The Global Methane Budget

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

Abstract

Methane is the second most important greenhouse gas contributing to human-induced global warming. Atmospheric methane concentrations have increased sharply since 2007, and dramatically in 2014, for reasons that are not properly understood.

The overall increase since 2007 is comparable to the largest growth events over the past 1000 years. The recent rises have occurred worldwide, but after an Arctic pulse in 2007, the growth has been primarily in the tropics and southern hemisphere. Strong growth continues in 2015. Carbon isotopic evidence suggests that the increase is due to sources that are predominantly biogenic in origin, with changes in the anthropogenic sources from fossil carbon and burning (e.g., natural gas leakage, coal mining and so on) playing a subordinate role. This, taken with the tropical locus on growth, suggests that the increase has primarily been driven by meteorological change (e.g., temperature, rainfall).

Moreover, the global methane budget is currently not well understood. "Bottom-up" estimates, made by aggregating inventories of emissions (e.g. from gas leaks, fires, landfills, cows, etc) or from process models (e.g., wetlands) balanced with known loss processes, are significantly different from '"top-down" budgets assessed by direct measurement of methane in the atmosphere. Why this discrepancy occurs is not known.

The project has four components:
1. Better Observations are needed to derive estimates of emissions. The project will support a UK observation network for methane and its isotopes. Continuous stations will be at Kjolnes (Norway), Weybourne, Jersey, NERC ship RRS JC Ross, Cape Verde, Ascension, Falklands, Halley Bay, Hong Kong, with associated stations in Canada, Spitsbergen, Bolivia, South Africa, India, Rwanda and Malaysia. Flask or bag sampling (for methane, 13C and D/H isotopes) will also be undertaken at these stations and at a number of continental stations in S. America, Africa and S, SE and E Asia, with offline analysis in the UK. A D/H measurement facility will be set up. The UK FAAM aircraft will carry out flights across the Atlantic tropics, from Azores to Cape Verde to Ascension.

2. Process Studies will address the largest information gaps in the global budget. Tropical emission fluxes and isotopic signatures are not well constrained. Field campaigns will be undertaken in tropical wetlands in Amazonia, Africa, India and SE Asia, and C4 savanna biomass burn regions. Poorly understood anthropogenic sources will be studied in Kuwait and S., S.E. and E. Asia. Characteristic isotopic signatures of regional emissions will be determined, to support global and regional modelling. Land surface modelling and satellite studies will study emissions and responses to change in temperature and precipitation. Major sink processes will be investigated in the tropical atmosphere, with vertically and latitudinally resolved OH and Cl budget studies by the FAAM aircraft, and quantification of tropical uptake by soils.

3. Atmospheric modelling will be used to derive regional and global fluxes, apportioned by source type and geography using integrated in situ and remote sensing observing systems. We will carry out regional trajectory studies using models like NAME to assess regional emissions. Global modelling using 3D models will test synthetic estimates of the methane mole fraction and isotopic record. Global inverse modelling for mole fraction, 13C and D/H will be used to estimate fluxes by geographic source and source type, including a comprehensive assessment of the uncertainties that remain once all available observations have been used.

4. Integrative studies will use the results from the project to test top-down and bottom-up emission estimates, and evaluate the responses of the global methane budget to projections of climate change.

The project will deliver a state of the art greenhouse gas monitoring network and much better knowledge of the global methane budget.

Planned Impact

This project will produce a much better understanding of atmospheric methane, and the role of climate feedbacks in driving emissions. The sharp increase since 2007 will be of major public interest. Simultaneously, there has been a shift in its carbon isotopes implying the increase is primarily biogenic, not driven by fossil fuel emissions. Is this a climate change signal? A better knowledge of the global methane budget is vital if we are to understand what is driving feedbacks and to predict future emissions. This work will have impact on a very wide range of beneficiaries, from scientists to policy-makers.

Measurement: The project will create an Observation network as a long-term outcome, to sustain and improve global methane mole fraction and isotopic measurement, especially in the tropics where data gathering is presently very weak. In particular, the project will continue measurement on Ascension Is., one of the very few tropical background stations globally, and currently unfunded from 2017. The data will be invaluable to climate modellers.

Policymakers: With the Paris Climate Conference later this year, policy makers and governmental bodies are strongly focussed on climate change. 195 nations participate in the United Nations Framework Convention on Climate Change (UNFCCC). This commits signatory countries to assess their greenhouse gas emissions. For methane, there is a major discrepancy between global total emissions as assessed by atmospheric measurement ('top-down' measurement) and the sum of national emissions declared under UNFCCC (the 'bottom-up' inventory). This project will make major advances towards resolving this problem.

Space: When Sentinel 5P, GOSAT-2 and MERLIN satellites are launched, this project's in-situ observation of equatorial and Southern Hemisphere methane will make a significant contribution to analysis of the satellite measurements and will help validate the TCCON station at Ascension Island, a key equatorial site for satellite ground-truthing.

In the modelling component of the project, interpretation of the observations will help ecologists and geographers understand the impact of climate change globally, and especially in less developed nations. There will be strong impact on those carrying out global security studies, benefitting from the significant improvement the work will bring to greenhouse gas emissions inventories in tropical nations, where methane is very poorly constrained at present. The work will support marked improvements in emissions estimate for these nations.

In the private sector, a direct beneficiary will be Isoprime Ltd. (Cheshire: Queen's Award 2013), who will partner the development of the D/H analysis system at Royal Holloway. Wider beneficiaries include the gas, coal and oil industries, as the strong improvement of isotopic work, especially in D/H, will facilitate leak identification and location. Cutting leaks will improve efficiency and productivity as well as help compliance with regulatory frameworks.

Education: The project will support a number of younger staff, who will sustain the UK's key skills in greenhouse gas measurement and modelling, especially in the use of isotopes to characterise emissions. Career development will come through skills learned, publications, conferences, and training opportunities.

Public/Media: The results of this work will also be of interest to the wider public. Greenhouse gas, global warming and climate change are high on the political and media agenda, especially with the Paris climate conference later this year. Decisions made there will have implications for all.

Methane and its feedbacks rank among the most important and the most poorly understood problems in the global climate system. In wide global constituencies, from specialist scientists to policy makers, there is great need for better knowledge. Thus this project will have unusually strong and very wide impacts worldwide.

Publications

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

 
Description Atmospheric methane is increasing, and though the causes are likely complex, this may be the result of growing biogenic emissions, as a feedback from climate change. The rise is rapid and may make attainment of the Paris Agreement target more difficult.
Exploitation Route Of major importance to policy makers.
Sectors Energy,Environment,Government, Democracy and Justice,Other

URL http://www.reuters.com/article/us-climatechange-emissions-science-idUSKCN11X1TG
 
Description The main finding is that methane is increasing, and the causes of the increase appear to be climate feedbacks. This has been heavily covered by news media, by the scientific community in the IPCC 6th Assessemtn discussions, and by policy makers. Several 'longer reads' in major media (e.g. LA Times, NZZ Zurich, S China Morning Post) and a BBC World Service documentary on our work are examples of the depth of interest. MOYA-focus Royal Society Discussion Meeting scheduled for October 2020 now postponed to Autumn 2021prior to COP26 meeting. Accompanying volume of Phil Trans R Soc London is scheduled for summer 2021 (submission deadline Feb 28, 2021) so that the results will be available prior to the COP 26 meeting in Glasgow.
First Year Of Impact 2017
Sector Agriculture, Food and Drink,Energy,Environment,Government, Democracy and Justice,Security and Diplomacy
Impact Types Societal,Economic,Policy & public services

 
Description UN Climate and Clean Air Consortium - UN Environment Kigali Assessment- Methane Science Study - Methane science advisory panel.
Geographic Reach Multiple continents/international 
Policy Influence Type Participation in a advisory committee
Impact UN Climate and Clean Air Consortium's Scientific Advisory Committee on Methane advises on ways to locate and quantify methane emissions, especially from the oil and gas industry, with the purpose of reducing greenhouse gas emissions.
 
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 Hong Kong Univ. Methane sampling 
Organisation University of Hong Kong
Department Swire Institute of Marine Science
Country Hong Kong 
Sector Academic/University 
PI Contribution Analysis of air samples : atmospheric methane emissions from China
Collaborator Contribution Regular sampling - collection of air
Impact Measurement time series.
Start Year 2015
 
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 Broadcast interview BBC World Service Newsday 8 Feb 2019 
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 Broadcast interview discussing our recent aircraft campaign in Africa
Year(s) Of Engagement Activity 2019
 
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 Los Angeles Times - longer read essay on results from MOYA 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Interview with Los Angeles Times, to discuss the Global Methane Budget
Year(s) Of Engagement Activity 2019
URL https://www.latimes.com/science/sciencenow/la-sci-sn-methane-atmosphere-accelerating-20190301-story....
 
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 Nature news report on African campaign 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Report in Nature on our Jan/Feb 2019 NERC FAAM aircraft campiagn in Africa

https://www.nature.com/articles/d41586-019-00457-7
Year(s) Of Engagement Activity 2019
 
Description Observer newspaper story on Methane, 17 Feb 2019 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Interview leading to major report on African methane campaign and the global methane budget
Year(s) Of Engagement Activity 2019
 
Description Press Report in Nature 14 Feb. 2019: Tropical Africa could be key to solving methane mystery. J. Tollefson, Nature v566, 165-166. 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Media interview leading to subsequent report.
Year(s) Of Engagement Activity 2019
URL https://www.nature.com/articles/d41586-019-00457-7
 
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