Glacial retreat a global problem

The issue of glacial recession is of particular interest to Canadians but by no means is the problem unique to our country.

On Friday, Aug. 27, Dr. Jeffrey McKenzie, an assistant professor in Earth Sciences at McGill University, will be discussing potential impacts of glacial recession on human livelihood in the Andean highlands of Peru.

His talk is from 11 to 11:30 a.m. in room WE2070 of the Alberta Water and Environmental Science Building.

Dr. McKenzie's research is highly interdisciplinary, involving both the latest techniques in groundwater modelling and the use of surveys to improve our understanding of local understanding and adaptive capacity as it pertains to potential impacts of climate change.

The Cordillera Blanca holds the world's largest concentration of tropical glaciers, most of which supply the Callejón de Huaylas watershed, with an area of 4900 km2 and home to 267,000 people. Livelihoods in the region depend on access to water for agricultural and livestock production, as more than 80 per cent of the population is engaged in smallholder production, and more than 50 per cent of the population lives in conditions of poverty, defined as lacking more than one basic necessity.

The potential for severe climate change impacts on water availability for household, irrigation, ore processing and hydroelectric generation is particularly acute in the dry Cordillera Blanca valleys, where glacial melt water services these needs almost entirely during the dry seasons. Dr. McKenzie's work includes the quantification of the extent of anthropogenic water consumption in the region.

His surveys indicate that rural farmers are aware of climate-induced glacier retreat, and that they attribute observed decreases in water availability to glacial recession. Stream discharge measurements, combined with hydrochemical tracing to quantify water source contributions, have revealed a net increase in the relative proportion of glacial melt on an annual basis, in tributaries and major rivers of the Cordillera Blanca, along with a 15 per cent decrease in glacial extent in recent decades. Eventually, a tipping point will be reached in which the negative effect of glacier retreat will exceed the increased flow that occurs in warmer seasons.

During the past few decades, there has been no decrease in the discharge of most glacially-fed tributaries, but river discharge has decreased at the regional scale since the 1980s.

McKenzie's research will contribute to our understanding of adaptive responses required to maintain sustainable and prosperous livelihoods in the face of the challenge of glacial retreat in a seasonally dry ecosystem.