Mediterranean hot-spot and Extreme Events: Italy at the Center of a “Perfect Storm”

Davide Donati, Salvatore Pascale January 12, 2022

podcast ep 3

The Mediterranean region can be considered a hot-spot for the ongoing anthropogenic climate change. Italy is located at the very center of this region, and therefore it can expect exacerbated impacts of extreme events. Our peninsula is therefore an ideal candidate for what seems to be a “perfect storm”. This can potentially lead to severe consequences from social, economical, and environmental perspectives.  

Human-caused global warming has already reached +1.2 °C temperature globally and will probably continue, thus affecting many physical aspects of our climate. Within this context, the Mediterranean area, and particularly the Italian peninsula, is expected to be impacted more and more severely than others.  Over the Mediterranean basin, mean temperature has increased more than the global average, mean annual precipitation has decreased since the mid-twentieth century, and trends toward more frequent and longer heat waves and fewer extremely cold days and nights have been observed. Increasing temperatures and reduced precipitation are projected by climate models under middle-to-high emission future scenarios. Higher temperature implies a larger capacity to hold water vapour for the atmosphere, and thus more intense rainfall events. Thus, a paradoxical situation may arise, for which a decrease in average yearly precipitation will be associated with more extreme rainfall events, as the rain is concentrated in fewer events.  This makes this macro-region, and especially its southern part (e.g., Northern Africa, Middle east, Sicily, etc.), very vulnerable to climate change. 

The impact of climate and climate change is not limited to processes that occur in the atmosphere. In fact, climate has an extremely significant impact on all those phenomena that occur at the surface of Earth. For instance, floods and landslides are strongly controlled by rainfall. 

Despite human activity being recognized to have played a primary role in climate change, recent studies that have also been included in the last IPCC report, have shown that there is, at this time, a low confidence (due to a lack of data) that anthropogenic warming is causing an increase in frequency or severity of events such as floods and landslides. Nevertheless, floods, landslides, and other extreme events are producing significant impacts on communities, as in the case of the floods that severely affected central Europe. Countries such as Germany, Belgium, Holland, Luxemburg, and others experienced extreme rainfall both in terms of quantity and intensity, which resulted in floods that happen statistically once every 500 years – this is called return time. 

In Italy, the 1966 Arno River flood in Firenze caused significant damage to people, houses, infrastructures, and also the national cultural heritage. The Arno River flood had a return time of 200 years, and resulted from the exceptional, extreme rainfall that occurred across the Arno River watershed. The intensity and duration of rainfall in some areas exceeded 500, or even 1000 years. The Arno River flood is impressed in Italian history, however, many regions in Italy experienced severe impacts of climate-driven events in much more recent years. For instance, the floods that affected Sicily in October 2021, and the Liguria and Piemonte region in October 2020. 

The impacts of these events are very significant from both social and economic perspectives. Between 1971 and 2020, floods and landslides in Italy alone caused 1630 fatalities, 1871 injured, and over 320,000 evacuees and homeless.  Between 1944 and 2012, 61.5 billion Euros od damage were registered in Italy due to floods and landslides. Between 2013 and 2019, another 20.3 billion in damage have been estimated, a 30% increase in just 7 years. It is not surprising to realize that the 23% of the Italian territory is characterized by landslide hazard, and the 20% by flood hazard. 91% of all municipalities have at least a part of territory affected by flood or landslide hazard. All this data translates to almost 10 million people living in areas that can be subjected to floods, where 884,000 businesses have also been established. Additionally, 5.6 million people live in areas subjected to landslide hazard. In these same areas, 404,000 businesses have been identified. Prevention, preparedness, and resilience are therefore of extreme importance in terms of urban planning and land use, in order to increase our ability to cope with more extreme climatic events. 

The next 10-20 years is probably the last time window available to reduce the negative impacts of climate change – the last chance to limit human-caused global warming to less than +2 °C.  Indeed, there is a significant lag between our actions and the response of the climate system, for two reasons. First, the CO2 emitted remains in the atmosphere for hundreds to thousands of years before being adsorbed by water, vegetation, and soil. Secondly, and importantly, the ocean has a very significant thermal inertia which means that we need to wait a few decades before we see it warming, which may look like a positive thing, but then we need a long time (centuries to millennia) to stop this warming. If this opportunity is missed, the climate will follow a trajectory that will lead a temperature increase over 2°C, which will be nearly impossible to reverse in the next tens of thousands of years.  

Remaining below +2°C by the end of this century requires to strongly reduce the net CO2 and other greenhouse-gas emissions by 50-80% by 2050, and then bring them to zero in the second half of this century.  This will require an enormous effort globally, however, regardless of the ongoing efforts, there is still a very long way to go.

This article is based on
Business 4 Climate Podcast ep. 3 | Mediterranean hot-spot and Extreme Events: Italy at the Center of a “Perfect Storm”
Davide Donati, Salvatore Pascale