Floods, the expert speaks:“It happens and will happen again, next year and in 10 years.We have to learn to live with it."

Nicola Casagli is one of the leading experts on large risks in Italy.Here's what he says about the floods:"When it rains 200, 300, 400 millimeters of rain in a few hours, there is no territory that can handle it."How to learn to live with it?

FLORENCE – The bad weather hits hard and hurts in Emilia-Romagna, in Tuscany, in Veneto.In the south as in the north, with events chasing each other and piling up in the news.“It happens and will happen this year, next year, in ten years.Because the problem of geological instability in Tuscany, as well as throughout Italy and I would say in much of southern Europe, is now chronic."This was reported to the Dire Agency by Nicola Casagli, geologist, professor at the University of Florence, president of the Ogs (the National Institute of Oceanography and Experimental Geophysics) and member of the large risk commission which supports Civil Protection.

“IF 200, 300, 400 MM OF RAIN FALL IN A FEW HOURS THERE IS NO GROUND THAT CAN HOLD IT”

The question starts from afar and is linked "to two equally important factors": climate change and massive land consumption.The first changed the face of the rains.In general, looking at annual averages, "it rains less, but more violently and concentrated in small areas".And here Casagli gets straight to the point:“The events that occur and will occur in the coming years will be of such violence as to put any territory in crisis, regardless of the works that can be done.Why, when it rains 200, 300, 400 millimeters of rain in a few hours, approximately half the rain that falls in Florence in a year, there is no territory that holds as much as I can regulate it“.This "is bad news", a fact which "however also contains positive aspects:we no longer expect recurring floods like the one in Florence in 1966.Which was not only the flood in Florence, but also in north-eastern Italy.I mean, things this big and extensive won't be impossible, but rarer."However, to stay in Tuscany, “events such as in Livorno in 2017, in Campi Bisenzio in 2023, in Marradi in 2023 and again in 2024, must now be put on the agenda“.

LAND CONSUMPTION DOESN'T STOP

Then there is the second factor of specific weight equal to the first, land consumption.“We built too cheerfully and casually everywhere, in landslide and alluvial areas, in river floodplains, on banks and unstable slopes, on volcanoes and on faults.And we continue to do it because land consumption, monitored every year by Ispra, shows no signs of decreasing“.And here the gear gets stuck above all for an economic question:“Building on virgin land costs much less than recovering an abandoned area.”Precisely for this reason, if on climate change the process of reversal of direction, to which the policies of the countries of the globe should be linked, "is very long", on land consumption "there is more possibility of acting, for example by making it more convenient , even with institutional incentives, build on what has been built and demolish so much rubbish done in the past to rebuild in a more appropriate way".

“YOU MUST LEARN TO LIVE WITH THE RISK”

This is the picture described by one of the leading experts on the market:“There is a combination of two factors and one is very difficult to influence.On the other hand, however, we could act.Everything else is palliative.For heaven's sake - he specifies - everything is good, but when it rains 2-300 millimeters of rain...".The key, therefore, “is learn to live with risk.And I quote the United Nations:at the forefront of the Sendai Protocol is precisely the understanding of disaster risk.We need to understand how a river, a landslide, an earthquake works.And make it understood by citizens, who, if they do so, can defend themselves better.Let me explain: the 226 millimeters of rain that fell on the Tuscan coast is a frightening amount.There is no territory that can resist.But people can organize themselves to suffer as little damage as possible“, saving his life.

THE WRONG BEHAVIORS

“Even today, in fact, the majority of victims, as well as injuries to people, occur through wrong behaviors.I'll give a typical example:it starts raining hard.There's a weather warning, but I don't pay too much attention to it I go out to move the car.This is the stupidest thing to do:when I have more than 50 centimeters of water on the ground the car starts to float;when I have more than 80 the doors no longer open and I'm trapped. If we taught this in driving school, a lot of people would be saved.People die in cars during floods, rarely at home.That happens too, but it's much more difficult."

AN ALERT SYSTEM THAT CAN BE IMPROVED

However, the reflection (and controversy) on the warning system becomes urgent and cyclical.A knot that for Casagli must be resolved by better systemising the data that the machine largely already possesses.“Until 2010-12, the alert was inaccessible to the population.Then they were introduced the colored codes:yellow, orange and red.There, with the traffic light system, people began to understand it.And I can testify, also on the basis of the experience gained in the major risks commission, that the plan has saved many lives".The point, rather, lies in the way in which the data is handled.“Satellite monitoring is already incorporated into the national warning system.”Alongside these there are “networks of sensors on the ground.Ten, fifteen years ago they cost a lot of money", now that costs have significantly lowered "we can spread them by the hundreds of thousands across the territory.This already happens", however "all the activities are a bit uncoordinated.There are many projects, but there is no organic and integrated system capable of bringing together all the actors to be able to play together as in an orchestra.There are many soloists, a lot of data and information, but we are still a little far from making them play together, in a harmonious way.Here, there is a need for this."