After a scorching summer, an autumn at risk of extreme events awaits us. At a global level, El Niño is of greatest concern, a natural climate phenomenon characterized by an unusual increase in the surface water temperature of the central and eastern Pacific Ocean, with possible repercussions on global weather conditions.
According to the World Meteorological Organization, El Niño is strengthening further and is expected to reach maximum intensity between November and December.
What will the weather be like in autumn? The forecasts
For the September-November 2026 quarter, World Meteorological Organization (WMO) indications show a high probability of above-normal temperatures in most land areas. For Italy, seasonal projections therefore indicate a warmer autumn on average, while the precipitation picture is much less defined. An important role is also played by the temperature of the oceans. Warmer seas mean greater availability of energy and humidity in the atmosphere and can contribute, under certain conditions, to the formation of particularly intense precipitation with a high risk of extreme events.
El Niño increases uncertainty about the weather in the coming months
One of the elements to keep under observation is El Niño which, according to the latest forecasts from the World Meteorological Organization (WMO), could strengthen in the coming months, reaching a very high intensity before the peak expected towards the end of 2026. The phenomenon could also continue until at least February 2027, with consequences on the world climate destined to continue into the first months of next year.
A phenomenon fueled by exceptionally warm conditions in the tropical Pacific Ocean. The temperatures of surface waters and those recorded in the underlying layers are in fact well above average, providing the necessary conditions for a further strengthening of El Niño. But the consequences are not just meteorological. In fact, when an extreme event hits an area, the damage is quickly transferred to the economy.
Floods, landslides and storms: the income statement of recent years
The Italian experience of recent years shows how high the cost of extreme weather events can be. ISPRA, the Higher Institute for Environmental Protection and Research, reports that the period 2022-2024 was characterized by several hydro-meteorological events of exceptional intensity, from floods in the Marche to landslides in Ischia, up to the floods that hit Emilia-Romagna in 2023 and the North-West in 2024. Particularly significant is the case of Emilia-Romagna in May 2023. According to data from the Region, the certified damages have reached approximately 8.5 billion euros, affecting infrastructure, homes, businesses and agriculture.
The problem did not end with that event. In September and October 2024 new floods hit several provinces of Emilia-Romagna, in some cases again affecting companies and land already damaged the previous year. The Region had to activate further support procedures for the agricultural sector.
Autumn 2022 had also shown the vulnerability of several territories. In the Marche region, the September 2022 flood required economic interventions for families and productive activities: the first support measures exceeded a total of 23.8 million euros, considering the aid intended for families and for businesses. In November of the same year, the landslide in Ischia caused flooding, landslides and damage to infrastructure, buildings and essential services.
The account of extreme heat: the numbers from the Allianz Climate Economics Report
However, the cost of extreme climate events does not only concern floods and landslides. A particularly significant indication comes from the Allianz Climate Economics Report 2026 analysis, according to which the extreme heat waves of summer 2026 would have resulted in an economic cost estimated at 113 billion euros in the 30 European countries analyzed. The figure is equivalent to approximately 0.46% of the overall GDP of these countries.
Allianz estimates the impact of heat waves on economic production, considering the loss of output associated with the most intense five-day heat episode recorded between June and August, together with humidity and population exposure. Italy is the European country with the greatest estimated loss, equal to 27.8 billion euros, ahead of Germany and France. Furthermore, the economic risk may not stop in Europe. According to the same Allianz analysis, a particularly intense El Niño could generate global losses of up to 451 billion dollars, concentrated mainly in 2027. The estimate indicates China, the United States and India among the most exposed countries in absolute terms, while for the European Union the overall impact is estimated at around 24 billion dollars.
