Dynamics and Change of Canadian Arctic Glaciers

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Over 600 million people live within 10m elevation of current sea level, and 270 million people and $13 trillion US of assets are exposed to the 1 in 100 year extreme sea level. Understanding how rapidly sea level will rise (and why) is critical for decision making about how/when/whether to respond to this threat, much of which results from melting of the world’s ice sheets and glaciers. Canada’s Queen Elizabeth Islands (QEI) contain 19% of the world’s glaciated area outside Greenland and Antarctica. If these glaciers and ice caps melted completely, global average sea level would rise by over 10 cm. Each year between 2003 and 2009, these glaciers added about 60 billion tons of water to the global ocean, equivalent to 0.16 mm of sea level rise. Glacier melt rates during this period were probably the highest in over 4000 years, and they approached rates last encountered during the Holocene thermal maximum ~9000 years ago. These high melt rates are attributable to strong summer warming after 2005, linked to unusually persistent high pressure systems over the region. My research program aims to document the recent history of glacier change in the QEI and its implications for global average sea level, to identify the processes by which this change is occurring and the factors that control the rate of change, and to develop the capability to predict what rates of change we might expect in future. Key questions I want to answer include: (i) How can we best measure how rapidly the total mass of ice in QEI glaciers has been changing in the recent past? (ii) How much have melting of snow and ice, and calving of icebergs into the ocean, contributed to past rates of mass loss? (iii) How will the relative contributions of these processes change in the future?, and (iv) How do feedbacks that come into play as the climate changes, such as the feedback associated with warming-induced decreases in the glacier surface albedo (the proportion of solar radiation arriving at a glacier surface that is reflected from it), affect the relationship between climate change and rates of glacier mass loss? As the QEI is a data-sparse region, I need to invest significant effort in building (and validating) the large, regional-scale datasets that are needed to support predictive modeling of future glacier changes. These include basic information on the surface topography, thickness and subglacial bedrock topography of the large ice caps, and the distribution of precipitation over the ice caps. As my research directly addresses an issue of concern to society, I try to make sure that, in addition to being published in the scientific literature, the results of my research find their way into major scientific assessments of climate change and its impacts. This ensures that they are available to decision makers confronting the challenges posed by future sea level rise.