Project highlights

  • Work at the cutting edge of global greenhouse gas modelling
  • Work with the internationally leading Met Office to examine ecosystem processes at scale.
  • Uncover novel linkages between pollution deposition and the emission of powerful greenhouse gases.


The response of the land to global change is an important factor in modulating the overall impact of both greenhouse gases and atmospheric pollutants such as sulphate, nitrogen oxides (NOx) and ozone (O3) concentrations.

Wetland emissions of the greenhouse gas methane (CH4) are expected to feedback on climate change. However there are important interactions between wetland emissions and several key atmospheric pollutants that have been largely omitted from the Earth System modelling of the CH4 cycle. For example, atmospheric sulphate (causing so-called “solar dimming”) and biomass burning aerosols impact on vegetation through the amount of (total and diffuse) radiation reaching the surface, and tropospheric O3 damages plants. These processes impact on vegetation productivity (NPP), and can therefore alter wetland CH4 production by changing the amount of carbon available to methane-generating microbes.  Moreover the deposition of sulphur and nitrogen on the land result in other interactions in the wetland soil, which can strongly modulate the amount of methane emitted.

The aim of this project is to answer the following questions:

  • How much have atmospheric pollutants modulated historical wetland CH4 emissions?
  • Can this be used to help constrain the current CH4 wetland budget?
  • To what extent has recovery from past pollution affected the current global CH4 budget?

This work will contribute to the newly developed Met Office capability in fully coupled methane cycling, where the UK Earth System Model has recently been extended so that dynamical wetlands CH4, full stratospheric-tropospheric CH4 chemistry, and CH4 surface deposition are fully interactive.

The JULES land surface scheme describes the main drivers of wetland CH4 emissions: wetland extent, water table depth, temperature and available carbon substrate. The latest version of JULES includes recent improvements in hydrology, including the representation of tropical soils, and groundwater and overbank inundation. The recent discovery of significant CH4 transfer through tropical trees has also been parameterised in JULES.  We will also utilise any JULES developments from the NERC Hydro-JULES program that further improve terrestrial water cycle modelling. The latest JULES terrestrial carbon and nitrogen parameterisations will also be used.

CENTA Flagship

This is a CENTA Flagship Project

Case funding

This project is suitable for CASE funding


University of Birmingham


  • Climate and Environmental Sustainability


Project investigator

  • Prof. Vincent Gauci (Birmingham,



  •  Dr Peter Hopcroft (Birmingham)
  • Dr Nicola Gedney (CASE partner Met Office)

How to apply


The student will develop a soil biogeochemistry model which encompasses the impact of sulphur and nitrogen on CH4 production and emission in the soil. The parameterisation will be incorporated into the latest version of the JULES model, which includes the latest carbon and nitrogen cycle descriptions, and hydrology and CH4 wetland models.

The impact of these pollutants on CH4 generation through changes in soil biogeochemistry, and direct and diffuse surface radiation will then be incorporated and assessed with JULES. This will include evaluation of both long-term trends and inter-annual variability. Validation will include comparisons against: field data; estimated large-scale emissions, such as from atmospheric inversion models; and historical atmospheric CH4 concentrations by using a simple model of atmospheric CH4 lifetime.

There is the potential to run the model off-line for future socio-economic scenarios such as how it affects estimates of allowed anthropogenic emissions consistent with Paris climate targets.

Training and skills

This project will give the student direct experience of high-performance computing and using the Met Office/NERC land surface model JULES. During the project the student will receive training in understanding and evaluating complex systems, land surface modelling and coding. Further, they will be given training in the issues surrounding the global methane cycle and the emission of pollutants.

Partners and collaboration

The project benefits for collaboration with our CASE partner Dr Nicola Gedney of the UK Met Office, world leaders in modelling all aspects of the Earth system including the exchange of greenhouse gases between ecosystems in the Earth surface and the atmosphere.  The CASE partner is based at the Joint Centre for Hydro-Meteorology Research in Wallingford, Oxfordshire along with the Centre for Ecology and Hydrology.

Further details

For further enquiries, please contact Prof. Vincent Gauci (

Applications need to be submitted via the University of Birmingham postgraduate portal,, by midnight 11.01.2021. Please first check whether the primary supervisor is within Geography, Earth and Environmental Sciences, or in Biosciences, and click on the corresponding PhD program on the application page.

This application should include

  • a brief cover letter, CV, and the contact details for at least two referees
  • a CENTA application form
  • the supervisor and title of the project you are applying for under the Research Information section of the application form.

Referee’s will be invited to submit their references once you submit your application, but we strongly encourage applicants to ensure referees are aware of your submission and expecting a reference request from us. Students are also encouraged to visit and explore the additional information available on the CENTA website.


Possible timeline

Year 1

Develop schemes for impact of pollutants on wetland biogeochemistry within JULES and evaluate against site measurements and atmospheric inversion models. Present a poster of work.

Year 2

Further develop schemes for sensitivity to diffuse/direct radiation interception and integrate improvements with latest wetland methane emissions schemes, including emission through trees. Present at a UK conference.

Year 3

Evaluate the influence of present-day and historical emissions of pollutants on the wetland biogeochemistry and methane emissions. Present at an international conference.

Further reading

Gauci, V., Matthews, E., Dise, N., Walter, B., Koch, D., Granberg, G. and Vile, M., 2004. Sulfur pollution suppression of the wetland methane source in the 20th and 21st centuries. Proceedings of the National Academy of Sciences101(34), pp.12583-12587.

Gedney, N., C. Huntingford, E. Comyn-Platt, and A. Wiltshire (2019). Significant feedbacks of wetland methane release on climate change and the causes of their uncertainty. Env Res Lett 14, 084027.

Saunois, M., A. Stavert, B. Poulter, et al. (2020). The global methane budget 2000-2017. Earth System Sci Data 12, 1561–1623.


This is a modelling project that will not require field or lab access and contingencies can be put in place for computer/server access as necessary. We foresee limited scope for disruption to the project.