The Arpas dossier: Sardinia hotter and hotter, maximum temperatures up 1.5 degrees

More rain, but concentrated in short periods, and increasing heat. «An exceptional vintage from a thermal point of view in Sardinia». Thus the Arpas Meteoclimatic Department defines the period from October 2021 to September 2022, in its agrometeorological and climatological analysis, which traces the meteorological conditions and their consequences on the regional territory.

As the summer of 2023 draws to a close, the environment agency releases the consolidated results of last year's data study: the dossier highlights the local effects of climate change, the greatest challenge for humanity.

Temperatures

«The annual averages of the minimums», explain the technicians, «are in line with or slightly higher than the reference climatological average, while the maximums show a positive anomaly compared to the decidedly more marked climatic average, with an average of +1.2 degrees up to to exceed +1.5 in the south-western part of the island». If we go into the detail of the territorial distribution, in terms of minimums «the altimetric gradient is evident, with the reliefs of the Gennargentu that drop below 8 °C. Only other small areas share these low temperatures», it is written, «and among these it is certainly worth noting how the mountains of Alà dei Sardi are at least as cold as the Marghine, which is higher. Furthermore, the cold anomaly of Campu Giavesu and Piana di Santa Lucia stands out, the most particular low-altitude area of Sardinia for the thermal regime. It is also noted that Monte Limbara, although as high as the Marghine and located further north, is appreciably hotter".

Even the distribution of the maximums "shows a clear altitudinal distribution, with the mountain peaks frequently below 18 °C, while they rise up to the 22 °C common on the coasts". Gallura and Baronia are more than 0.5°C warmer than the average. Sulcis and Costa Verde are almost 2°C warmer. In between is the rest of the island, almost 1.5°C warmer than the average.

«Also this year», explain from Arpas, «therefore had highs decidedly above the average, and this is mainly due to the contribution of the summer heat waves, frequent, persistent and which mainly affected the western two thirds of the island ».

The change in the average highs over the very long term was also analysed: "a cold forty years (1880-1920) was recorded with highs constantly below the average, often by more than one degree". Then «a fluctuating seventy years (1920-1990) with maxima sometimes lower, sometimes higher than the average, but with a smaller anomaly, generally lower in absolute value than 1 °C». And finally a hot thirty years (1990-today) with highs constantly above the climatic average», with deviations that in recent years have reached and exceeded +2 °C. «The 2021-2022 vintage fits fully into the latter trend, with an anomaly close to +1.5 °C».

Rains

On the rainfall front, "compared to the 1981-2010 climatology, the rainfall of the year confirms the trend of the years following 2017-2018 (a particularly dry year), all characterized by a slightly positive anomaly".
On a large part of the island, the cumulus generally exceeded 600 mm. The maxima affected the main reliefs, with values even above 1000 mm on Gennargentu, Montiferru, Limbara and Monti del Sulcis. The wettest locality of the year was Pula Is Cannoneris, where 1319.8 mm fell, followed by Arzana Sicca d'Erba with 1139.6 mm. Accumulations of less than 600 mm occurred in the Sassarese area, in the Coghinas Valley, in the Oristano area and in the Medio-Basso Campidano area. The least rainy meteorological station of the year was Sassari University, with 375.4 mm.

Compared to the climatic average, most of the region received cumulated in line with or slightly above, up to 25% more. The ratio is minimal in the North-West, particularly in the Sassari area, where the cumulative figures were even 50% lower than the average. In Southern Sardinia, on the other hand, the values were above 25% and locally in Cagliari even above 50%.