Research Results
Through establishing a long-term environmental monitoring network, enabling quantification of the ecological impacts of climate change, the research team has found substantial evidence that permafrost is warming at both study areas. In the Mackenzie Mountains, landforms with a permafrost core continue to shrink - circumstances which appear to be driven by warmer air temperatures, as recorded by the scientists at six permanent monitoring sites since 1990. The scientists have confirmed that warming has been occurring at an increasing rate up to the present day by using an instrumental record of climatic conditions upheld since the late 1800s and a proxy record that provides data from as far back as the mid-1600s. Climate proxies are indirect methods for deducing climate patterns of the past, by measuring a record that has been laid down over a long period of time. For example, tree ring width and other characteristics infer variations in temperature over time. The Mackenzie Mountains record from the last 20 years confirms permafrost warming of ~1.25°C. Tree ring chronologies are the proxy being used by the scientists and have revealed periods of enhanced and suppressed tree growth back to circa 1650. During the early part of the record, good correlations were found between growth characteristics and recruitment (origin date of tree) but these relationships were not found in the most recent portion of the record for the late 1900s onwards. This suggests a decoupling of climate and tree growth in the warmest part of the record, which needs further study to determine why this has happened and what the implications are. In terms of seedling ages, there is good evidence of recent recruitment which can only occur with successful seed production and germination. Arctic treeline ecosystems exist right on the edge of their tolerance limits and are particularly susceptible to extreme weather events (often infrequent and ephemeral), which can significantly affect their ecological function and status.
Progress is continuing on establishing the amount of carbon within specific organic stores in the region, such as peatlands, with an archive of soil carbon values created for the Churchill LTEMS. Soil pits are being excavated, described and sampled, and organic matter depth measurements taken. In areas of thick peat, permafrost coring has been conducted to measure carbon content with depth. Similar studies in the Mackenzie Mountains are providing data for comparisons between mountainous and lowland environments. At Churchill the soil carbon pool varies from ~300g to 900kg. The lowest value was found after a forest fire while the highest was in peat plateaus or fens.
Nationally, the data on permafrost status and environmental conditions across the country are providing a more accurate picture of the current situation and trends so that predictions of future change can inform decisions on park management. Wapusk National Park has been indicated to be entirely underlain by permafrost and polar bear, classified as Vulnerable (IUCN Red List), are common in the park during the ice-free season and pregnant females den here until mid winter. The permafrost provides perfect thermally regulated conditions for dens constructed within it.
Kershaw, G.P., Mamet, S.D. & Suter, J.A. (2009) Climatological, snowpack, and dendroclimatological investigations, Wapusk National Park. Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton.
Kershaw, G.P. (2008) Snow and temperature relationships on polygonal peat plateaus, Churchill, Manitoba, Canada. In: Kane, D.L. & Hinkel,
K.M. (Eds.) Proceedings of the Ninth International Conference on Permafrost. Institute of Northern Engineering, University of Alaska, Fairbanks, Alaska.