Positive tipping points for the sustainable growth of shellfish aquaculture

By Dr Lisa Bickley

Shellfish mariculture (the farming of bivalve shellfish – mainly mussels and Pacific oysters) is an important part of the rural economy of England and other devolved nations of the UK. As low trophic aquaculture species, shellfish are a highly sustainable source of protein with high nutritional value. Shellfish can also provide a number of additional ecosystem services, including habitat provisioning, nutrient assimilation and carbon sequestration, and in turn can potentially play a wider role in supporting productive, resilient and ecologically diverse coastal and marine economies.

Sustainable expansion of the shellfish sector is an important component of national strategies within the UK to increase seafood consumption, offering benefits to food security, the environment and human health. Despite these multiple benefits, this growth has not yet been realised.

A recent project, funded by the University of Exeter’s Knowledge Exchange Culture Programme and supported by the Higher Education Funding Council for England, has been examining the application of the Positive Tipping Points Framework developed by the GSI in partnership with the Food and Land Use Coalition (FOLU), for catalysing the sustainable growth of shellfish aquaculture in England and Wales.

The project team (Tom Powell (of the GSI) and Charles Tyler, Ross Brown and Lisa Bickley (of the Centre for Sustainable Aquaculture Futures and Biosciences) recently led a multi-stakeholder workshop to evaluate the positive tipping point approach to identify key opportunities and interventions to unlock future potential of bivalve shellfish mariculture to contribute to sustainable food production in England and Wales.

The workshop was attended by a cross section of participants representing industry, policy, regulatory and academic stakeholders. The workshop focused initially on five case studies from around south west England, covering new policy developments, new risk-based methods for assuring product safety, and new quantitative evidence of both positive and negative interactions between shellfish aquaculture and the environment. Following a review of the accumulating evidence on the current status and constraints of the sector, participants worked together to identify key opportunities and leverage points, interventions and enabling conditions, and optimal sequencing of interventions for maximising the potential for positive change.

The resulting report and policy brief (in preparation) will be publicly available and circulated to regulators, statutory authorities and consultees, industry bodies, water companies, watchdogs and academics.

It is hoped this work will provide a template for applying the positive tipping points approach to other food productions systems, including other aquaculture sectors.

Workshop participants, Reed Hall, University of Exeter 15 September 2022. Photo courtesy of Ross Brown.

‘The Territory’ film screening and panel Q&A, Exeter Phoenix 30 November

My perspective – blog by Katie Milsom, first year Astrophysics PhD student

The Territory’s title scene for the movie shows a satellite image of the Amazon rainforest in Brazil. There are scars across the landscape where humans have created roads through the forest. The scars expand as we watch, the forest shrinking as trees make way for farmland. I find myself wishing for it to stop. I feel helpless; there are people out there who are making the decision for the rest of humanity to destroy this rainforest.

The movie follows the lives of the Uru-eu-wau-wau people who live in the rainforest. Their love of the forest is infectious – I find myself wanting to swim in its rivers and lie under the canopy. As the movie progresses, we learn more about their lives in the forest, but also their connections with each other and people in the outside world. They know the politics involved in keeping the forest safe and they understand how important the Amazon is to every country across the world.

We also see the perspectives of the people wanting to cut the forest down. For me, it was difficult watching them burn the forest, and saw down huge trees which have been standing for years. The Amazon stores so much carbon for us. We need this rainforest. There are 3 million species living in the Amazon. It feels precious, like a gift from the Earth that we have no right to destroy.

Watching the destruction on the forest was heart breaking, I could feel the melancholy with every tree struck down. Seeing the Uru-eu-wau-wau people work tirelessly to protect it was inspiring, a balm to my sadness. They are a symbol of hope for the amazon. Between the panel of experts showcased at this event, the Brazilian peoples who don’t live in the forest but care deeply about it, it strikes me there are enough people out there who care, and that we are equipped to do something about this. Just as we need the Amazon to protect our environment, the Amazon needs us to protect it.

‘The Territory’ film screening and panel Q&A, Exeter Phoenix 30 November

Blog by event organiser: Michelle Fabienne Bieger, fourth year Astrophysics PhD student

The Territory is a film that seeps into your consciousness, lingering in the chill of your bones. The authenticity of any media can always be measured by how closely your memory of it, after first viewing, matches your impressions of it after the second. Rewatching it (https://3degreesreading.github.io/books/theterritory.html) honed my impression of how the film was crafted, but my core feelings and memory of the story it at hand was unwavering, and indeed, perhaps even stronger.

It’s hard to find anyone who watches The Territory and comes away emotionally untouched. The cinematography flickers between delicate and brutal, reflecting the Amazon and its relationship to man in doing so. It always invites the viewer to place themselves unjudgementally in the shoes of whoever’s perspective we are gracefully occupying.

It felt easy to organise a panel for this event—the film laid out the threads of the issues at the heart of deforestation deceptively clearly. There are political and economic motivations—the deep recession of 2014 in Brazil was a strong factor in the election of populist Bolsonaro in 2018, who’s charisma and neighbour-next-door attitude won a victory reminiscent of Trump in 2016 in the United States.

There are the cultural motivations—farmers, who have been promised land rights by social and religious contract; tribe members, who have had a connection to their home and showcase these ties by the mere ease in which they pass through dense forest. There is, of course, the science behind it all, looming in the background, spelled out by one of the main characters, Bitate. The Amazon is the heart of the world, he says. No Amazon, no CO2 scrubbing, no liveable global climate.

I am so grateful to have heard from our panel members. Richard and Lucy laid out so clearly what’s at stake, in terms of the climate science.  Lucy and her family’s personal experiences seeing the diminishing Amazon rainforest riveted the audience.

Malcolm reminded us of the fact that the story behind this is bigger than just one tribe, bigger than just Brazil: the Amazon spans many Latin and South American countries. The consequences to the people involved are so very real, not just because of losing land, but because standing up to human rights infringements is dangerous to one’s own personal safety when going up against conglomerates and governments.

Chendi did a stupendous job laying out the difficulties that lie in holding corporations and countries to account—and that there is a distinct difference between creating regulation, and what it takes to actually enforce it. Monitoring data is desperately needed in order to fill in the gaps for sustainable finance. Chendi also did a fantastic job of showcasing how complicated and complex these problems are—sustainable regulations in one country in the Global North can create unsustainable knock-on effects in the Global South.

The audience members also deserve heaps of accolade; they helped make this the community event that I hoped for. It was a shame the panel section couldn’t go on any longer, as we were just getting into very meaty audience questions. I look forward to organising future film events and welcome any feedback from attendees.

A year with the Global Systems Institute

By Darcy Howle, GSI Student Intern 2021-2022

It is coming to the end of my year long placement at the Global Systems Institute (GSI) and I wanted to reflect on my experience of what a fantastic year it has been.

Although there is a sense of hopelessness when it coming to the unscalable issue of sustainability, the academics, and other members of the GSI remain positive at their outlook on the future. Working for the GSI has given me a glimpse of how academics are able to collaborate with artists, social scientist, policy makers, the community and other stake holders to create and implement solutions on a regional and global scale. It is remarkable to watch projects such as Global Carbon Budget Office, OPALS and the GSI policy network develop over the course of my year placement.

The concept of systems thinking, a focus of the GSI, has really opened my eyes to the importance of transdisciplinary research. It is the idea that all things are interconnected therefore to solve an issue sustainably all aspects of the system involved need to be considered. Moving forward, I aim to implement this this concept into my future work.

I thoroughly enjoyed my time working with the wildfire lab. It exposed me to an area of research that I hadn’t experience before. Working towards a tailored UK fire danger rating system built on my previous lab and fieldwork experience.

Over the course of COP26, the GSI received great media coverage and I was given the opportunity to help with the campaign.  This showed me how important it is to communicate with the public and share our research to create the greatest impact possible. By doing this more people will act against the climate crisis and help secure a flourishing future.

I want to thank the members of the GSI for being friendly and welcoming to me. I was fortunate enough to be given the responsibility of organising the 3-day GSI Retreat where I was able to meet the 50 core members of the GSI community. Everyone was open to listen to my ideas and input despite how new I was to the team and how early I am on my academic journey. In particular, I want to thank Andy Richards and Anne Nicholls who I have worked closely with over the past year and have made my experience so positive.

GSI Workshop: Exploring synergies between Earth sciences and astronomy

Blog by workshop convenor, Dr Raphaëlle Haywood

The GSI Workshop: Exploring synergies between Earth sciences and astronomy took place on 18 February 2022, bringing together around 40 academics from a wide range of disciplines, both in person and online. Prof. Tim Lenton talked about Exo-Earth system science at Exeter. He emphasized that we need to get the message out that planets beyond the solar system are being discovered. Tim discussed what life might look like on exoplanets and our prospects for detecting it. Simple life emerged on Earth as soon as conditions were favourable, so we can expect it to have evolved on many other planets. Tim argued that “life is not a passive actor set on a stage”; it completely transforms its planet, so we should be able to detect biosignatures  on exoplanets in coming decades (notably with upcoming direct-imaging missions). On the other hand, complex life, including ourselves, results from some very difficult and improbable transformations, so it is unlikely to exist elsewhere.

The Pale Blue Dot was a recurring theme throughout the Workshop. Prof. Tim Lenton pondered: “[We are] thinking about how common life is. Is it going to touch us emotionally in a way that allows us to reflect back on our own presence and existence on Earth, [and will this help us] alter our relationship with Earth?” (slide by Prof. Tim Lenton).

Jake Eager talked about his ongoing PhD work Towards coupled modelling of the biosphere and atmosphere for Archean-like climates. Jake focuses on terrestrial planets that orbit small, cool M dwarf stars. These are the most common stars in our galaxy, and have long lifetimes, which could give life more time to emerge. If life exists on these exoplanets, it might resemble life that existed on Earth during the Archean (about 3 billion years ago) more closely than present-day life. Jake is using the Met Office’s Unified Model for Archean Earth to estimate methane concentrations for these planets. Jake’s work shows that by modelling the atmosphere and biosphere together, we can ultimately improve our understanding of both.

Dr Arwen Nicholson talked about Biosignatures independent of population dynamics. Arwen has created a simple model based on an Archean Earth-like planet that considers air-ocean exchange, carbon-silicate cycling and a very simple biosphere in the form of microbes which produce methane, which then acts as a strong biosignature for the planet. By varying the death rate of microbes, Arwen finds that the concentration of methane in the atmopshere, and thus the planet’s biosignature are relatively insensitive to the detailed properties of the biota.

Prof. Tim Naylor presented the Terra Hunting Experiment, of which Exeter is a major partner. Terra Hunting is the world’s most viable experiment to discover terrestrial, temperate planets orbiting stars like our Sun within the coming decade. For this, Terra Hunting will measure the wobble of 30 stars, on every observable night over 10 years. Based on the occurence rate of these planets (as measured by recent surveys such as Kepler), we expect to discover a handful of planets with similar mass and stellar irradiation as Earth. These planets will be prime targets for direct imaging in the next 20-30 years.

The majority of in-person participants mingled at tea and coffee after the talks (which are available to watch on the GSI’s Youtube playlist). Stay tuned for more talks and opportunities to discuss this exciting topic in future events! Please get in touch with  if you have any ideas and suggestions.

The Climate Change, Conflict and Migration Nexus: Through the Lens of the Syrian Civil War

Blog by Tabitha Watson

Over the past few decades, there has been increasing conversation – and significant news coverage – linking climate change, conflict and migration. However, analysis of the topic remains largely qualitative and anecdotal in nature. This lack of quantitative data makes the development of robust, evidence-based policy challenging, leading to the growth of more reactionary approaches (e.g. securitisation of migration). In this context, with growing nationalism and xenophobia, it is vital to gain a more nuanced, data-driven perspective on the situation. This is where the concept of whole-system analysis of the climate change, conflict and migration nexus comes into play.

Although all three aspects of the nexus have been conclusively linked, the majority of quantitative studies have tended to address pairwise interactions. There is vibrant academic debate over the role of climate; its role in both conflict and migration has been disputed. However, regardless of the current perceived significance of the global climate, without drastic mitigatory action we are projected to vastly exceed the 2C threshold set out in the Paris Agreement. This will have severe consequences for large swathes of the population, and there are likely to be knock-on effects that ripple across society. It is, therefore, important to consider the ways in which this could impact both mobility and security.

In some spheres, the ongoing Syrian civil war is considered to be one of the first climate-affiliated conflicts. To unpack this, and the controversy around it, it is important to delve a little into the context. Historically, Syria has been relatively fertile and agriculturally productive. However, since the 1980s, it has experienced three severe droughts. The most recent of these, starting in 2006/7, has been recorded as the worst in 900 years. As an exacerbating factor, this drought came on the heels of a deep and long-term agrarian crisis; this had been brewing for decades as the Syrian regime pursued an agrarian development plan which relied on the super-exploitation of water resources, especially groundwater. Groundwater extraction, in turn, relied on the availability of cheap diesel – kept that way by massive government subsidies.

For a variety of reasons, Assad chose to remove these subsidies in 2008/9. This caused the price of diesel to rocket up by over 300%, rendering vast areas of land unviable and causing the displacement of at least 1.5 million people from rural to urban areas. The infrastructure in cities and towns was already sub-par, and it has been argued that the influx of the rural population caused some degree of tension on top of pre-existing ethnic fractures and tensions within Syrian society.

So, with the scene in Syria set with drought, loss of livelihood, mass displacement,  creaking national infrastructure and a general undercurrent of discontent, the Arab Spring began rippling out from Tunisia across the Middle East. In March 2011, pro-democracy protests in Syria were crushed with deadly force. This sparked further protests and, as we know, spiralled into the ongoing conflict. As various factions became involved and the fighting intensified, people began to flee and seek refuge. This has been framed by Western media as a migration ‘crisis’. Here, we see the contested link between climate and conflict snowball into conflict leading to migration. This can then be seen to lead to a different type of, largely ideological, conflict in the destination countries.

However, the presence of a climate signal in the outbreak of civil war in Syria is disputed. Geopolitical events have muddied the water; this is especially sensitive in this case, as the Assad regime have sought to push the climate-conflict narrative in order to absolve themselves of the blame for fomenting the catastrophic agrarian crisis that preceded the drought. Some commentators have also pointed out that neighbouring countries experienced a similar lack of precipitation but did not topple into civil conflict. Therefore, there must have been some Syria-specific factors. However, neither of these arguments are mutually exclusive of a climate signal.

It is important to note that those who argue that there is a climate signal are not stating that climate change is a primary cause of the conflict, rather, that the presence of the drought exacerbated existing conflict precursors and ‘oiled the wheels’, causing the conflict state to occur faster than it may otherwise have done. The question, for both sides, is: would the agrarian crisis alone have been sufficient to trigger the civil war?

To answer this, modelling the climate change, conflict and migration nexus as a complex system is the next logical step. It will allow for the identification of emergent properties, such as a conflict, from the combination of social, environmental and political variables. A vehicle for complex systems analysis is agent-based modelling. Here, the system is made up by a set of agents, each with bounded free will. By programming these agents with relevant parameters, it should be possible to gain a bottom-up perspective of human behaviour under different conditions and scenarios. Through this, it should be possible to elucidate the significance of each factor within the climate change, conflict and migration nexus in relation to each other.

GSI Seminar Series: Dr Raphaelle D. Haywood – There’s no place like home: Placing Earth in its astronomical and geological contexts

Blog written by Daneen Cowling

A new year and a new set of interesting seminars!

The first of 2022 was from Dr Raphaëlle Haywood, a Senior Lecturer in Physics and Astronomy at the University of Exeter. Dr Haywood gave an immense talk covering the hunt for exoplanets, how we find another Earth-like planet, and shared some important insights into why we should not assume there is a planet B.


On a finite world, a cosmic perspective is not a luxury, it’s a necessity

Caleb A. Scharf, 2014

Dr Haywood began with thought-provoking set of quotes and statistics that brought home the importance of why we need to have this astronomical view and appreciation of our position within it. To realise – like our humble blue planet – the existence of planets orbiting other stars is extremely common.

Particularly important – the occurrence of “Earth-like planets” are also common, potentially between 9-21% of suns have a planet like Earth. But what is a planet like Earth?

An Earth-like planet is similar to us in size – around a 1/2 to 1 radius of Earth. But importantly, it also sits within the habitable zone. This means it is a suitable distance from it’s sun to allow for 30-100% of heat received on Earth to permit liquid water.

Dr Haywood estimated that there could be 63 BILLION temperate Earth size planets in our galaxy.


How to find other Earths

Find Earth-like planets goes far beyond it’s size and sun distance – we have tools that help us find the signatures of Earth – of life.

Earth is a complex self-regulating system composed of interacting systems of the planets rocks, atmosphere, ocean and biosphere. We can use the biosphere and the signatures it produces to help in our exploration. But what does this look like?

Key components of our biosphere can be identified through their signature wavelengths. through the reflectance signatures, we can identify:

  • Water and Water Vapour
  • Oxygen and Methane – this tells us there is a chemical disequilibrium and therefore there is life, as oxygen and methane are the bi-products
  • Near-Infared (NIR) “red-edge” – a sharp rise at around 700nm on the reflectance spectrum tells us there is a prevalence of vegetation

This means, using these signatures and tools we can understand what might be on another planet.

This is an exciting time for planet search and discovery – as from this year (2022) a new TerraHunting project will kick off a 10-year survey of 40 sun-like stars, to explore the planets and their resemblance to Earth. From this project and the huge dataset it will create, NASA plan to use this data to strategically begin a direct-imaging project, able to measure actual temperatures and investigate the prevalence of atmosphere on these potential Earth-like planets, and ultimately contribute great strides to the search for extra-terrestrial life!


No Planet B

As exciting as finding another planet with life on, Dr Haywood set it straight that regardless, there is no planet B. Even if we wanted to set up camp on another planet, the distances involved are way beyond our technological capacities – our nearest Earth-like planet is 300 years away at the speed of light. Even our Mars neighbour is out of our technological capability to transform into a habitable planet for humans.

Dr Haywood then went onto remind us that our planet, through its geological history, has never been the same state – it has consistently shifted into new versions of itself. Even human civilisations have shifted the planet trajectory of Earth – in its appearance and its observable signatures from space. Our current state of Earth has electromagnetic signatures, masses of waste, chemical signatures in our atmosphere – but what would an Earth signature look like it if it was inhabited by only indigenous communities? Communities that are able to live harmoniously with the Earth and the complex systems that regulate it. Maybe, this sustainable way of life isn’t even detectable? What’s to say other occurrences of life won’t be living so sustainable they are undetectable?

Lots of questions and exciting developments taken to get closer to answer them will make the next decades of planetary exploration an exciting one.


To learn more about Dr Haywood’s work, see her profile here.

If you’re a member of staff or student of the University of Exeter, feel free to join a mini-module called “No Place Like Home”: https://vle.exeter.ac.uk/course/view.php?id=13080

It was created by Dr Arwen Nicholson, Federica Rescigno and Dr Haywood as part of last year’s Summer School on Sustainability that was organised by CEMPS.

To view the full seminar, you can watch the recording here.

For more GSI events, stay up to date on the GSI website.

GSI Seminar Series: Prof. Patrick Devine Wright – Are local climate emergency declarations leading to transformation in the politics of climate change?

Blog post by Daneen Cowling

On 17/11/2021 Professor Patrick Devine-Wright, Dr Fionnguala Sherry-Brennan and Dr Alice Moseley, gave a seminar discussing whether local climate emergency declarations are followed by a transformation in the politics and solutions around climate change. Professor Devine-Wright, Dr Fionnguala Sherry-Brennan and Dr Alice Moseley gave a valuable insight into the planning, structure and outcomes of the first climate change citizen assembly in Devon to inform the Carbon Plan. The seminar was met with a lively discussion and positive messages to end on.


We were first introduced to the structure of the climate emergency and Devon Net Zero Task Force organisation at Devon Council, and how this filtered into the Carbon Plan. The citizen Assembly was then discussed, with the risks that come with hosting such a discussion. Deliberations and an interim Carbon Plan brought out before the assembly due to covid, meant topics for the assembly were reduced from 6 to 3, resulting in:

  • Oneshore wind
  • Roads and Mobility
  • Retrofitting

Food and diet was one of the topics dropped from the final decision to run 3. From this followed discussion in the chat around the importance for this topic in Devon, given the extensive farming presence in the county and the carbon footprint it carries. Explanations and discussions were shared in the Q&A, viewable here.

With context given to the question framing and speaker selections, the outcomes of the assembly were outlined. Although anticipated to be largely rejected, onshore wind as a net zero resolution was supported by 89% participants. While resolutions provided for mobility such as increased parking charges and workplace parking levies, were largely rejected. This is likely a representation of the relatively greater reliance on private transport in rural Devon, where public transport is not sufficient to be an appropriate alternative.

It was clear the citizens assembly was a useful tool to provide a platform to voices representative of rurality, which usually go unrecognised. However, there still remains complexities to contend with for the value and effectiveness of the assembly. For example, the value can be relative for different participants – stakeholders may hold more value to the solutions whereas the citizens involved might value the space to discuss issues affecting them, more.

It was also interesting to consider the key concept of place from the outcomes of the assembly. What is Devon? What inequalities are there to consider and contend with for these discussions? Where does trust lie in communities and how does this alter decisions? Centring thinking around Devon as a place helps contextualise the rejection to such mobility suggestions, and (hopefully) will result in a fairer acknowledgement of these inequalities across the county and avoid a blanket urban-centric solution.


To watch the full seminar as well as the discussion after, please click here.

The interim Devon Carbon Plan can be found here.

All Devon Climate Emergency information can be found here.

Voices of the Dart – hearing and helping our water bodies

A September workshop activity by Darcy Howle (GSI Intern) and John Bruun (GSI SDG Zero Hunger theme lead). Blog post by John

We can view the Dart as a form of living entity that many people share and benefit from. The Dart, one of our local rivers flows from its upland Dartmoor catchment, and as it gathers momentum travels down and past the wood and grassy landscapes, local villages and towns and joining the sea at Dartmouth. In recent years the land is getting drier, climatic we think. Since 2015 water has been extracted from the river to irrigate the land, which had not been needed before. There is a deep concern about how we can adapt to these changes.  The Bioregional learning centre, a South Devon Community Interest Company have convened a generic conversation to identify the Voice of the Dart. In September groups from GSI, Tidelines, South West Water, Soundart Radio, Westcountry Rivers Trust, the Environment Agency, the Bioregional learning centre (host) as well as artists and film makers, gathered for a workshop next to the river in Dartington: the start of a six month activity. A few from GSI joined: Darcy Howle found: ‘The artistic approach to viewing water was really eye opening. The mindfulness approach heightened your senses and made you experience aspects of the Dart that we take for granted.’ We all participated through walking 1-1 meetings down to the river, then group ideas sharing both at the river, later around a fire and a river story board. The emphasis was on active listening to one another, enabling formation of creative sharing ideas for the science and art. In essence the goal of finding the Voice of the Dart (and indeed any river) is to help save and share our water resources more effectively with this art and science fusion showing the importance of water in people’s lives – we heard the feeling of hope.

One of the workshop feedback activity sessions – where we all found these mushrooms living in a tree next to the river; experiencing the river (John Bruun): with sound, its living smell’s and touch.