auto_awesome_motion View all 2 versions
organization

AADNC

Aboriginal Affairs Northern Dev Canada
3 Projects, page 1 of 1
  • Funder: UKRI Project Code: NE/K000284/1
    Funder Contribution: 286,071 GBP
    Partners: NERC Radiocarbon Laboratory, University of Sheffield, University of Sussex, McMaster University, University of Ottawa, University of Edinburgh, AUS (United States), AADNC, EnviroSim (Canada)

    The Arctic is undergoing rapid climatic change, with dramatic consequences for the 'Frozen World' (the 'cryosphere'), including reductions in the depth, extent and duration of sea ice, and seasonal snow cover on land, retreat of ice sheets/glaciers, and melting of permafrost ("ground that remains at or below 0 degrees C for at least two consecutive years"). This is important not only for local and regional ecosystems and human communities, but also for the functioning of the entire earth system. Evidence is growing that organic matter frozen in permafrost soils (often for many millennia) is now thawing, making it available for decomposition by soil organisms, with the release of carbon dioxide (CO2) and methane (CH4), both greenhouse gases (GHGs), as by-products. A major concern now is that, because permafrost soils contain 1672 petagrams (1 Pg = 1 billion tonnes) of organic carbon (C), which is about 50% of the total global below-ground pool of organic C, and permafrost underlies ~ 25% (23 million km2) of the N hemisphere land surface, a melting-induced release of GHGs to the atmosphere from permafrost soils could result in a major acceleration of global warming. This is called a 'positive biogeochemical feedback' on global change; in other words, an unintentional side-effect in the global C cycle and climate system. Unfortunately, the interacting biological, chemical and physical controls on CO2 and CH4 emissions from permafrost (and melting permafrost) environments to the atmosphere are the subject of much speculation because the scientific community does not know enough about the interactions between C and water cycling in permafrost systems. Warmer and drier soils may release more CO2, while warmer/wetter soils might release more CH4. Permafrost thawing also causes changes in the way water flows though the landscape (because frozen ground if often impermeable to water), and some areas may become drier, while others wetter. How the relative proportions of CO2 and CH4 emissions change, and their absolute amount, is critical for the overall 'global warming potential' (GWP) because these two gases have different potency as GHGs. Release of C from soils into freshwaters also needs to be taken into account because down-stream 'de-gassing' and decomposition of organic materials also influences releases of CO2 and CH4 from freshwater, or delivery of C to lakes/oceans. All-in-all, predicting the GWP of permafrost regions is scientifically challenging, and the interactions between the water (hydrological) and C cycles are poorly known. In this project we recognise the key role that hydrological processes play in landscape-scale C fluxes in arctic and boreal regions. In permafrost catchments in NW Canada (including areas where permafrost is known to be thawing) we will measure the capture of C from the atmosphere (through photosynthesis), its distribution in plants and soils, and the biological, physical and chemical controls of C transport and delivery from soils to freshwaters, and ultimately to the atmosphere as CO2 and CH4. In essence we wish to 'close the C cycle'. Field-based measurements of key processes in the water and C cycles, including geochemical tracer and state-of-the-art C, hydrogen and oxygen isotope approaches, will be linked by computer modelling. The project team, together with partners in Canada, the US and UK, is in a unique position to link the water and C cycles in permafrost environments, and we will deliver essential scientific knowledge on the potential consequences of climate warming, and permafrost thawing, for GHG emissions from northern high latitudes. Both for local peoples directly dependent on arctic tundra/boreal forest ecosystems for their livelihoods and cultural identity, and for the global community who must respond to, and anticipate, potential consequences of climate and environmental change, this project will represent a significant step forward in understanding/predictive capacity.

  • Funder: UKRI Project Code: NE/K000284/2
    Funder Contribution: 196,397 GBP
    Partners: EnviroSim (Canada), AUS (United States), AADNC, University of Sussex, McMaster University, Heriot-Watt University, University of Edinburgh, University of Ottawa, NERC Radiocarbon Laboratory

    The Arctic is undergoing rapid climatic change, with dramatic consequences for the 'Frozen World' (the 'cryosphere'), including reductions in the depth, extent and duration of sea ice, and seasonal snow cover on land, retreat of ice sheets/glaciers, and melting of permafrost ("ground that remains at or below 0 degrees C for at least two consecutive years"). This is important not only for local and regional ecosystems and human communities, but also for the functioning of the entire earth system. Evidence is growing that organic matter frozen in permafrost soils (often for many millennia) is now thawing, making it available for decomposition by soil organisms, with the release of carbon dioxide (CO2) and methane (CH4), both greenhouse gases (GHGs), as by-products. A major concern now is that, because permafrost soils contain 1672 petagrams (1 Pg = 1 billion tonnes) of organic carbon (C), which is about 50% of the total global below-ground pool of organic C, and permafrost underlies ~ 25% (23 million km2) of the N hemisphere land surface, a melting-induced release of GHGs to the atmosphere from permafrost soils could result in a major acceleration of global warming. This is called a 'positive biogeochemical feedback' on global change; in other words, an unintentional side-effect in the global C cycle and climate system. Unfortunately, the interacting biological, chemical and physical controls on CO2 and CH4 emissions from permafrost (and melting permafrost) environments to the atmosphere are the subject of much speculation because the scientific community does not know enough about the interactions between C and water cycling in permafrost systems. Warmer and drier soils may release more CO2, while warmer/wetter soils might release more CH4. Permafrost thawing also causes changes in the way water flows though the landscape (because frozen ground if often impermeable to water), and some areas may become drier, while others wetter. How the relative proportions of CO2 and CH4 emissions change, and their absolute amount, is critical for the overall 'global warming potential' (GWP) because these two gases have different potency as GHGs. Release of C from soils into freshwaters also needs to be taken into account because down-stream 'de-gassing' and decomposition of organic materials also influences releases of CO2 and CH4 from freshwater, or delivery of C to lakes/oceans. All-in-all, predicting the GWP of permafrost regions is scientifically challenging, and the interactions between the water (hydrological) and C cycles are poorly known. In this project we recognise the key role that hydrological processes play in landscape-scale C fluxes in arctic and boreal regions. In permafrost catchments in NW Canada (including areas where permafrost is known to be thawing) we will measure the capture of C from the atmosphere (through photosynthesis), its distribution in plants and soils, and the biological, physical and chemical controls of C transport and delivery from soils to freshwaters, and ultimately to the atmosphere as CO2 and CH4. In essence we wish to 'close the C cycle'. Field-based measurements of key processes in the water and C cycles, including geochemical tracer and state-of-the-art C, hydrogen and oxygen isotope approaches, will be linked by computer modelling. The project team, together with partners in Canada, the US and UK, is in a unique position to link the water and C cycles in permafrost environments, and we will deliver essential scientific knowledge on the potential consequences of climate warming, and permafrost thawing, for GHG emissions from northern high latitudes. Both for local peoples directly dependent on arctic tundra/boreal forest ecosystems for their livelihoods and cultural identity, and for the global community who must respond to, and anticipate, potential consequences of climate and environmental change, this project will represent a significant step forward in understanding/predictive capacity.

  • Funder: UKRI Project Code: NE/K000292/1
    Funder Contribution: 280,484 GBP
    Partners: AADNC, University of Edinburgh, University of Ottawa, Met Office, University of Aberdeen, NERC Radiocarbon Laboratory, University of Exeter, NRCan, Carleton University, University of Stirling...

    Terrestrial ecosystems currently absorb one quarter of the carbon dioxide released by fossil fuel burning into the atmosphere, and thus reduce the rate of climate change. As conditions become more favourable for plant growth, most models predict that high latitudes will take up more carbon during the 21st century. However, vast stores of carbon are frozen in boreal and arctic permafrost, and warming may result in some of this carbon being released to the atmosphere. The recent inclusion of permafrost thaw in large-scale model simulations has suggested that the permafrost feedback is potentially so significant that it could reduce substantially the predicted global net uptake of carbon by terrestrial ecosystems during the 21st century, with major implications for the rate of climate change. Large uncertainties remain in predicting rates of permafrost thaw and in determining the impacts of thaw in contrasting ecosystems, with many of the key processes missing from carbon-climate models. Firstly, the role that different plant communities play in insulating soils and protecting permafrost is poorly quantified, with key groups such as mosses absent in most models. In addition, fire disturbance can substantially accelerate permafrost thaw, and hence the ability of permafrost-protecting plant communities to recover from fire may play a key role in determining permafrost resilience. Secondly, different ecosystems may respond differently to thaw with contrasting effects on release of greenhouse gasses. In free-draining ecosystems, thaw may result in the net release of carbon due to increased decomposition of previously frozen organic matter. On the other hand, when thawing takes place in peatlands, soil subsidence can effectively raise the water table, which could result in carbon accumulation. However, this potential negative feedback may be offset by enhanced release of the more powerful greenhouse gas, methane. Importantly, the full range of feedbacks to permafrost thaw in these contrasting ecosystems is not currently reflected in process-based models. To address these issues, we will undertake directed fieldwork campaigns to determine (1) the role that different plant communities play in protecting permafrost within different soil types, and in unburned and fire-disturbed ecosystems, and (2) the impacts of permafrost thaw on fluxes of carbon dioxide and methane in free-draining versus peatland systems. Through links to Canadian partners, data will be collected from a range of field sites where permafrost monitoring is ongoing, including: (i) two contrasting boreal peatlands differing in permafrost extent, and where there is permafrost degradation; (ii) burnt and unburned sites within three important forest types in boreal Canada. Data will be provided from burnt and unburned moist acidic tundra within the continuous permafrost zone in Alaska by our US partners. The spatially variable vegetation recovery at the fire sites allows relationships between vegetation and permafrost to be tested in detail, while comparisons between the tundra, forest and peatland sites provide insights into the impacts of permafrost thaw in contrasting ecosystems. Critically, these data will be used to develop, parameterise and evaluate a detailed process-based model of vegetation-soil-permafrost interactions. The in-depth representation of vegetation-permafrost linkages will improve predictions of rates of permafrost thaw. The model will be the first to simulate the full range of biogeochemical feedbacks (methane and carbon dioxide) in free-draining versus wetland ecosystems. Furthermore, through links with Met Office scientists, our model will be coupled to the Joint UK Land Environment Simulator (JULES), allowing regional simulations to be run, coupled to a climate model. Ultimately, our project will improve predictions of both the rates and consequences of permafrost thaw, and help determine the potential impacts on 21st century climate change.