The bi-polar seesaw and CO2: Is there anything special about 'Terminal seesaw events'?

Lead Research Organisation: University of Cambridge
Department Name: Earth Sciences


A new paradigm has emerged in recent years for explaining late Pleistocene glacial-interglacial climate transitions. According to this paradigm, a clear distinction between mechanisms that operate on 'orbital' and on 'millennial' timescales is no longer made. The slow orbital (insolation) pacing of the ice-ages would thus engender strong positive feedbacks, which could themselves emerge on much shorter timescales. Glacial-interglacial fluctuations in atmospheric CO2 are emblematic of this notion; they clearly make an important contribution to glacial-interglacial radiative forcing, but they appear to accrue through rapid changes that are somehow linked with asymmetric inter-hemispheric climate anomalies (the 'bipolar seessaw'). However, not all rapid changes in atmospheric CO2 are associated with glacial-interglacial transitions. This raises the important question of what has controlled millennial CO2 changes in the past, and what (if anything) is special about deglacial versus mid-glacial CO2 pulses. Current data does not allow us to address these questions adequately. What is needed is a new set of high-resolution reconstructions of Southern Ocean up-welling and deep-water ventilation, which can be linked to the ice-core chronology and thus compared with similarly detailed records of abrupt North Atlantic climate variability. This project sets out to provide these reconstructions, and on thus place our understanding of past millennial CO2 variability on a more robust observational footing than has hitherto been possible.

Planned Impact

The primary non-academic beneficiaries of this work will include educationalists and policy-makers. Benefits will accrue to these stakeholders through new insights into the operation of the climate system and its sensitivity to abrupt perturbations. These insights may ultimately inform on anthropogenic climate change and may help in developing appropriate responses to the challenges that climate change will raise in the medium term. Benefits will also accrue to the wider public through the provision of case studies of past environmental change. Such case studies are particularly useful for engaging with members of the public, and thus fostering public understanding of the science of climate change. Science-society interfaces that are available to us include the Department of Earth Sciences undergraduate-led 'Time Truck' (, the Sedgwick Museum at the University of Cambridge (which attracts over 84,000 visitors per year) and the Cambridge Science Festival ( Through involvement in an art installation project (MUD, by the registered company and charity '30 Bird Productions'), we will also engage directly with primary schools in Cambridgeshire. These science-society interfaces will permit us to engage with a wide range of non-academic beneficiaries, from a range of social backgrounds and age groups. Only by capturing the public imagination through avenues such as these, can real progress be made in fostering greater public understanding of earth system science. Ultimately this can benefit health, well-being, and economic innovation in the UK through long-term influences on the educational and economic choices of our future leaders of industry and future entrepreneurs.


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Roberts J (2016) Evolution of South Atlantic density and chemical stratification across the last deglaciation. in Proceedings of the National Academy of Sciences of the United States of America

Title MUD (Collaboration with Arts Council funded work at local primary school) 
Description MUD encourages people to use the built environment, memories and creative play to explore their sense of place. The project, led by 30 Bird is a partnership with Public Works and St Matthew's Primary School, Cambridge in collaboration with Cambridge University's Department for Earth Sciences and Kier Construction. 
Type Of Art Artwork 
Year Produced 2013 
Impact Increased public awareness and interest in school children, further developments for interaction with school age children at the intersection of art and science. 
Description The research has provided unprecedented new insights into the role of the Southern Ocean as a key locus for changes in climate and carbon cycling. In particular we have provided observations to substantiate the long-standing speculation that changes in the 'ventilation' of the deep ocean, specifically via the Southern high latitudes, have played a key role in driving changes in atmospheric CO2 during the last glaciation and deglaciation. Furthermore, using novel proxy measurements we have been able to tentatively quantify the likely impact of observed ocean ventilation changes on atmospheric CO2. We have also been able to demonstrate the active role in these carbon cycle perturbations of ocean circulation changes originating in the North Atlantic. These were transmitted extremely rapidly to the Southern Hemisphere via oceanic teleconnections primarily, overturning the oft-cited paradigm that ocean circulation-mediated climate changes are necessarily relatively slow. Finally, we have extended all of our analyses to the penultimate glaciation, which demonstrates the contribution of the same mechanisms to millennial carbon cycle change during both of the last two glacial periods.
Exploitation Route Design of further research, combination with numerical climate modelling.
Sectors Other

Description It is not clear that our findings have been useful for any economically aspirational activity; however, our work has been useful in contributing to improving our understanding of the world we live in and sharing that understanding with the public.
First Year Of Impact 2014
Sector Education,Environment,Other
Impact Types Societal

Description MUD Project (primary school art/science intersections) 
Organisation 30 Bird Productions
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution Contribution to design of activity, development of future funding opportunities.
Collaborator Contribution Contribution to design of activity, development of future funding opportunities, leading workshops with school children, design and construction of play polyvalent play structure.
Impact Improved environment for learning at local primary school, ongoing development of engagement activities both between arts/science fields and between professionals and schools and school-age children.
Start Year 2012
Description Open Day for prospective undergraduate students 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact talk sparked interest in studying Earth Sciences and climate at university

none apparent
Year(s) Of Engagement Activity 2013