Signals of 20th-century warming from the glaciers in the Central Italian Alps

The Lombard Alps in the central sector of the Italian Alps are one of the most intensively glacierized regions on the southern side of the chain (about 113 km2 of ice cover). All of the glaciers have been retreating since the beginning of the 20th century, but the trend is not uniform. Since the 1950s there has been a drop in the percentage of retreating snouts and an increase in stationary and advancing snouts. After 1985 the glaciers in the Lombard Alps began a new recession phase that is still going on. This pattern is consistent with temperature variations in Lombardy in the 20th century. According to data from Sondrio station, four alternating warming and cooling phases ran be distinguished in 20th-century warming. The Lombard glaciers well recorded the last three phases, showing evident signs of the 1955–88 cold phase, with a response time of about 20 years, and may be considered good indicators of 20th-century temperature trends