The increasing intensity and frequency of high-temperature events in response to climate change can potentially impact the aviation industry, since aircraft takeoff and landing performances depend on near-surface air temperature. Previous studies have combined climate data with aircraft technical data to estimate the future impact of rising high temperatures on aircraft takeoff. They found a decrease of maximum takeoff weights and the lengthening of takeoff distances. The Mediterranean region is a climate change “hot spot” area, specially concerned by extreme high-temperatures increase. In this study, the magnitude and trends of the daily maximum near-surface temperature extremes in summer were analysed over major airports in Southwestern Europe. Trends in the period 1961–2014 were analysed from observations and reanalysis. Future changes by 2021–2050 and 2071–2100, with respect to 1961–2005, were analysed from simulations performed with Regional and Global Climate Models (RCMs and GCMs). Before assessing future climate projections, climate models were evaluated in present climate, and the RCM and GCM ensembles were compared to each other. No clear added value was found for RCMs over GCMs in present climate at the airport scale in these terms. GCMs project larger temperature changes than RCMs over the same locations. Multi-model ensemble mean projected changes under the RCP8.5 scenario range between + 1.7 and + 3.2 $$^{\circ }$$∘ C by the near term, and between + 4.9 and + 8.5 $$^{\circ }$$∘ C by the long term, across the airports and the RCM and GCM ensembles. This increase of high-temperature extremes would impact airport operations. Adaptation or mitigation policies would become necessary.

The primary goal of this study is to introduce the initial phase of developing an impact-based forecasting system for extreme heatwaves, utilizing a novel multivariate index which, at this early stage, already employs a combination of a statistical approach and physical principles related to human body water loss. This system also incorporates a mitigation plan with hydration-focused measures. Since 1990, heatwaves have become increasingly frequent and intense across many regions worldwide, particularly in Europe and Asia. The main health impacts of heatwaves include organ strain and damage, exacerbation of cardiovascular and kidney diseases, and adverse reproductive effects. These consequences are most pronounced in individuals aged 65 and older. Many national meteorological services have established metrics to assess the frequency and severity of heatwaves within their borders. These metrics typically rely on specific threshold values or ranges of near-surface (2 m) air temperature, often derived from historical extreme temperature records. However, to our knowledge, only a few of these metrics consider the persistence of heatwave events, and even fewer account for relative humidity. In response, this study aims to develop a globally applicable normalized index that can be used across various temporal scales and regions. This index incorporates the potential health risks associated with relative humidity, accounts for the duration of extreme heatwave events, and is exponentially sensitive to exposure to extreme heat conditions above critical thresholds of temperature. This novel index could be more suitable/adapted to guide national meteorological services when emitting warnings during extreme heatwave events about the health risks on the population. The index was computed under two scenarios: first, in forecasting heatwave episodes over a specific temporal horizon using the WRF model; second, in evaluating the relationship between the index, mortality data, and maximum temperature anomalies during the 2003 summer heatwave in Spain. Moreover, the study assessed the annual trend of increasing extreme heatwaves in Spain using ERA5 data on a climatic scale. The results show that this index has considerable potential as a decision-support and health risk assessment tool. It demonstrates greater sensitivity to extreme risk episodes compared to linear evaluations of extreme temperatures. Furthermore, its formulation aligns with the physical mechanisms of water loss in the human body, while also factoring in the effects of relative humidity.

The increasing intensity and frequency of high-temperature events in response to climate change can potentially impact the aviation industry, since aircraft takeoff and landing performances depend on near-surface air temperature. Previous studies have combined climate data with aircraft technical data to estimate the future impact of rising high temperatures on aircraft takeoff. They found a decrease of maximum takeoff weights and the lengthening of takeoff distances. The Mediterranean region is a climate change ”hot spot” area, specially concerned by extreme high-temperatures increase. In this study, the amplitude and trends of the daily maximum near-surface temperature extremes in summer were analysed over the main airports in Southwestern Europe. Changes in the period 1961-2014 were analysed from observations and reanalysis. Future changes by 2021-2050 and 2071-2100, with respect to 1961-2005, were analysed from simulations performed with Regional and Global Climate Models (RCMs and GCMs). Before assessing future climate projections, climate models were evaluated in present climate, and the RCM and GCM ensembles were compared to each other. No clear added value was found for RCMs over GCMs in present climate at the airport scale in these terms. GCMs project larger temperature changes than RCMs over the same locations. Multi-Model Ensemble mean projected changes under the RCP8.5 scenario range between +1.7 and +3.2 ◦ C by the near term, and between +4.9 and +8.5 ◦ C by the long term. This dramatic increase of high-temperature extremes would deduce negative impacts on airport operations. Therefore, adaptation or mitigation policies would become necessary to face the derived socio-economic impact.

Warmer ambient conditions results in lower lift and engine thrust, reducing the aircraft weight-lifting capacity at takeoff. The potential impacts on aircraft Maximum Takeoff Weight (MTOW) induced by the warming of surface air temperatures in future climate are assessed in this study at the airports in the Euro-Mediterranean region—a climate change hotspot. Major, regional and small airports are considered. The induced changes in MTOW are estimated for wide-body, narrow-body and small regional aircraft, widely used in global commercial aviation. First, the evolution of high-temperature extremes at the airports is assessed using climate observations for the baseline period 1961–1990, and future climate projections under the high-emissions scenario RCP8.5 for the periods 2021–2050 (near-term future) and 2041–2070 (medium-term future). Simulations from both Regional and Global Climate Models (RCMs and GCMs) belonging to the Euro-CORDEX and CMIP5 frameworks, respectively, are considered in a Multi-Model Ensemble approach. Second, the MTOW is obtained by combining the climate data with aircraft technical data and applying an empirical law from the aeronautical sector, which relates the MTOW to the ambient temperature. Results indicate that most Euro-Mediterranean airports could experience a decrease in MTOW, as early as the next three decades, at least for one aircraft type. For wide-body and narrow-body aircraft, these reductions are of the order of tonnes, according to the MME means of the RCMs and the GCMs: up to 7 tonnes in the near term and up to 11 tonnes in the medium term. Regional aircraft would experience MTOW reductions of hundreds of kgs. This could have a socio-economic impact, either from possible weight restrictions, flight delays or cancellations. The results of this study could guide the design of adaptation strategies at the European level, aimed at building a climate change-resilient aviation network and ensuring that European aviation will be prepared for future extreme heat events.

The increasing intensity and frequency of high-temperature extreme events due to climate change negatively affects aircraft takeoff performances. Warmer near-surface air temperatures result in lower aircraft lift and engine thrust, thereby reducing the aircraft’s weight-lifting capacity at takeoff. This study evaluates the potential impact of the future changes in high-temperature extremes on the aircraft’s Maximum Takeoff Weight (MTOW) at the airports in the Euro-Mediterranean region —a climate change hotspot. Major, regional and small airports are considered. First, the evolution of high-temperature extremes at the airports is assessed using climate observations for the baseline period 1961-1990, and future climate projections under the most severe climate change scenario RCP8.5 for the periods 2021-2050 (near-term future) and 2041-2071 (medium-term future). Simulations from both Regional and Global Climate Models (RCMs and GCMs) belonging to the Euro-CORDEX and CMIP5 frameworks, respectively, are considered in a Multi-Model Ensemble approach. Second, the MTOW is obtained by combining the climate data with aircraft technical data and applying an empirical law from the aeronautical sector, which relates the MTOW to the ambient temperature. The induced changes in MTOWare estimated for widebody, narrow-body and small regional aircrafts, widely used in global commercial aviation. Results indicate that most of Euro-Mediterranean airports could experience a decrease in MTOW, as early as the next three decades, at least for one aircraft type. For wide-bodies and narrow-bodies, these reductions are of the order of tons, according to the MME means of the RCMs and the GCMs: up to 7 tons in the near term and up to 11 tons in the medium term. Regional aircrafts would experience MTOW reductions of hundreds of kgs. This could have a socio-economic impact, either from possible weight restrictions, flight delays or cancellations. The results of this study could guide the design of adaptation strategies at the European level, aimed at building a climate change-resilient aviation network and ensuring that European aviation will be prepared for future extreme heat events.

Impacts de l'augmentation des extrêmes de hautes températures sur la performance du décollage des avions dans la région Euro-Méditerranéenne: Es conditions de chaleur extrême affectent négativement les performances des avions et la capacité et le rendement opérationnels des aéroports. Une augmentation de l'intensité et de la fréquence des extrêmes de hautes températures due au changement climatique pourrait impacter les opérations aériennes, avec des conséquences socio-économiques, environnementales et même sanitaires. La région Euro-Méditerranéenne est spécialement sensible au changement climatique; elle est particulièrement concernée par l'augmentation des hautes températures. Dans cette thèse, les impacts potentiels futurs de l'augmentation des extrêmes de hautes températures sur la performance du décollage des avions sont évalués dans la région Euro-Méditerranéenne. Le problème est abordé de la façon suivante: 1) l'évolution future des extrêmes de hautes températures est étudiée à partir de simulations de modèles climatiques, et 2) les impacts potentiels induits sont évalués en termes des niveaux d'émissions de polluants, en particulier d'oxydes d'azote (NOx), et des performances du moteur, et aussi en termes de la capacité maximale de l'avion à décoller du poids. Avant d'évaluer les impacts potentiels des changements futurs des extrêmes de hautes températures, l'évolution passée et future de ces événements est analysée sur une liste d'aéroports à partir d'observations et de simulations et projections de modèles climatiques. Nous nous focalisons sur la température maximale journalière (TX) en été. Tout d'abord, la magnitude des valeurs extrêmes observées au cours des dernières décennies est caractérisée, et les tendances des quantiles de la TX sont calculées. Une augmentation robuste et généralisée est trouvée dans les aéroports pour tous les quantiles. Certains aéroports ont connu une augmentation plus forte des percentiles supérieurs que de la médiane ou des percentiles inférieurs, ce qui pourrait être particulièrement problématique pour l'aviation. Dans un deuxième temps, les modèles climatiques sont évalués dans le climat présent sur les aéroports. Il s'agit d'une étape cruciale pour l'évaluation ultérieure des projections climatiques futures et de leurs impacts. Les simulations réalisées à l'aide de Modèles Climatiques Régionaux et Globaux (RCMs et GCMs) sont prises en compte dans une approche multi-ensembliste. En particulier, l'ensemble multi-RCM Euro-CORDEX et l'ensemble de GCMs forceurs de CMIP5 sont utilisés. Les deux ensembles sont comparés entre eux. Il n'y a pas de valeur ajoutée généralement dominante des RCMs pour l'étude des valeurs extrêmes de hautes températures ni de leurs tendances à l'échelle de l'aéroport, malgré leur résolution spatiale plus élevée. Troisièmement, l'évolution future des extrêmes estivaux de la TX est évaluée. Une augmentation robuste est trouvée pour tous les aéroports. Dans la deuxième partie de la thèse, l'augmentation potentielle des niveaux d'émissions de NOx est évaluée à l'aide d'un outil-métier qui émule le comportement du moteur de l'avion. La valeur en entrée du logiciel pour la température ambiante est déclarée comme la magnitude future des extrêmes de la TX d'été sur les aéroports, qui est estimée à partir des projections climatiques. Une augmentation générale des niveaux d'émissions de NOx est constatée sur les aéroports sélectionnés. Elle pourrait conduire à une augmentation des émissions absolues de NOx de l'ordre de kgs sur les aéroports lors des futurs événements extrêmes. La diminution potentielle de la masse maximale décollable de l'avion (MTOW) induite par l'augmentation de la TX est évaluée pour chaque aéroport, à partir d'une loi empirique fournie par AIRBUS. Les réductions sur la MTOW trouvées sont généralement de l'ordre de tonnes pour les longs et moyens courriers, ce qui pourrait entraîner des restrictions de poids correspondant à des dizaines de passagers et/ou des retards ou des annulations. Pour les courts courriers, l'impact sur la MTOW serait faible ou nul.