Food Security – Cabot Institute for the Environment blog

Peatlands urgently need to be restored for UK to meet emissions targets

Posted on December 3, 2024 by amanda.woodman-hardy

The headline goal of the UK’s peatland strategy – a framework published by the International Union for Conservation of Nature (IUCN) that sets out how to improve UK peatlands – is simple, yet ambitious. The aim is for 20,000km² (2 million hectares) of UK peatland to be kept in good condition, restored or sustainably managed by 2040.

Yet, with approximately 30,000km² (3 million hectares) of these soggy ecosystems forming a complex mosaic across the UK’s four nations, 80% of it in poor condition, this is a monumental task. Five years after its launch in 2018, the experts behind the IUCN’s UK peatland programme have been reflecting on the progress.

Peat forms where wet and oxygen-limited soil conditions slow the decay of dead vegetation. This builds up over thousands of years leading to thick accumulations of organic matter, or peat. Given the continuing climate emergency, it is imperative that the carbon this contains is kept in the ground and out of the atmosphere where it will contribute to climate change.

However, land use practices over the last century have deeply drained the UK’s peatlands, destroying the waterlogged and oxygen-free conditions that preserve them and releasing the equivalent of 20 million tonnes of CO₂ each year.

Peat restoration is an important nature-based solution that can mitigate climate change and will be an essential part of reaching the UK’s legally binding emissions targets.

By restoring the UK’s peatlands, we avoid further emissions and, in time, convert them back into carbon sinks. Not only that, peatland restoration restores important functions of the ecosystem that help to reduce flood risk, clean water and improve biodiversity.

There are some reasons for optimism. Peat restoration began in the 1990s but has been rapidly accelerating in the last decade, largely focusing on raising water tables to restore low-oxygen conditions.

Around 2,550km² (255,000 hectares) of restoration have been completed. Despite problems in collating reliable data, a preliminary milestone of “1 million hectares in good condition by 2020” has probably been achieved. However, this number includes the best peatlands, which had never been extremely degraded and required little intervention.

Peatlands are finally being recognised in policy. Scotland, England and Wales all now have national peatland strategies that drive restoration of each unique landscape. And progress has been made in legislating against the effect of peat burning, with all burning on deep peat banned in England since 2021 and unlicensed burning on Scottish peatlands set to be implemented from 2025.

The peatlands of Scotland’s Flow Country, the world’s largest and most intact expanse of blanket bog, was recently designated a Unesco world heritage site.

peat cut on peatland, left out to dry — Peat turf cut and left to dry on a wetland in the Scottish Highlands.
DrimaFilm/Shutterstock

The way that peatland landscapes are being managed is advancing too. Paludiculture, a way of farming that allows groundwater to remain near the surface, has been a success in Europe and recent trials have shown promise in the UK.

This wetter farming could produce sustainable construction materials and biofuels with crops like bulrushes or reeds and wetland food crops like cranberry, celery and watercress. It could help convert intensive grasslands to wet meadows that can be grazed by carefully chosen breeds of cows or even water buffalo.

Although not ready to be widely implemented, recent trials suggest that this could be key to UK land management in the future.

Despite all this attention, there has been limited progress towards most key areas of the peatland strategy, with both conservation of the best peatlands and restoration of the others falling well below target levels. Indeed, the UK government’s climate change committee consider progress to be “significantly off-track”.

In this latest report, the IUCN UK peatland team says: “The progress we talk about in our report has been made across the whole of the UK since the 1990s.” Scotland, for example, needs to complete as much restoration in only ten years as they have in the last 30. They have scaled up – just nowhere near enough.

Shortfalls and long-term goals

So why, with all this effort and goodwill, are we still falling short? Funding is a problem.

It is widely accepted that public funding will not deliver the estimated £8-22 billion needed to restore all peatlands, but private financing schemes like carbon credits are in their infancy.

There are still no universally agreed definitions of either “peatland” or “restoration”, so eligibility for the various environmental schemes that allow landowners to fund restoration is confusing and off-putting.

Even where restoration can overcome these limitations, there is no centralised way to record the progress in transforming peatlands and very little capacity for the long-term monitoring needed to show whether particular projects are being successful. So tracking progress is near impossible.

Most frustratingly, despite collectively investing £318 million in peat restoration projects, no government has banned the extraction of peat and the long-promised ban on peat sales for horticulture has not materialised anywhere in the UK.

Although progress has been slow, the capacity and knowledge built over these last five years is huge. There has never been such awareness of a need to protect and restore our peatlands, so many people available with the right skills to do it and so much political will and public or private funding to carry it out.

There are many reasons progress has been slow but, with the right funding and legislation, the progress made in the last five years can be accelerated and two million hectares of healthy UK peat may still be possible by 2040.

Now that the UN’s climate summit, Cop29 in Azerbaijan, is over, it is clearer than ever that almost every peat-containing nation in the world is grappling with the same trade-offs. Just as we are debating how to raise water tables in Somerset without ending hundreds of years of dairy farming, south-east Asian countries struggle to reduce emissions from their vast regions of degraded agricultural peatland while still sustaining populations with enormous requirements for rice.

Keeping peat in wet ground, from Scottish peat bogs to the rice paddies of China, is one of the most cost-effective ways of keeping greenhouse gas emissions down, and we need to preserve and restore as much of it as possible.

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This blog is written by Cabot Institute for the Environment member, Dr Casey Bryce, Senior Lecturer, School of Earth Sciences, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Casey Bryce

Tiny oceanic plankton adapted to warming during the last ice age, but probably won’t survive future climate change – new study

Posted on December 2, 2024 by amanda.woodman-hardy

Global temperature records are expected to exceed the 1.5 °C threshold for the first time this year. This has happened much sooner than predicted. So can life on the planet adapt quickly enough?

In our new research, published today in Nature, we explored the ability of tiny marine organisms called plankton to adapt to global warming. Our conclusion: some plankton are less able to adapt now than they were in the past.

Plankton live in the top few metres of ocean. These algae (phytoplankton) and animals (zooplankton) are transported by ocean currents as they do not actively swim.

Climate change is increasing the frequency of heatwaves in the sea. But predicting the future effects of climate change is difficult because some projections depend on ocean physics and chemistry, while others consider the effects on ecosystems and their services.

Some data suggest that current climate change have already altered the marine plankton dramatically. Models project a shift of plankton towards both poles (where ocean temperatures are cooler), and losses to zooplankton in the tropics but might not predict the patterns we see in data. Satellite data for plankton biomass are still too short term to determine trends through time.

To overcome these problems, we have compared how plankton responded to past environmental change and modelled how they could respond to future climate changes. As the scientist Charles Lyell said, “the past is the key to the present”.

We explored one of the best fossil records from a group of marine plankton with hard shells called Foraminifera. This comprehensive database of current and past distributions, compiled by researchers at the University of Bremen, has been collected by hundreds of scientists from the seafloor across the globe since the 1960s. We compared data from the last ice age, around 21,000 years ago, and modern records to see what happened when the world has previously warmed.

We used computational models, which combine climate trends with traits of marine plankton and their effect on marine plankton, to simulate the oceanic ecosystems from the last ice age to the pre-industrial age. Comparing the model with the data from the fossil record is giving us support that the model simulated the rules determining plankton growth and distribution.

We found that some subtropical and tropical species’ optimum temperature for peak growth and reproduction could deal with seawater warming in the past, supported by both fossil data and model. Colder water species of plankton managed to drift to flourish under more favourable water temperatures.

Our analysis shows that Foraminifera could handle the natural climate change, even without the need to adapt via evolution. But could they deal with the current warming and future changes in ocean conditions, such as temperature?

Future of the food chain

We used this model to predict the future under four different degrees of warming from 1.5 to 4 °C. Unfortunately, this type of plankton’s ability to deal with climate change is much more limited than it was during past warming. Our study highlights the difference between faster human-induced and slower-paced geological warming for marine plankton. Current climate change is too rapid and is reducing food supply due to ocean stratification, both making plankton difficult to adapt to this time.

Phytoplankton produce around 50% of the world’s oxygen. So every second breath we take comes from marine algae, while the rest comes from plants on land. Some plankton eat other plankton. That in turn gets eaten by fish and then marine mammals, so energy transfers further up the food chain. As it photosynthesises, phytoplankton is also a natural carbon fixation machine, storing 45 times more carbon than the atmosphere.

Around the world, many people depend heavily on food from the ocean as their primary protein sources. When climate change threatens marine plankton, this has huge knock-on effects throughout the rest of the marine food web. Plankton-eating marine mammals like whales won’t have enough food to prey on and there’ll be fewer fish to eat for predators (and people). Reducing warming magnitude and slowing down the warming rate are necessary to protect ocean health.

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This blog is written by Rui Ying, Postdoctoral Researcher, Marine Ecology, and Daniela Schmidt, Professor in Palaebiology, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Breaking down ‘the beef’: Unpacking British animal farmers’ attitudes towards veganism

Posted on November 12, 2024November 12, 2024 by amanda.woodman-hardy

In recent years, plant-based diets have spiked across the UK. These trends are accompanied by increased discussions about consumption choices, in which vegans and livestock farmers are often depicted as rivals in a highly polarised public debate. Debates often centre on the modern meat industry, predominately criticised for its exploitative animal husbandry and/or its unsustainable farming practices. As livestock farmers’ activities are placed under the microscope, are their reputations falling in respectability?

Attempts have been made to improve communication between farmers and consumers, addressing a so called urban-rural ‘disconnect’. The thought goes that when communication is poor between these parties, polarization and stereotypes are given greater space to thrive. This issue became the springboard for my project. As veganism’s objections to animal farming are well-documented, I wanted to hear more from UK farmers’ themselves about their relatively unheard views on veganism.

Research realities

The nature of this study called for qualitative research: semi-structured interviews aiming to gain detailed, ‘close-up’ information on farmers’ lived experiences. With resources limited, my participants comprised of 12 British meat and dairy farmers, allowing me to explore sheep, cattle and pig farms of different shapes-and-sizes.

Although UK farming communities are recognised as an especially hard-to-reach demographic for research engagement, I was able to utilize my ‘insider’ status to secure a high response rate. Whilst I am from a farming background, I am also a vegetarian: an ‘outsider’ dietary choice that is frequently met with negativity in the agricultural world.

Spatial distribution of interviewees across the UK

Farmers’ ‘issues’

The livestock farmers I interviewed expressed two broad issues with veganism. The first issue spoke of the ‘urban disconnect’ from everyday, rural cultures and lifestyles on the farm. Farmers cast vegans as estranged ‘city people’ who therefore create misconceptions about farming practices. Speaking of artificial insemination, one farmer with a micro-dairy explained that animal rights activists are “just totally wrong” by commonly naming AI as “raping a cow”. He named these claims as an “anthropocentrism […] [The cows are] not in any distress with it […] The idea that it goes against the will of the cow is just incorrect” (Farmer J).

Farmers also saw veganism’s disconnection from the realities of livestock farming as leaving no scope for there to be any positive kind of relationships between farmer and animal. Things like

sheep running through the field […] the farmer helping a ewe give birth […] The kind of joyful sides of it […] If a farmer says: ‘but no, there’s a relationship and it’s like a symbiotic thing’, it’s like ‘fuck off is it symbiotic, it’s the most exploitative relationship possible’ (Mixed livestock farmer).

In general, farmers spoke of complicated and intimate farmer-animal relationships. Whilst acknowledging that livestock are kept for economic purposes, they felt that animals can equally shape ways of being in the world for farmers. They believed that most vegans failed to recognise this, only having the scope to consider the worst bits of livestock farming. In other words, they see “the end product, and the end product is death”.

Secondly, many farmers problematised veganism as an unsuitable paradigm for UK agriculture to holistically follow:

I think that veganism is still just as dependent on the worst bits of our food system, as in the agro chemistries […] I think it’s just as dependent on all of these, but it has falsely blamed animals as the consequence of the environmental degradation (Sheep farmer).

Situated in the no-meat/pro-meat debate, many farmers I spoke with joined the rising number of people championing small-scale, naturalistic animal farming. Contrary to veganism, they saw livestock — extensively managed — as necessary for any healthy, farmed ecosystem. This mirrors one micro-dairy farmers’ discussion on the reintegration of livestock onto degraded arable land:

There could be a really important role for livestock on repairing arable lands that could also help with transitioning away from artificial fertilizers and heavy use of fossil fuels in arable.

Overall, farmers critiqued veganism for failing to recognise the damage that conventional farming practices elicit, whilst promoting a singularly negative view of animal farming. They named the movement responsible for the successful “demonizing of cows”, claiming instead that it’s not the cow, it’s the how.

A less politically charged takeaway, however, is the idea that the UK’s fundamentally unsustainable food system is not being challenged by veganism. Farmers spoke about the need to reform the UK’s import-culture, in which only 55% of our food is home-grown. One believed that an ethical diet can’t be based on “unjust global structures either” as, for example, “problems [are] being caused for Mexican people by [the UK] importing so many avocados”.

Farmers felt that veganism falsely implies that ‘the food system is fine, just as long as customers do the correct thing and don’t eat animal produce’. Instead, many prefer to aspire towards a system that they felt does address deeper food system issues, such as a ‘farm-gate to plate’ model of local, agroecologically produced food.

Livestock farmers praise veganism

However, to focus solely on livestock farmers’ issues with veganism would paint a false image of what was said. Most farmers interviewed defended certain aspects of veganism, with a minority actively praising the movement:

So, where I think they do [understand the realities of livestock farming] is the […] refusal to look away from the bad aspects, from the dirtier aspects or the bloodier aspects of livestock farming […] I think a lot of meat-eaters just totally disavow that as if it doesn’t exist […] So I think vegans understand sometimes the realities of eating meat more than meat-eaters (Sheep farmer).

Here, this farmer approved of veganism for encouraging animal welfare debates. This reveals veganism’s potentially positive role in farmers’ eyes, overcoming some of the romantic ignorance about primary food production that persists in the UK. These welfare discussions often led to farmers passionately claiming that, as a nation, we need to drastically reduce our meat consumption, naming it “quite frightening” that meat consumption continues to rise “even with the vegan movement”.

Unlike existing narratives — casting vegans and livestock farmers as opposites — many farmers in my study sympathised with veganism’s goals. When discussing vegans’ decisions to eschew animal produce, one sheep farmer even said: “I totally get it and I certainly get the point where I don’t want to kill it because it’s beautiful”. These results reveal novel connections between two seemingly polarised groups. One mixed-livestock farmer even claimed that “for people to make a stance and make a decision, I applaud that”.

Farmers’ perspectives will always be diverse and complex. Nonetheless, there was a strong sense that many farmers are feeling that, within the realm of consumption, ignorance may just lie in focusing too much on what we eat, and not enough on the environment in which our food is from.

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This blog was written by Sophie Wise, a postgraduate student in Sociology (with a study abroad) at the University of Bristol.

Building resilience of the UK food system to weather and climate shocks

Posted on September 11, 2024 by amanda.woodman-hardy

Climate-driven changes in extreme weather events are one of the highest-risk future shocks to the UK food system, underlining the importance of preparedness across the food chain. However, the CCC’s 2023 report on adaptation progress highlighted that current climate adaptation plans and policies, and their delivery and implementation for UK food security are either insufficient or limited. Through an ongoing Met Office cross-academic partnership activity (‘SuperRAP’) working across all eight partner universities (including Bristol), Defra, the Food Standards Agency, UKRI-BBSRC and the Global Food Security Programme, a recent perspective paper, and associated online workshops and surveys in January 2023 have:

Scoped out the direct impacts of weather and climate extremes on the UK food supply chain,
Highlighted areas where weather and climate information could support resilience across time and space scales through decision making and action,
Identified key knowledge gaps,
Made recommendations for future research and funding, and
Scoped out the potential adaptation/policy responses to the direct impacts of weather and climate extremes on the food chain, and the resulting trade-offs and consequences

The potential for weather and climate information to support decision making in agricultural and food system-related activities, and improved resilience to weather and climate shocks across time and space scales. Grey background boxes represent generalised meteorological capabilities; light blue ellipses with white outlines denote potential applications. © Crown Copyright 2021, Met Office. From Falloon et al. 2022.

However, a major gap remains in understanding the changes needed to rapidly increase the delivery and implementation of climate adaptation in support of resilience in the UK food system. A workshop on this topic was held at the University of Reading’s Henley Business School on 13-14 June 2024 bringing together academics across a wide range of disciplines and presented findings back to industry and government stakeholders for their feedback and prioritisation.

The workshop aimed to consider key areas for supporting resilience and adaptation to climate change identified by the January 2023 workshop including innovation and trialling novel management and production approaches, social innovation and enabling behavioural shifts, mutual learning, and underpinning evidence gaps. The workshop was supported by a cross-sector survey on adaptation barriers and priorities.

Overarching themes identified in the workshop included the need for a strategic, system-wide, and long-term approach, underpinned by strong inter- and transdisciplinary collaboration.

Critical evidence gaps include improving understanding of:

Impacts of international dimensions and trade on UK food ingredient and packaging availability, compared to UK-sourced products – and their interactions
Impacts of climate extremes on production and transport and effective adaptation options
Impacts of climate shocks on UK livelihood systems, households and consumers
Broader adaptation and transformation needed to escape existing ‘doom loops’
Application of tech solutions (e.g. GM/gene editing) for climate resilience and adaptation

Other issues raised included thresholds for change, land pressures, substitutability of different foods, impacts of government policy, nutrition, regenerative practices, and interactions with the energy sector.

Recommended ways forward include:

Tools, models, and methods that consider risks across the food chain and system outcomes
A focus on inter- and trans-disciplinary approaches.
Increased international collaboration/cooperation, and stronger government-science interactions
Enhancing food chain data access, use and integration, and a supportive enabling environment
Long-term trials: to provide evidence of impacts of alternative practices
Preparing the transport network for climate extremes.
A refresh of the National Food Strategy, building on latest science
A new funding landscape: long-term, strategic, visionary, systemic, trans- and interdisciplinary, co-designed and coordinated.

Other issues raised included: sharing responsibility and joined-up, transparent approaches across sectors and institutions; risk mitigation tools; use cases and roadmaps; welfare responses; interdisciplinary skills training; and research across a wider range of crops.

We are aiming to produce a peer-reviewed perspective paper on critical research (and practice) gaps, and recommendations for the way forward.

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This blog was written by Professor Pete Falloon from the Cabot Institute for the Environment and Met Office.

A bald headed man smiling with dark rimmed glasses. — Professor Pete Falloon

Wisdom of Generations: Learning from the Hills and Valleys of the Northeast India

Posted on June 4, 2024June 4, 2024 by amanda.woodman-hardy

A tea garden in Dibrugarh, Assam. Image credit: Nborkakoty at English Wikipedia.

Northeast (NE) India is more than just a region on the map; it is a treasure trove of beautiful
natural landscapes and ecological wealth that plays an essential role in our planet’s health. As
we celebrate World Environment Day 2024 with the theme of restoration, let us highlight the
ecological richness of Assam and the other Northeastern states of India. From the slopes of
Arunachal Pradesh to the lowlands of Assam, the NE region is a biodiversity hotspot, home to
unique species found nowhere else on Earth. The more we explore this ecological richness,
the more we discover the wonders and mysteries it holds, sparking our curiosity and interest.

The scenic landscapes of the NE region exemplify a dynamic and harmonious relationship
between humans and nature. Indigenous communities here have cultivated a profound
repository of traditional ecological knowledge passed down through generations. The Bodos,
Mishings, Karbis, Nyishis, Angamis, Khasis, and many others have developed a deep-rooted
understanding of their natural surroundings through intimate interactions with forests, rivers,
and mountains.

One of the most remarkable aspects of this traditional wisdom is the extensive knowledge of
local plants and their uses. These communities have identified and utilized numerous plant
species for food, medicine, shelter, and rituals, demonstrating a profound understanding of
the ecological roles of each species. For instance, the Bodos have long made use of medicinal
plants like Bhut Jolokia (ghost chili) for their therapeutic properties, contributing to the
preservation of traditional healing practices. This knowledge not only highlights the ecological
and cultural diversity of the region but also supports sustainable development and
conservation efforts.

Beyond plant knowledge, these communities have developed sophisticated ecosystem
management practices. Indigenous forest management practices in NE India have
significantly contributed to maintaining biodiversity hotspots and preserving wildlife habitats.
Traditional agroforestry systems, such as jhum cultivation practiced by the Karbi and Khasi
tribes, have shown resilience to climate variability while supporting local livelihoods. According
to a recent United Nations report, indigenous peoples’ territories encompass about 80% of the
world’s remaining biodiversity, underscoring the importance of their stewardship in
conservation efforts.

The wisdom of the hills and valleys also embodies resilience—a capacity to adapt and thrive
amidst changing circumstances. Indigenous communities have overcome challenges like
floods, droughts, and shifting climates by drawing on their deep ecological knowledge.

According to the Indian State Forest Report 2021, Assam’s forest cover is around 35% of its
geographical area, highlighting its critical role in biodiversity conservation and carbon
sequestration. However, this forest cover is declining, and the region faces environmental and
climate challenges, including deforestation, riverbank erosion, and climate change impacts.

Preserving and promoting traditional ecological knowledge is crucial in the face of the global
climate crisis. According to UNESCO, indigenous communities’ traditional knowledge
significantly contributes to the sustainable management of natural resources, benefiting both
local communities and global biodiversity. Recognizing, valuing, and supporting these
practices are essential for environmental conservation, cultural identity, and community
resilience.

Celebrating the wisdom of Assam and Northeast India’s hills and valleys on World
Environment Day reminds us of the transformative power of indigenous knowledge.
Integrating their insights into broader restoration efforts can contribute to building a sustainable
future for all. By embracing the wisdom passed down through generations and augmenting it
with contemporary research and statistics, we, the #GenerationRestoration, can pave the way
toward ecological harmony and resilience in the years to come.

Let us change gears to the tea communities of the NE region. Assam also plays a vital role in
India’s tea production, boasting over 312 210 hectares of tea cultivation. These tea plantations
not only fuel the state’s economy but also hold significant cultural and ecological value. Assam
is among the world’s largest tea-producing regions, with an annual production of 500-700
million kilograms (Mkgs) of tea leaves. The tea industry employs a vast workforce and
supports livelihoods throughout the region, contributing significantly to India’s overall tea
production. The tea plantations in Assam are not only unique but also serve as a prime
example of the harmonious blend of agriculture and biodiversity conservation. The lush green
tea bushes are seamlessly intertwined with shade trees, providing a habitat for various birds
and insects. Assam’s tea is globally renowned for its robust flavor and represents a heritage
deeply rooted in the land and its ecosystems. However, climate and environmental changes
threaten these lush industries, impacting the ecological and socio-economic balance in the
region.

The government has launched several key initiatives to promote development, ecological
conservation, and socio-economic growth across the state. Notable initiatives include the
Assam Budget for Sustainable Development, Assam Tea Tribes Welfare Board, Jal Jeevan
Mission (Har Ghar Jal), Assam Arunodoi Scheme, Assam Green Mission, Assam Skill
Development Mission, and Assam Startup. Effective implementation of these programs aims
to address climate change, promote environmental conservation, and improve the overall
quality of life for the people of Assam. However, the success of these programs depends on
thorough execution at the grassroots level.

What unfolds in the remote corners of Assam reverberates across continents. The lessons
gleaned from this region—on biodiversity conservation, traditional knowledge integration, and
community-led resilience—are universal. They inform global discussions on sustainable
development, emphasizing the need for inclusive approaches that prioritize both people and
the planet.

This World Environment Day, let us heed the call of Northeast India—a call to action for
environmental engagement and climate action involving youth, communities, government
agencies, and non-profit organizations. The region’s youth must understand the challenges
facing their environment and take action to safeguard their communities and natural
surroundings amidst infrastructural growth and development for their own and future
generations. Climate mitigation and adaptation strategies tailored to the region’s unique
context are critical, including afforestation, sustainable agriculture, and flood management
solutions. Youth can lead the way in developing context-specific climate adaptation and
environment restoration strategies that respect local cultures and ecosystems. By immersing
themselves in environmental education, research, and activism, young students can amplify
their voices and influence decision-makers at all levels.

Assam and its neighboring states in India stand out as a distinctive and valuable addition to
the mosaic of Earth’s landscapes. They serve as a beacon of hope and possibility in our
collective journey toward planetary stewardship. The region’s unique natural heritage,
combined with its rich cultural and ethnic diversity, makes it an important site for scientific
research and cultural exchange. As we strive to better understand and protect our planet,
regions like Northeast India offer invaluable insights and opportunities for collaboration.

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This blog is written by Dr Jagannath Biswakarma, School of Earth Sciences, University of Bristol, UK. jagannath.biswakarma@bristol.ac.uk.

‘They don’t have enough’ – schools in England are running food banks for families

Posted on May 13, 2024May 13, 2024 by adele.hulin

The peak of the cost-of-living crisis may have passed, but millions of families are struggling to buy enough food to feed their children. Experiencing food insecurity can be deeply damaging for children and negatively affects their achievement at school.

My research, alongside other studies, shows that schools are operating their own food banks and providing charitable food aid to families. This shows how the education system – from early years to secondary schools – is increasingly at the front line in responding to child poverty, food insecurity, and destitution.

At the start of the financial crisis in 2008 there were few food banks in the UK. Now they are in towns and cities across the country. In 2010-11, charity the Trussell Trust operated 35 food bank centres. Now, the charity runs over 1400.

Recent research from the charity the Food Foundation estimates that one in five families with children do not have secure access to food.

After almost a decade and a half of Conservative governments, a significant number of schools are running food banks to support families and children.

I interviewed school staff at 25 schools across England, in towns and cities including Bristol, Liverpool and London. I wanted to understand how and why schools are providing charitable food to families.

The message was clear: schools were running food banks because they were faced with growing poverty and families struggling financially. Parents can’t afford to buy food or pay bills, and turn to schools for help. As one staff member I spoke to said:

They don’t have enough food, they don’t eat typically well because they can’t afford it, and that’s no fault of their own.

Teachers talked about the cost of living crisis and changes to the UK’s benefit system – in particular the replacement of a number of previous benefit allowances with universal credit – as reasons the food banks were necessary. Research has suggested that the switch to universal credit is leaving some families worse off. “It’s less than what they’re on before. And we have that period where you swap [systems] where you haven’t got any money,” one teacher said.

Child receiving school lunch — Some of the children whose families used school food banks did not qualify for free school meals. Africa Studio/Shutterstock

Some of the families supported by school food banks did not qualify for free school meals for their children but were still struggling. Commenting on who made use of the foodbank, one teacher said:

Sometimes it’s the ones who have free school meals and sometimes it’s the next lot up that are working families and just have absolutely no money at all and no-one to support them or help them with that because they just miss it.

The growth of food banks in schools shows how schools are often acting as an emergency service. “The government has dismantled public services over the past decade and schools are the last people standing,” Ann Longfield, former children’s commissioner for England, has recently commented.

A growing problem

The latest research I am working on with colleagues throws the situation facing families and schools into even starker relief. We are currently investigating how many school-based food banks there are in England and the sorts of schools they are located in.

Our new research, which has not yet been published in a peer-reviewed journal, suggests that 21% of primary and secondary schools operate some kind of food bank. We estimate that this amounts to over 4,000 school-based food banks across England.

This would mean that there are now more food banks inside schools than the combined total of food banks operated by charities the Trussell Trust – the UK’s largest food bank operator – and the Independent Food Aid Network.

If schools are now systematically supporting families through charitable food aid, they need guidance, support and funding. Families need well-paid and secure work and a social security system that provides people with both dignity and the financial means to buy essentials, which includes being able to buy food and clothes and heat their homes.

It’s worth remembering that the goal of a well-functioning welfare state should be to prevent poverty and destitution in the first place rather than provide relief for them after the fact.

Plans to dramatically reduce child poverty, food insecurity and inequality must be central to all political parties’ election manifestos.

This blog is written by Dr Will Baker, Senior Lecturer, School of Education, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Vaccinating livestock against common diseases is a form of direct climate action

Posted on February 26, 2024 by amanda.woodman-hardy

Animal diseases have a devastating impact on livestock production. In 2022, for example, 131 million domestic poultry died or were culled as a result of avian influenza (also called “bird flu”).

Yet the cost of livestock disease goes beyond a shortage of turkeys for the holiday season. Every animal that is lost to a preventable disease is also associated with greenhouse gas emissions that the planet cannot afford.

Animal diseases reduce the productivity of a farm. This is because livestock grow at a slower pace, are unable to reach target weights or fail to reproduce. Diseases may also drastically increase the rate at which livestock die.

Diseases with high mortality levels, such as classical swine fever or avian influenza, mean farmers need to use more resources and raise additional animals to maintain food production. This will cause the generation of more greenhouse gas emissions.

However, controlling common animal diseases effectively through tools like vaccination proves to be a sustainable way of tackling climate change. According to new research that was carried out by one of us (Jude Capper), controlling “high pathogenicity” avian influenza – a virus that can cause severe disease and death in infected poultry – with vaccines would reduce greenhouse gas emissions by almost 16% per kilogram of meat without having to resort to culling.

A vet removing the carcasses of chickens on a farm that have died from bird flu. — Bird flu caused the death of 131 million domestic poultry in 2022.
Pordee_Aomboon/Shutterstock

Reducing emissions

Using vaccines to prevent disease also supports better food security and livelihoods. Porcine reproductive and respiratory syndrome is endemic in countries including the US, China and Vietnam. The virus does not always kill infected pigs, but it limits output from swine farms as it affects reproduction and growth. In affected herds, up to 19% of sows fail to produce piglets and 75% of young pigs die before weaning.

Every 100,000 sows spared from porcine reproductive and respiratory syndrome would prevent more than 420,000 tonnes of greenhouse gas emissions. This is equivalent to removing more than 230,000 cars from the road, and means greenhouse gas emissions per kilogram of pork would fall by 22.5%.

Similarly, eliminating foot and mouth disease where it is endemic (many low- and middle-income countries in Africa and Asia) would cut emissions by more than 10% per kilogram of product. Foot and mouth disease is highly contagious and led to a crisis for UK agriculture when it hit in 2001. The disease is a major cause of reduced production around the globe, despite not always killing livestock.

Traffic on a motorway surrounded by heavy smog. — Vaccinating 100,000 sows against porcine reproductive and respiratory syndrome could reduce emissions by an amount comparable to that produced by 230,000 cars.
testing/Shutterstock

Controlling outbreaks

More than 80% of farms in low-income countries are smallholder or backyard operations. This type of farm generates more greenhouse gas emissions per unit of meat, milk and eggs than commercial farms because of lower productivity.

Farms in these countries are reservoirs of disease. This means the threat of a global outbreak – and the associated implications for greenhouse gas emissions – is never zero. These reservoirs occur because of a lack of disease surveillance, infrastructure, trained personnel and available medicines to detect, record and control livestock diseases.

Nevertheless, controlling endemic livestock diseases through vaccination reduces the risk of outbreaks across species and regional borders. By controlling avian bronchitis (a highly contagious respiratory disease mainly in chickens) where it is endemic among backyard poultry, we can reduce emissions by more than 11% while also limiting the risk of an outbreak.

Outbreaks can undermine global trade, production and food security. Economic analysis of an African swine fever outbreak in China found that low pork supply would increase global pork prices by between 17% and 85%. The findings also suggest that unmet demand would have significant consequences for the affordability of other meats.

Vaccination also helps to address the threat of antimicrobial resistance, which poses a major threat to human health around the world. Research estimates that antimicrobial resistance was associated with around 5 million deaths globally in 2019.

Free range chicken on a poultry farm. — Most farms in low-income countries are smallholder or backyard operations.
goodbishop/Shutterstock

Moving towards sustainability

Our food system is responsible for one-third of global greenhouse gas emissions. Improving animal health would thus make a significant contribution to meeting the IPCC’s challenge of halving emissions by 2030.

At the same time, it would minimise the broader environmental impact of farming through efficiency gains. This is particularly crucial in low-income countries where the inability to control or treat livestock diseases has greater consequences for malnutrition, poverty and human health.

Sustainable food production balances three components: environmental responsibility, economic viability and social acceptability. Using vaccines to reduce livestock disease around the globe is one of the few innovations that improves all three – benefiting animals, people and the planet.

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This blog is written by David Barrett, Professor of Bovine Medicine, Production and Reproduction, University of Bristol and Jude Capper, Professor of Sustainable Beef and Sheep Production, Harper Adams University. This article is republished from The Conversation under a Creative Commons license. Read the original article.

UK peatlands are being destroyed to grow mushrooms, lettuce and houseplants – here’s how to stop it

Posted on February 8, 2024 by amanda.woodman-hardy

Peat is a natural carbon sink but is often found in house plants and other retail products, particularly within the food and farming industry.
New Africa/Shutterstock

During the long, solitary days of lockdown, I found solace in raising houseplants. Suddenly stuck at home, I had more time to perfect the watering routine of a fussy Swiss cheese plant, and lovingly train our devil’s ivy to delicately frame the bookcases.

But I started noticing that these plants, sourced online, often arrived in the post with a passport. Most had travelled from all over Europe, with one common tagline: contains peat.

As a peatland scientist, these labels instantly filled me with horror. Hidden Peat, a new campaign launched by The Wildlife Trusts, is now highlighting the presence of peat in all sorts of consumer products, including house plants.

Peatlands, such as bogs and fens, store more carbon than all of the world’s forests combined. They trap this carbon in the ground for centuries, preventing it from being released into the atmosphere as greenhouse gases that would further warm the climate.

Peatlands have multiple environmental benefits. They are havens for wildlife, providing habitat for wetland birds, insects and reptiles. They supply more than 70% of our drinking water and help protect our homes from flooding.

So why on earth is peat being ripped from these vital ecosystems and stuffed inside plant pots?

From sink to source

Despite their importance, peatlands have been systematically drained, farmed, dug up and sold over the last century. In the UK, only 1% of lowland peat remains in its natural state.

Instead of acting as a carbon sink, it has become one of the largest sources of greenhouse gas emissions in the UK’s land use sector. When waterlogged peat soils are drained, microbes decompose the plant material within it and that results in the release of greenhouse gases such as methane into the air.

Most of the peat excavated, bagged up and sold in the UK is used as a growing medium for plants. Gardeners have become increasingly aware of this problem. Peat-free alternatives have been gaining popularity and major retailers have been phasing out peat-based bagged compost in recent years.

Indeed, the UK government announced they would ban sales of all peat-based compost by 2024. But this legislation has not yet been written and it seems unlikely it will be enacted before the end of the current parliament.

Even if brought in to law, this ban would only stop the sales of peat-based bagged compost of the type you might pick up in the garden centre. Legislation for commercial growers is not expected until 2030 at the earliest. So the continued decimation of the UK’s peatlands could remain hidden in supply chains long after we stop spreading peat on our gardens.

Hide and seek peat

For consumers, it’s almost impossible to identify products that contain peat or use peat in their production. All large-scale commercial mushroom farming involves peat and it is used for growing most leafy salads. It gives that characteristic peaty aroma to whisky, and, as I found out, is a popular growing medium for potted plants.

But you’d struggle to find a peat-free lettuce in the supermarket. The Hidden Peat campaign asks consumers to call for clear labelling that would enable shoppers to more easily identify peat-containing products. Shoppers are also encouraged to demand transparency from retailers on their commitment to removing peat from their supply chains.

You can ask your local supermarket about how they plan to phase out peat from their produce. Some supermarkets are actively investing in new technologies for peat-free mushroom farming.

Make informed purchases by checking the labels on garden centre potted plants or source plants from peat-free nurseries. The Royal Horticultural Society lists more than 70 UK nurseries dedicated to peat-free growing.

You can write to your MP to support a ban on peat extraction and, crucially, the sale of peat and peat-containing products in the UK. That ensures that peat wouldn’t just get imported from other European countries.

Pilots and progress

The UK government recently announced £3.1m funding for pilot projects to rewet and preserve lowland peat, with peat restoration seen as a cornerstone of net zero ambitions. This campaign calls for further acceleration of peatland restoration across the UK.

As a research of the science behind peatland restoration, I see firsthand the enormous effort involved in this: the installation of dams to block old agricultural drainage ditches, the delicate management of water levels and painstaking monitoring of the peat wetness.

I spend a lot of time taking samples, monitoring the progress, feeding results back to the land managers. Like many other conservationists, I work hard to find ways to preserve these critical habitats.

But sometimes, there may be a digger in the adjacent field doing more damage in a day than we could undo in a lifetime. That’s the reality, and the insanity, of the UK’s current peatland policies.

We heavily invest in restoring peatlands, yet fail to ban its extraction – the one action that would have the most dramatic impact. By demanding that peat is not only eradicated from garden compost, but weeded out of our supply chains, we can keep peat in the ground, not in pots.

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This blog is written by Cabot Institute for the Environment member, Dr Casey Bryce, Senior Lecturer, School of Earth Sciences, University of Bristol.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Casey Bryce

How do you manage a dam when there’s a tropical cyclone in Mozambique?

Posted on January 8, 2024January 8, 2024 by amanda.woodman-hardy

Mozambique dam

I’d never given a huge amount of thought of what a dam manager did until I visited Pequenos Libombos dam in Mozambique in October 2023. Standing at the dam, in hot conditions, listening to the lived experience of people who work on the ground and explain what they do during a tropical cyclone leaves you with more understanding than any peer reviewed journal article. Context is everything. It’s why visiting the countries I’m researching is something I do given the chance.

That’s what members of Bristol projects REPRESA (co-led by Prof Elizabeth Kendon at University of Bristol & UK Met Office, Dr Luis Artur from Eduardo Mondlane University and Prof Francois Engelbrecht from University of the Witwatersrand) and SALIENT (led by Dr Rachel James, University of Bristol) did in October. The REPRESA project aims to understand compound tropical cyclone risks, impacts of tropical cyclones and improve early warning systems in Mozambique, Malawi and Madagascar. Seeing the research alignment in projects, the SALIENT team also joined. The SALIENT project aims to improve the characterisation and communication of future climate information for national adaptation planning in southern Africa.

On the field trip day, we travelled to Pequenos Libombos dam and heard from a government official from the Vila De Boane Municipality. It was this day where I had my epiphany that if I ever left academia, dam management is not my calling. Providing water to the local population is the dams primary role and it provides 2 million people within Maputo Province with access to water. That is more than 4 times the population of Bristol.

The management of Pequenos Libombos dam is difficult as there are many other people and industries to consider and keep safe and happy when making decisions. From the businesses who want to use the dam’s water for industrial purposes to the farming communities that are reliant on the water for irrigation, and hydroelectricity companies that want to use the dam to create energy to the communities downstream that may be flooded if the dam releases water too quickly. The dam catchment is also shared with 2 of Mozambique’s neighbouring countries; eSwatini and South Africa, adding another element of complexity to the dams management.

Management must carefully balance both periods of water surplus and deficit and Maputo has experienced numerous extreme weather events in recent years. The 2015-2016 southern African drought impacted Central and Southern Mozambique and more recently the remnants of tropical cyclones in 2019, 2011, 2022 and 2023. During February 2023, Tropical Cyclone (TC) Freddy passed over Madagascar and southern Mozambique before returning a couple of weeks later to central Mozambique. It is thought to be the longest lived and have the highest accumulated cyclone energy of any cyclone on record, awaiting formal investigation from the World Meteorological Organization. Although TC Freddy didn’t directly pass over Pequenos Limbombos, its associated rainfall resulted in 250 mm of rainfall at the dam in one day. For context, the Bristol experiences 265mm rainfall, on average, in October, November and December combined. To avoid a breach of the dam, discharge was released at the maximum rate, which is more than 500 time more than normal.

Globally there is evidence that TCs and their impacts are being impacted by climate change. The frequency, intensity and storm tracks of TCs may be changing meanwhile, rising sea levels may lead to higher storm surges. Yet we know a limited amount about how tropical cyclones may act in a future with increased global sea surface and air temperatures. TCs in the Indian Ocean are particularly under researched, but recent and frequent events have highlighted the importance of understanding TCs in a changing climate.

After hearing about the vast amount of rain that fell in February 2023, we walk past the disused hydroelectric generator that was forced to cease operation during the drought as it was no longer economically viable. It really hammered home the complexities faced when trying to manage such a huge piece of infrastructure during extreme events. Similarly, it is clear why research projects like REPRESA and SALIENT are needed to understand how tropical cyclones may behave in the future and explore how early warning systems and climate change adaptation can be strengthened.

Mozambique dam

The human side of extreme weather

After the talk at Pequenos Libombos Dam, we visited the Municipality of Vila de Boane. Vila de Boane is located roughly 15 km downstream from the dam and the River Umbuluzi passes through the municipality. The municipality experienced large scale flooding after the dam was forced to increase to maximum discharge during the February 2023 rainfall.

Despite already hearing about TC’s Freddy’s impacts at the dam, they were not as focused on the human impact. The leader of the municipality compellingly described how 16,000 people were impacted overnight, 6000 people were displaced and 6 people sadly died. The community water pump was destroyed, leaving people without water for 3 months. The municipality leader said he had never seen that amount of water passing through the municipality at such high speed before. Meanwhile, money that had been budgeted for development initiatives, had to be redirected to repair and response. It was not clear if extra money had been sourced for the development initiatives.

It was also highlighted that the increased release of water from the dam occurred over night with little warning. The municipality had been told to expect “above normal” rainfall and to avoid being close to rivers and move farming machinery further inland. But as the municipality leader questioned, what does “above normal” actually mean? People will perceive this message differently, which will influence how they act upon it. As part of the SALIENT research project, I am researching how we best communicate future climate information to decision makers and this anecdote will stay with me. It’s clear that improved communications are needed in both weather and climate services, something REPRESA is also aiming to research further.

Reflections and collaboration

After hearing about the vast amount of impacts the flooding had on Villa de Boane, we waited for our transport back to Maputo under the shade as it was too hot to stand in the sun. It was clear everyone from the REPRESA and SALIENT teams, both physical scientists and social scientists, had taken a lot from the field day. There was discussion about what the research should consider as well as the different angles that could be taken. It also fostered collaboration, SALIENT team member, Alan-Kennedy Asser, is providing the REPRESA team with analysis of precipitation trends from a multiple ensembles of climate models to characterise the range in future projections over the region. Meanwhile I spoke with some REPRESA team members in more depth about future climate information and will be providing risk communication training session in the future.

My personal key take away is that understanding the context and hearing the lived experiences of people working and living with extreme weather events enriches me as a researcher. Similarly, collaborating with researchers and practitioners on different projects enhances your work by providing questions and inputs from different standpoints. And finally, I’m too indecisive a person to ever be a good dam manager.

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This blog is written by Cabot Institute for the Environment member, Dr Ailish Craig, School of Geographical Sciences, University of Bristol with contributions from Dr Alan Kennedy-Asser, School of Geographical Sciences, University of Bristol and Dr Rachel James, School of Geographical Sciences, University of Bristol.

The clam before the storm

Posted on December 8, 2023 by amanda.woodman-hardy

Cornish mussels

How can you not love a bivalve? I certainly spent seaside holidays picking long, thin razor shells out of the sand on the beach, marvelling at their sharp edges and brown and cream patterned growth lines. I still love clambering over rocky shorelines thick with the blue-black ovals of mussels, encrusted with limpets and rough barnacles, layered with salty strands of seaweed.

Bivalves are a keystone part of a rich ocean fauna, interlocked with the ecology of the marine environment and intertwined with lives of both ancestral and modern humans. Seafood, and particularly shellfish such as mussels, oysters, cockles, scallops and clams have long been part of the human diet. The European market for mussels alone topped 600,000 kg last year (FAO.org), the majority of which are consumed in France, Spain and Italy. Just take a moment to imagine the delicious fragrance of a seafood paella, and you will appreciate why they are so popular. Unfortunately, the future of shellfish is becoming more uncertain as the climate heats up. The days when oysters are used to fire the passions of young lovers, or indeed for lovers to gift each other nacre jewellery or pearls, may be coming to an end. Climate change is likely to lead to a scarcity of oysters and an inability for them to thrive, meaning much smaller individuals, which will make such tokens harder to obtain, more expensive or simply not available anymore.

Aside from being a food source, bivalves are an essential part of the ecosystem in both marine and freshwater habitats. One important task that bivalves do is to filter the water, collecting particles of microalgae, phytoplankton, bacteria and silt. The indigestible particles are packaged with mucus and excreted as a sandy deposit that sinks to the sea floor. In this way, bivalves help to clean murky, turbid water. Some bivalves do this at an incredible rate; green mussels (Perna analiculus) or sea scallops (Placopecten magellanicus) can filter in excess of 10 gallons of water every day. Removing and digesting the algae reduces the number of algal blooms that occur, and sticking sediment particles together so they sink, clears the water. This allows light to penetrate deeper into the ocean, benefitting photosynthetic organisms attached to the seabed.

The structure of the seabed is altered by the presence of bivalves. Some bivalves, such as Venus clams (Veneridae) bury themselves in soft sediments, helping to stabilise the sand. Others attach themselves to rocks using strong root-like threads. Reefs are reinforced by encrusting bivalves, which help to reduce shoreline erosion. This feature is becoming more important as the frequency and intensity of severe weather events is set to increase.

The shells of bivalves are made from either calcite or aragonite, which are different forms of calcium carbonate. The two forms are found in different species and at different stages of the life cycle. They have slightly different chemical properties but they both contain carbon in the form of carbonate, which molluscs extract from seawater. When the shellfish die, the shells drift to the ocean floor to begin the transition into rock such as limestones, ultimately locking carbon away and becoming an important carbon sink. Increasing carbon dioxide in the atmosphere means more carbon dioxide is dissolving in the oceans. Although this might seem like a bonus for the shell-building fauna, the carbon dioxide forms a weak solution of carbonic acid, and this is altering the pH of seawater. Acid reacts with carbonate, dissolving it, so that shelly sea creatures have to work harder to build and maintain their shells.

The complexity of reefs and other underwater habitats is enhanced by bivalves, not just with structural strength, but with complex architecture, which provides niches, refuges and points of attachment for other species. Plenty of creatures apart from humans enjoy munching on bivalves. Squid and octopods can prise the hinged shells apart using the suckers on their tentacles to get at the tasty meat inside. Bivalves also contribute to the food web by spawning large volumes of eggs and larvae. These drift on the ocean currents, providing an essential food source for pelagic fish and other hunters, such as baleen whales.

Having convinced you that bivalves are amazing, what does the future hold for hinged molluscs? Many studies have looked at how different conditions affect bivalves, with some coming to positive, and some to negative conclusions. Cherry picking the answer you want does not necessarily reflect the overall trend and can be quite misleading. One way that scientists use to get an overview of multiple studies is to carry out a meta-analysis. This is a way of combining all the studies to give a statistical probability to each value being tested.

We gathered data on how well bivalves grow under different conditions predicted to change by climate change models. Growth rate can be altered by temperature, pH, oxygen availability and salinity. Ocean temperature is increasing, and this will affect the metabolism of cold-blooded organisms, who rely on the external environment for internal temperature regulation. The pH of the oceans is becoming more acidic, causing the thinning of shells in some shelled sea creatures.

Areas of the ocean are becoming periodically, or permanently short of oxygen. This is happening in two ways. There are widespread dead zones spreading out from the estuaries of major rivers (e.g the Ganges or Mississippi) where nitrates and other pollutants are causing eutrophication, which uses up all the dissolved oxygen. Across water courses as a whole, less oxygen is present in water at higher temperatures because oxygen doesn’t dissolve as well in warm as opposed to cold water. Recent summer heat-waves have left a raft of dead, floating, aquatic organisms, both in marine settings and in inland lakes and rivers. Last summer I caught the fire-brigade pumping air into a local fishing pond, trying, mostly unsuccessfully, to prevent the fish from suffocating.

The last climate stressor that we included in our meta-analysis was salinity. As the planet warms, leading to the melting of ice-caps and glaciers, the sea level will rise with the influx of fresh water. This will alter the salinity, especially in the areas of melt-water run-off around coasts where most species of bivalves tend to live. We wanted to see if salinity changes would be problematic for bivalves, and how that would interact with the other climatic changes. One of the interesting things about meta-analyses is that the effect not only of individual stressors can be evaluated, but also the effect of the interaction of stressors. Do they combine to become more than the sum of their parts, or do they counteract each other to have an overall negligible effect?

What we found was that each of the environmental stressors individually reduced bivalve growth, but that combinations of stressors – such as a temperature increase coupled with an increase in acidity – acted together to reduce growth in a more pronounced way. If climate changes in the way that most models are predicting, then they are also predicting fewer, smaller bivalves that take longer to mature. This may disproportionally affect low-income, island nations, such as the Maldives, where a large proportion of the diet is sourced directly from the sea. For the fishing industry, this means sustainable harvesting limits will need to be adjusted over time to allow time for bivalves to grow to maturity.

This is particularly pertinent because the types of bivalves that have been studied are nearly all either commercial or easy-to-collect reef-building species. They come predominately from the northern hemisphere, and there is a distinct lack of studies on African and tropical species. There are over 100 families of bivalves, of which just 18 have had quantitative growth studies carried out. In the studies we used, 81% of them were on just four families: oysters (Ostreidae), mussels (Mytilidae), scallops (Pectinidae) and Venus clams (Veneridae). There are an awful lot of families we know nothing about, and it isn’t necessarily true that how one species responds informs us accurately about what another species might do. Temperature, for example, really slows down the growth of oysters, scallops and mussels, but can increase the growth of Venus clams and pen shells (Pinnidae). I can see you throwing your hands in the air and asking “Why??”

In this case, the answer seems to lie in the habitat or mode of life that the bivalve inhabits. The families that grow faster in warm waters are the type that bury themselves deep in the soft sand or mud of the seabed. This seems to act as a protective buffer against temperature changes, whereas bivalves attached to the surface are exposed to temperature extremes and so they show reduced growth.

The data became even more interesting when we looked at how different life stages responded to environmental stressors. Nearly all (84%) of the studies we could include in our meta-analysis had been carried out on eggs/larvae or juveniles. This of course, makes perfect sense if you are studying growth, as young organisms do an awful lot more growing than adults. It does, however, leave a hole in the data, and that can lead to biased conclusions.

Very young bivalves, which are generally a free-living part of marine plankton, grow less well in warm, acidic or low oxygen conditions. Low salinity doesn’t seem to be an issue. Adults, on the other hand, can tolerate warm, acidic or low oxygen conditions singly, but struggle when these occur in combination. Adults are also strongly affected by low salinity (in the very few studies that have tested this). Again, this makes reasonable sense. Adults are fixed to whichever rock they settled on, and so survival depends far more on metabolic tolerance to environmental extremes. Mobile, free-swimming larval forms have a greater ability to move away from uncomfortable conditions, searching for somewhere they can flourish.

However, larval vulnerability indicates that in the future bivalve populations (as opposed to individuals) will grow more slowly and may suffer from recruitment and settlement problems. It may be difficult, slow or impossible for bivalve colonies to regenerate after disturbance or harvesting, leading to major population crashes.

Climate change is going to pose some challenges to the populations of bivalves. Bivalves supply the seafood industry, filter our water, stabilise our shorelines and produce planktonic larvae, which bolsters the ocean food web. Minimising the effects of climate change will help to protect this keystone fauna and enable them to continue to form such an essential part of the natural world. I hope my children’s children can still delight in finding ropes of mussels and living pearls.

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This blog is written by Rachel Kruft Welton. With thanks to George Hoppit for proof-reading and suggestions. Read more about their research.

Rachel Kruft Welton