Vulnerabilities - Italy

Changes in dry and wet spell characteristics in Europe have been projected for 2021–2050 compared with 1961–1990, based on Regional Climate Model simulations under the A1B emission scenario. From the results it can be concluded that significant changes in dry and wet event characteristics are expected with high confidence in the southernmost (mainly France, Italy, and Spain) and northernmost (mainly Iceland and Scandinavia) regions of Europe, respectively. Southern Europe is most probably facing an increased risk of longer, more frequent, severe, and widespread droughts, while northern Europe is facing increased risk of intensified wet events. For precipitation, the most pronounced changes are found for the Iberian Peninsula in summer (−17.2%) and for Scandinavia in winter (+14.6%) (25).

Northern Italy

Northern Italy currently experiences some of the highest rates of annual water availability in Europe (15). Approximately two-thirds of this, mainly surface water, is used for irrigation with stress from groundwater abstraction a problem in only a few areas (16). Changes in the quantity and timing of meltwater from the Alps due to future warming may result in water availability in the catchment becoming increasingly dominated by seasonal rainfall patterns. The uncertainty in future projections for short-duration droughts could thus become more important towards the end of the century and may require a more integrated approach to the management of irrigation schemes than is observed at present (26). Extremely low snow accumulation has been reported at all altitudes in the Italian Alps for the winters 2022 and 2023, compared with a long-term time series for the period 1930–2023, contributing to critical low-flow conditions in the Po and Adige rivers (27). 

Future projections have been made of changes in droughts in Northern Italy for the near (2021–2050) and far future (2071–2100) compared to the reference period 1971–2000. This was done for a moderate (RCP 4.5) and high-end scenario of climate change (RCP 8.5), based on 6 combinations of global and regional climate models for each of these time slices. Although the area is historically rich in water resources and the availability of water for irrigated and rainfed farming is traditionally high, drought events have increased in the last twenty years. A further increase is projected for the future. In northern Italy, heavy drought events were homogenously distributed over the area in the period 1971–2000 and lasted between 6 and 8 weeks. In this period, the number of extreme drought events was 3 to 5; these droughts covered up to 32 - 47% of the area (26).

The projections indicate that the number of extreme drought events may increase from 3 - 5 in the reference period 1971–2000 to 5 - 8 in the near future, with a further increase for the far future. The percentage of the area affected by these droughts in the near future is expected to be comparable with that of the reference period. An increase up to 55% (RCP 4.5) or 68% (RCP 8.5) is projected for the far future. The duration of drought events is projected to increase by a few weeks in the near future and several weeks in the far future. If global warming were to reach +2°C, heavy drought events in the area would last 5 to 15 weeks. A further increase to +3°C is expected to further increase the duration of extreme droughts (26).

Southern Italy

It was concluded that under the A2 emissions scenario, all of Italy is projected to undergo a substantial drying, with precipitation decreasing by about −10% to over −40% in summer (21). Another study showed that a 1%/year CO2 increase may result in a reduction by 2050 in groundwater recharge of 21-31% and runoff of 16-23% in the Candelaro catchment in southern Italy (22). Similarly, it was concluded that the “water stress period” for the Crati River basin of southern Italy may increase by an average 15 days per annum, while mean runoff was projected to decrease between 25% and 41%, under the SRES A2 and A1B emissions scenarios for 2070-2099 compared with 1961-1990 (23).

In the summer of 2002, farmers in southern Italy and Sicily could not irrigate their fields because of the hardest drought in decades. The Italian government had to provide relief funds of 500 million euro (19).

The definition of drought

Drought is a natural phenomenon defined as sustained and extensive occurrence of below average water availability. Drought should not be confused with aridity, which is a long-term average feature of a dry climate. It is also distinct from water scarcity, which constitutes an imbalance between water availability and demand (1).

Three general types of drought may be recognized (7):

• meteorological droughts – defined on the basis of rainfall deficiency;
• hydrological droughts – where accumulated shortfalls in river flows or groundwater replenishment are of primary importance;
• agricultural droughts where the availability of soil water through the growing season is the critical factor.

During lengthy droughts, all three categories may combine to increase water stress. High temperatures are not a necessary component of drought conditions, dry winters can lead to water resources stress in the following summer.

Droughts might manifest themselves either as short but extreme single season droughts (such as the hot summer of 2003) or longer-term, multi-season droughts, and they might be local or widespread in nature (7).

Vulnerabilities in Europe

The European Commission has estimated that at least 11 % of Europe's population and 17 % of its territory have been affected by water scarcity to date and put the cost of droughts in Europe over the past thirty years at EUR 100 billion (1).The drought of 2003 caused a total economic cost of over €13 billion in around twenty European countries (2,7).

Vulnerabilities – European trends in the past

In 2012 the IPCC concluded that there is medium confidence that since the 1950s in particular southern Europe has experienced a trend toward more intense and longer droughts (24). There is no evidence that river flow droughts have become more severe or frequent over Europe in general in recent decades (3), nor is there conclusive proof of a general increase in summer dryness in Europe over the past 50 years due to reduced summer moisture availability (4). Strong increases in the area of combined severe dry and wet conditions in Europe over the last three decades have also been identified, though, and it has been suggested that without global warming droughts would have been smaller and less pervasive (13).

Regional differences

Despite the absence of a general trend in Europe, there have been distinct regional differences. In particular, more severe river flow droughts have been observed in Spain, the eastern part of eastern Europe and large parts of the United Kingdom (3). However, in the United Kingdom there is no evidence of a significant increase in the frequency of occurrence of low river flows (5).

Increasing drought deficits were observed in Spain, eastern Europe and large parts of central Europe with changes in precipitation cited as a major explanatory factor (11). Others (12) have indicated that the proportion of Europe experiencing extreme and/or moderate drought conditions has changed significantly during the twentieth century with fewer droughts over Scandinavia, Netherlands and the Ukraine and more in areas of eastern Europe and western Russia.

Water extraction

Water extraction as well as water management across catchments and changes in land use and management also make it very difficult to attribute changes in average water discharge, floods and droughts to climate-change forcing (8).

Changes in drought severity for western Europe have been attributed to a changing climate but for eastern European countries the increased extraction of water for economic expansion is also a significant factor (17). It has been suggested that the influence of increases in water consumption on future droughts may even be of the same magnitude as the projected impact of climate change (18).

Vulnerabilities – Future projections for Europe

In 2012 the IPCC concluded that there is medium confidence in a projected increase in duration and intensity of droughts in some regions of the world, including southern Europe and the Mediterranean region, and central Europe (24).

River flow droughts are projected to increase in frequency and severity in southern and south‑eastern Europe, the United Kingdom, France, Benelux, and western parts of Germany over the coming decades. In snow-dominated regions, where droughts typically occur in winter, river flow droughts are projected to become less severe because a lower fraction of precipitation will fall as snow in warmer winters. In most of Europe, the projected decrease in summer precipitation, accompanied by rising temperatures which enhances evaporative demand, may lead to more frequent and intense summer droughts (9).

As a result of both climate change and increasing water withdrawals, more river basins will be affected by severe water stress, resulting in increased competition for water resources. The regions most prone to an increase in drought risk are the Mediterranean and south-eastern parts of Europe, which already suffer most from water stress (10).

According to research based on six regional climate models, there is not a simple north–south pattern of decreased–increased drought, with models projecting fewer events for parts of the Iberian Peninsula and parts of the Mediterranean. Considerable uncertainty exists at the regional scale. For example, for Britain and northern Spain, different models project both increases and decreases. … All models project longer and more severe droughts in the Mediterranean and shorter, less severe, events for Scandinavia with greater uncertainty as to the direction of change for the rest of Europe (14).

The use of six regional climate models has demonstrated the range of uncertainty in future projections of even mean precipitation across Europe, but also enables some generalizations to be made. Increases in precipitation are likely during winter and these are likely to be largest and most persistent for northern Europe. In contrast, large decreases in precipitation are likely during summer, these being largest in southern Europe (14).

For longer-duration droughts there is a clearer spatial pattern, which indicates fewer droughts in northern Europe due to larger increases in winter precipitation and more droughts of increasing severity in the south (14).

Biodiversity

Droughts may strongly affect biodiversity all across Europe. Some examples (8):

• The environmental impacts of droughts can be exacerbated by unsustainable trends in water use. The worst combination appears when drought strikes freshwater ecosystems already weakened by excessive water withdrawals. For example, Lake Iliki, some 100 km northeast of Athens, has been reduced to a third of its original size, partly by a severe drought in 2000 but also as a result of increasing drinking water demand. Likewise, Lake Djoran, located between Greece and the Former Yugoslav Republic of Macedonia, is at risk of drying up, thus threatening one of the richest inland fishing stocks in Europe.
• Wetlands are particularly vulnerable to drought. The drought that affected Spain in the first half of the 1990s reduced by 97 % the flooded area of the Natural Park of the ‘Tablas de Daimiel’, the most important wetland area in the interior of the Iberian peninsula. Here too, water withdrawals, in this case for agricultural purposes, contributed to the loss.
• Droughts can cause the deterioration of water quality in rivers, lakes and reservoirs by exacerbating algal blooms that reduce the oxygen available for aquatic species. In the summer of 1999, for instance, these processes affected many lakes in Finland.
• Droughts may also weaken the resistance of certain plant species to plagues and increase their susceptibility to forest fires, as happened in the Greek island of Samos in the summer of 2000.
• Finally, drought can threaten the very survival of species in certain areas. The prolonged drought that affected southern Spain in the mid 1990s caused a high mortality rate among maritime pines and severely withered green oak and cork oak forests.

Soil erosion

Droughts may also trigger soil erosion, mainly in Mediterranean areas. One way this happens is through a reduction in vegetation cover caused by forest fires or by increased plant mortality due to water stress. In addition, when the soil is very dry, the water infiltration rate decreases. Consequently, if a period of drought is followed by heavy storms, erosion is triggered by surface runoff. The problem is especially acute in the arid and semi-arid Mediterranean areas where the process may lead to desertification (8).

Adaptation strategies

Pan-European

Europe should view 2003 as a wake-up call. The 2003 drought should be the catalyst for actions aimed at reducing drought impacts across all relevant sectors (7). Drought is not mentioned in European energy policies. Similarly European transport navigation policy makes no reference to low flow conditions, whereas health policies make few provisions for reduced water supplies and deteriorating water quality. Drought is one criterion for exemption to the requirements of the Water Framework Directive – an increasingly likely situation. It makes no provision for managing biodiversity protection during severe droughts (7).

In contrast to internal policy, drought is addressed as a real issue in EU development policies. Drought is seen as a threat to sustainable development, a humanitarian issue and a driver of mass migration and political instability (7).

EU policy orientations for future action

According to the EU, policy orientations for the way forward are (20):

• Putting the right price tag on water;
• Allocating water and water-related funding more efficiently: Improving land-use planning, and Financing water efficiency;
• Improving drought risk management: Developing drought risk management plans, Developing an observatory and an early warning system on droughts, and Further optimising the use of the EU Solidarity Fund and European Mechanism for Civil Protection;
• Considering additional water supply infrastructures;
• Fostering water efficient technologies and practices;
• Fostering the emergence of a water-saving culture in Europe;
• Improve knowledge and data collection: A water scarcity and drought information system throughout Europe, and Research and technological development opportunities.

National

Adaptation activities currently seem to be focused on flood management and defence, while adaptation measures related to the management of water scarcity and drought, although recognized as equally damaging, do not yet seem to be widespread (2).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Italy.

1. EC (2007a), in: EEA (2009)
2. Anderson (ed.) (2007)
3. Hisdal et al. (2001), in: EEA, JRC and WHO (2008)
4. Van der Schrier et al.(2006), in: EEA, JRC and WHO (2008)
5. Hanneford and Marsh (2006), in: EEA, JRC and WHO (2008)
6. Van Lanen et al. (2007), in: EEA (2009)
7. Eisenreich (2005)
8. EEA, JRC and WHO (2008)
9. Douville et al. (2002); Lehner et al. (2006); Feyen and Dankers (2008), in:EEA, JRC and WHO (2008)
10. Alcamo et al. (2003); Schröter et al. (2005), in: EEA, JRC and WHO (2008)
11. Demuth and Stahl, 2001, in: Blenkinsop and Fowler (2007)
12. Lloyd-Hughes and Saunders (2002), in: Blenkinsop and Fowler (2007)
13. Dai et al. (2004), in: Blenkinsop and Fowler (2007)
14. Blenkinsop and Fowler (2007)
15. Henrichs and Alcamo, 2001, in: Blenkinsop and Fowler (2007)
16. Massarutto (1999), in: Blenkinsop and Fowler (2007)
17. Lehner et al. (2006), in: Blenkinsop and Fowler (2007)
18. Lehner and Döll (2001), in: Blenkinsop and Fowler (2007)
19. European Environment Agency (2003)
20. Commission of the European Communities (2007)
21. Coppola and Giorgi (2010), in: MET Office (2011)
22. D’Agnostino et al. (2010), in: MET Office (2011)
23. Senatore et al. (2011), in: MET Office (2011)
24. IPCC (2012)
25. Heinrich and Gobiet (2012)
26. Baronetti et al. (2022)
27. Colombo et al., 2023