What the data tell us

On the basis of constantly collected and pooled data, the Index is able to establish accurate trends and scenarios concerning the evolution of the weather and climate in the territories covered.

Extreme event trends

The historical data on which the Index is based consist of a database called “ERA5”, belonging to the European Centre for Medium-Range Weather Forecasts (ECMWF), which brings together information dating back to 1940. On the basis of this huge body of data, the Index is able to provide comparative models concerning the seven dynamics monitored – Heat stress, Cold stress, Extreme precipitation, Drought, Extreme wind, Hail storms and Fires – for identifying trends and making forecasts.

More specifically, the Index shows how the number of extreme meteorological events has increased constantly since 1990, with a clear peak in the last decade. In other words, extreme events are more and more common and will increasingly be so.

Percentage of total months affected by extreme events over the years.

Percentage of total months affected by extreme events over the years.

Percentage of total months affected by extreme events over the years

All extreme events detected in the period 1981-2023 (credits to Cinzia Bongino).

All extreme phenomena detected in the period 1981-2023
(credits to Cinzia Bongino)

How is Italy faring?

In the paper “How is Italy faring?”, starting from the data of the European Extreme Events Climate Index, the extraordinary meteorological events that characterized Italy in the hydrological year from September 2022 to August 2023 are analyzed, quantified, and monitored. The analysis not only allows us to better understand the magnitude of certain phenomena but also to identify trends and provide scientific and visual support to what is happening at the climatic level.

Using the Index for forecasting purposes

The Index takes on a fundamental role above all for outlining future meteorological and climatic scenarios.
Using dedicated forecasting models, it has returned trend forecasts for five specific dynamics – Heat stress, Cold stress, Extreme precipitation, Drought and Extreme wind – for three greenhouse gas concentration scenarios:

  • Optimistic scenario (RCP 2.6), in which CO2 emissions are halved by 2050
  • An “in-between” scenario (RCP 4.5), calculated as intermediate
  • Pessimistic scenario (RCP 8.5), in which emissions continue to increase at the current rates

The trend of the five dynamics for Italy, from the current day to 2100, is shown below.

Extreme maximum temperature trend
Extreme maximum temperature trend
Projected trends of extreme maximum temperature events for the periods 2011-2040, 2041-2070, 2071-2100. The optimistic scenario (RCP 2.6) is shown in green, the in-between scenario (RCP 4.5) in blue, and the pessimistic scenario (RCP 8.5) in red.

The trend predicted by the Index shows a constant increase in heat waves over time. The intensity of this increase varies considerably, from a very slight increase in the case of the optimistic scenario to an almost 300% increase for the pessimistic scenario.

Extreme minimum temperature events trend
Extreme minimum temperature events trend
Projected trends of extreme minimum temperature events for the periods 2011-2040, 2041-2070, 2071-2100. The optimistic scenario (RCP 2.6) is shown in green, the in-between scenario (RCP 4.5) in blue, and the pessimistic scenario (RCP 8.5) in red.

All three hypothesised scenarios suggest a decrease in cold waves compared to the current values, and only diversify in terms of entity in the last period considered (2071-2100).

Extreme precipitations trend
Extreme precipitations trend
Projected trends of extreme precipitations for the periods 2011-2040, 2041-2070, 2071-2100. The optimistic scenario (RCP 2.6) is shown in green, the in-between scenario (RCP 4.5) in blue, and the pessimistic scenario (RCP 8.5) in red.

Regardless of the scenario considered, the trends suggest an even evolution in extreme precipitation, which will therefore continue to increase regardless of the measures taken to reduce greenhouse gas emissions.

Extreme drought trend
Extreme drought trend
Projected trends of extreme drought events for the periods 2011-2040, 2041-2070, 2071-2100. The optimistic scenario (RCP 2.6) is shown in green, the in-between scenario (RCP 4.5) in blue, and the pessimistic scenario (RCP 8.5) in red.

As time goes by, drought trends start to diverge considerably. In the optimistic scenario, there will be a slight decrease in drought periods in the last period analysed (2071-2100), whereas the pessimistic scenario hypothesises long periods of drought during the summer months.

Extreme wind trend
Extreme wind trend
Projected trends of extreme wind events for the periods 2011-2040, 2041-2070, 2071-2100. The optimistic scenario (RCP 2.6) is shown in green, the in-between scenario (RCP 4.5) in blue, and the pessimistic scenario (RCP 8.5) in red.

As time advances, the indicator for the events associated with extreme wind will evolve almost homogeneously, regardless of the scenario analysed. The scenarios are also concordant that there will be a peak in the month of June during the last period considered (2071-2100).