CYCLOPS: Carbon Cycling Linkages of Permafrost Systems

Lead Research Organisation: University of Sheffield
Department Name: Animal and Plant Sciences

Abstract

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.

Planned Impact

We aim to improve predictions of the rate and consequences of permafrost thaw, including feedbacks to climate. Therefore, the outputs of this research will be of interest to stakeholders in the Arctic, and policy makers nationally and internationally, as well as the general public.
Land managers and governmental organisations such as Natural Resources Canada (NRC) and the Department of Indian Affairs and Northern Development (DIAND) have mandates to preserve the natural environment. Through our contacts (partners Wolfe and Kokelj) we have constructed key parts of our proposal to build on and extend NRC and DIAND research. Our project outputs will benefit these organisations in understanding permafrost systems and carbon cycling, with this being of heightened benefit to them given that our work will occur within, and extend, their framework of ongoing monitoring. We will visit NRC and DIAND partners to strengthen our relationship with the Canadian government and to increase the impact of our project for Canadian partners. We will contribute our data to their databases, and work with our partners to implement a knowledge exchange plan. Our project partners have been involved since the initiation of the proposal and will join us on our field work, including our preparatory field visits, ensuring optimum benefit of our work to them.
Our links with the UK Met Office (see Academic Beneficiaries) means that our findings will be incorporated into coupled climate-carbon cycle modelling, and thus influence predictions of 21st century climate change. This link will maximise the impact of work in terms of its relevance to the Intergovernmental Panel on Climate Change and international policy makers.
Our work will be of interest to communities concerned about sustainability of their way of life, water resources, and changes to permafrost and thermokarst. We will engage with local communities in Canada, to explain our research and to learn more about their views on, and experiences with, climate change. We will inform the public of our activities through information displays and talks at the Yellowknife Northern Heritage Centre and Yukon College at Whitehorse.
The subject area lends itself well to engagement of public interest, and will be an excellent opportunity to promote NERC science in the UK. The public are interested in high latitude ecosystems (e.g. BBC Frozen Planet series), and there is increasing reporting of permafrost issues in the media. The PI and Co-Is are committed to communicating science to the general public. For instance, we had a successful exhibit at the Royal Society Summer Exhibition (2007) on arctic warming. The Impact funding will also allow us to enhance our schools and museum outreach. These activities will include new presentations and development of mobile stands that can be used at museums (we already have good outreach experience with these) and with SciFun, the Scottish Science and Technology Roadshow. In addition, the PDRAs will visit local schools to explain their research, and promote science as a career. We will use the communication offices of our institutions to inform local and national media of our major findings.
Finally, a project website will be established to communicate project outcomes to key stakeholders and the public. We will include videos and footage from field sites and social networking technologies, including experiments with twitter to facilitate broad dissemination.
In summary, together with our plans for academic dissemination, our impact plan will ensure our results have the maximum impact in improving the representation of permafrost in IPCC-facing, coupled climate-C-cycle modelling. We will outline our findings to local government organisations through lectures and through links with our project partners. Furthermore, we will use various media, and museum, school and college outreach activities, to ensure that our research reaches wider society in the UK and Canada.

Publications

10 25 50
 
Description Permafrost, ground which remains at or below 0 ºC for at least two years, is globally important because it stores approximately twice as much carbon as is present in the atmosphere. As the temperatures rise in northern regions permafrost will thaw and the active layer, which is the seasonally thawed layer of ground between the permafrost and the surface, will thicken. Permafrost thaw will not respond in a uniform way to temperature changes but will be controlled by a range of factors including vegetation and soil characteristics. Understanding which soil and vegetation characteristics are affected by climate change, and what the consequences of vegetation change are for carbon cycling is crucial if we are to assess the impact permafrost thaw will have on the global carbon cycle.
We have found that moss plays a strong role in protecting permafrost from thaw by insulating the ground from heat during summer. We also demonstrated that as the ground become wetter the importance of this insulating effect of mosses becomes greater, because moisture increases the rate at which heat is conducted down through the soil. We have also shown that organic soil can play a similar insulating role to mosses when it is dry, but that wet organic soil may promote permafrost thaw, perhaps because by retaining moisture it remains conductive to heat for longer periods of time than free-draining mineral soils would. The ability of plants to prevent heating of the ground by providing shade has also been revealed. Our uniquely detailed fine scale survey has allowed the quantitative relationship between thaw depth and these important soil and vegetation characteristics to be determined.
Our carbon flux measurements have shown that CO2 uptake by understory plants is similar sites which have experienced fire and those which have not (fire is a major disturbance factor in the boreal forests where this research focusses). This was contrary to what we expected as we predicted that the increased nutrients that are liberated during fire and the decrease in competition for light from the tree canopy would have increased rates of photosynthesis in the post fire regrowth. However, we did see increases in productivity of the ground covering vegetation in wetlands that form after permafrost thaw, which may partially offset the loss of CO2 uptake by trees which die during wetland formation.
Exploitation Route These results can be used by the modelling community to improve predictions of the consequences of future temperature changes on permafrost thaw. Our work already feeds directly into the SPA model as part of this consortium, and his will then go on to inform JULES. This will refine our understanding of the influence that permafrost thaw will have on the global carbon cycle.
Sectors Environment

URL http://www.geos.ed.ac.uk/cyclops/
 
Title Carbon fluxes from ecosystems of contrasting permafrost status 
Description CO2 flux and leaf-level photosynthesis data from boreal ecosystems of contrasting permafrost and fire status. 
Type Of Material Database/Collection of data 
Year Produced 2014 
Provided To Others? Yes  
Impact Data has been used to parameterise and test the biogeochemical module of the SPA model of Prof Mat Williams (University of Edinburgh). 
 
Title Ecosystem characteristics as drivers of Active Layer Depth 
Description The thaw depth, moss layer thickness and organic matter depth data generated in this project has already been used to extend the soil physics module of the SPA model originally developed by Mat Williams. 
Type Of Material Database/Collection of data 
Year Produced 2014 
Provided To Others? Yes  
Impact This process based model can now predict the impact of varying moss and organic soil layer thickness on permafrost thaw depth. 
 
Description Permafrost research collaboration network review of understanding of ecosystem controls on permafrost 
Organisation Colgate University
Country United States 
Sector Academic/University 
PI Contribution Our work and my understanding gained from it contributed to the review of ecosystem controls on soil their regimes on permafrost thaw.
Collaborator Contribution Colgate university academics lead the review.
Impact Loranty, M.M., Abbott, B.W., Blok, D., Douglas, T.A., Epstein, H.E., Forbes, B.C., Jones, B.M., Kholodov, A.L., Kropp, H., Malhotra, A., et al. (2018). Reviews and syntheses: Changing ecosystem influences on soil thermal regimes in northern high-latitude permafrost regions. Biogeosciences 15, 5287-5313.
Start Year 2016
 
Description Steve Wolfe CYCLOPS 
Organisation Geological Survey of Iran (GSI)
Country Iran, Islamic Republic of 
Sector Public 
PI Contribution We conducted the core research on the influence of ecosystem properties on active layer thickness of permafrost, using sites we selected but with considerable guidance from the local expertise of the collaborator. We wrote the paper.
Collaborator Contribution Considerable guidance on site selection and knowledge of site characteristics. Input as co-author on the paper.
Impact Paper: "The influence of vegetation and soil characteristics on active-layer thickness of permafrost soils in boreal forest", Global Change Biology (in press) doi: 10.1111/gcb.13248
Start Year 2012
 
Description Ecology North (public engagement August 2014) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact (12/8/2014) While in Yellowknife we gave a public lecture which was hosted by Ecology North, a charitable organisation which aims to promote public awareness of issues surrounding climate change and sustainable living. Our talk was attended by approximately 20 people, including Ecology North volunteers and interested members of the public.

Our talk was followed by a lively public debate.
Year(s) Of Engagement Activity 2014
 
Description Fir Vale School visit (October 2014) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact James Fisher, the PDRA visited Fir Vale School in Sheffield to deliver a series of activities focusing on Arctic climate change to Year 7 students. The students were engaged with the activities and showed an awareness of some of the general issues surrounding climate change.

None.
Year(s) Of Engagement Activity 2013,2014