Antonio Contino

The year-long unprecedented European heat and drought of 1540 – a worst case

The heat waves of 2003 in Western Europe and 2010 in Russia, commonly labelled as rare climatic anomalies outside of previous experience, are often taken as harbingers of more frequent extremes in the global warming-influenced future. However, a recent reconstruction of spring–summer temperatures for WE resulted in the likelihood of significantly higher temperatures in 1540. In order to check the plausibility of this result we investigated the severity of the 1540 drought by putting forward the argument of the known soil desiccation-temperature feedback. Based on more than 300 first-hand documentary weather report sources originating from an area of 2 to 3 million km2, we show that Europe was affected by an unprecedented 11-month-long Megadrought. The estimated number of precipitation days and precipitation amount for Central and Western Europe in 1540 is significantly lower than the 100-year minima of the instrumental measurement period for spring, summer and autumn. This result is supported by independent documentary evidence about extremely low river flows and Europe-wide wild-, forest- and settlement fires. We found that an event of this severity cannot be simulated by state-of-the-art climate models.

Tree-rings and people – different views on the 1540 Megadrought. Reply to Büntgen et al. 2015

Buntgen et al. (2015; hereinafter B15) present the result of new research which question the results of Wetter et al. 2014, (hereinafter W14) and Wetter et al. (2013, hereinafter W13)regarding European climate in 1540. B15 conclude from tree-ring evidence that the results based on documentary data of W14 probably overstated the intensity and duration of the 1540 drought event. W14 termed it Megadrought because of its extreme duration and spatial extent compared to other drought events in central Europe, although they note that the term is generally used for decadal rather than for single-year droughts (Seneviratne et al. 2012). We take the opportunity to recall the following issues. Firstly, when dealing with drought the complexity of this phenomenon should be kept in mind. Meteorological drought defined as a large negative precipitation anomaly during a certain period can trigger agricultural, hydrological, groundwater and socioeconomic droughts. Lloyd-Hughes (2013] and references cited herein) concluded that any workable objective definition of drought does not exist. To quantify droughts, various indices based on precipitation, temperature and evapotranspiration are used such as the Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), Z-index and PDSI. Their calculation depends on different periods (seasons, combination of months) and so different indices may classify the same drought episode differently (e.g. Brazdil et al.2014).

Contour map of the top of the regional geothermal reservoir of Sicily (Italy)

An integrated review of existing geological and geophysical data – partly acquired during oil and gas exploration – combined with new data provided by deep geothermal studies of selected key areas, was used for the 3D modeling and mapping of the top of the geothermal reservoir developed at a regional scale in Sicily (Central Mediterranean). The resulting 1:500,000 scale map covers the area of the whole Sicily (about 25,700 km2) and is devoted to represent the main input for both the thermal modeling and the evaluation of geothermal potential at a regional scale. As the map indicates the distribution at depth of a likely target for geothermal drilling, it can be also used as a rough indicator of expected drilling cost for geothermal projects. Such a map can be seen as a useful planning tool for any geothermal project, and related exploration to be carried out in the Sicily region in the future.

Quaternary marine and continental unconformity-bounded stratigraphic units of the NW Sicily coastal belt

ABSTRACT In the coastal sector of NW Sicily, the regional correlation of relevant unconformities recognised within the Quaternary sedimentary successions allowed the mapping of seven unconformity-bounded stratigraphic units (UBSUs). The regional unconformities are marine or subaerial erosional surfaces, as well as non-depositional surfaces, locally marked by paleosoils. The erosional surfaces were produced from marine abrasion, surface water overland/concentrated flow, river erosion, karst solution, mass movement, or wind erosion. The main lithofacies of the Quaternary UBSUs consist of: (a) marine and coastal bioclastic calcarenites, (b) aeolian sandstones, (c) river deposits, (d) colluvial deposits, (e) talus slope deposits, (f) landslide deposits, and (g) chemical carbonates (travertines and speleothems). Quaternary environmental changes, due to tectonics, climate, and sea-level oscillations, are the causes that favoured the development of erosion/deposition processes responsible for the genesis of unconformities and deposits. As a result, through the UBSU map of the NW Sicilian coastal belt, it is possible to: (i) recognise stratigraphic units controlled by tectonic, climatic, and environmental processes (and their interplay) and (ii) detect Quaternary sedimentary evolution.

Biostratigraphy, chronostratigraphy and paleonvironmental reconstruction of the Palermo historical centre Quaternary succession

Marine deposits from the Palermo Plain were historically relevant for the Quaternary Period definition. Here we show lithostratigraphic, biostratigraphic and chronostratigraphic data collected on three boreholes in the Palermo historical centre that recovered 36.8, 42.0 and 52.0 metres of sediments overlaying the Numidian Flysch. Marine sedimentary sequences span from the Calabrian Stage (calcareous nannofossil Zone MNN 19d) to the Middle Pleistocene (dominance of medium-sized gephyrocapsids within the MNN 19f Zone) and also include a short Holocene depositional event. Calcareous nannofossil, benthic and planktonic foraminifera assemblages point to a shallow coastal environment, possibly < 50 m deep. This study highlights the need of a modern and reliable stratigraphic interpretation of lithotypes, to identify stratigraphic gaps and to draw deep geological structures in an area extremely vulnerable to seismic and hydrogeological hazard.

Water resource assessment in karst and fractured aquifers of Termini Imerese-Trabia Mts. (Northern central Sicily, Italy).

The carbonatic siliciclastic Mesozoic reliefs of Termini Imerese-Trabia Mts. (Northern central Sicily) were selected in order to investigate groundwater resources, as these fissured to karstic aquifers are used for potable water supply. These reliefs, part of the Sicilian Apennine Chain, consist of a tectonic units (deformed and emplaced during the Miocene-Pleistocene, and collapsed during the Plio-Pleistocene) mostly formed by clayey pelagic limestones (Sicilidi domain) overthrusting Meso-Cenozoic carbonate and silicoclastic rocks (Imerese Basin, Late Triassic-Early Oligocene) and terrigenous covers (Numidian Flysch, Late Oligocene-Early Miocene). The evolution of karstic network and subsurface drainage systems has been favoured by tectonic structures, the Messinian Salinity crisis (latest Miocene) and Quaternary eustatic sea-level changes. Several large-capacity wells drilled in the area, are strategic for water supply of both the city of Palermo (about 800.000 inhabitants) and eastern metropolitan region. Water shortage in some towns has been intensified by the indiscriminate exploitation of several springs most of which have disappeared. These events have produced a progressive groundwater resource reduction and threat of seawater intrusion. Moreover, the occurrence of potential pollution producing industries (Termini Imerese industrial zone) could also compromise freshwater quality. Several hydrothermal superficial manifestations, related to deep carbonate reservoir, occur in this region. The groundwater flow is controlled by the main tectonic fractures and by several karstic forms. The importance of a qualitative and quantitative study of the water resources in some hydrostructures influenced by the potential interaction of several factors is here proposed.

Erratum to: The year-long unprecedented European heat and drought of 1540 – a worst case

Oliver Wetter & Christian Pfister & Johannes P. Werner & Eduardo Zorita & Sebastian Wagner & Sonia I. Seneviratne & Jurgen Herget & Uwe Grunewald & Jurg Luterbacher & Maria-Joao Alcoforado & Mariano Barriendos & Ursula Bieber & Rudolf Brazdil & Karl H. Burmeister & Chantal Camenisch & Antonio Contino & Petr Dobrovolný & Rudiger Glaser & Iso Himmelsbach & Andrea Kiss & Oldřich Kotyza & Thomas Labbe & Danuta Limanowka & Laurent Litzenburger & Oyvind Nordli & Kathleen Pribyl & Dag Retso & Dirk Riemann & Christian Rohr & Werner Siegfried & Johan Soderberg & Jean-Laurent Spring