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Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity and variability of the atmosphere has hindered elucidation of the fundamental mechanism of new-particle formation from gaseous precursors. We show, in experiments performed with the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid and oxidized organic vapors at atmospheric concentrations reproduce particle nucleation rates observed in the lower atmosphere. The experiments reveal a nucleation mechanism involving the formation of clusters containing sulfuric acid and oxidized organic molecules from the very first step. Inclusion of this mechanism in a global aerosol model yields a photochemically and biologically driven seasonal cycle of particle concentrations in the continental boundary layer, in good agreement with observations., (Copyright © 2014, American Association for the Advancement of Science.)

• Climate change will decrease water availability in the Mediterranean. • Adaptation strategies should be co-designed by experts and stakeholders. • Hydrological modelling can quantify the effectiveness of adaptation options. • Dynamic Adaptive Policy Pathways integrate expert and stakeholder knowledge. • Stakeholders in the Algarve chose small and incremental measures over large ones. Irrigation is essential for a large part of Mediterranean agricultural systems, but scarce resources may cause conflicts between agricultural and domestic uses. These conflicts might be exacerbated by climate change, which could bring a drier climate and thus increase irrigation water demands while lowering supplies. These issues were addressed when designing a climate change adaptation plan for water resources in the Algarve region (southern Portugal), which was co-created between hydrologists and local stakeholders and policy-makers, by using the Dynamic Adaptive Policy Pathways (DAPP) approach to synthetize and communicate the results from hydrological modelling of future scenarios. The evolution of water availability and irrigation demands for key water assets in Algarve (southern Portugal) were simulated until 2100 for climate scenarios RCP4.5 and RCP8.5, using a modified version of Thornthwaite-Mather. The results show an increase in water stress, mainly in the RCP8.5 scenario. The results and need for adaptation were discussed with local and regional decision-makers and other stakeholders, and a set of adaptation measures was agreed upon. The discussed adaptation measures were then modelled and integrated the design of tailor-made DAPP. Finally, decision-makers and stakeholders were presented with DAPP and selected the most suitable and political reliable adaptation pathway that tackles projected climate change impacts in water resources until the end of the 21 st century. Stakeholders showed a strong preference for incremental and distributed small-scale measures, including the promotion of water use efficiency and landscape water retention, to large-scale measures such as wastewater recycling or new dams. A decrease in irrigation water use for agriculture was not considered socially desirable. Desalination was considered too costly for irrigation in the short term but kept in reserve in case other measures fail to keep water supplies at an acceptable level. [ABSTRACT FROM AUTHOR]

Europe’s climate change vulnerability pushes for initiatives such as the European Adaptation Strategy and the associated Covenant of Mayors for Climate and Energy. What are the triggers and barriers, for which sectors and for which risks and how is adaptation funded? This paper examines 147 Local Adaptation Strategies in Europe. Key triggers were incentives via research projects, implementation of EU policies and the increasing frequency of extreme climate events. Insufficient resources, capacity, political commitment and uncertainty were the main barriers. Prioritized sectors reflected the main local vulnerabilities - flood protection and water management, built environment and urban planning. Differing patterns of adaptation planning and adaptive capacity were identified among different regions in Europe. Large municipalities generally fund adaptation locally, whereas international and national funding appears to be more important for adaptation in less urban or densely populated territories. The database of LAS described in the present study can be expanded and used to increase the understanding of and promotion of local adaptation action in Europe and beyond. [ABSTRACT FROM AUTHOR]

This article describes a climate change adaptation planning process triggered by a group of researchers and stakeholders in a context where no collective responses or long-term plans for protecting a vulnerable coastal system had been initiated, despite local perceptions of vulnerability and risk. The case study shows the application of two methods: scenario workshops and adaptation pathways in the context of a participatory action research methodological design. Participatory action research and qualitative scenario methods are highlighted as accelerators of climate change adaptation processes by calling to action, facilitating and connecting diverse social groups with a stake in a long-term plan towards a more adapted society. The experience leads to the conclusion that planning climate change adaptation has to go far beyond the technical dimension and take into account those affected (in the present and the future) by decisions made. A holistic approach to climate change adaptation planning will depend on the interrelations of managerial and top-down approaches with localized initiatives driven through an inclusive and collective action research process. [ABSTRACT FROM AUTHOR]

[Display omitted] • We review the evolution of emission scenarios 1990–2022 via 280 emission scenario critiques & responses. • Critiques comprise four key categories: assumptions and ranges (scenario substance), methods and user relevance. • Critiques became increasingly influential since 2000, enhancing scenarios and their credibility. • The intergovernmental exclusion of mitigation scenarios 1992–2010 compromised scientific credibility. • IPCC critique disappeared after 2011, while convergence & probability discussions decreased. Long-term global emission scenarios enable the analysis of future climate change, impacts, and response strategies by providing insight into possible future developments and linking these different climate research elements. Such scenarios play a crucial role in the climate change literature informing the Intergovernmental Panel on Climate Change's (IPCC) Assessment Reports (ARs) and support policymakers. This article reviews the evolution of emission scenarios, since 1990, by focusing on scenario critiques and responses as published in the literature. We focus on the issues raised in the critiques and the possible impact on scenario development. The critique (280) focuses on four areas: 1) key scenario assumptions (40%), 2) the emissions range covered by the scenarios and missing scenarios (25%), 3) methodological issues (24%), and 4) the policy relevance and handling of uncertainty (11%). Scenario critiques have become increasingly influential since 2000. Some areas of critique have decreased or become less prominent (probability, development process, convergence assumptions, and economic metrics). Other areas have become more dominant over time (e.g., policy relevance & implications of scenarios, transparency, Negative Emissions Technologies (NETs) assumptions, missing scenarios). Several changes have been made in developing scenarios and their content that respond to the critique. [ABSTRACT FROM AUTHOR]

Portugal is on a climate change hot spot region, where precipitation is expected to decrease with important impacts regarding future water availability. As one of the European countries affected more by droughts in the last decades, it is important to assess how future precipitation regimes will change in order to study its impacts on water resources. Due to the coarse scale of global circulation models, it is often needed to downscale climate variables to the regional or local scale using statistical and/or dynamical techniques. In this study, we tested the use of a generalized linear model, as implemented in the program GLIMCLIM, to downscale precipitation for the center of Portugal where the Tagus basin is located. An analysis of the method performance is done as well as an evaluation of future precipitation trends and extremes for the twenty-first century. Additionally, we perform the first analysis of the evolution of droughts in climate change scenarios by the Standardized Precipitation Index in the study area. Results show that GLIMCLIM is able to capture the precipitation's interannual variation and seasonality correctly. However, summer precipitation is considerably overestimated. Additionally, precipitation extremes are in general well recovered, but high daily rainfall may be overestimated, and dry spell lengths are not correctly recovered by the model. Downscaled projections show a reduction in precipitation between 19 and 28 % at the end of the century. Results indicate that precipitation extremes will decrease and the magnitude of droughts can increase up to three times in relation to the 1961-1990 period which can have strong ecological, social, and economic impacts. [ABSTRACT FROM AUTHOR]

Schmidt, L., Delicado, A., Gomes, C., Granjo P., Guerreiro, S., Horta, A., Mourato, J., Prista, P., Saraiva, T., Truninger, M., O'Riordan, T., Santos, F.D., and Penha-Lopes, G. 2013. Change in the way we live and plan the coast: stakeholders discussions on future scenarios and adaptation strategies A scenario of increased risks due to climate change and coastal erosion, coupled with a stringent economic recession, is threatening the Portuguese coast. Three particular locations are the focus of CHANGE - Changing Coasts, Changing Climate, Changing Communities, a 3-year study (2010-2013) that aims to understand social perceptions about coastal risks and to examine new ways of adaptive management. The project involved assessing peoples' representations about the coastal present and possible coastal futures and discussed coastal change with local populations, in a country in which the protection of vulnerable coast to date has had little public involvement. The three coastal stretches studied face increasing coastal risks and the perspective of reduced public spending, fuelling uncertainty about their future. Public participation in coastal management has been almost entirely absent, which makes the social science based contribution of this research even more relevant. This research combines: a) scientific assessments on the past and future evolution of the shoreline, taking into account the impacts of climate change; b) interviews with policy-makers, coastal experts and stakeholders, as well as local public opinion surveys; c) the outputs of a model for coastal governance and community building, based on local discussions through focus groups and workshops. This paper is based on the surveys and focus groups undertaken in the case-study area most at risk from coastal change, Vagueira. We conclude that there is a growing perception of coastal threat and potential for the development of adaptive coastal management, taking advantage of local knowledge and initiative. [ABSTRACT FROM AUTHOR]

Abstract: Larvae of various coastal fish undergo immigration from spawning grounds towards estuarine nurseries. Several environmental factors can have an important impact on survival at this stage making it crucial for recruitment. Generalized linear models were applied in order to investigate the relation between river drainage, sea surface temperature (SST), NAO index and the North-South wind component intensity, over the two months prior to the estuarine colonization peak, and the densities of Platichthys flesus, Dicentrarchus labrax, Diplodus vulgaris and Diplodus bellottii in the nursery grounds based on a discontinuous historical dataset (from 1978 to 2006), for the Tagus estuary. The relation between SST over the 12 months prior to the estuarine colonization peak and fish densities in the nurseries was also investigated, as it integrates the periods of spawning stock maturation, spawning and larval immigration. While SST over the prior 12 months was negatively correlated with the abundance of P. flesus, it was positively correlated with the abundance of D. bellottii. Abundance of D. vulgaris was positively correlated with SST in the two months prior to the estuarine colonization peak, while the abundance of D. labrax was positively correlated with river drainage. The relations between SST and the abundance of P. flesus, a cold-water species with declining densities, and the subtropical species D. bellottii and D. vulgaris, which are increasing in abundance, are indicative of species abundance alterations related to climate warming. Dicentrarchus labrax will probably also be affected by climate change because of lowered precipitation and consequently river drainage. [Copyright &y& Elsevier]

In this study we investigated the potential impact of climate change in Portugal on heat-related mortality, air pollution-related health effects, and selected vectorborne diseases. The assessment used climate scenarios from two regional climate models for a range of future time periods. The annual heat-related death rates in Lisbon may increase from between 5.4 and 6 per 100,000 in 1980-1998 to between 8.5 and 12.1 by the 2020s and to a maximum of 29.5 by the 2050s, if no adaptations occur. The projected warmer and more variable weather may result in better dispersion of nitrogen dioxide levels in winter, whereas the higher temperatures may reduce air quality during the warmer months by increasing tropospheric ozone levels. We estimated the future risk of zoonoses using ecologic scenarios to describe future changes in vectors and parasites. Malaria and schistosomiasis, which are currently not endemic in Portugal, are more sensitive to the introduction of infected vectors than to temperature changes. Higher temperatures may increase the transmission risk of zoonoses that are currently endemic to Portugal, such as leishmaniasis, Lyme disease, and Mediterranean spotted fever. [ABSTRACT FROM AUTHOR]

Adaptation Pathways is a decision support tool designed to create adaptation policies under different climate change scenarios. This tool has been used successfully in several sectors and contexts such as coastal and river adaptation, urban heat waves, floods and rural livelihoods but its use in natural resource management, has faced several challenges and limitations. In the sector of agroforestry its use has seldom been done or documented and one of the reasons for this may due to some of its specific challenges. In this study, these challenges were addressed when using the Adaptation Pathways for the adaptation planning of three case studies in the semi-arid Alentejo region, a Mediterranean dryland of southern Portugal. This tool was integrated in a participatory approach combined with the Scenario Workshop method, to plan the adaptation of the agriculture and forestry sector of one municipality (Mértola) and two agroforestry farms (221 ha and 1000 ha). The methodology included, for each case study, 20 interviews, two workshops, literature review, expert analysis and the use of indicators of efficacy of adaptation measures, to define tipping points. The adaptation process and the resulting adaptation plans were evaluated by questionnaire and expert review. This combination of methods has supported the choice of effective adaptation measures for the case studies and when combined with several adaptation pathways and a landscape approach it supported the creation of integrated climate change adaptation plans that are now in implementation. We discuss how this combination of methods deals with limitation to Adaptation Pathways identified in the literature, conclude that the method was able to create adaptation plans that are now under implementation and present avenues for future research. • There is a growing need for climate adaptation planning and decision making support tools. • Participatory adaptation planning in the field of agroforestry has rarely been done or documented. • Adaptation Pathways approach was successfully used in three case studies. • Limitations of Adaptation Pathways were addressed and discussed. [ABSTRACT FROM AUTHOR]

Monitoring lakes in high-latitude areas can provide a better understanding of freshwater systems sensitivity and accrete knowledge on climate change impacts. Phytoplankton are sensitive to various conditions: warmer temperatures, earlier ice-melt and changing nutrient sources. While satellite imagery can monitor phytoplankton biomass using chlorophyll a (Chl) as a proxy over large areas, detection of Chl in small lakes is hindered by the low spatial resolution of conventional ocean color satellites. The short time-series of the newest generation of space-borne sensors (e.g., Sentinel-2) is a bottleneck for assessing long-term trends. Although previous studies have evaluated the use of high-resolution sensors for assessing lakes' Chl, it is still unclear how the spatial and temporal variability of Chl concentration affect the performance of satellite estimates. We discuss the suitability of Landsat (LT) 30 m resolution imagery to assess lakes' Chl concentrations under varying trophic conditions, across extensive high-latitude areas in Finland. We use in situ data obtained from field campaigns in 19 lakes and generate remote sensing estimates of Chl, taking advantage of the long-time span of the LT-5 and LT-7 archives, from 1984 to 2017. Our results show that linear models based on LT data can explain approximately 50% of the Chl interannual variability. However, we demonstrate that the accuracy of the estimates is dependent on the lake's trophic state, with models performing in average twice as better in lakes with higher Chl concentration (>20 µg/L) in comparison with less eutrophic lakes. Finally, we demonstrate that linear models based on LT data can achieve high accuracy (R2 = 0.9; p-value < 0.05) in determining lakes' mean Chl concentration, allowing the mapping of the trophic state of lakes across large regions. Given the long time-series and high spatial resolution, LT-based estimates of Chl provide a tool for assessing the impacts of environmental change. [ABSTRACT FROM AUTHOR]