Terrestrial Methane Cycling During Paleogene Greenhouse Climates

Lead Research Organisation: University of Bristol
Department Name: Chemistry

Abstract

Human activity has led to an increase in pCO2 and methane levels from pre-industrial times to today. While the former increase is primarily due to fossil fuel burning, the increase in methane concentrations is more complex, reflecting not only direct human activity but also feedback mechanisms in the climate system related to temperature and hydrology-induced changes in methane emissions. To unravel these complex relationships, scientists are increasingly interrogating ancient climate systems. Similarly, one of the major challenges in palaeoclimate research is understanding the role of methane biogeochemistry in governing the climate of ice-free, high-pCO2 greenhouse worlds, such as during the early Paleogene (around 50Ma). The lack of proxies for methane concentrations is problematic, as methane emissions from wetlands are governed by precipitation and temperature, such that they could act as important positive or negative feedbacks on climate. In fact, the only estimates for past methane levels (pCH4) arise from our climate-biogeochemistry simulations wherein GCMs have driven the Sheffield dynamic vegetation model, from which methane fluxes have been derived. These suggest that Paleogene pCH4 could have been almost 6x modern pre-industrial levels, and such values would have had a radiative forcing effect nearly equivalent to a doubling of pCO2, an impact that could have been particularly dramatic during time intervals when CO2 levels were already much higher than today's. Thus, an improved understanding of Paleogene pCH4 is crucial to understanding both how biogeochemical processes operate on a warmer Earth and understanding the climate of this important interval in Earth history.

We propose to improve, expand and interrogate those model results using improved soil biogeochemistry algorithms, conducting model sensitivity experiments and comparing our results to proxy records for methane cycling in ancient wetlands. The former will provide a better, process-orientated understanding of biogenic trace gas emissions, particularly the emissions of CH4, NOx and N2O. The sensitivity experiments will focus on varying pCO2 levels and manipulation of atmospheric parameters that dictate cloud formation; together, these experiments will constrain the uncertainty in our trace greenhouse gas estimates. To qualitatively test these models, we will quantify lipid biomarkers and determine their carbon isotopic compositions to estimate the size of past methanogenic and methanotrophic populations, and compare them to modern mires and Holocene peat. The final component of our project will be the determination of how these elevated methane (and other trace gas) concentrations served as a positive feedback on global warming.

In combination our work will test the hypothesis that elevated pCO2, continental temperatures and precipitation during the Eocene greenhouse caused increased wetland GHG emissions and atmospheric concentrations with a significant feedback on climate, missing from most modelling studies to date. This work is crucial to our understanding of greenhouse climates but such an integrated approach is not being conducted anywhere else in the world; here, it is being led by international experts in organic geochemistry, climate, vegetation and atmospheric modelling, and palaeobotany and coal petrology. It will represent a major step forward in our understanding of ancient biogeochemical cycles as well as their potential response to future global warming.

Planned Impact

Our proposal is of wide and direct relevance to the Earth Sciences academic community and associated stakeholders. It explicitly addresses two strategic themes of the new NERC strategy for 2007-2012: Earth System Science and Biodiversity. In particular, our research meets three of the six key outcomes identified in the overarching 'Earth system science' theme, as NERC seeks to provide "knowledge of the impact of potential mitigation and adaptation strategies to forthcoming climate change", "understand tipping points and rates of change", and aims to provide "better assessment of the risk of changes in the Earth system to inform policy decisions". The results of this proposal help the UK meet the strategy challenges to "provide forewarning of abrupt changes in the Earth System", to "improve knowledge of the interaction between the evolution of life and the Earth", and to "understand the forces and feedbacks that drive the Earth System". As such, prompt and high profile delivery of our results to our scientific peers is a key component of our Impact strategy, and we have requested funds for conference attendance by the PI, CoIs and PDRAs. We have a very strong track record in conference attendance (including invited keynote presentations) and rapid, high profile publication of our work; that good practice will be continued as part of the proposed work.

Of course, our conclusions will also be of wide interest to the public, policy makers, climate-orientated NGOs and other NERC stakeholders; we, as a society, will benefit from this research because it furthers our understanding of climate change and informs our predictions for future change. As such, we have an ambitious impact programme built around two main (non-academic) themes:

1. Public engagement. The University of Bristol is a national leader in public engagement: Bristol, along with the University of the West of England, is the coordinator of the national engagement beacons; we had the first Professor of Public Engagement (K Sykes); and our two Centres of Excellence in Chemistry and Anatomy are world leading in terms of the quantity and quality of outreach activity. The PI and our Co-Is have been particularly active in this capacity, including serving on the organising committee for the Bristol Festival of Nature, hosting BBC series, giving >100 talks to fellow scientists and the wider public and writing books marketed to the general public (The Emerald Planet: How Plants Changed Earth's History by DJB). Funds to support our Impact Plan will allow us to exploit the best practices developed elsewhere, allowing us to: embed a methane component in the Bristol ChemLabS lecture series (>100 lectures to ca 30,000 people per year); develop a website, complete with interactive tools; and have a prominent display at the Bristol Festival of Nature hosted by ourselves but also Sixth Form students who will have done summer internships in our labs.

2. Stakeholder engagement: We have hosted MPs in the past, and Pancost and Singarayer have numerous connections with the Bristol City Council via our involvement in the University of Bristol centenary fund and the Bristol Festival of Nature. Also via the Festival of Nature, we have excellent connections with the Environment Agency and charitable trusts devoted to wetland awareness and conservation. We will use these connections to host events where our research is explained to and discussed with a range of stakeholders. It is our intention to make our political leaders more aware of the sensitivity of wetlands to climate change - and therefore, the need to better understand these environments. Of course, this will also be an ideal mechanism to update policy makers with the most up-to-date research on this particular 'tipping point' in the Earth System, a particularly important goal of the NERC.

Publications

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Inglis G (2017) Mid-latitude continental temperatures through the early Eocene in western Europe in Earth and Planetary Science Letters

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Lunt DJ (2013) Warm climates of the past--a lesson for the future? in Philosophical transactions. Series A, Mathematical, physical, and engineering sciences

 
Title Bristol Green Capital Arts Programme 
Description The 2015 Green Capital Arts Programme comprised dozens of events, exhibits and neighbourhood arts projects. 
Type Of Art Artistic/Creative Exhibition 
Year Produced 2015 
Impact I made numerous contributions, all informed by past climate research funded by the NERC (and others), including: 1) Writing the introduction to the programme brochure 2) Partnering with the Festival of Ideas to deliver the Coleridge Lectures and other talks 3) Co-curating the Fog Bridge Exhibit (Fujiko Nakaya) as part of the In Between Time Festival 4) Helped to develop a programme around climate change, past and present, as part of the Withdrawn installation in Leigh Woods (Luke Jerrams) in partnership with the National Trust 
URL https://www.bristol2015.co.uk/
 
Title The Uncertain World by Alex Lucas 
Description The Uncertain World was commissioned by me and done by local street artist Alex Lucas. It is a series of drawings of modern-day Bristol, inundated by prehistoric levels of flooding and populated by Cretaceous sea creatures; the goal was to show how past climate can be used to explore and constrain uncertainty. Numerous postcards were distributed and some images were sold in Alex Lucas's shop. A major mural was painted on a University owned building that abuts one of Bristol's busiest roads. 
Type Of Art Artwork 
Year Produced 2015 
Impact The art has been used in numerous publications, including in various Bristol Green Capital programmes (Future Leaders Summit Programme and Arts Programme). It will also be used in an upcoming commentary in Nature Geoscience. The mural was featured in online video Magazine Made in Bristol and 24/7 Magazine (note link below is brief; main articles have now been removed) 
URL http://www.bristol247.com/channel/culture/art/street-art/plesiosaurs-on-park-row
 
Description This project has now delivered several key findings on ancient greenhouse climates and associated vegetation and biogeochemical impacts. This project has shown that:

Fires became less globally widespread during the Eocene, likely reflecting a change in vegetation and wider global climatic conditions. Related work has generated a synthesis of global hydrological change at the PETM, highlighting the regionally and temporally complex variation in rainfall patters.

European continental temperatures were high and relatively stable during the Eocene and increased during the Early Eocene; crucially, this finding validates marine temperature reconstructions both in terms of absolute temperatures and long-term trends. And it represents the first application of GDGT-based temperature proxies in lignites.

Our work has confirmed the presence of Sphagnum moss in a >50 million year old peat, using a combination of pollen and chemical approaches. This work has also revealed important new insights into the microbial ecology of both modern peat and ancient lignites.

We have made numerous advances in our climate modelling, including improved treatment of daily rainfall functions, an exploration of orbital forcing on methane emissions during greenhouse climates, revised transfer functions from soil models to calculate methane emissions and a new algorithmic approach to estimating methane emissions.
Exploitation Route In an academic context, this work has shown for the first time the value of lignites as archives of past climate conditions (and reinforces the role of biomarkers in probing ancient biogeochemical processes). The modelling results will likely provide new tools and/or guidance on past reconstruction of terrestrial hydrology and biogeochemistry.

But perhaps most importantly, from a societal perspective, this work highlights the profound complexity of biogeochemical feedbacks during global warming with important implications for the public (and policy-making) understanding of future climate change impacts.
Sectors Environment

 
Description We increasingly are relying on the changes throughout Earth history to provide context and depth to the decisions we make about the future. Historically, this has been rooted in reconstructing carbon dioxide concentrations and temperature, to better constrain Earth system sensitivity. However, Earth history can reveal a far deeper of the more complex changes that happen as our planet warms, especially with respect to hydrological, vegetation and biogeochemical change that occurred during both long-term and transient warming events. This project has shown that Eocene terrestrial temperatures were far warmer than those of today, that hydrological and fire-related processes changed dramatically in the Eocene, and that wetland carbon biogeochemistry was markedly different during greenhouse climate. These findings both reinforce our understanding of the Earth system (that elevated pCO2 causes warming) but underscore the complexity of biogeochemical risks associated with that warming. An emphasis on that duality - and especially the unexpected risks - has underscored Pancost's policy and public engagement, starting with the Bristol Green Capital and continuing with his involvement in Bristol's 50 Year Planning, via the Resilience Sounding Board and now Bristol's One City Plan. Crucially, it creates a framing of contextualised uncertainty - that what we know about climates of the past sharpens our perspectives on future uncertainty. This is directly manifested in Bristol's Resiliency Report which derives from the uncertain impacts of climate change (and other factors) a strategy that emphasises soft and flexible adaptation, including citizen empowerment and community cohesion. Now that the Report has been approved, it is serving as the foundation of Bristol's new Mayor's One City Plan; to enable that I am part of the City's One City Plan Partnership Board as well as a member of its International Strategy Board.
Sector Communities and Social Services/Policy,Digital/Communication/Information Technologies (including Software),Environment,Government, Democracy and Justice
Impact Types Cultural,Societal,Policy & public services

 
Description Bristol Resilience Strategy
Geographic Reach Local/Municipal/Regional 
Policy Influence Type Participation in a advisory committee
URL https://www.bristol.gov.uk/policies-plans-strategies/bristol-resilience-strategy
 
Description Advanced ERC Grant
Amount € 2,500,000 (EUR)
Funding ID T-GRES 
Organisation European Union 
Sector Public
Country European Union (EU)
Start 01/2014 
End 12/2018
 
Description Bristol Green Capital Partnership and Member Organisations 
Organisation Bristol Green Capital Partnership
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution The partnership comprises over 850 organisations and via them I have developed a number of specific ad hoc advisor relationships; these include the Schumacher Institute, Bristol is Open, the Festival of Ideas and Ujima Radio. My main contributions have been via a combination of talks, co-ordinated events and ad hoc advising on strategy.
Collaborator Contribution These have largely been around informing priority needs, thereby guiding future research directions.
Impact Specific outcomes include various talks, but there are various in-process outcomes derived from the ad hoc nature of my advisorial role.
Start Year 2014
 
Description Collaboration with Bristol City Council and Resilience Group 
Organisation Bristol City Council
Country United Kingdom 
Sector Public 
PI Contribution I have collaborated with Bristol City Council in a) publicity for the Green Capital; b) attendance at COP21, representing the UK and Bristol; and c) serving on various strategic groups including the city's Resilience Sounding Board.
Collaborator Contribution They have helped raise the profile of the research (i.e. attendance at COP21) and helped identify priority areas.
Impact Many of the talks, events and blogs are related to this activity and noted where appropriate.
Start Year 2014
 
Description Pancost Invited to join the Board of Preventable Surprises 
Organisation Preventable Surprises C.I.C.
Country United Kingdom 
Sector Private 
PI Contribution Preventable Surprises is a CIC that challenges Investors to engage with their invested corporate partners on climate change mitigation and adaptation risks. It avoids politicised approaches like divestment campaigns but instead adopts a cooperative approach with investors to probe risks arising from companies' exposure to, for example, over-reliance on fossil fuels. We do, however, challenge major investment groups on inconsistencies in voting behaviour (i.e. the Missing 60 Campaign which showed how many investors voted inconsistently at corporate AGMs, simply following the company policy, thereby not exercising their fiduciary duty to challenge). I was invited to join the Board in 2015.
Collaborator Contribution The ongoing dialogue with investors, fund managers and colleagues at PS illustrates crucial vulnerabilities in the fiscal sector that informs where greater Earth System understanding is required.
Impact Numerous campaigns - see URL In addition, see commentaries prepared for Pancost in partnership with PS: • http://www.huffingtonpost.com/bill-baue/the-missing-60-exxonmobil_b_10265140.html • https://www.responsible-investor.com/home/article/can_forceful_stewardship_lead_climate_action/ • https://preventablesurprises.com/blog/climate-change-mitigation-or-adaptation/ • http://www.huffingtonpost.com/entry/investors-face-a-choice-trump-or-transition_us_58a6fe4fe4b026a89a7a299e? • https://preventablesurprises.com/blog/a-hierarchy-of-action-for-the-planet/ • http://blueandgreentomorrow.com/reports/guide-sustainable-investment-may-2016/ (Page 29)
Start Year 2015
 
Description Pancost invited to join Board of Trustees of Bristol Zoo 
Organisation Bristol Zoo Gardens
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution On the basis of my expertise, I was invited to join the Board of Trustees of the Zoo, including serving on its Conservation Committee.
Collaborator Contribution I have advised and provided advise on new appointments as appropriate for a Trustee.
Impact None
Start Year 2017
 
Description Pancost invited to serve on Bristol's One City Plan Partnership Board and International Strategy Board 
Organisation Bristol City Council
Country United Kingdom 
Sector Public 
PI Contribution Through these Boards I am helping advise Bristol City Council and the Mayor's Office. This includes advising on sustainability and internationalisation strategy. Most importantly, I am involved with crafting Bristol's One City Plan which will help guide our city through 2050.
Collaborator Contribution These initiatives are central to Bristol's long term planning, of which Sustainability and Climate resilience are central.
Impact N/A
Start Year 2017
 
Description 2017 Public Talks and Arts Exhibits 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact RDP continues to engage the public, with 5 new events/workshops/talks during 2017. These were mainly in the Bristol region.
Year(s) Of Engagement Activity 2017
 
Description Climate change and natural patterns combined to bring wettest winter ever - Blog on The Conversation 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Blog read by over 1200
Year(s) Of Engagement Activity 2014
URL https://theconversation.com/climate-change-and-natural-patterns-combined-to-bring-wettest-winter-eve...
 
Description Living in the Futures Past 
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 Public/other audiences
Results and Impact During 2015-2016, Pancost was interviewed by Susan Kucera on past and future climate change. Those conversations - as well as others - were compiled into the film Living in Futures Past, released at film festivals in early 2018. The film was produced by and stars Jeff Bridges. Info available at: http://www.imdb.com/title/tt7683148/ and http://reneelertzman.com/appearance/living-in-the-futures-past/
Year(s) Of Engagement Activity 2018
URL http://www.imdb.com/title/tt7683148/
 
Description Miscellaneous Blogs Associated with Bristol being the Green Capital and Attending COP21 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact In the lead-up to Bristol serving as the European Green Capital in 2015 and our attendance at COP21, I wrote over 30 blogs. Some were for our Cabot Institute Blog (>5000 visitors per month), the Green Capital Partnership, and the Bristol 2015 Company (which ran the year). The latter included the article framing the entire year, Bridging the Gap, and articles for international visitors and delegations. Many were picked up internationally.
Year(s) Of Engagement Activity 2014,2015,2016
URL https://www.bristol2015.co.uk/news/why-we-must-bridge-gap/
 
Description Public talks 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Deriving from our palaeoclimate research, we have given over 50 talks, science cafes, debates in various venues (mostly but not exclusively local to Bristol). Collectively, these have reached over 5000 people. In many cases, these were discussions/debates with important figures, including Mayor of Bristol George Ferguson, the Bristol Youth Mayors, members of Bristol City Council, our MPs and MEPs.

Much discussion with public, further talks and film screenings arranged, talks blogged about.
Year(s) Of Engagement Activity 2011,2012,2013,2014,2015
URL http://transitionclevedon.wordpress.com/2013/03/14/notes-from-tuesdays-talk-on-climate-change-dr-mar...
 
Description School visits 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Schools
Results and Impact Students visiting the School of Chemistry attended talks on current research, leading to questions and short discussions after the presentations.

The presentations sparked interest in current research in the chemical sciences.
Year(s) Of Engagement Activity 2014
 
Description Studying Earth's distant past can teach us lessons about its climate for the future - Blog Post on The Conversation 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? Yes
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Over 6000 Views

Platform for University of Bristol and Cabot Institute engagement during European Green Capital 2015 activity
Year(s) Of Engagement Activity 2014
URL https://theconversation.com/studying-earths-distant-past-can-teach-us-lessons-about-its-climate-for-...
 
Description The Green and Black Conversation and the The Green and Black Ambassadors 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Third sector organisations
Results and Impact During 2015, the city of Bristol delivered an extensive programme of activity around its role as the European Green Capital, the first British city to win this accolade. Despite numerous activities, the year was widely perceived as failing to crack through the long-standing inclusion issues that affect the city of Bristol and other British core cities as well as much of the global 'green' movement. Given these inclusion concerns, Pancost (on behalf of the University of Bristol Cabot Institute) and the Bristol Green Capital Partnership funded Ujima Radio to continue its Green and Black Programme of activity; we jointly convened a variety of workshops with BME leaders in Bristol, documenting their concerns and learning about how subtle issues had a collective negative impact on inclusion. We found little evidence for active exclusion. Nonetheless, many implicit assumptions and behaviours of that 'in-crowd' - from choosing venues that were perceived as 'off-limits' to last-minute planning - effectively disenfranchised some citizens. This implicit exclusion made it difficult to entrain the alternative voices needed to develop an ongoing dialogue about NERC-derived environmental and climate change research that appeals to, connects to and learns from the experiences of Britain's BME communities. To address this, we created the Green and Black Ambassadors Programme. This programme has several goals, supported by the Cabot Institute, BGCP and the NERC (£22K between all three), but the two that arose directly from connecting diverse communities to NERC research are: 1) Initiating a dialogue with BME communities to identify new and vital research directions, inspired by their concerns, needs, experience and knowledge; and 2) exploring the ways in which environmental research resonates with BME communities, revealing opportunities for stronger, more relevant and more inspiring sharing of our findings. Since its launch, the two Ambassadors have engaged hundreds of citizens in Bristol and thousands more through a monthly radio broadcast on Ujima Radio (NOTE: only some of this directly reflected or was inspired by the NERC research, but it was part of the overall portfolio). In 2016, the programme was awarded NERC Engagement funding as well as further Cabot Institute support which has allowed it to continue into 2018 and allowed it to engage both more audiences but also entrain support from city leaders, including Councillors and Mayor Marvin Rees.
Year(s) Of Engagement Activity 2015,2016,2017
URL http://www.bristol.ac.uk/cabot/research/casestudies/2016/green-black-ambassadors.html
 
Description Why climate 'uncertainty' is no excuse for doing nothing - blog post on The Conversation 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? Yes
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact The blog post attracted nearly 100 comments and over 7000 views

Blog was picked up by several other outlets, including Scientific American and The Ecologist
Year(s) Of Engagement Activity 2014
URL https://theconversation.com/why-climate-uncertainty-is-no-excuse-for-doing-nothing-32924