Fire is an important ecosystem disturbance, having significant socio-economic consequences on the one hand, while fulfilling a vital ecological role on the other. Across fire-prone ecosystems, different fire regimes can be found, reflecting a combination of climatic factors and of different plant species characteristics. Ecosystem flammability and fuel load are the most evident and well-studied aspects of plant interactions with fire regimes. Only recently, has there been a major focus on how other plant traits, and especially fire responses, shape the fire regime. For example, invasive alien species with highly competitive traits, when introduced by humans into novel ranges, can have dramatic impact on the local fire regimes. The aim of this research is to determine the role that plant traits have in driving fire regimes in different ecosystems across the world and for various climates, including also the role played by invasive species.

An increase in precipitation extremes is one of the most robust aspects of anthropogenic climate change, but not in the Mediterranean region, where the confidence on the effects of climate change remains low. Italy, in particular, features unclear trends in the intensity of precipitation extremes, with spatially and seasonally dependent signals. Yet, a number of cyclones, i.e intense mid-latitude storms, caused precipitation extremes and considerable economic damage in Italy in the past decade. The extent that climate change has contributed to these events is poorly understood.
The overarching objective of ENCIRCLE is to provide credible, understandable and useful information of how climate change affects the frequency, intensity and duration of precipitation extremes driven by extratropical and Mediterranean cyclones in Italy.

Rainfall-related hazards are among the most damaging natural hazards, in Italy and globally. Risk management and societal
resilience to these hazards crucially depend on quantitative information on the probability of occurrence of extreme rainfall. The long historical rainfall records available from rain gauges allow us to derive these probabilities for the gauge locations, but suffer from important shortcomings: they hardly represent the multi-scale information required for hazard assessment, and they cannot adequately sample the spatial variability of extreme rainfall in areas with strong climatological gradients, such as orographic and coastal regions. Unfortunately, these are the areas where most rainfall-related hazards occur, especially in Italy. INTENSE will address these issues by combining observations from rain gauges, weather radars and satellites, state-of-the-art statistical approaches, stochastic weather generators, and physically-based models. With the increasing length of their records, weather radars and satellites have now become a realistic opportunity to overcome the observational limitations of rain gauges.

Convective events pose a serious hazard to societies due to their associated heavy rainfalls, large hail, strong winds, and lightning.
Location and timing determination of convective precipitation is still a challenge of modern meteorology. Despite the good skills of current weather forecasting tools in the prediction of the large-scale environment facilitating the onset of convective phenomena, the multitude of spatial scales involved in such events makes their characterization, observation and forecast a difficult task. The problem is further complicated by their rapid temporal development, which lasts from minutes to a few hours depending on the specific case.
Recent research indicates that the predictability of these events can be strongly improved accounting for local meteorological observations.
The goal of ICREN is to enhance the forecast of deep convective events by properly exploiting the information made available by local standard and non-conventional observations of meteorological variables through an ad hoc developed integrated forecasting model.

The Arctic is warming faster than other areas, with a double temperature increase compared to the global average (Arctic Amplification,AA). This affects climate on a large scale, perturbing meteorological parameters and hydrological cycles even at
Mid-latitudes, including Italy, in particular affecting extreme events.
Current models for climate change (CC) are highly limited by large uncertainties on the role of atmospheric aerosol, including the aerosol-radiation interactions in all sky conditions (depending on cloud type and cloudiness in the atmosphere) and on the climatic impact of different aerosol sources, including those emerging from the CC in the Arctic. Despite the vastness of the Arctic area, few monitoring stations are present and are on land, so no full description of the spatial variability of the needed parameters is available on the sea that covers most of the area. Finally, a detailed description of the aerosol spatial variability in the Arctic is not enough to investigate the aerosol effect on the AA: several modelling studies point to the possible role of the transport of heat due to aerosol absorption of solar radiation, from mid-latitudes to the Arctic.

Atmospheric rivers (ARs) have emerged as a global relevant driver for extreme hydrometeorological events and water budget modulator in many areas of the globe. Defined as narrow corridors of enhanced horizontal transport of moisture, ARs transfer huge amounts of water vapour from the tropics to the mid-latitudes. Low-latitude moisture export can be important for extreme events at
higher latitudes because it may cause critical precipitation thresholds for flooding to be exceeded. ARs have been studied in the last 20 years along the Pacific US Coast, being responsible for heavy precipitation originated by the interaction -up lift- with the coastal
orography. In the last decade, emerging regions such as Europe have been explored, where ARs have been connected to extreme events, especially those areas facing the Atlantic coast. The detection and investigation of ARs in the Mediterranean basin have started only in the very last years, so that the knowledge on this phenomenon is scarse. Only few studies showed the relevant role of
an AR in severe hydrometeorological events affecting the Mediterranean coast of Spain or the Italian peninsula.

During the Early Eocene, about 55 millions years ago, the climate of the Earth was characterized by radically different conditions than today: atmospheric CO2 exceeding 1000ppm, 10-15°C higher mean global surface temperature (GST) and strongly reduced pole-to-equator temperature gradient.
On top of this extraordinary mean state, the Earth was struck by a series of sudden global warming events, known as hyperthermals, which lasted a few millennia and saw further GST rise by as much as 5°C. They were entirely natural climatic events and were driven by an estimated 2000-5000 Gton carbon release into the atmosphere. Hyperthermals represent the fastest carbon release in the paleoclimatic records and our comprehension of their onset and decay is still partial, also because of the limited spatial and temporal frequency of proxy data.
A powerful tool to investigate hyperthermals - and Eocene climate in general - is represented by numerical Earth System Models (ESMs). Due to their capacity of filling gaps in proxy data and to the opportunity they provide for studying climate interactions under different mean states, ESMs are rapidly gaining ground for paleoclimatic applications.

As our climate system climbs through its current warming path, temperature and precipitation aregreatly affected also in their extremes. Owing to their increasing societal impact, climate extremeshave recently attracted large international programmes (IPCC, WCRP grand challenges) with aneffort to standardize their detection (e.g. through climate extremes indices) and to allow attributionto climate change. There is a general concern that climate change may affect also the magnitudeand frequency of river fl oods and, as a consequence, that existing and planned hydraulicstructures and fl ood defences may become inadequate to provide the required protection level inthe future. While a wide body of literature on the detection of fl ood changes is available, theidentifi cation of their underlying causes (i.e. fl ood change attribution) is still debated. In particular,in alpine areas, changes in heavy precipitation is only one of the drivers of fl ood change, beingsnow-rain partitioning and snowmelt other key processes in the formation of river fl oods of differenttype.

Convection is a vital process which helps to redistribute energy in the Earth atmosphere with different implications in terms of large-scale atmospheric circulation and vertical uplift of water vapor, aerosol, and trace gases. This process is often conducive toc loud formation affecting the production of high clouds in the form of cloud anvils, which represent a key element in the high cloud radiative feedbacks and provide a substantial amount of precipitation often connected to severe weather events worldwide.
Nevertheless, the topic still deserves detailed studies as it also underpins the convection representation in weather and climate models, where progresses are required in understanding of convective mass flux (CMF) within storms and its representation. In this respect recent works illustrated the benefits of merging the highly temporally resolved measurements from GEO platforms and the detailed, range-resolved snapshots provided by spaceborne radars in LEO orbit, and the usefulness of a synergistic use of passive and active sensors from the A-train satellite constellation for the CMF estimate.