The impact of climate change on mid-latitude Mediterranean glaciers over the past 75 years

Glaciers are sensitive indicators of climate change, yet only a small number that remain in the Mediterranean region. Of these, most have retreated well into cirques, persisting as small, isolated glaciers or ice patches. The climatic drivers of glacier and snowpack changes across the Mediterranean mountains over the past 75 years are assessed using temperature, precipitation, snow cover, and glacier mass balance data. Summer temperatures in the Mediterranean region have risen dramatically since the 1970s with the average increasing by >1.9 °C by 2024 relative to the 1991–2020 mean. Winter precipitation in the Mediterranean region has shown a slight decline over the last 75 years. From 2019 to 2023, snow cover duration declined across most of the Mediterranean. Regression analysis indicates that the North Atlantic Oscillation (NAO) exerts only a limited influence on glacier mass balance and snowpack variability in the Mediterranean. This is because the dominant control on mass balance change in the Mediterranean is summer temperature rather than precipitation, much more so than further north in Europe where NAO has more influence on glaciers. Despite this strong temperature sensitivity, some Mediterranean glaciers persist due to favourable local topoclimatic conditions. In particular, enhanced snow accumulation from snow avalanching and windblown snow compensates high summer ablation, highlighting the key influence of local topoclimatic conditions on glacier survival in the Mediterranean region. Although Mediterranean glaciers are sustained by high accumulation, they are strongly affected by summer temperature variability, reflecting the broader global pattern whereby warm–wet glaciers show greater temperature sensitivity than cold–dry glaciers. Understanding how glaciers and snowpack respond to climate change in the Mediterranean mountains has relevance beyond this region and provides an important comparison for other mid-latitude regions, such as the Alps, the Caucasus, and the Tibetan Plateau, where glaciers and snowpack are crucial for water supply.