Last year Romagna, now Lombardy and Veneto: no, it's not a coincidence. The storms that are hitting our country more and more often are weather anomalies that are becoming more and more frequent, due to global warming.
Higher average temperatures, like those we are seeing in recent years, also mean greater evaporation, and therefore more fuel for the clouds which, in the right conditions, can cause deadly water bombs which are not manageable by infrastructures designed on climate models rendered obsolete by climate change.
Veneto, perfect storm
The storms that continue to hit the Veneto are caused by a mix of extremely rare weather phenomena: the encounter between a so-called omega block, a self-healing storm, and a high sea water temperature for the period. The omega block, or zonal flow, is a configuration in which a central anticyclone is created with two low pressure areas on its flanks. The anticyclone is currently positioned over Scandinavia, and by interacting with a disturbance over Eastern Europe it is creating a blocking situation, in which the disturbed fronts are unable to evolve naturally towards the east, and remain concentrated for longer than usual on small spaces such as the Veneto, producing more intense and extensive rainfall.
This in itself anomalous weather situation was associated with what meteorologists define as a self-healing thunderstorm, a thunderstorm phenomenon linked to the contrast between a warm and humid air mass at low altitudes, and a colder and drier one at high altitudes. This contact keeps active an intense upward motion which sucks the air upwards at high speed, favoring its cooling and causing the condensation of large quantities of water vapor which fuel the precipitation. The third element of this perfect storm, the temperatures: the sea waters are already very warm for the period, and this increases evaporation, and therefore the quantity of water vapor present in the atmosphere, ready to be transformed into rain.
Rare events, but increasingly common
The result of these three phenomena caused the record rainfall seen in Veneto in recent days. According to researchers from the University of Padua, the 230 millimeters of water that fell in six hours in Velo d'Astico is an event that happens on average every 300 years. And even the 70 millimeters in 30 minutes seen in other areas are once-in-200-year events. Or at least, they were based on the statistics of the past decades: it is the same director of the study center on the impacts of climate change at the University of Padua, Marco Marani, who explains that these are calculations carried out with a model that does not take into consideration the climate changes. And that with the climate changes that our planet is experiencing, and the constant increase in average temperatures, extreme weather events of this type, even on Italian territory, are destined to become increasingly common. And unfortunately, we just have to accept it: reducing emissions will allow us to limit the damage in the coming decades, but not to bring the climate back to what we knew. To prevent disasters like those seen in recent years from becoming the order of the day, all that remains is to invest in climate adaptation, creating safety infrastructures capable of managing rainfall of an intensity that we once considered anomalous in our territory.