## 1 Introduction  
The evidence of anthropogenic climate change is widely accepted in the scientific community and many of the observed changes for the period 1950 onwards are unprecedented from over decades to centuries [1]. As it is well known, climate change potentially alters natural processes, causing the modification of precipitation patterns, melting of glaciers, the rise of sea levels, and so on. Whatever the warming scenarios and the level of success of mitigation policies, it is expected that, in the coming decades, climate change effects will become more relevant all around the world, with the impacts of greenhouse gas emissions being time-delayed. For this reason, climate change needs to be considered, taking into account the economic, environmental, and social consequences in many different research fields, inter alia, in structural engineering. Structural design is often governed by climatic actions, like wind, snow, thermal effects, atmospheric icing, currents, and wave-induced actions. As a consequence, variations of climatic actions due to climate change could significantly affect the design of new structures and infrastructures, as well as the assessment of existing ones, designed in accordance to the provisions of current or past codes [2]. This aspect is crucial since both new and existing structures are supposed to be able to withstand, with the intended degree of reliability, all climatic actions occurring during their whole real life. It must be highlighted that the real life of structures should not be confused with the notional design working life given in structural codes, as, for example, in Eurocode EN1990 [3], where it is recommended to be at least 50 years for buildings and other common structures and 100 years for monumental buildings and bridges. The notional design working life is intended as a reference time period, during which the structure should meet, without major interventions or repairs, the intended time-dependent performances (e.g., limitation of deterioration or fatigue-induced effects). As it is evident from common experience, constructions, provided that they are properly used and maintained, exhibit real life periods generally significantly greater than their notional design working life, resulting to be extremely sensitive to climate change implications. As a consequence of the above considerations, constructions designed nowadays will face climatic actions and extreme events, which will be unavoidably be affected by climate change influences. The challenge to estimate these influences is becoming more and more pressing [4]. The definition of climatic actions on structures is currently based on the extreme value analysis applied to past observations of the natural phenomena, under the assumption of stationary climate conditions. Obviously, climate change [1] makes this assumption doubtful, even if a stationary return level and no changes in the frequency of extremes are still often assumed to simplify the problem. The study of the impact of climate change on climatic actions and consequently on the design of new structures and the assessment of the structural performance of existing structures is then a key aspect in the future evolution of standards. This topic is crucial to achieving an increased resilience of long-life structures and infrastructures to climate change consequences [5], as requested for the second generation of the Eurocodes by the Mandate M/515 of the European Commission to CEN [6]. Characteristic values of climatic actions given in codes are based on observed data series generally covering 40-50 years of measurements; these series are thus not enough extended over time to reflect the effects of the climate change [7] or even to predict future trends. Aiming to account for these aspects, it is, therefore, necessary to rely on climate projections, resulting from appropriate global or regional climate models, which currently are the major source of knowledge about future climate change [8].