The first internationally coordinated initiatives to observe the environment in Alpine regions date back to the 19th century. Around 1880, the first mountain observatories were established on European mountains. Today, the record of their activities provides a meteorological time series covering more than a century. Continuous meteorological measurements on high mountains in other continents started in the 1930s. Worldwide glacier monitoring began in 1894 with the establishment of the International Glacier Commission in Zurich, Switzerland. The aim of this worldwide monitoring program has been to record glacier variations over time and to understand the mechanisms leading to change. Thanks to observations performed under this programme, glacier dynamics, in particular dramatic recent glacial retreats, have been documented over the last 100 years. The observed retreats are the clearest evidence for the ongoing process of global warming
