This study examines the long-term trends in temperature, precipitation and evapotranspiration across three smaller Mediterranean Italian islands such as Pantelleria, Ponza and Ustica. These islands are classified as ultraperipheral internal areas due to their significant distance from the urban centres that provide essential or relevant services. Trend analyses were conducted for temperature (mean, maximum, and minimum) annually and monthly over 72 years (1951–2022) and for total precipitation and evapotranspiration annually and monthly over 68 years (1951–2018). The results showed a significant positive annual trend in the mean temperature, with slopes of 0.0308, 0.0363 and 0.0311 °C/year for Pantelleria, Ustica, and Ponza, respectively. Significant positive annual trends were also observed for both the maximum and the minimum temperature. The maximum temperature showed slopes of 0.0264, 0.0463 and 0.0328 °C/year, and the minimum temperature showed slopes of 0.0353, 0.0263 and 0.0297 °C/year, for Pantelleria, Ustica and Ponza, respectively. The monthly trend analysis of mean, maximum and minimum temperatures showed positive significant trends, with usually a higher slope in August and a lower slope in February for the three considered islands, with some exceptions. Significant positive annual trends were also observed for total precipitation in Pantelleria and Ustica, with slopes of 4.04 and 2.08 mm/year, respectively. Ponza did not show any significant statistical annual trend. In Pantelleria, the monthly trend analysis of total precipitation showed a significant positive trend in February, March, September, November and December. In Ustica, a significant positive trend of monthly total precipitations was also observed in September. In Ponza, no significant trends of the monthly total precipitation were observed. Significant positive annual trend of evapotranspiration was also estimated across all the studied islands. In Ustica, the annual evapotranspiration showed a positive upward trend with a slope of 3.16 mm/year. In the other two islands, evapotranspiration did not show any trend. In Pantelleria, a monthly trend analysis of evapotranspiration revealed a significant negative trend for the months of February, November and December. In Ponza, a significant positive trend of monthly evapotranspiration was recorded in March and December, while the trend was negative in July. In Ustica, all months exhibited a significant evapotranspiration trend, which was consistently positive. In both Ustica and Pantelleria, evapotranspiration exceeded precipitation, indicating a potential rainfall deficit. These findings highlight concerning trends of rising temperatures and water scarcity, suggesting the need to plan and adopt strategies to improve climate resilience through sustainable resource management, thereby protecting island communities and ecosystems.
Long-term trend in temperature, precipitation and evapotranspiration in three small mediterranean Italian islands: Pantelleria, Ponza and Ustica
Antonio Speranza
Primo
2026
Abstract
This study examines the long-term trends in temperature, precipitation and evapotranspiration across three smaller Mediterranean Italian islands such as Pantelleria, Ponza and Ustica. These islands are classified as ultraperipheral internal areas due to their significant distance from the urban centres that provide essential or relevant services. Trend analyses were conducted for temperature (mean, maximum, and minimum) annually and monthly over 72 years (1951–2022) and for total precipitation and evapotranspiration annually and monthly over 68 years (1951–2018). The results showed a significant positive annual trend in the mean temperature, with slopes of 0.0308, 0.0363 and 0.0311 °C/year for Pantelleria, Ustica, and Ponza, respectively. Significant positive annual trends were also observed for both the maximum and the minimum temperature. The maximum temperature showed slopes of 0.0264, 0.0463 and 0.0328 °C/year, and the minimum temperature showed slopes of 0.0353, 0.0263 and 0.0297 °C/year, for Pantelleria, Ustica and Ponza, respectively. The monthly trend analysis of mean, maximum and minimum temperatures showed positive significant trends, with usually a higher slope in August and a lower slope in February for the three considered islands, with some exceptions. Significant positive annual trends were also observed for total precipitation in Pantelleria and Ustica, with slopes of 4.04 and 2.08 mm/year, respectively. Ponza did not show any significant statistical annual trend. In Pantelleria, the monthly trend analysis of total precipitation showed a significant positive trend in February, March, September, November and December. In Ustica, a significant positive trend of monthly total precipitations was also observed in September. In Ponza, no significant trends of the monthly total precipitation were observed. Significant positive annual trend of evapotranspiration was also estimated across all the studied islands. In Ustica, the annual evapotranspiration showed a positive upward trend with a slope of 3.16 mm/year. In the other two islands, evapotranspiration did not show any trend. In Pantelleria, a monthly trend analysis of evapotranspiration revealed a significant negative trend for the months of February, November and December. In Ponza, a significant positive trend of monthly evapotranspiration was recorded in March and December, while the trend was negative in July. In Ustica, all months exhibited a significant evapotranspiration trend, which was consistently positive. In both Ustica and Pantelleria, evapotranspiration exceeded precipitation, indicating a potential rainfall deficit. These findings highlight concerning trends of rising temperatures and water scarcity, suggesting the need to plan and adopt strategies to improve climate resilience through sustainable resource management, thereby protecting island communities and ecosystems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
