Tambora 1815 as a test case for high impact volcanic eruptions: Earth system effects

The eruption of Tambora (Indonesia) in April 1815 had substantial effects on global climate and led to the ‘Year Without a Summer’ of 1816 in Europe and North America. Although a tragic event—tens of thousands of people lost their lives—the eruption also was an ‘experiment of nature’ from which science has learned until today. The aim of this study is to summarize our current understanding of the Tambora eruption and its effects on climate as expressed in early instrumental observations, climate proxies and geological evidence, climate reconstructions, and model simulations. Progress has been made with respect to our understanding of the eruption process and estimated amount of SO2 injected into the atmosphere, although large uncertainties still exist with respect to altitude and hemispheric distribution of Tambora aerosols. With respect to climate effects, the global and Northern Hemispheric cooling are well constrained by proxies whereas there is no strong signal in Southern Hemisphere proxies. Newly recovered early instrumental information for Western Europe and parts of North America, regions with particularly strong climate effects, allow Tambora's effect on the weather systems to be addressed. Climate models respond to prescribed Tambora-like forcing with a strengthening of the wintertime stratospheric polar vortex, global cooling and a slowdown of the water cycle, weakening of the summer monsoon circulations, a strengthening of the Atlantic Meridional Overturning Circulation, and a decrease of atmospheric CO2. Combining observations, climate proxies, and model simulations for the case of Tambora, a better understanding of climate processes has emerged

Heat in Germany: Health risks and preventive measures

Background: Climate change has already led to a significant temperature increase in Germany. The average temperature in the past decade was approximately 2°C above the pre-industrial level and eight of the ten hottest summers since the beginning of systematic weather records in 1881 were recorded in the last 30 years. Methods: Based on a selective literature search and authors’ evaluations, the article summarises the current state of knowledge on heat and its health impacts for Germany, addresses adaptation measures, and gives an outlook on implementation and research questions. Results: Heat can aggravate pre-existing conditions such as diseases of the cardiovascular system, the respiratory tract, or the kidneys and trigger potentially harmful side effects for numerous medications. A significant increase in mortality is regularly observed during heat events. Previous approaches to mitigate the health impact of high temperatures include, for example, the heat alerts of the German Meteorological Service and recommendations for the preparation of heat-health action plans. Conclusions: Evidence on health impacts of heat and awareness of the need for heat-related health protection have grown in recent years, but there is still a need for further action and research. This is part of a series of articles that constitute the German Status Report on Climate Change and Health 2023

Open-Source Ansatz zur Abschätzung Sozioökonomischer Klimafolgen für Deutschland am Beispiel Extremer Hitze

Vorhersage und ProjektionDie Zunahme von Wetter- und Klimaextremen durch den voranschreitenden Klimawandel ist zunehmend mit gesellschaftlichen Beeinträchtigungen und ökonomischen Kosten verbunden. Eine umfassende Quantifizierung und nutzerspezifische Kommunikation dieser sozioökonomischen Klimafolgen an politische und privatwirtschaftliche Entscheider ist für die Vermeidung möglicher Folgen oder eine adäquate Anpassung unerlässlich. Eine Abschätzung sozioökonomischer Klimafolgen erfordert (i) Daten zur klimatischen Gefährdung, (ii) Informationen zur räumlichen Exposition sozioökonomischer Größen, (iii) Annahmen zur ihrer Sensitivität, als auch (iv) eine Maschinerie, um diese Größen gekoppelt auszuwerten. Hierfür wird in diesem Vortrag die open-source python Plattform CLIMADA [1,2] vorgestellt und zur sozioökonomischen Folgenabschätzung durch Wetter- und Klimaextreme auf Deutschland angewendet. Am Beispiel von extremer Hitze wird demonstriert, wie projizierte klimatische Trends mit unterschiedlichen Szenarien für den demographischen Wandel auf sub-nationaler Skala wechselwirken und so die möglichen Auswirkungen (z.B. durch hitzebedingte Übersterblichkeit [3]) verstärkt werden könnten. Die Anwendung von CLIMADA ist nicht nur auf Klimaprojektionen beschränkt, sondern erlaubt eine räumlich aufgelöste und nahtlose Bereitstellung von sozioökonomischen Risiken und ökonomischen Schäden durch Wetter- und Klimaextreme von der Wettervorhersage bis zum Ende des Jahrhunderts

Coupling of Arctic ozone and stratospheric dynamics and its influence on surface climate : the role of CFC concentrations

Arctic stratospheric ozone has been shown to exert a statistically significant influence on Northern Hemispheric surface climate. This suggests that Arctic ozone is not only passively responding to dynamical variability in the stratosphere, but actively feeds back into the circulation through chemical and radiative processes. However, the extent and causality of the chemistry-dynamics coupling is still unknown. Since many state-of-the-art climate models lack a sufficient representation of ozone-dynamic feedbacks, a quantification of this coupling can be used to improve intra-seasonal weather and long-term climate forecasts. We assess the importance of the ozone-dynamics coupling by performing simulations with and without interactive chemistry in two Chemistry Climate Models. The chemistry-dynamics coupling was examined in two different sets of time-slice simulations: one using pre-industrial, and one using year-2000 boundary conditions. We focus on the impact of sudden stratospheric warmings (SSW) and strong vortex events on stratosphere-troposphere coupling, since these go along with strong ozone anomalies and therefore an intensified ozone feedback. We compare the runs with and without interactive chemistry. For pre-industrial conditions, simulations without interactive ozone show a more intense and longer lasting surface signature of SSWs compared to simulations with interactive chemistry. Conversely, for year-2000 conditions, the opposite effect is found: interactive chemistry amplifies the surface signature of SSWs. Following these results, atmospheric CFC concentrations, which differ greatly in the pre-industrial and year-2000 runs, determine the sign of the ozone-circulation feedback, and thus have a strong impact on chemistry-climate coupling. Implications for modeling of stratosphere-troposphere coupling and future projections are discussed

Multidecadal variations of the effects of the Quasi-Biennial Oscillation on the climate system

Effects of the Quasi-Biennial Oscillation (QBO) on tropospheric climate are not always strong or they appear only intermittently. Studying them requires long time series of both the QBO and climate variables, which has restricted previous studies to the past 30–50 years. Here we use the benefits of an existing QBO reconstruction back to 1908. We first investigate additional, newly digitized historical observations of stratospheric winds to test the reconstruction. Then we use the QBO time series to analyse atmospheric data sets (reconstructions and reanalyses) as well as the results of coupled ocean–atmosphere-chemistry climate model simulations that were forced with the reconstructed QBO. We investigate effects related to (1) tropical-extratropical interaction in the stratosphere, wave-mean flow interaction and subsequent downward propagation, and (2) interaction between deep tropical convection and stratospheric flow. We generally find weak connections, though some are statistically significant over the 100-year period and consistent with model results. Apparent multidecadal variations in the connection between the QBO and the investigated climate responses are consistent with a small effect in the presence of large variability, with one exception: the imprint on the northern polar vortex, which is seen in recent reanalysis data, is not found in the period 1908-1957. Conversely, an imprint in Berlin surface air temperature is only found in 1908-1957 but not in the recent period. Likewise, in the model simulations both links tend to appear alternatingly, suggesting a more systematic modulation due to a shift in the circulation, for example. Over the Pacific warm pool, we find increased convection during easterly QBO, mainly in boreal winter in observation-based data as well as in the model simulations, with large variability. No QBO effects were found in the Indian monsoon strength or Atlantic hurricane frequency

Hitze in Deutschland: Gesundheitliche Risiken und Maßnahmen zur Prävention

Hintergrund: Der Klimawandel hat in Deutschland bereits zu einer deutlichen Temperaturzunahme geführt. So lag die Mitteltemperatur im vergangenen Jahrzehnt rund 2 °C über dem vorindustriellen Niveau und acht der zehn heißesten Sommer seit Beginn der systematischen Wetteraufzeichnungen im Jahr 1881 wurden in den letzten 30 Jahren verzeichnet. Methode: Der Artikel fasst, basierend auf einer selektiven Literaturrecherche und eigenen Auswertungen, den aktuellen Wissensstand zu Hitze und ihren gesundheitlichen Auswirkungen für Deutschland zusammen, geht auf Anpassungsmaßnahmen ein und gibt einen Ausblick auf Umsetzungs- und Forschungsfragen. Ergebnisse: Hitze kann bestehende Beschwerden wie Erkrankungen des Herz-Kreislauf-Systems, der Atemwege oder der Nieren verschlimmern und bei zahlreichen Medikamenten teils schwerwiegende Nebenwirkungen auslösen. Während Hitzeperioden wird regelmäßig ein deutlicher Anstieg der Sterbefälle beobachtet. Bisherige Ansätze zur Abmilderung gesundheitlicher Auswirkungen hoher Temperaturen umfassen z. B. die Hitzewarnungen des Deutschen Wetterdienstes sowie Handlungsempfehlungen für die Erstellung von Hitzeaktionsplänen

A glossary for biometeorology

Here we present, for the first time, a glossary of biometeorological terms. The glossary aims to address the need for a reliable source of biometeorological definitions, thereby facilitating communication and mutual understanding in this rapidly expanding field. A total of 171 terms are defined, with reference to 234 citations. It is anticipated that the glossary will be revisited in coming years, updating terms and adding new terms, as appropriate. The glossary is intended to provide a useful resource to the biometeorology community, and to this end, readers are encouraged to contact the lead author to suggest additional terms for inclusion in later versions of the glossary as a result of new and emerging developments in the field

Hitzewellen in Deutschland und Europa

Hitzewellen in Deutschland und Europa: Hitzewellen beeinträchtigen die menschliche Gesundheit, die Ökosysteme und die Wirtschaft. In den letzten Jahrzehnten wurde in Europa eine zunehmende Häufigkeit von Hitzewellen beobachtet. Der Begriff Hitzewelle wird dabei jedoch sehr unterschiedlich definiert. Allgemein kann eine Definition über relative oder absolute Schwellenwerte erfolgen. In diesem Kapitel vergleichen wir die räumlichen Unterschiede in den Trends jeweils für eine absolute (5 Tage in Folge mit einer mittleren Tagesmaximumtemperatur über 30 °C) und eine relative Definition (5 Tage in Folge mit einer mittleren Tagesmaximumtemperatur über dem 95. Perzentil des Referenzzeitraums) für Europa. Hitzewellen mit Temperaturen über 30 °C treten von West- bis Ost-Europa sowie im Mittelmeerraum auf. In all diesen Regionen (bis auf wenige kleinräumige Ausnahmen) hat die Häufigkeit von Hitzewellen zwischen 1981-2010 zugenommen. Hitzewellen auf Basis des 95. Perzentils haben weitgehend überall in Europa zugenommen (mit Ausnahme der Britischen Inseln und kleinerer Gebiete im Mittelmeerraum). Am Beispiel Baden-Württembergs wird außerdem gezeigt, dass neben dem vielfach beachteten Sommer 2003 auch der Sommer 2015 zu einer deutlichen Zunahme der hitzebedingten Todesfälle geführt hat. Heatwaves in Germany and Europe: Heat waves are a major risk factor for human health, ecosystems and the economy. In recent decades, an increasing frequency of heat waves has been observed in Europe. So far, however, there exists no uniform definition of a heat wave. Here, we present a comparison of heat wave trends for Europe, using an absolute (5 days with a mean maximum temperature > 30 °C) and a relative (5 days with a mean maximum temperature above the 95. percentile) heat wave definition. Heat waves with a maximum temperature above 30 °C are found only in Middle, Eastern and Southern Europe. Here, an increasing trend is observed almost everywhere. Using the relative heat wave definition increasing trends are found for most parts of Europe (except for Great Britain, Ireland and small regions in the Mediterranean area). Using the example of Baden-Württemberg (federal state of Germany) we furthermore show, that besides the well studies heat summer 2003, also the summer 2015 was characterized by a pronounced increase in heat related mortalit

Climate Change and Mortality in Vienna—A Human Biometeorological Analysis Based on Regional Climate Modeling

The potential development of heat-related mortality in the 21th century for Vienna (Austria) was assessed by the use of two regional climate models based on the IPCC emissions scenarios A1B and B1. Heat stress was described with the human-biometeorological index PET (Physiologically Equivalent Temperature). Based on the relation between heat stress and mortality in 1970–2007, we developed two approaches to estimate the increases with and without long-term adaptation. Until 2011–2040 no significant changes will take place compared to 1970–2000, but in the following decades heat-related mortality could increase up to 129% until the end of the century, if no adaptation takes place. The strongest increase occurred due to extreme heat stress (PET ≥ 41 °C). With long-term adaptation the increase is less pronounced, but still notable. This encourages the requirement for additional adaptation measurements