Isotopic constraints on the Arctic methane budget

Lead Research Organisation: Royal Holloway, University of London
Department Name: Earth Sciences

Abstract

This project is designed to determine the active methane sources in the Arctic by measurement of d13C(CH4) at several key sites, and by trajectory modelling studies to identify the location, nature and seasonality of inputs. Understanding the sources of Arctic methane is essential, given the risk of positive-feedback responses to greenhouse warming. Examples include clathrate release, enhanced wetland output and sharply increased fire emissions. The danger of sudden runaway methane release is arguably among the greatest unknowns in global warming: here lies a significant potential risk of abrupt, rather than gradual climate change. The best tool to understand sources is isotopic fingerprinting, identifying them by their d13C(CH4) isotopic signature in winds, traced back to source by back-trajectory analysis. The intentions in this project are: 1. To collect samples of ambient air at chosen key locations and analyse them for CH4 mixing ratio and d13C(CH4). 2. To study a variety of Arctic CH4 sources, especially wetlands, but also fires, gas deposits and clathrates, to assess timing of emissions, isotopic character, and distribution. 3. To use back-trajectory analysis, compared to regional background, to locate sources and their isotopic character and seasonality. The project has several components: 1: d13C measurements of ambient air. In the High Arctic, at Ny Alesund (Spitsbergen, Svalbard), regular bag samples will be collected at Zeppelin mountain station, sampling air both from the westerly Atlantic background and also easterly Arctic (Siberian) air from varied sources (especially gas in winter; wetland in summer). At Pallas station in Arctic Finland, just above the Arctic circle, a similar sampling program will be implemented to sample westerly air from less northerly Atlantic, and easterly air from Russia. Flasks will also be collected for mixing ratio analysis only (St. Petersburg lab) at Teriberka (Russian Kola) and in the Ob River estuary (gasfields). At Weybourne, incursions of Arctic air arrive at the N. Sea coast. Tanks of air will be collected for high precision analysis of d13C(CH4). Finally, at Mace Head, Ireland, or an alternative North Atlantic site, the d13C(CH4) seasonality in background Atlantic air will be sampled, for distant inputs of fire or wetland methane from Canada and the high Arctic. 2 Source studies.will include wetland and forest studies at Pallas, to observe d13C(CH4) in ambient air (i.e. after release) in a set of field campaigns in several seasons. Measurements and sample collection will be made above wetlands and forests (tower), including diurnal air sampling and chamber experiments. Other source studies will include fire sampling (Canada), and gas sampling. 3. Back-trajectory modelling will use the data to identify regional methane emissions. Single-trajectory studies of air arriving at the collection stations will be used, compared against regional and seasonal background air, to locate individual sources. This study will characterise emissions by isotopic signature and hence suggest source type, and will watch these change over the seasons as emission strength varies. Multiple trajectory studies wil use sector analysis, to identify major regions of Arctic input. The Arctic is now and is in future likely to be the fastest-warming region of the planet. Potentially it could become a very major source of methane, and hence a source of strong positive feedback into greenhouse warming. This is one of the most dangerous regions of the planet in terms of 'warming feeding the warming'. The work will provide a UK contribution both to International Polar studies in the aftermath of IPY, and to the UN's Global Atmosphere Watch, under the aegis of the World Meteorological Organisation and (for isotopes) the International Atomic Energy Agency. More widely, the results will be important to the global understanding of the carbon budget and the Kyoto process.

Publications

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Berchet A (2016) Atmospheric constraints on the methane emissions from the East Siberian Shelf in Atmospheric Chemistry and Physics

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Krey V (2009) Gas hydrates: entrance to a methane age or climate threat? in Environmental Research Letters

 
Description The Arctic is a major methane source region with a wide variety of different emissions. The work has used isotopic measurements to show the dominant sources are wetlands in summer, and gas leaks in winter. Hydrate emissions occur but at present are not making a major contribution to the atmsopheric methane burden.
Exploitation Route Arctic methane is a very important topic - the measurements will support ongoing modelling studies.
Sectors Energy,Environment,Other

 
Description The project began the use of isotopes to study the sources of Arctic methane. This pointed to a major wetland source in summer and gas leaks in winter. The project developed methodology that proved widely useful both in the UK and Europe. Successor projects that use the methodology include our own work, the EU Ingos project, Norwegian MOCA and now also UK GUAGE. The work contributed to a major paper presented by the Canadians (chairman) to the Arctic Council.
First Year Of Impact 2013
Sector Energy,Environment
Impact Types Cultural,Societal,Economic,Policy & public services

 
Description Report to Arctic Council (AMAP): Co-authorship of major Canadian goverment report on Arctic methane, presented during the Canadian presidency of the Arctic Council. Report is listed in publication list.
Geographic Reach Multiple continents/international 
Policy Influence Type Gave evidence to a government review
Impact Arora et al (2015) Arctic Monitoring and Assessment Program (AMAP) assessment 2015: Methane as a climate forcer. Report by Canadian government to the Arctic Council.
 
Description Atmospheric sampling with the Norwegian Inst. for Air Research (NILU) 
Organisation Norwegian Institute for Air Research
Country Norway 
Sector Charity/Non Profit 
PI Contribution Joint Arctic air sampling at Zeppelin, Spitsbergen and Antarctic sampling at Troll base.
Collaborator Contribution Collaborative isotopic analysis: NILU collect air samples and RHUL analyses them for d13C in methane.
Impact Collaborative papers, reported in publications
 
Description Award winner, 'The Engineer'/EPSRC Collaborate to Innovate awards. 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Award winner, The Engineer, Innovation prize
Year(s) Of Engagement Activity 2016
URL https://www.theengineer.co.uk/collaborate-to-innovate-winners-annnounced/
 
Description BBC World Service documentary - radio. "Discovery - cheating the atmsophere" 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Participation in BBC World Service documentary "Disocvery - cheating the atmosphere". Long interview on the problems of assessing greenhouse gas emissions inventories for the United Nations Framework Convention on Climate Change - Paris Agreement. Broadcast several times in second week of Dec, 2017
Year(s) Of Engagement Activity 2017
URL http://www.bbc.co.uk/programmes/w3csvpfz
 
Description LONCON3 World Science fiction convention 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Several Activities - all invited.
1. Exhibition of methane measurement "Discover your inner cow" sampling methane in breath.
2. Panel discussion on climate in science fiction
3. Panel discussion on sci fiction and policy.
Year(s) Of Engagement Activity 2014
 
Description NERC UnEarthed Showcase 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact NERC UnEarthed Showcase event, Edinburgh. MOYA presentation on the Global methane budget, focussed on school age students. ~7000 schoolchildren and many members of the general public. 17,18,19 and 20 Novermber 2017
Year(s) Of Engagement Activity 2017
URL http://www.nerc.ac.uk/latest/events/archive/unearthed/
 
Description Public Lecture: 56th Annual Bennett Lecture, Leicester Literary and Philosophical Society 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Public lecture - annual 'named' lecture of the Leicester Literary and Philosophical Society, Univ. of Leicester
Year(s) Of Engagement Activity 2015
URL http://www2.le.ac.uk/hosted/litandphil/documents-1/transactions/transactions_2015
 
Description Royal Holloway Science festival 2015 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Several activities - all coordinated by us;
1. fossil trail
2. Volcano exhibit and eruption
3. lecture
4. Gold panning
Year(s) Of Engagement Activity 2015