Research for Mountain Area Development: Climatic Fluctuations in the Mountains of the Americas and Their Significance

Twentieth century temperature trends in the Western Cordilleras of the Americas broadly reflect the global signal of warming and decreasing diunal temperature range. Precipitation changes are more modest and vary strongly with region. Mountain glaciers have retreated considerably since the Little Ice Age in response particularly to the temperature rise and an upward shift in tropical freezing level over the last three decades. The changes are already affecting hydrologic regimes. Potential negative ecological consequences for the cloud forest ecosystem have also been suggested. Andean agriculture might benefit, however, from an upward shift in the zone of frequent frosts.