A meteorologist, climatologist and science educator, Luca Mercalli is one of Italy’s greatest experts in the field. President of the Società Meteorologica Italiana (Italian Meteorological Society), he is also founder and editor of the magazine Nimbus.
Italy finds itself today having to face yet another summer drought. But its impact appears to be more dramatic than those of previous years.
“This year, we risk having the most intense drought ever to be recorded in Italy. That means the worst in at least 250 years. We should have more precise data by the end of the summer – September at the earliest. Just the same, from what we have seen so far, this will likely be a record.”
Do you think we have to prepare ourselves to live through crises like this one?
“It’s not what I think, but what the entire scientific community thinks. All you have to do is read the United National report on climate change. The report by the IPCC – the Intergovernmental Panel on Climate Change – has been saying this over and over again for the past 30 years. Unfortunately, scenarios of a warming planet point to this kind of impact. As temperatures rise across the globe, so do the number of extreme weather events, whether they be droughts, floods, tornados, an African heat wave like the one we are witnessing now… On top of that, we have the problem of the rising oceans caused by melting glaciers at the poles. Oceans are rising by four millimetres a year, and this is going to influence our decisions in the future.”
How much will this climate crisis cost the Italian economy?
“It is going to cost a lot because this drought began in December 2021. There hasn’t been any rain in the last eight months. Then there have been these heatwaves that have made the lack of water even more problematic. There needs to be a plan to build the infrastructure that we need, such as dams, aqueducts, water supply networks. And these things aren’t built in a month.”
To make matters worse, there is a lack of maintenance across the national water supply network and other infrastructure…
“It’s a complex issue. There is never a single cause, and it is never the same one for the entire country. We know that Italy’s aqueducts are in a poor shape, losing 38% of the water they carry. But even in this case there are enormous differences among regions. In the south, there are aqueducts that lose 70%, while in the north there are areas where there are aqueducts that have been fixed and well-maintained and leak 15-20%. Nonetheless, it’s obvious that Italy’s aqueducts are more than 100 years old. They need to be modernised. It’s absurd that – in the face of a water shortage – we lose half of it just through the water network.”
What is needed to reverse this trend?
“We need the political will to invest more, with a long-term vision for the sector. The climate and the consequences of global warming are issues that concern us all. But they are still relegated to being debated among technicians.”
Is Italy prepared to manage this crisis?
“What we have to recognise is that Italy has a lot of expertise and great infrastructure. But we have to do better, especially in planning for the future. In light of these big changes, we can’t plan for the future as we have done in the past. Climate change has changed the conditions of the future. So we need to prepare for them today without looking in the rear-view mirror. The past as we knew it will no longer exist. In order to plan our water infrastructure, for example, we can’t look at the precipitation levels of 30 years ago, but what will happen 30 years from now. That is the real challenge.”
What can be expected of infrastructure companies?
“I think the key message is to invest in upgrading. A major part of the work to be done today in the construction sector is to improve, upgrade, restore and maybe tear down and redo.”
To stop climate change, is it necessary to put a stop to growth?
“It depends on what you mean by growth. The land is easy to view as a limited resource because it is limited by geography. There are natural limits that we can’t overcome. These limits do not mean we cannot progress any further. We just need to use other indicators to establish what progress is.”
Can you use data and scientific analysis to explain to us the devastating progress of climate change?
“The temperature on the planet has already risen by one degree in the last century and that’s a lot for an entire planet. Just think of your body when its temperature rises by one degree: you get a fever. So there are now two scenarios. The first one is the more prudent one with a rapid decarbonisation of the economy, getting out of fossil fuels, switching to renewables, and respecting the terms of the (United Nations) Paris Agreement. In this scenario, we will be able to stay within a two-degree rise by the end of the century. The second scenario, which entails ignoring the terms of the Paris Agreement, would lead to a rise in temperatures by up to five degrees by the end of the century.”
In Italy, the collapse of the Marmolata glacier and the death of 11 people reopened a debate about the effect of climate change. Is this another sign?
“The heat was definitely the factor that set it off. The glacier had been at temperatures above zero for days and days. There was a lot of water streaming down. But we can say that every glacier had been exposed to the same temperatures. So in the special case of the Marmolata, there were a series of conditions – even casual ones. I would say that it had to do with an isolated incident that unfortunately happened at a place that was crowded at that hour. So the debate that we have to have has to be wider. As we speak, a temperature of zero degrees can be registered at Mont Blanc. This means that snow is melting at the top of Mont Blanc at 4,800 metres. This tells us that, in the next 50 years, when it comes to the glaciers of the Alps, there will be a bit of ice on Mont Blanc and Monte Rosa, with the rest of the glaciers destined to disappear.”
What is Earth Overshoot Day?
“Earth Overshoot Day is the day when people have used up all the biological resources that the Earth can regenerate during the entire year. From that day, people start to consume on credit, using more than what the Earth can supply in a single year. Today, it’s said that we’re using 1.7 Earths, or more than one Earth and a half. And this 70 percent more Earth that we are using now is simply what we are borrowing from future generations – something that they will not have.”
What about the deniers? How can you respond to them?
“We’re actually talking about a few isolated individuals who often have an ideological or economic interest in the debate. The best way to fight them is not to give them any media attention. Today more than ever, the scientific community of climatologists agrees on the analysis of what is happening.”
In what way can companies that build infrastructure contribute?
“Infrastructure plays a big role, even in the solutions to the climate problem because they are public works that last a long time. We need energy and raw materials to do them, technology, respect for the principles of sustainability, maximum reduction in energy use – as much in the construction models to be designed as in the use of materials. That’s why I am convinced that the construction sector is strategic. It is one of the sectors that more than others can adapt to the changes of tomorrow.”