A decade of discovery at the Arctic's edge
In Canada's frozen Arctic Circle, unprecedented changes are taking place. Landforms are shrinking, forests are advancing, snowfalls are shifting, and permafrost is thawing. These high latitude lands are expected to experience some of the severest warming associated with climate change, which will significantly affect the ecology and landscape on a regional scale, as well as accelerating factors which contribute to further change in the wider climate system. To increase our understanding of these crucial changes, Dr Peter Kershaw has been conducting long-term research for nearly 40 years in the Arctic tundra, and Earthwatch volunteers are on hand to help with vital data collection in all seasons and all weathers. 2010 was a landmark year for the team, marking a decade of discovery with Earthwatch support, and the findings are revealing an important picture of the complex changes ahead.
Earthwatch volunteers have been involved in the project for the past ten years.
Over the past ten years Earthwatch volunteers have been involved in an ambitious long-term investigation to quantify the impacts of climate change at the Arctic's edge. Building on existing records in the area, teams are based at two research sites which include different characterisations of permafrost tundra and treeline environments. The permafrost environment is hugely significant to the global climate, and is particularly susceptible to the effects of warming, with an instrumental record showing a 2oC increase at one of the research sites over little more than a century. Dr Kershaw explains that although it is exciting and rare to be working on a project where scientific change can be seen and measured on such short timescales, he has no doubt that these changes are the effects of global warming, which implies that the long-term prognosis is not a happy one.
The team's primary research goal is to understand the dominant environmental processes that occur near the treeline at the edge of the permafrost. This goal is being addressed on a grand scale across the habitats of the Canadian Arctic, with specific focus on studying how the environmental processes will respond to a warming climate. To achieve this, it is necessary for the team to compile a long-term record of current conditions, as well as researching the environmental conditions of the past, across the two complementary research sites.
The research sites
The site near the mouth of the Churchill River at Hudson Bay, on the east coast, has continuous permafrost extending throughout the area. There is a distinct treeline boundary, and the landscape changes from tundra to boreal forest within a few kilometres. Similar interactions are also being monitored at the Mackenzie Mountains site in western Canada, where discontinuous permafrost in the extensive peatlands at higher elevations forms distinctive landforms. Wildlife such as caribou, wild sheep, birds of prey and wetland fowl are commonly spotted, and in late autumn polar bears gather around the shores of Lake Hudson as the ice begins to freeze.
Permafrost and climate change
Permafrost and the tundra environment are amongst the most climatically important environments on the planet, since they hold vast reserves of carbon and provide a reflective surface which reduces surface warming. These two features have strong implications for the climate system on a global scale.
Much of the Arctic permafrost environment includes frozen peat, which is estimated to hold 90 per cent of the world's terrestrial carbon in the form of decomposing organic matter. As temperatures rise and the permafrost recedes, decomposition of organic matter can accelerate, allowing further release of carbon into the atmosphere. Alarmingly, much of the carbon currently locked in the permafrost is in the form of methane, which can cause over 20 times as much warming as carbon dioxide for the same quantity released. This leads to what is known as a positive feedback system, in which increased warming drives increased melting and therefore increased carbon release.
Melting permafrost is changing the shape of the landscape.
Melting permafrost is also causing changes to landscape characteristics. Frost-formed palsas (low, flattened oval frost heaves) are degrading, and melting permafrost is enabling increased development of wetlands as the frost-free land subsides. This has important implications for the biodiversity of the landscape, including millions of migratory waterfowl and other wetland bird species which will be strongly affected as a result.
A decade of discovery
Since 2000, ten long-term environmental monitoring sites have been established in a transect across the ecosystem boundary between boreal forest and Arctic tundra at the Churchill site. A set of ecosystem components are measured at each site, including climate, snowpack and permafrost depth. Earthwatch volunteers help by operating equipment such as ground-penetrating radar systems, to determine permafrost thickness, as well as collecting tree ring and species data to assess the state of forest expansion. Results were fed into global research during the 2008-2009 International Polar Year, and the research sites form part of a circumpolar monitoring network.
Despite having accomplished ten years of data collection, there is not yet any apparent trend for the treeline and permafrost distribution because the climate-ecosystem interactions in the area are so complex. However, historical temperature record data reveal some of the most important indications of change in the area. Measurements from the past 10 years can be compared as far back as 1880 when records began, and indicate an average warming of around 2oC at the Churchill site, which in terms of the global climate is highly significant. If the whole planet were to warm by this amount, it could result in extinction of between 19 and 44 per cent of the world's species by 20501, so the integrity of ecosystems in the face of this danger is another main feature in Dr Kershaw's research.
One of the research sites is in Mackenzie Mountains in western Canada.
Further work on this project aims to build on existing information to quantify the factors causing ecosystem changes as a response to climate change - such as winter heat loss, permafrost and oxidation of organic matter (producing methane and carbon dioxide).
Understanding this will give climate scientists a vital chance to help mitigate the potential damage that will be caused by climate change. To achieve this, Dr Kershaw and his team are now planning to expand their research on climate-ecosystem interactions into the currently less well-studied winter months. As always, the work of adventurous Earthwatch volunteers will be crucial to their success.
1 Thomas, C.D., Cameron, A., Green, R.E., Bakkenes, M., Beaumont, L.J., Collingham, Y.C., Erasmus, B.F.N., de Siqueira, M.F., Grainger, A., Hannah, L., Hughes, L., Huntley, B., van Jaarsveld, A.S., Midgley, G.F., Miles, L., Ortega-Huerta, M.A., Townsend Peterson, A., Phillips, O.L. & Williams, S.E. (2004) Extinction risk from climate change. Nature, 427 (6970), pp.145-148.
Extinction risk from Climate Change
Report by Ellie Gilvin.
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