Glaciers on the world's high tropical mountains are among the most sensitive components of the Earth's climate system. The current melting of these glaciers is a spectacular example of anthropogenic climate change. However, tropical glaciers are strongly sensitive to precipitation, humidity, and various other climate processes, not just air temperature. A major objective of glaciology and climate research is thus to understand the responses of tropical glaciers to climate change, and to evaluate which aspects of past climate change control glacier advance and retreat. This project seeks to test whether changes in temperature control the behavior of tropical mountain glaciers by reconstructing past temperature changes and glacier movement in the Rwenzori Mountains, Uganda-Congo. Specifically we will generate new records of glacier advance by dating glacier moraine deposits using cosmogenic radinulides, generate a new temperature record based from lake sediment cores, and compare the timing of periods of cooling with the timing of glacier advances. The Rwenzori Mountains host the most extensive glacier and moraine systems in Africa, but there are virtually no direct dates to constrain the age of past glaciations. Moreover, there are virtually no quantitative temperature reconstructions from tropical African mountains derived independently of glacial mass balance estimates. Our work will provide new insight into the timing of major glaciations, glacier sensitivity, and temperature changes in tropical Africa, where few such chronologies exist, and will elucidate the climate processes that control tropical glacier dynamics.
