, in contrast to species' interactions. We argue that proactive European conservation strategies might gain relevance by turning their eyes toward interaction networks that are both unique and vulnerable. • The interaction dissimilarity between networks can measure their spatial uniqueness • Networks in southern Europe are unique and vulnerable to human footprint • Networks in the Arctic are unique and vulnerable to future climate change • Considering trophic groups instead of interactions, networks are rather redundant Gaüzère et al. estimate the spatial uniqueness of vertebrates' trophic networks in Europe based on interaction dissimilarities. Unique networks situated in southern Europe are exposed to human footprint, while Arctic ones are at risk from future climate change. In terms of functional groups, trophic networks are redundant across Europe. [ABSTRACT FROM AUTHOR]

The management of Soil Organic Carbon (SOC) is a critical component of both nature-based solutions for climate change mitigation and global food security. Agriculture has contributed substantially to a reduction in global SOC through cultivation, thus there has been renewed focus on management practices which minimize SOC losses and increase SOC gain as pathways towards maintaining healthy soils and reducing net greenhouse gas emissions. Mechanistic models are frequently used to aid in identifying these pathways due to their scalability and cost-effectiveness. Yet, they are often computationally costly and rely on input data that are often only available at coarse spatial resolutions. Herein, we build statistical meta-models of a multifactorial crop model in order to both (a) obtain a simplified model response and (b) explore the biophysical determinants of SOC responses to management and the geospatial heterogeneity of SOC dynamics across Europe. Using 5600 unique simulations of crop growth from the gridded Environmental Policy Integrated Climate-based Gridded Agricultural Model (EPIC-IIASA GAM) covering 86,000 simulation units across Europe, we build multiple polynomial regression ensemble meta-models for unique combinations of climate and soil across Europe in order to predict SOC responses to varying management intensities. We find that our biophysically-explicit meta models are highly accurate (R2 = 0.97) representations of the full mechanistic model and can be used in lieu of the full EPIC-IIASA GAM model for the estimation of SOC responses to cropland management. Model stratification by means of climate and soil clustering improved the performance of the meta-models compared to the full EU-scale model. In regional and local validations of the meta-model predictions, we find that the meta-models largely capture broad SOC dynamics such as the linear nature of SOC responses to residue application, yet they often underestimate the magnitude of SOC responses to management. Furthermore, we find notable differences between the results from the biophysically-specific models throughout Europe, which point to spatially-distinct SOC responses to management choices such as nitrogen fertilizer application rates and residue retention that illustrate the potential for these models to be used for future management applications. While more accurate input data, calibration, and validation will be needed to accurately predict SOC change, we demonstrate the use of our meta-models for biophysical cluster and field study scale analyses of broad SOC dynamics with basically zero fine-tuning of the models needed. This work provides a framework for simplifying large-scale agricultural models and identifies the opportunities for using these meta-models for assessing SOC responses to management at a variety of scales. • Meta-model approach used to simplify process based crop model. • Exploration of the determinants of soil organic carbon responses to management. • Meta-model predictions validated with regional and local data. • Meta-models largely capture broad dynamics, underestimate magnitude of responses. • More accurate input data, calibration, and validation needed to improve accuracy. [ABSTRACT FROM AUTHOR]

• Assessing generalizability of age prediction across cities and countries based on urban form. • Evaluating amount of local data needed to fill data gaps. • Detailed analysis of predictive performance across regions, construction periods, settlement and buildings types. • Assessing the usability of predictions to improve prioritization of large-scale retrofits. • Highlighting climate relevance of scalable, spatially explicit building attribute prediction. • Filling data gaps within countries is possible. • 10% local data allow inference of remaining unknown building ages. • Massive training data improves generalization across regions. • Generalizing across countries is not (yet) possible. • Age predictions can inform retrofit policies and may significantly increase energy savings. To stay within 1.5 °C of global warming, reducing energy-related emissions in the building sector is essential. Rather than generic climate recommendations, this requires tailored, low-carbon urban planning solutions and spatially explicit methods that can inform policy measures at urban, street and building scale. Here, we propose a scalable method that is able to predict building age information in different European countries using only open urban morphology data. We find that spatially cross-validated regression models are sufficiently robust to generalize and predict building age in unseen cities with a mean absolute error (MAE) between 15.3 years (Netherlands) and 19.9 years (Spain). Our experiments show that large-scale models improve generalization for predicting across cities, but are not needed to infer missing data within known cities. Filling data gaps within known cities is possible with a MAE between 9.6 years (Netherlands) and 16.7 years (Spain). Overall, our results demonstrate the feasibility of generating missing age data in different contexts across Europe and informing climate mitigation policies such as large-scale energy retrofits. For the French residential building stock, we find that using age predictions to target retrofit efforts can increase energy savings by more than 50% compared to missing age data. Finally, we highlight challenges posed by data inconsistencies and urban form differences between countries that need to be addressed for an actual roll-out of such methods. [ABSTRACT FROM AUTHOR]

Extensive scientific literature exists on the risks associated with climate change in cities. Contrarily, the analysis on the risks local governments face in moving towards zero emissions targets is sparse, topical, and local. In this study, we provide a first-of-its-kind synoptic risk analysis directly based on cities' experiences, inputs, and prospects for the future, collated through the questionnaire to express interest in the European Mission for 100 Climate-Neutral and Smart Cities by 2030. This novel dataset contains a variety of information 362 cities provided in relation to all critical (technological and non-technological) elements that contribute to climate mitigation, while enucleating the risks that may arise along the way. The analysis focuses on nine risk domains (including political, financial, regulatory, operational, organisational, collaborative, social, environmental, and safety/security risks) and delves into possible solutions. These insights will be extremely useful and timely to i) design precautions and safeguards, ii) motivate new policies and instruments, iii) inform assistance services and forms of support, and iv) inspire other cities in the creation of an enabling and inclusive environment for zero-emission futures. Furthermore, the analysis reveals a substantial lack of supportive scientific literature when it comes to non-technological aspects of the transition to climate neutrality. [Display omitted] • A broad analysis of risks cities face in pursuing climate neutrality is performed. • The analysis builds on a unique survey of climate-ambitious cities. • Nine risk categories are identified and analysed. • Solutions and recommendations to design safeguards and precautions are extracted. [ABSTRACT FROM AUTHOR]

Scattered trees in wood-pastures represent outstanding conservation value by providing microhabitats for a variety of organisms. They also diversify ecosystem services by creating shade for livestock, and capturing and storing carbon. However, trees in wood-pastures are declining Europe-wide and an appropriate legal environment to maintain them is mostly lacking. Here we looked beyond the well-documented beneficial effects of trees and assessed potential ecosystem disservices, which may drive the controversial appreciation of trees. In a grazing exclusion experiment, we assessed the effect of trees on herbage production in wood-pastures from semi-arid continental to humid montane areas in the temperate deciduous forest ecoregion, and found that trees have a suppressive effect throughout the year, although herbage nutritive value, as indicated by herbage nitrogen content, seems to be improved in spring. When we up-scaled the local ecosystem disservice on herbage yield to entire wood-pastures, the loss remained below 3%, which is lower than reported gains in livestock production due to free access to shade. Thus, the motivation for the under-appreciation of trees by land managers and decision makers may lie in that trees suppress herbage production, but the importance of this effects is offset by the magnitude of the beneficial services of trees. We recommend current wood-pasture stakeholders to revisit their attitude towards scattered trees and encourage tree planting campaigns and tree-based climate mitigation strategies to consider the protection of trees in wood-pastures and the establishment of young ones in currently open pastures up to traditionally low tree cover proportions, as livestock production is unlikely to be compromised by this action. • Wood-pastures are widespread, high nature and cultural value landscapes. • Scattered trees in wood-pastures boost biodiversity and diversify ecosystem services. • In temperate deciduous forest ecoregions, they reduce sub-canopy biomass production. • When scaled up to the whole wood-pasture, the loss of biomass remains negligible. • Climate strategies are encouraged to involve scattered trees on pastureland. [ABSTRACT FROM AUTHOR]

• MAOM-C content was modeled for arable fields with different management. • Organic fertilization, crop rotation, and soil texture define MAOM-C content. • A POM-C/MAOM-C ratio indicator was developed and tested. • This indicator contains information on MAOM-C saturation deficits. • POM-C/MAOM-C ratio indicators might support climate mitigation strategies. Soil organic matter (SOM) is indispensable for soil health and, in the context of climate change, is considered a significant CO 2 sink. Improving agricultural management to increase long-term soil organic carbon (SOC) stocks for mitigating climate change requires tools that estimate short and long-cycling SOM pools. In this study, we analyzed changes in fast-cycling particulate organic matter (POM) and slow-cycling mineral-associated organic matter (MAOM) induced by common management practices, i.e., fertilization and crop rotation in topsoils from 25 Central European long-term field experiments. When relating MAOM-C contents to recent MAOM-C saturation levels, estimated sequestration potentials were only met in coarse-textured soils under appropriate agricultural management or fine-textured soils under extreme organic fertilization. Soil texture, organic fertilization, and below-ground OC inputs through root exudates and root biomass were decisive for estimating MAOM-C, allowing for calibration of a mixed-effects model (Nakagawa's: marginal R2 m = 0.6, conditional R2 c = 0.89). While the models containing soil texture and organic fertilization parameters can be validated and generalized (R2 = 0.43), the below-ground OC input predictor substantially decreases the generalizability of the validated models (R2 = 0.14). According to quantile regression models, we estimate the average difference in MAOM-C concentration between well-managed and control site (without organic fertilization) topsoils to 4.1 mg g−1 soil. In dependence on the soil bulk density, this amounts to 1.38 – 1.84 t ha−1 MAOM-C stocks or 5.06 – 10.1 t ha−1 CO 2 -equivalents. POM-C was difficult to predict (R2 = 0.28), presumably due to strong POM dynamics. The POM-C / MAOM-C ratio can inform on the effects of agricultural practices in before/after management change comparisons. Under increasing SOC concentration, an increasing POM-C / MAOM-C ratio indicates that the effects of organic fertilization do not transfer to real effects on long-term SOC sequestration. Because MAOM-C depends on soil texture, this ratio is also a covariate of soil texture, limiting it for comparisons between sites with different textures. However, our data indicate that agricultural long-term field experiment soils constantly approximate MAOM-C saturation when the POM-C/MAOM-C ratio is >0.35. This ratio might be used as a management goal to prevent organic over-fertilization and N loss, especially on coarse-textured soils. Thereby, the POM-C / MAOM-C ratio can help to optimize SOC management and sequestration on agricultural soils and support climate change mitigation strategies in Central Europe. [ABSTRACT FROM AUTHOR]

The ongoing global climate change is challenging all sectors, forestry notwithstanding. On the one hand, forest ecosystems are exposed to and threatened by climate change, but on the other hand, forests can influence the course of climate change by regulating the water regime, air quality, carbon sequestration, and even reduce climate extremes. Therefore, it is crucial to see climate change not only as a risk causing forest disturbances and economic consequences but also as an opportunity for innovative approaches to forest management, conservation, and silviculture based on the results of long-term research. We reviewed 365 studies evaluating the impact of climate change on European forest ecosystems, all published during the last 30 years (1993–2022). The most significant consequences of climate change include more frequent and destructive large-scale forest disturbances (wildfire, windstorm, drought, flood, bark beetle, root rot), and tree species migration. Species distribution shifts and changes in tree growth rate have substantial effects on ecosystem carbon storage. Diameter/volume increment changed from −1 to +99% in Central and Northern Europe, while it decreased from −12 to −49% in Southern Europe across tree species over the last ca. 50 years. However, it is important to sharply focus on the causes of climate change and subsequently, on adaptive strategies, which can successfully include the creation of species-diverse, spatially and age-wise structured stands (decrease drought stress and increase production), prolongation of the regenerative period, or the use of suitable introduced tree species (e.g., Douglas fir, black pine, and Mediterranean oaks). But the desired changes are based on increasing diversity and the mitigation of climate change, and will require significantly higher initial costs for silviculture practices. In conclusion, the scope and complexity of the topic require further comprehensive and long-term studies focusing on international cooperation. We see a critical gap in the transfer of research results into actual forest practice, which will be the key factor influencing afforestation of forest stands and forest growth in the following decades. What our forests will look like for future generations and what the resulting impact of climate change will be on forestry is in the hands of forest managers, depending on supportive forestry research and climate change policy, including adaptive and mitigation strategies. • We review main factors influencing forest growth processes under climate change (CC). • We concentrate on potential direct and indirect impacts of CC on forest ecosystems. • Consequences of CC include large-scale forest disturbances and tree species migration. • Review is focused on management adaptive strategies and mitigation of CC. • Opportunity and risk of introduced tree species are discussed. [ABSTRACT FROM AUTHOR]

The residential sector has been targeted as the one with a huge potential for reducing carbon emissions. In order to determine the present carbon footprint and the potential for achieving carbon neutrality, the study examines electricity consumption in average households, whose electricity is supplied by their national power grids. 31 European countries (27 EU and 4 non-EU countries) were included in this analysis. Our results indicate that the annual carbon emissions of these average households range from 0.09 to 6.44 tCO 2 e (1.36 tCO 2 e on average), depending on a country. In addition, the calculated electricity costs per tCO 2 e emission for an average household vary significantly (from 94 to 10,135 EUR/tCO 2 e).Carbon offsetting is a mechanism which enables households to achieve carbon neutrality, i.e. households can compensate for the emissions caused by their electricity consumption by purchasing voluntary carbon offsets. This study also analyses the financial implications of purchasing voluntary carbon offsets. The results indicate that voluntary carbon offsets do not burden household budgets significantly because their share in total electricity costs is small. European households, particularly those in countries where electricity is more expensive, can comfortably achieve carbon neutrality with voluntary carbon offsets. In this way, they can contribute to global sustainable development. [Display omitted] • Average carbon footprint of grid-connected household in Europe is less than 2 tCO2e. • The cost of electricity per CO2 emissions varies from 94 to 10,135 EUR/tCO2. • Voluntary carbon offset costs in electricity costs vary widely across Europe. • Carbon offsetting is a practical solution for achieving a carbon-neutral household. [ABSTRACT FROM AUTHOR]

Climate-smart sustainable management of agricultural soil is critical to improve soil health, enhance food and water security, contribute to climate change mitigation and adaptation, biodiversity preservation, and improve human health and wellbeing. The European Joint Programme for Soil (EJP SOIL) started in 2020 with the aim to significantly improve soil management knowledge and create a sustainable and integrated European soil research system. EJP SOIL involves more than 350 scientists across 24 Countries and has been addressing multiple aspects associated with soil management across different European agroecosystems. This study summarizes the key findings of stakeholder consultations conducted at the national level across 20 countries with the aim to identify important barriers and challenges currently affecting soil knowledge but also assess opportunities to overcome these obstacles. Our findings demonstrate that there is significant room for improvement in terms of knowledge production, dissemination and adoption. Among the most important barriers identified by consulted stakeholders are technical, political, social and economic obstacles, which strongly limit the development and full exploitation of the outcomes of soil research. The main soil challenge across consulted member states remains to improve soil organic matter and peat soil conservation while soil water storage capacity is a key challenge in Southern Europe. Findings from this study clearly suggest that going forward climate-smart sustainable soil management will benefit from (1) increases in research funding, (2) the maintenance and valorisation of long-term (field) experiments, (3) the creation of knowledge sharing networks and interlinked national and European infrastructures, and (4) the development of regionally-tailored soil management strategies. All the above-mentioned interventions can contribute to the creation of healthy, resilient and sustainable soil ecosystems across Europe. • Survey in 20 countries: 314 stakeholders, 10 soil challenges, 4 soil knowledge. • Increasing organic matter and conserve peat soils is the priority soil challenge. • The 2nd most important soil challenge is soil water storage capacity. • The priority barriers are the lack of research funding and communication. • The most important opportunity is to fully exploit the outcomes of soil research. [ABSTRACT FROM AUTHOR]

Climate change and CO 2 emissions intertwine corporations and society in current political, social, environmental, and economic debates, specifically in Europe. The climate action plan formulated by the European Commission aims to achieve net zero emissions through eco-innovation by 2050. The objective of this study is to investigate the impact of the European eco-innovation index on CO 2 emissions produced by European firms. Using a dataset of 735 firms from 17 European countries listed during 2010–2018, we found a significant negative association between the country-level eco-innovation index and CO 2 emissions directly produced by the European firms. We also found a significant negative association between the eco-innovation index and indirect CO 2 emissions produced by the value chain of these firms. The results provide evidence that via eco-innovation, supportive steps taken by European countries provide a conducive environment for the European firms to adopt eco-innovative strategies that significantly reduce their direct and indirect CO 2 emissions per dollar of their corporate assets and make their value chains eco-friendly. The results also reveal that financial development brings in some environmental monitoring that cultivates a supportive culture for the corporations to promote corporate efforts to reduce CO 2 emissions. • The first study that uses an eco-innovation index, based on 5 dimensions, developed by the European Commission. • We find a negative impact of country-level eco-innovation on the reduction in direct and indirect corporate CO 2 emissions. • Eco-innovation initiatives taken by the European countries are helping European firms in reducing their CO 2 emissions. [ABSTRACT FROM AUTHOR]

Agri-environmental policies in Europe are failing to sufficiently address ongoing environmental degradation, biodiversity decline, climate impacts, and societal demands for sustainability. To reverse this, policymakers, practitioners, and farmers need better guidance on which specific agricultural practice/s should be promoted and how to adapt current practices to reach the desired objectives. Here we use social valuation tools to elucidate the relationship between agricultural practices and the provision of key ecosystem services in mountains, including maintenance of scenery from agricultural landscapes, conservation of biodiversity, regulation of climate change through carbon sequestration, production of local quality products, maintenance of soil fertility, and prevention of forest wildfires. We use as case studies two contrasting but representative mountain agroecosystems in the Mediterranean and Nordic regions of Europe. We analyze the best agricultural practices in both agroecosystems to reach the targeted environmental outcomes under three plausible policy scenarios. We find significant differences in the average contribution of agricultural practices to ecosystem services provision, which suggest the need for regionalizing the research efforts and, consequently, the design of agri-environmental policies. However, we also identify practices for ecosystem service delivery across policy scenarios and agroecosystems. Among these, grazing and silviculture practices such as extending the grazing period, grazing in semi-natural habitats, grazing in remote and abandoned areas, adapting stocking rate to the carrying capacity, and moving flocks seasonally, stand out for their relevance in all policy scenarios. These results highlight the potential of adequate grazing and silviculture practices to deliver bundles of ecosystem services. Our study provides guidance to design agri-environmental policies in Europe that focus on rewarding farmers for their sustainable management of natural resources, climate change mitigation and adaption and biodiversity conservation. • We elucidate the effects of agricultural practices on the provision of key ecosystem services. • We test three policy scenarios in two contrasting mountain agroecosystems in Europe. • Contribution of practices to ecosystem services differ significantly between agroecosystems. • Several practices are relevant across policy scenarios and agroecosystems. • We provide guidance for management-based payments in European agrienvironmental policy. [ABSTRACT FROM AUTHOR]

Simulating cropland soil carbon changes following a reduction in tillage intensity is necessary to determine the utility of this management practice in climate change mitigation. In instances where reduced or no tillage increases soil carbon stocks, this is typically due to reduced decomposition rates of plant residues. Although some soil carbon models contain a priori decomposition rate modifiers to account for tillage regime, these are typically not calibrated to specific climatic regions, and none are currently available for the Rothamsted Carbon Model (RothC). Here, we present a modelling framework to estimate a tillage rate modifier (TRM) for the decomposition rate constants in RothC-26.3 which determine decay between soil carbon pools. We demonstrate this for north-west Europe, using published data assembled through a recent systematic review with propagation of error from input parameters throughout the framework. The small magnitude of soil carbon change following a reduction in tillage intensity in this region is reflected in our TRM estimates for no-till of 0.95, with 95% Credible Intervals [0.91, 1.00], and reduced tillage of 0.93 [0.90, 0.97], relative to conventional high-intensity tillage with a default TRM of 1. These TRMs facilitate realistic simulation of soil carbon dynamics following a reduction of tillage intensity using RothC, and our simple, transparent, and repeatable modelling framework is suitable for application in other climatic regions using input data generalisable to the context of interest. • We estimate rate modifiers to capture reduced tillage in the soil carbon model RothC. • Our model is parametrised from systematic review data with propagation of error. • Our framework can be used in other regions to derive empirical rate modifiers. [ABSTRACT FROM AUTHOR]

Diesel vehicles are one of many sources of black carbon (BC) emissions in Europe; nevertheless, due to recent changes in fuel composition towards renewable fuel such as biodiesel, advances in engine design and pollution control technology, BC and organic carbon (OC) emissions may worsen air quality and encourage global warming. As there are no regulatory terms on BC mass concentration levels, assessment of pollution sources is crucial for air quality improvement policies and mitigation of climate change. BC mass concentration and aerosol optical absorption were derived using 7-wavelenght Aethalometer during 3 measurement campaigns in 2014, 2017, and 2020. BC source apportionment analysis was performed using 18 combinations of absorption Ångström exponent (AAE) values for assessing BC to fossil fuel combustion and biomass burning. The choice of the most suitable AAE combination (0.9 and 2.2, respectively) was supported by organic aerosol (OA) source apportionment results. AAE value for transport exhaust emission (0.95) from locally available diesel fuel was established using (CI) 1.9 TDI engine with different engine torque regimes and 7-wavelenght Aethalometer. Statistically and experimentally obtained values were compared and showed great agreement. Subsequently, a statistically obtained AAE tr value was used for BC source apportionment and long-term analysis. A significant increase in the contribution of transport-related BC contribution was observed between years 2014 and 2020 (from 51% to 65%) which was associated with a boost in the use of diesel vehicles (by 83.9% of diesel passenger cars comparing 2014 and 2020) and growing diesel fuel consumption. These findings underline the diesel transport-induced problem for local air quality together with its impact on atmospheric radiative balance and raise concerns for public health. • The choice of AAE combination was supported by OA source apportionment results. • BC source apportionment revealed increasing trend of transport-related pollution. • A significant increase in BC tr light absorption was observed during 2014–2020. [ABSTRACT FROM AUTHOR]

• We predict climate change hotspots and coldspots based on climate change velocity in Europe. • Velocities are projected highest in the Continental region, lowest in the Mediterranean region. • The Alpine region will likely contain largest areal proportions of hotspots, the Mediterranean region largest proportions of coldspots. • Natura 2000 area overlapping with hotspots is largest in the Alpine region, with coldspots much smaller in any region. • The outcomes suggest climate-smart conservation prioritization across Europe and the Natura 2000 network. Anthropogenic climate change is challenging biodiversity conservation worldwide. Climate change metrics derived from future climate predictions help to assess potential impacts of climate change on biodiversity. Here we calculated future climate change velocities across biogeographical regions of terrestrial Europe and the Natura 2000 protected area network, the largest protected area network on Earth. We applied climate projections for the year 2070, considering two emission scenarios, six global climate models and a fine spatial resolution. Areas with very high climate change velocity were identified as climate change hotspots, while areas with very low velocity were recognized as coldspots. We further revealed where and to what extent climate change hotspots and coldspots coincide with Natura 2000 sites. We found that climate change velocities are projected highest in the Continental and Boreal regions, and lowest in the Mediterranean and Anatolian regions. However, the Alpine region will likely contain largest areal proportions of climate change hotspots, while areal proportions of coldspots are projected largest in the Mediterranean region. High mountain regions such as the Alps show a high proportion of Natura 2000 sites that coincide with climate change hotspots. Both, hotspots and coldspots, are geographically associated with areas of topographic diversity. Low topographical diversity indicates high climate change exposure. The impact of hotspots increases with spatial isolation. Oceanic climate buffers climate change exposure in contrast to continental climate. However, continental regions of Europe tend to exhibit less spatial isolation. We recommend conservation action in climate change hotspots and coldspots to simultaneously protect the most climate-exposed biodiversity as well as climate change refugia. Climate change hotspots and coldspots overlapping with Natura 2000 sites should be considered priority conservation sites because new protected areas are hard to realize in densely populated landscapes of Europe. This study directs European conservation management and policy towards meeting international conservation goals in a climate-smart way. [ABSTRACT FROM AUTHOR]