Final answer:
The retreat of Central Andes Mountains glaciers in Bolivia and Peru over the past 30 years is primarily due to increased climate change events, reflecting global patterns of glacier recession.
Step-by-step explanation:
The glaciers of the Central Andes Mountains of Bolivia and Peru have been retreating in the past 30 years primarily as a result of more frequent and intense climate change events.
This phenomenon, known as glacier recession, mirrors patterns observed in Glacier National Park, where significant retreat has occurred since the mid-19th century. Various factors contribute to this retreat, including increased mean annual temperatures, which have led to reduced ice mass and size across the planet's glacial regions.
For example, the Grinnell Glacier in Montana experienced a 40 percent reduction in size between 1966 and 2005. Similarly, ice sheets in Greenland and the Antarctic have seen pronounced declines in mass, with Greenland losing between 150-250 km³ of ice annually between 2002 and 2006. The loss of glaciers has dire consequences, including the reduction of summer meltwaters, which in turn sharply reduce seasonal water supplies and severely affect local ecosystems.