Grant: Discovery Grants Program - Individual

Climate change is leading to broad scale impactson global ecosystems through changing temperature and precipitation patterns.Forexample, climate change is altering disturbanceregimes, changing the seasonal patterns of precipitation, altering the frequency ofextreme weather events, and changing species distributions and phenological patterns. Innorthern regions, the impacts of climate change are heightened due to Arcticamplification which has caused the Arctic to warm nearly 2X faster than mid-latituderegions. The rapid warming in the Arctic is leading to changes to physical and biologicalcomponents of high-latitude ecosystems. For example, within the field of dendroclimatology, recent studies have noted that since the 1970-80s, there has beenan increasing off-set between tree-ring temperature reconstructions and measured temperatures at some high-latitude sites. This offset between actual temperatures andthose reconstructed from tree ring studies is known as the "" Divergence Problem "". Divergence is potentially an ecosystem response to recent climate change andchallenges the assumption that tree ring chronologies can be used as a reliable predictor of past climate. In addition, the spatial extent of the Divergence Problem islargely unexplored. My research will further our understanding of climate and environmental change innorthern Canada using highly-resolved proxy data sources (tree ring records). I will address the Divergence issue intree ring research in Canada, especially the spatial occurrence of divergence acrossnorthern Canada and the potential factors leading to divergence.Themain geographic areas that will be investigated are Inuvik and Norman Wells innorthwest Canada;Yellowknife near the central Canadian treeline; and Churchill, MB neartreeline on the coast of Hudson Bay. The specific objectives of this research projectare: 1: Determine the spatial signature of the Divergence Problem acrosstreeline in north-central Canada. 2: Determine the cause(s) of the Divergence Problem. 3: Develop long, highly resolved quantitative records of past climatefor the three study regions using multiple sources of tree ring data that do not displaydiverging climate-growth relations. Few annually-resolved millennial length recordsof climate exist for Arctic/subArctic regions of Canada. I will explore the possibility of developing supra-long tree ring chronologies for northern Canada by recoveringsubmerged logs from the bottom of lakes. 4: Explore the utility of wood anatomical features (lumen area, cellwall thickness) as proxies for reconstructing past climatic conditions at treeline sites. My research program will provide insights useful in a number offields of study within the natural sciences (climate and ecosystem modellers, ecologists, policy analysts) and advance our knowledge of climate change and its impacts in theArctic.