Climate feedbacks from wetlands and permafrost thaw in a warming world (CLIFFTOP)

Carbon dioxide and methane are the most important long-lived greenhouse gases causing global warming and climate change. These two gases, which are the major components of the global carbon cycle, are added to and removed from the atmosphere in a wide range of ways, from both natural and human activities. Wetlands are the largest natural source of methane and methane emissions from wetlands are expected to increase in a warming world. Further, in high northern latitudes, large amounts of carbon are stored in frozen soils or permafrost. The polar regions are warming faster than other parts of the Earth. As these soils warm causing the permafrost to thaw, the stored carbon can be converted by microbial activity over time and released to the atmosphere as carbon dioxide or methane, leading to further warming and hence a positive feedback. Combined with landscape changes, this may lead to the formation of new wetlands resulting in further emissions of methane.

Wetlands and permafrost thaw are therefore important biogeochemical processes that need to be included in models of the Earth's climate. Through their inclusion, climate, or now Earth System, models will then account for the feedbacks that wetlands and permafrost thaw produce on the physical climate system (e.g., on future temperature changes). Following the international climate agreement in 2015 to limit future temperature rises to less than 1.5-2 degrees centigrade above pre-industrial levels, there is an urgent need to quantify this contribution of wetlands and permafrost thaw as this will constrain the accumulated emissions of greenhouse gases that can be released from human activities such as fossil fuel combustion if global temperatures are to be stabilised.

In this study, we will use the UK community state-of-the-art land surface model, the Joint UK Land Environment Simulator (JULES) to model wetlands and permafrost thaw. We plan targeted development of the land-surface model to enhance its capability for considering wetlands, permafrost thaw, methane and carbon dioxide emissions in a more consistent and integrated manner. For this work, we will use this improved version of JULES with a simplified but robust climate emulator, IMOGEN. IMOGEN replicates the behaviour of a wide range of more complex and resource intensive climate and Earth System models that contributed to the latest climate change assessment of the IPCC.

We will undertake model runs with the JULES-IMOGEN modelling system (a) to assess the impact of Arctic carbon releases that are not included in many climate models, (b) to quantify the corresponding climate feedbacks and the impact of these additional emissions on allowed human emissions for 1.5 or 2 degree C climate stabilisations. The research proposed will provide important evidence to support the commitments made in the Paris Agreement to 'strengthen the global response to the threat of climate change.... and to pursue efforts to limit the temperature increase to 1.5 degree C above pre-industrial levels'.

The outputs of the work will include:
* papers for publication in the scientific literature, which will be included in the special IPCC assessment of the IPCC
* wetland methane emission datasets for current day and future conditions that will be of value for the atmospheric modelling community

The project links to and will complement ongoing work at the Met Office, our project partner, for the UK government.

The key beneficiaries are
(1) policymakers
(2) the scientific research community
(3) UK and international public and school
(4) Arctic communities

(1) Policymakers

The call for this application is explicit that the research will be policy relevant, either nationally or internationally. The research proposed here will contribute strongly to the work of the UN Framework Convention on Climate Change and particularly the Intergovernmental Panel on Climate Change (IPCC). It is our intention to publish the work in the scientific literature and to make it available for inclusion in the special IPCC assessment. We will also use the existing strong links of the Met Office to brief policymakers in the Department of Business, Energy and Industrial Strategy about the work.

This study has a polar focus. The Arctic is a key region in the context of impacts from and the opportunities provided by climate change. We will look to present our work at suitable international conferences on the Arctic to engage with a broader range of non-academic groups. We have contacted and will work with the NERC Arctic Office to identify other opportunities to promote this work.

The international Global Carbon Project (GCP) produces an annual carbon budget (http://www.globalcarbonproject.org/). The GCP has recently started producing global CH4 budgets and our project partner (Met Office) has provided JULES wetland methane emission estimates. We will continue our participation in this activity, which will lead to publications in the scientific literature and will inform future IPCC assessment of the Global Methane cycle.

(2) Scientific research community

The improved modelling of wetlands and permafrost and the resulting emission datasets will be of interest to climate, land surface and atmospheric scientists (see section on Academic Beneficiaries).

(3) UK and international public and schools

There is a thirst in sectors of the UK public for access to the latest science, and a need to motivate schoolchildren about the excitement and importance of environmental science. The Centre for Ecology & Hydrology has a very strong track record in engaging policy makers and the wider public on scientific issues around environmental issues such as those addressed by this project. The research will be advertised to the public through press releases via CEH and NERC's Press Offices.

The Big Bang is a national programme which celebrates Science, Technology, Engineering and Maths. Events in the South West are organised by the Education Business Partnership (South West) and the University of Exeter. We would present our work at the 2017 'Big Bang' exhibition.

(4) Arctic communities

The new NERC project Under-recognized Cold Season and Upland Tundra Arctic Methane Sources has a strong focus on the Alaskan Arctic. We will work with the PI of that project (Oechel, Open University) and contribute to outreach events for the local communities on the North Slope (e.g., seminars organized by the Barrow Arctic Science Consortium).


We will also use relevant impact activities of other NERC-funded (e.g., Global Methane) and international (EU CRESCENDO) projects to enhance the impact of this project.