How will Northern Ecosystems respond to Global Environmental Change?

"Over the past 100 years, the northern high latitudes have warmed more rapidly than anywhere else on Earth due to amplifying (positive) physical feedbacks associated with sea-ice and snow cover changes. Observed biological responses of terrestrial ecosystems to this recent high-latitude warming may also drive feedbacks to regional and global climate warming, but our current understanding of these feedbacks is more limited. Positive feedbacks that may be important are due to changes in vegetation albedo associated with northward migration of tree lines and increased growth of shrubs in tundra regions, as well as carbon dioxide and methane emissions from increasing fire occurrences and warming-driven losses of soil carbon from large terrestrial reservoirs. Stabilizing (negative) feedbacks may emerge from increased plant growth and carbon uptake, and changes in dominant growth forms which cause changes in albedo forcings.
As this trend of northern high-latitude accelerated warming is expected to continue over the next century, this proposed research is designed to produce new knowledge needed to understand how climate change impacts terrestrial ecosystems in the northern high latitudes and how these biological responses induce feedbacks to regional and global climate. Dynamic global vegetation models (DGVMs) predict that the vast boreal forest (second largest biome after tropical rainforests) is particularly prone to large-scale dieback and biome shift during the 21st century because of high climate sensitivities in the interplay between ecosystem dynamics and important disturbance regimes. This biome is thus identified as one of the critical ‘tipping elements’ in the Earth’s climate system. Yet, many open questions remain in regards to how this hypothesized biome shift would manifest itself (e.g. gradual geographic range shift or rapid dieback) and what the impacts will be for important ecosystem services (e.g. carbon sequestration).
The aim of this project is to better understand the regional responses of northern ecosystems to global environmental change and related consequences for terrestrial carbon cycling using a combination of observational and modelling analyses.
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http://www.nercdtp.leeds.ac.uk/projects/index.php?id=561