Rwenzori glaciers melting
Oct 27, 2003
AN international team of scientists has recently observed a rapid decline in the extent of glaciers that cap the Rwenzori Mountains in western Uganda.
AN international team of scientists has recently observed a rapid decline in the extent of glaciers that cap the Rwenzori Mountains in western Uganda.
Field observations from one, the Speke glacier, indicate that it has receded more than 300m in the last decade. The team from Makerere University, the University College London in the UK, the University of Innsbruck in Austria and the Water Resources Management Department of Uganda, will estimate the area covered by this and other glaciers on the mountains over the next year.
The rate of snow loss suggested by field observations is however, of concern not only because of its potential impact on water resources and ecology of the Rwenzori Mountains, but because of how this may affect the livelihood of communities that depend upon this environment as well.
During a ten-day expedition through the Rwenzori National Park, the team of scientists mapped the current position of two glaciers, Speke and Elena, by tracing the edge of the glaciers on foot with a hand-held global positioning system (GPS). The extent of other glaciers will be assessed using photographs taken during the expedition and through the application of satellite imagery. As the Rwenzori Mountains are usually covered by clouds, the team will explore the use of radar rather than satellite photographs to monitor the snow cover.
Of significance is the fact that the research team has recorded the first measurements of ice thickness. This will help in the understanding of the volume of water stored in the glaciers.
Evidence from snow pits dug during this expedition reveals a very thin layer of snow of less than 20 cm and no firm layer (more dense snow) before ice is reached. Unfortunately, these observations suggest that very little ice is currently accumulating on the glaciers.
A major focus of the international expedition which is supported by the Royal Geographical Society (UK) and Rwenzori Beverage Company (Uganda), is a determination of how the loss of snow and ice on the summit of the mountains affects water resources and specifically, streamflow at lower elevations.
In Kasese, flow from the principal river drawing water from the glaciers, the River Mubuku, is used for community water supplies and the generation of hydro-electric power. During the expedition, measurements of streamflow were taken throughout the Rwenzori National Park. This data will be used alongside the analysis of natural chemical tracers of the water movement, in an effort to determine the relative contribution of different water sources such as precipitation, glaciers and springs to alpine streamflow.
The research team will also consult historical records of streamflow collected by the Water Resources Management Department and the Kasese Cobalt Company, in order to explore whether the total amount or seasonality of streamflow has changed in response to the retreating glaciers.
Recent incidents on the River Mubuku such as the erosion of the foundations of the Nyakabugha-Bikone bridge in January this year and the displacement of 200 people from Byabubale village in July, suggest that flash flood events have become more frequent in recent years. This is supported by streamflow records and makes sense if the proportion of precipitation falling as snow and hence stored by glaciers, has decreased in recent times.
To test this theory, the research team will investigate the relationship between precipitation and streamflow over the last 50 years. A key constraint, however, to such a comparison is the fact that local, long-term records of rainfall are only available from Kasese Airport which has an elevation 3.5 km below the headwaters of the streams and glaciers on the Rwenzori Mountains.
To improve future analyses, the possibility of establishing meteorological stations within the Rwenzori National Park will be explored with the Uganda Wildlife Authority and Meteorological Department.
Another major focus of the research team’s expedition to the Rwenzori Mountains is to assess whether observed changes in glacial extent are a short-term phenomenon or part of a long-term trend. In the absence of climatological records over the last 200 years, the team will analyse the archives of environmental conditions stored in lake sediment.
Environmental indicators such as pollen from plants are blown into lake waters and become trapped in lake sediment. As the sediment accumulates over time in the bottom of lakes, an archive of past environmental conditions is produced. To sample the archive, the team extracted 10 cores of lake sediment from three lakes in the Rwenzori National Park, Lake Mahoma, Lake Bujuku and Lower Kitandara Lake.
This required the use of a boat, equipped with an outboard engine that was ably carried by the Rwenzori Mountaineering Service.
The analysis of the environmental archives in lake sediment by the research team will enable observations taken during the relatively brief expedition to be placed in the context of environmental changes over the last 200 years.
Indeed, despite a overall trend towards reduced snow cover during the 20th century, there is evidence of a brief expansion of the glaciers in the early 1960s that may be linked to increased amounts of precipitation when water levels in the River Nile and Lake Victoria rose by more than one metre.
Recession of alpine glaciers across the tropics suggests that the causes of rapid snow loss are global in nature. As a result, little may be done locally to halt this trend.
Nevertheless, placing the research team’s observations and findings into the correct historical context is essential since the outcome of this preliminary study and any subsequent research may have important implications not only for the future condition of the Rwenzori National Park, a World Heritage Site, but also the livelihood of the Bakonzo and Bamba communities who depend upon the continued vitality of their local environment and the money earned from tourist visits to these magnificent snow capped mountains on the Equator.
Dr Richard Taylor who led the research team is a lecturer in the Department of Geography at the University College, London and Adjunct Lecturer in the Department of Geology at Makerere University, Kampala.
Field observations from one, the Speke glacier, indicate that it has receded more than 300m in the last decade. The team from Makerere University, the University College London in the UK, the University of Innsbruck in Austria and the Water Resources Management Department of Uganda, will estimate the area covered by this and other glaciers on the mountains over the next year.
The rate of snow loss suggested by field observations is however, of concern not only because of its potential impact on water resources and ecology of the Rwenzori Mountains, but because of how this may affect the livelihood of communities that depend upon this environment as well.
During a ten-day expedition through the Rwenzori National Park, the team of scientists mapped the current position of two glaciers, Speke and Elena, by tracing the edge of the glaciers on foot with a hand-held global positioning system (GPS). The extent of other glaciers will be assessed using photographs taken during the expedition and through the application of satellite imagery. As the Rwenzori Mountains are usually covered by clouds, the team will explore the use of radar rather than satellite photographs to monitor the snow cover.
Of significance is the fact that the research team has recorded the first measurements of ice thickness. This will help in the understanding of the volume of water stored in the glaciers.
Evidence from snow pits dug during this expedition reveals a very thin layer of snow of less than 20 cm and no firm layer (more dense snow) before ice is reached. Unfortunately, these observations suggest that very little ice is currently accumulating on the glaciers.
A major focus of the international expedition which is supported by the Royal Geographical Society (UK) and Rwenzori Beverage Company (Uganda), is a determination of how the loss of snow and ice on the summit of the mountains affects water resources and specifically, streamflow at lower elevations.
In Kasese, flow from the principal river drawing water from the glaciers, the River Mubuku, is used for community water supplies and the generation of hydro-electric power. During the expedition, measurements of streamflow were taken throughout the Rwenzori National Park. This data will be used alongside the analysis of natural chemical tracers of the water movement, in an effort to determine the relative contribution of different water sources such as precipitation, glaciers and springs to alpine streamflow.
The research team will also consult historical records of streamflow collected by the Water Resources Management Department and the Kasese Cobalt Company, in order to explore whether the total amount or seasonality of streamflow has changed in response to the retreating glaciers.
Recent incidents on the River Mubuku such as the erosion of the foundations of the Nyakabugha-Bikone bridge in January this year and the displacement of 200 people from Byabubale village in July, suggest that flash flood events have become more frequent in recent years. This is supported by streamflow records and makes sense if the proportion of precipitation falling as snow and hence stored by glaciers, has decreased in recent times.
To test this theory, the research team will investigate the relationship between precipitation and streamflow over the last 50 years. A key constraint, however, to such a comparison is the fact that local, long-term records of rainfall are only available from Kasese Airport which has an elevation 3.5 km below the headwaters of the streams and glaciers on the Rwenzori Mountains.
To improve future analyses, the possibility of establishing meteorological stations within the Rwenzori National Park will be explored with the Uganda Wildlife Authority and Meteorological Department.
Another major focus of the research team’s expedition to the Rwenzori Mountains is to assess whether observed changes in glacial extent are a short-term phenomenon or part of a long-term trend. In the absence of climatological records over the last 200 years, the team will analyse the archives of environmental conditions stored in lake sediment.
Environmental indicators such as pollen from plants are blown into lake waters and become trapped in lake sediment. As the sediment accumulates over time in the bottom of lakes, an archive of past environmental conditions is produced. To sample the archive, the team extracted 10 cores of lake sediment from three lakes in the Rwenzori National Park, Lake Mahoma, Lake Bujuku and Lower Kitandara Lake.
This required the use of a boat, equipped with an outboard engine that was ably carried by the Rwenzori Mountaineering Service.
The analysis of the environmental archives in lake sediment by the research team will enable observations taken during the relatively brief expedition to be placed in the context of environmental changes over the last 200 years.
Indeed, despite a overall trend towards reduced snow cover during the 20th century, there is evidence of a brief expansion of the glaciers in the early 1960s that may be linked to increased amounts of precipitation when water levels in the River Nile and Lake Victoria rose by more than one metre.
Recession of alpine glaciers across the tropics suggests that the causes of rapid snow loss are global in nature. As a result, little may be done locally to halt this trend.
Nevertheless, placing the research team’s observations and findings into the correct historical context is essential since the outcome of this preliminary study and any subsequent research may have important implications not only for the future condition of the Rwenzori National Park, a World Heritage Site, but also the livelihood of the Bakonzo and Bamba communities who depend upon the continued vitality of their local environment and the money earned from tourist visits to these magnificent snow capped mountains on the Equator.
Dr Richard Taylor who led the research team is a lecturer in the Department of Geography at the University College, London and Adjunct Lecturer in the Department of Geology at Makerere University, Kampala.