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Abstract. The intensity of precipitation events is expected to increase in the future.
The rate of increase depends on the strength or rarity of the events; very
strong and rare events tend to follow the Clausius–Clapeyron relation,
whereas weaker events or precipitation averages increase at a smaller rate
than expected from the Clausius–Clapeyron relation. An often overlooked
aspect is seasonal occurrence of such events, which might change in the
future. To address the impact of seasonality, we use a large ensemble of
regional and global climate model simulations, comprising tens of thousands
of model years of daily temperature and precipitation for the past, present,
and future. In order to make the data comparable, they are quantile mapped to
observation-based time series representative of the Aare catchment in
Switzerland. Model simulations show no increase in annual maximum 1-day
precipitation events (Rx1day) over the last 400 years and an increase of
10 %–20 % until the end of the century for a strong (RCP8.5) forcing
scenario. This fits with a Clausius–Clapeyron scaling of temperature at the
event day, which increases less than annual mean temperature. An important
reason for this is a shift in seasonality. Rx1day events become less frequent
in late summer and more frequent in early summer and early autumn, when it is
cooler. The seasonality shift is shown to be related to summer drying. Models
with decreasing annual mean or summer mean precipitation show this behaviour
more strongly. The highest Rx1day per decade, in contrast, shows no change in
seasonality in the future. This discrepancy implies that decadal-scale
extremes are thermodynamically limited; conditions conducive to strong events
still occur during the hottest time of the year on a decadal scale. In
contrast, Rx1day events are also limited by other factors. Conducive
conditions are not reached every summer in the present, and even less so in
the future. Results suggest that changes in the seasonal cycle need to be
accounted for when preparing for moderately extreme precipitation events and
assessing their socio-economic impacts.

Uncertainties of climate projections are routinely assessed by considering simulations from different models. Observations are used to evaluate models, yet there is a debate about whether and how to explicitly weight model projections by agreement with observations. Here we present a straightforward weighting scheme that accounts both for the large differences in model performance and for model interdependencies, and we test reliability in a perfect model setup. We provide weighted multimodel projections of Arctic sea ice and temperature as a case study to demonstrate that, for some questions at least, it is meaningless to treat all models equally. The constrained ensemble shows reduced spread and a more rapid sea ice decline than the unweighted ensemble. We argue that the growing number of models with different characteristics and considerable interdependence finally justifies abandoning strict model democracy, and we provide guidance on when and how this can be achieved robustly. ; ISSN:0094-8276 ; ISSN:1944-8007

Uncertainties of climate projections are routinely assessed by considering simulations from different models. Observations are used to evaluate models, yet there is a debate about whether and how to explicitly weight model projections by agreement with observations. Here we present a straightforward weighting scheme that accounts both for the large differences in model performance and for model interdependencies, and we test reliability in a perfect model setup. We provide weighted multimodel projections of Arctic sea ice and temperature as a case study to demonstrate that, for some questions at least, it is meaningless to treat all models equally. The constrained ensemble shows reduced spread and a more rapid sea ice decline than the unweighted ensemble. We argue that the growing number of models with different characteristics and considerable interdependence finally justifies abandoning strict model democracy, and we provide guidance on when and how this can be achieved robustly.

A Bacia do Alto Paraguai (BAP) inclui a planície inundável do Pantanal e as áreas altas no entorno que drenam para o rio Paraguai, uma região de transição entre quatro grandes domínios fitofisionômicos da América do Sul – Cerrado, Chaco, Amazônia e Mata Atlântica. A fauna da região é pobre em endemismos, porém as posições central e transicional no continente conferem enorme riqueza de animais vertebrados, oriundos de diferentes domínios, especialmente quanto à ordem Chiroptera. Aqui, revisamos as espécies de morcegos registradas na BAP e apresentamos mapas de distribuição e breve descrição de cada espécie, incluindo dados de tamanho, forma, cor, ambientes, abrigos, hábito alimentar e interações com predadores e parasitas. Encontramos registro de 93 espécies em sete famílias – Emballonuridae (3), Noctilionidae (2), Mormoopidae (2), Phyllostomidae (51), Natalidae (1), Molossidae (20) e Vespertilionidae (14). Foram registradas 66 espécies na planície e 84 no entorno; com 59 espécies reportadas na planície e no entorno. Quase dois terços das espécies (63%) foram registrados em cinco ou mais localidades na BAP, e um quinto (19%) em apenas uma localidade. A fauna de morcegos da BAP destaca a grande importância dessa região para a manutenção da diversidade de morcegos na América do Sul.

Su invito della presidente del Consiglio nazionale Irène Kälin e del presidente del Consiglio degli Stati Thomas Hefti, il 2 maggio 2022 il Parlamento ha discusso con i ricercatori le sfide della crisi del clima e della biodiversità. I politici hanno scambiato opinioni con scienziati che lavorano in Svizzera e con gli autori dei rapporti del Gruppo intergovernativo sui cambiamenti climatici e del Gruppo intergovernativo sulla biodiversità. ; Guisan A, Huggel C, Seneviratne SI, Steinberger J (2022). Inversione di tendenza clima e biodiversità. Il Parlamento incontra la scienza. Swiss Academies Communications 17 (6)

Auf Einladung der Nationalratspräsidentin Irène Kälin und des Ständeratspräsidenten Thomas Hefti diskutierte das Parlament am 2. Mai mit Forschenden die Herausforderungen der Klima- und Biodiversitätskrise. Die Politikerinnen und Politiker tauschten sich mit den in der Schweiz tätigen Wissenschaftlern und Verfasserinnen der Berichte des Weltklimarates und des Weltbiodiversitätsrates aus. ; Guisan A, Huggel C, Seneviratne SI, Steinberger J (2022) Trendwende Klima und Biodiversität. Parlament trifft Wissenschaft Swiss Academies Communications 17 (6).

Irène Kälin, présidente du Conseil national, et Thomas Hefti, président du Conseil des Etats, ont convié les scientifiques et le Parlement à une séance de discussion sur la crise climatique et la perte de la biodiversité qui aura lieu le 2 mai 2022. En vue de cet événement, les auteur·e·s suisses du 6e rapport d'évaluation du groupe d'expert·e·s intergouvernemental sur l'évolution du climat (GIEC) et des rapports de la plateforme intergouvernementale scientifique et politique sur la biodiversité et les services écosystémiques (IPBES) ont compilé les principales constations pour la Suisse. ; Guisan A, Huggel C, Seneviratne SI, Steinberger J (2022) Inverser la tendance : climat et biodiversité. Rencontre entre le Parlement et les scientifiques. Swiss Academies Communications 17 (6).

To make sound decisions in the face of climate change, government agencies, policymakers and private stakeholders require suitable climate information on local to regional scales. In Switzerland, the development of climate change scenarios is strongly linked to the climate adaptation strategy of the Confederation. The current climate scenarios for Switzerland CH2018 - released in form of six user-oriented products - were the result of an intensive collaboration between academia and administration under the umbrella of the National Centre for Climate Services (NCCS), accounting for user needs and stakeholder dialogues from the beginning. A rigorous scientific concept ensured consistency throughout the various analysis steps of the EURO-CORDEX projections and a common procedure on how to extract robust results and deal with associated uncertainties. The main results show that Switzerland's climate will face dry summers, heavy precipitation, more hot days and snow-scarce winters. Approximately half of these changes could be alleviated by mid-century through strong global mitigation efforts. A comprehensive communication concept ensured that the results were rolled out and distilled in specific user-oriented communication measures to increase their uptake and to make them actionable. A narrative approach with four fictitious persons was used to communicate the key messages to the general public. Three years after the release, the climate scenarios have proven to be an indispensable information basis for users in climate adaptation and for downstream applications. Potential for extensions and updates has been identified since then and will shape the concept and planning of the next scenario generation in Switzerland. ; Climate Scenarios for Switzerland CH2018 – Approach and Implications ; publishedVersion