Timing, Causes and Consequences of the Decline in Pliocene pCO2

Lead Research Organisation: University of Bristol
Department Name: Chemistry

Abstract

Human activity has led to an increase in atmospheric carbon dioxide levels from 275 to 285 parts per million (ppm) in preindustrial times to >380 ppm today. This greenhouse gas contributes more to the human-induced warming of the planet than any other gas. Therefore, understanding the relationship between carbon dioxide and climate is a major research focus of Earth Scientists predicting future climate change. Although General Circulation Models are the primary tool by which we anticipate future change, they remain imperfect tools that require validations. Therefore, the study of ancient climate is now an integral part in informing policy makers on climate change issues. If climate models successfully reproduce large scale climate changes that occurred in the past, this will give us more confidence in their prediction for the future. The most informative analogues will be in the recent geological past where geographical configurations, ocean currents and ecosystems are similar to today. The Mid-Pliocene (about 3.3 to 3.0 Ma) is the most recent time in Earth's history when mean global temperatures were substantially warmer and sea levels much higher than they are today. Immediately following this period of comparative warmth, the Earth cooled dramatically and ice sheets grew: the modern ice sheet on Greenland is testament to our current 'icehouse' climate. A reduction in the concentration of CO2 is widely believed to be the cause of this critical climate transition, yet this understanding depends on knowing exactly what atmospheric CO2 concentrations were in the Pliocene, how they changed and how those changes impacted the climate. However, this is currently based on a few extremely low resolution and limited studies. Therefore, we propose to determine Pliocene CO2 concentrations with particular emphasis on determining the timing of its decrease with respect to the glaciation of the northern hemisphere. This will involve revised estimates of CO2 concentrations and globally widespread estimates of sea surface temperature, environmental parameters that cannot be directly determined for the past. We will study the fossil remains of sea-dwelling microscopic organisms, the foraminifers and coccolithophorids. These organisms are very abundant in the mud on the floor of the oceans, providing an invaluable archive of past ocean climate data, and by looking at the chemical composition of their shells or the organic compounds they biosynthesise we can determine how warm or how acidic the ocean was. And from such parameters, we can also deduce how much CO2 was in their environment. We will use several complementary approaches to determine CO2 concentrations, including the boron isotopic composition of foraminifera and the carbon isotopic composition of organic compounds. Methodological advances have only recently made such a multi disciplinary approach possible. Armed with this improved understanding of the evolution of CO2 in the atmosphere over the last ~3 million years, we will determine what natural processes resulted in changing its concentration. We will initially compare the timings of CO2 change to tectonic events such as the closure of the Indonesian Seaway and changes in global ice volume to examine a) what might have triggered the decrease in carbon dioxide, and b) if that truly was the main driver of global cooling and the expansion of the great northern hemisphere ice sheets observed at that time. Finally, we will test those ideas using climate models. First, we will use a coupled ocean-atmosphere model to test whether the magnitude and timing of carbon dioxide change is consistent with associated cooling. Second, we will couple that model to a model of the carbon cycle to test if positive feedbacks during global cooling played an important role in carbon dioxide removal from the atmosphere.

Publications

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Badger MP (2013) High-resolution alkenone palaeobarometry indicates relatively stable pCO(2) during the Pliocene (3.3-2.8 Ma). in Philosophical transactions. Series A, Mathematical, physical, and engineering sciences

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Bragg F (2012) Mid-Pliocene climate modelled using the UK Hadley Centre Model: PlioMIP Experiments 1 and 2 in Geoscientific Model Development Discussions

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Davis C (2013) Calcification response to climate change in the Pliocene? in Biogeosciences Discussions

 
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 We have continued to refine both the boron isotope and algal carbon isotope based pCO2 proxies, improving analyses and better constraining other variables. This work is now at the forefront of understanding both, setting the pace for application of the boron-based pCO2 approach but revealing deficiencies in the algal carbon isotope proxy that has inspired a suite of new investigations.

Our ongoing work reveals broad agreement between two distinct proxies for Pliocene pCO2 - and climate models - confirming that it has been 3 million years since the Earth last experienced 400 ppm pCO2 and that it was the decline in pCO2 that ultimately triggered the strong glacial cycles of the Pleistocene.

Despite broad agreement, the two approaches do differ in important respects. In particular, the algal isotope based barometer suggests that Pliocene glacials were characterised by minor CO2 change. The boron isotope approach suggests larger variations, comparable to those of the Pleistocene. We have resolved this by testing the proxies against Pleistocene glacial-interglacial cycles and the ice core record, which reveal a muted sensitivity for the algal pCO2 proxy. This potentially resolves discrepancies seen during earlier time intervals.
Exploitation Route Developing collaborations with renewable energy sector: Our results highlight the important role of atmospheric carbon dioxide as a climate driver, emphasising the need to move to a carbon neutral economy.
Sectors Energy,Environment

 
Description This project has had two major findings that are now integral cornerstones in the climate change dialogue. First, this work represents the strongest evidence that pCO2 has not been above the symbolic - and recently exceeded - milestone value of 400 ppm for about 3 million years. Second, it shows that climate sensitivity was broadly consistent between the cooler Pleistocene glacials and the warmer Pliocene - and that these ancient estimates of climate sensitivity are broadly consistent with climate models. The work also continues to be a benchmark for the discipline, as this research team continues to be the only one applying diverse pCO2 proxies to the same samples. Given these findings of wide societal interest, we have used this grant as a platform for extensive public engagement, including numerous public lectures, an international workshop on the Pliocene, an article for science education, a video for public dissemination and a blog post on the Conversation (that was viewed by over 5000 and that was subsequently picked up by over 20 other outlets). Subsequent, high impact papers in Nature led to media coverage, for example the BBC and the profile of the work contributed to Pancost's invitations to join several major Bristol and national climate change related initiatives, including advising Bristol City Council during the Green Capital Year (and accompanying the Mayor and BCC to COP21), serving on the Rockefeller Foundation supported (100 Resilient Cities) Resilience Sounding Board that was also charged with drafting a framework for the city's 50 Year Trajectory, and being invited to join Preventable Surprises. Crucially, the reflections informed by a palaeoclimate perspective - integrated with an understanding of contemporary and future climate change impacts - influenced Bristol's strategic thinking across multiple sectors, including for example, smart city technology and communities.
First Year Of Impact 2015
Sector Communities and Social Services/Policy,Digital/Communication/Information Technologies (including Software),Environment,Financial Services, and Management Consultancy,Culture, Heritage, Museums and Collections
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
 
Title Badger 2013 dataset 
Description Dataset from Badger et al 2013 
Type Of Material Database/Collection of data 
Year Produced 2014 
Provided To Others? Yes  
Impact Publicly available dataset 
URL http://doi.pangaea.de/10.1594/PANGAEA.836116
 
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 Crucial new information about how the ice ages came about: Press Release and a Radio Interview 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Radio interview, blog post and press release

Increased visibility of publication, and disseminated results to wide public audience.
Year(s) Of Engagement Activity 2014
URL http://descentintotheicehouse.org.uk/crucial-new-information-about-how-the-ice-ages-came-about-press...
 
Description Scientists on the Road travel to Science Festivals 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact stimulated the imagination of the young students and during the lively discussion afterwards they were able to offer us some out of box thinking and we came up with some rather pioneering ideas and innovative solutions of how to combat ocean acidification.

n/a
Year(s) Of Engagement Activity 2013
URL http://descentintotheicehouse.org.uk/scientists-on-the-road-travel-to-science-festivals/
 
Description When was CO2 last at 400 ppm? And what was the climate like? 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Sparked discussion in the scientific community and beyond

Increased relevance of Pliocene research to 400 ppm crossing.
Year(s) Of Engagement Activity 2013
URL http://descentintotheicehouse.org.uk/when-was-co2-last-at-400-ppm-and-what-was-the-climate-like/
 
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 Barcelona Pliocene Workshop 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Identified areas of future research collaboration and outstanding fundamental questions. GL Foster was co-organizer.

n/a
Year(s) Of Engagement Activity 2014
URL http://jornades.uab.cat/plioclim/
 
Description Chasing Ice with the All Party Parliamentary Climate Change Group 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact Visit to parliament engaged with policymakers and blog post spurred discussion

n/a
Year(s) Of Engagement Activity 2013
URL http://cabot-institute.blogspot.co.uk/2013/03/chasing-ice-with-all-party.html
 
Description Haug Cabot Institute lecture 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Public lecture with youtube video

n/a
Year(s) Of Engagement Activity 2010
URL https://www.youtube.com/watch?v=Y2cYzqd1rG0
 
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 Pliocene workshop video 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Video on Pliocene science on Youtube

High views
Year(s) Of Engagement Activity 2010
URL http://www.youtube.com/watch?v=KpLvPT5a6jg
 
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
 
Description Why the Pliocene period is important in the upcoming IPCC report 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Increased visibility of publication and spurred debate

n/a
Year(s) Of Engagement Activity 2013
URL http://cabot-institute.blogspot.co.uk/2013/09/why-pliocene-period-is-important-in.html