The ISPRA report on the national water resource balance shows a strong recovery compared to 2022, a horribilis year for drought. However, the decline continues compared to the average of the last 70 years
In 2023, Italy turned the page after two years of severe drought, except in some southern areas, with Sicily at the forefront. The annual rainfall volumes have returned to levels very close to the long-term average. However, water availability in the country is down by over 18% compared to the average of the last 70 years. The reasons? They are linked to the impact of climate change. This is what emerges from the ISPRA report on Italy’s hydrological balance, updated to 2023.
At first glance, it might seem that 2023 was a “normal” year in terms of water resources. In 2021-2022, Italy experienced the worst drought since World War II, with severe repercussions on agriculture, industry, energy production, and domestic consumption. However, last year’s balance marks a clear reversal of this trend.
A “Normal” 2023?
In 2023, the total annual precipitation in Italy was 923.8 mm, corresponding to about 279.1 billion cubic meters. The amount of water resources linked to precipitation increased by 28.5% compared to 2022 (which saw a historical low of 719 mm since 1951).
However, the data on Italy’s water balance in 2023 is far from “normal” for three reasons:
- It’s not normal in absolute terms because it is still slightly below the long-term average, which is nearly 950 mm.
- It’s not normal in terms of the distribution of precipitation, both over time and across regions. Almost the entire increase compared to 2022 occurred in May 2023. In just 30 days, nearly 163 mm of rain fell, about 49 billion cubic meters—more than twice the average. The majority of this precipitation occurred in Emilia-Romagna (which caused the flooding), Sicily, and Calabria.
- It’s not normal because the rain replenished aquifers less than usual. Only 19% of the precipitation ended up in the groundwater, compared to the historical average of 22.7%. Additionally, water resources evaporated much more than usual. In 2023, evapotranspiration accounted for 59.4% of the total rainfall, compared to the long-term average of 52%.
All of these factors are influenced by the climate crisis. ISPRA specifies that the increase in evapotranspiration was caused by high temperatures, exceeding the climatological averages, which also occurred in 2023. The alteration in the frequency of extreme events, including torrential rainfall, is also a reflection of climate change.
Collapse of Italy’s Hydrological Balance: -16% in Just 30 Years
Summing up, it emerges that Italy’s hydrological balance shows a significant deficit both in the long and medium term. The key figure is the natural availability of renewable water resources, i.e., the amount of precipitation—net of losses due to evapotranspiration—that remains available in the environment for ecosystems and various uses.
In 2023, the natural availability of water resources was about 373 mm, or 112.4 billion cubic meters across the country. Compared to the disastrous 2022, this marks an increase of 68%. However, when compared to the long-term average from 1951 to 2023, the decline is 18.4%. Compared to the 30-year average from 1991 to 2020, the reduction in renewable water resource availability is nearly 16%.
“This reduction is the combined effect of a precipitation deficit, especially in February, March, September, and December, and an increase in water evaporation from water bodies and soil, as well as evapotranspiration from vegetation,” ISPRA clarifies.
