Climate change threatens global cocoa production: New study highlights pollination-based solutions

University of Oxford

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Training smallholding farmers to hand pollinate cocoa trees
in Bahia, Brazil

Credit: Prof Tom Cherico Wanger

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Credit: Prof Tom Cherico Wanger

Cocoa (Theobroma cacao L.) is a vital cash-crop for four to six million small-holder farmers across the tropics, and supports a global chocolate industry valued at over USD 100 billion annually. The combination of millions of farmers relying on cocoa for their livelihoods, and increasing global demand for the crop, has driven cocoa plantation expansion and intensification of farming practices, often at the expense of biodiversity and long-term sustainability.

A new research study led by the University of Oxford, in collaboration with Westlake University, China, Universidade Estadual de Santa Cruz, Brazil, and University of Göttingen, Germany, has highlighted the significant risks posed to cocoa production by climate change. However, the authors also identified farm management solutions that can both climate-proof cocoa crops and boost productivity without the need to expand plantations into forests.

The research, conducted across three major cocoa-producing countries—Brazil, Ghana, and Indonesia, which together account for 33% of global cocoa production—investigated key factors influencing cocoa yields. The findings revealed that increasing pollination rates above current levels could boost yields by 20%. This demonstrates that insufficient pollination is occurring to produce the maximum possible yield for many cocoa plantations. Separate to the impact of pollination, sites where temperatures were up to 7 degrees warmer had 20-31% lower cocoa yields, underscoring the vulnerability of cocoa-producing regions to the effects of climate change.

Co-author Dr Acheampong Atta-Boateng, who recently completed his doctoral work at the University of Oxford, said: ‘Cocoa is pollinated by tiny insects such as midges and thrips, and it comes as quite a surprise that most of the time there simply isn’t enough pollination happening to produce the cocoa crop that is possible.’

To support sustainable cocoa production, researchers recommend practical strategies to enhance pollination, such as maintaining leaf litter and other understory biomass, preserving soil organic matter, providing moderate shade, and reducing agricultural chemical use. These practices not only increase pollinator abundance, but also help regulate plantation temperatures and improve soil health, ensuring long-term plantation resilience.

Dr Tonya Lander, from the University of Oxford and first author of the study said: ‘This research shows that sustainable agricultural methods can significantly improve cocoa yields without farm expansion or intensification. By adopting biodiversity-centred, climate-resilient farming techniques, the cocoa sector can both increase production and safeguard farmers' livelihoods.’

Dr Tom Wanger of Westlake University, China added: ‘The rising demand for cocoa and the short-term economic benefits to farmers has led to plantation expansion and ecological homogenization at the expense of biodiversity and vital ecosystem services, like pollination. This study highlights the long-term risks of this approach, and how pollination can be a solution that works alongside climate-resilient agricultural systems to achieve long-term, ecologically and financially sustainable solutions.’

 

Notes to editors

The paper ‘Global chocolate supply is limited by low pollination and high temperatures’  will be published in Nature Portfolio, Communications Earth & Environment at 10 am GMT / 5 am ET Friday 14 February 2025 at: https://www.nature.com/articles/s43247-025-02072-z

 

Additional details

Images and videos related to the study are available at https://drive.google.com/drive/folders/1xBJazPOUkKxZ5BcbLc3jnBndAJ1cmFv7?usp=sharing. These are for editorial purposes only and MUST be credited (see caption file in folder). They must NOT be sold on to third parties.

Harvesting cocoa in agroforests of Bahia, Brazil

Credit: Patrick H. Böttger

An unripe cocoa pod in Ghana

Credit: Dr Andrew Wood

 

About the University of Oxford

Oxford University has been placed number 1 in the Times Higher Education World University Rankings for the ninth year running, and ​number 3 in the QS World Rankings 2024. At the heart of this success are the twin-pillars of our ground-breaking research and innovation and our distinctive educational offer.

Oxford is world-famous for research and teaching excellence and home to some of the most talented people from across the globe. Our work helps the lives of millions, solving real-world problems through a huge network of partnerships and collaborations. The breadth and interdisciplinary nature of our research alongside our personalised approach to teaching sparks imaginative and inventive insights and solutions.

Through its research commercialisation arm, Oxford University Innovation, Oxford is the highest university patent filer in the UK and is ranked first in the UK for university spinouts, having created more than 300 new companies since 1988. Over a third of these companies have been created in the past five years. The university is a catalyst for prosperity in Oxfordshire and the United Kingdom, contributing £15.7 billion to the UK economy in 2018/19, and supports more than 28,000 full time jobs.

The Department of Biology is a University of Oxford department within the Maths, Physical, and Life Sciences Division. It utilises academic strength in a broad range of bioscience disciplines to tackle global challenges such as food security, biodiversity loss, climate change and global pandemics. It also helps to train and equip the biologists of the future through holistic undergraduate and graduate courses. For more information visit www.biology.ox.ac.uk.

About Westlake University, China

Westlake University was inaugurated in 2018 as the first private university in China. Westlake University has four schools, School of Science, School of Engineering, School of Life Sciences and the School of Medicine to contribute to research and teaching with almost 2,000 employees and 2,200 doctoral students. The Sustainable Agricultural Systems & Engineering lab conducts data-driven work on the benefits of diversified agricultural systems, develops environmental monitoring technology, and translates results into effective policy recommendations

About the Universidade Estadual de Santa Cruz, Brazil

Located in Ilhéus, Bahia, Brazil, the Universidade Estadual de Santa Cruz (UESC) stands at the heart of the country’s historic cocoa-producing region. With approximately 8,000 students enrolled across 35 undergraduate and 27 graduate programs, UESC is a leading institution in research and education. One of its greatest strengths is the study of the Atlantic Forest, a globally recognized biodiversity hotspot. A key focus of this research is the role of cabrucas—a traditional cocoa agroforestry system where cacao is cultivated under the shade of old-growth Atlantic Forest trees. This sustainable practice plays a crucial role in preserving the extraordinary plant and animal diversity of southern Bahia, reinforcing UESC’s commitment to environmental conservation and sustainable development.

About the University of Göttingen, Germany

The University of Göttingen is an internationally renowned research university. Founded in 1737 in the Age of Enlightenment, the University is committed to the values of social responsibility of science, democracy, tolerance and justice. It offers a comprehensive range of subjects across 13 faculties: in the natural sciences, humanities, social sciences and medicine. With about 28,000 students and more than 210 degree programmes, the University is one of the largest in Germany. Research of the Functional Agrobiodiversity and Agroecology group focuses on socio-economically relevant topics in agroecology, such as the loss of biodiversity and associated ecosystem services by the intensification and expansion of agriculture and climate change in temperate and tropical regions.

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Journal

Communications Earth & Environment

Method of Research

Commentary/editorial

Subject of Research

Not applicable

Article Title

Global chocolate supply is limited by low pollination and high temperatures

Article Publication Date

14-Feb-2025

 

Report documents the devastation of the ancient city of Palmyra, a World Heritage Site, after the fall of the Assad regime

Conducted by archaeologists from the CSIC’s Milà i Fontanals Institution (IMF-CSIC), it describes the destruction of the archaeological remains, the destruction of the modern city and the displacement of more than 90% of the population

Spanish National Research Council (CSIC)

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Palmyra is one of the most famous sites in Syria for its extraordinary heritage and archaeological remains. Inscribed on the World Heritage List in 1980, the city saw much of its heritage destroyed during the war. Following the liberation of Syria from the Assad regime on 8 December, a multidisciplinary team has carried out a field study in Palmyra to assess the current state of the archaeological monuments and the surrounding residential areas, comparing them with their condition before the start of the Syrian uprising in 2011. The report is an initiative of Palmyrene Voices of the NGO Heritage for Peace in collaboration with the CSIC's Milà i Fontanals Institution.

‘We want,’ says Isber Sabrine, a CSIC archaeologist and one of the report's coordinators, ’to raise awareness among both local communities and the international community about the serious threats facing Palmyra's heritage’. Sabrine is an archaeologist of Syrian origin and currently a researcher at IMF-CSIC. Hasan Ali and Mohammed Fares, also archaeologists and members of the Palmyrene Voices initiative, coordinated the report. A team of 15 observers contributed data for the report, including citizens of Palmyra, archaeologists and refugees who have recently returned to the city. 

80% of the city destroyed or on the verge of collapse

The report highlights historical and recent challenges, including periods of repression under the presidencies of Hafez al-Assad (1971-2000) and Bashar al-Assad (2000-2024), as well as devastating damage during the occupation by the Islamic State (ISIS).

The documented buildings and archaeological remains cover approximately 12 square kilometres, including the Efqa Oasis.

The latter, some 400 hectares in size, was burnt to the ground in the 2020 fires set by the Assad regime. The remaining trees in parts that no longer receive water have dried out and turned into dead wood. At present, as observers have documented, some returning orchard owners are trying to save what is left of their palm and olive trees.

Eighty per cent of the city's buildings are destroyed or at risk of collapse, the report says, and landmines and weapons are scattered everywhere. Basic services such as water, electricity, internet, education and health are almost non-existent in the population, which suffers from severe poverty. Some 10,000 people have returned, about 10 per cent of Palmyra's 100,000 inhabitants.

Damage to archaeological heritage

Observers have documented damage to the 12 most important monuments and archaeological sites, including Roman remains such as the Tetrapylon (a monumental square platform bearing at each corner a tight grouping of four columns, dating from the 2nd century), and the Roman theatre (both 2nd century), the Camp of Diocletian (3rd century), the Castle of Palmyra or Qalʿat Ibn Maʿn (13th century), the Valley of the Tombs (1st century), the Archaeological Museum of Palmyra, among others.

Thus, for example, the four structures of the Tetrapylon were destroyed by explosions that reduced their columns to rubble and scattered stone fragments. It is also noted that there is no evidence of documentation or numbering of the stones, which, if present, could be helpful in their reconstruction. The BaalShamin Temple, around 2,200 years old, has been reduced to rubble.

On the Roman theatre, researchers have found evidence of a collapse of the façade, damaged by bombing. Signs of illegal excavations have also been found.

Regarding the Archaeological Museum, the report notes that most of the heavy statues and funerary beds are smashed or broken, and the structure of the building is badly damaged by aerial bombardment. The museum is not operational, but guards from the Directorate of Antiquities and some local volunteers protect it without support from the new administration. In addition, there are no administrative staff to supervise the museum. 

The availability of more staff for heritage protection and conservation in Palmyra is directly linked to the return of its population, say the report's authors. ‘The city currently faces significant challenges due to the devastation caused by the conflict, which has led to the massive displacement of its inhabitants.

Acute need to rebuild

The report notes that in order for Palmyra to regain its vitality and human resources to manage its heritage, it is essential to prioritise the reconstruction of its basic infrastructure and habitable areas. ‘Without housing, essential services and economic opportunities, the return of the population will be limited, making it difficult for local professionals and workers to be available for heritage conservation,’ notes Isber Sabrine.

The report ‘seeks to inspire local and international communities to recognise the threats facing Palmyra and the pressing need to rehabilitate and reconstruct its archaeological site, oasis and residential areas’.

It also ‘underlines the urgent need to implement rehabilitation and reconstruction strategies for the archaeological site and the modern city of Palmyra to ensure the conservation of this globally important site and the return of the people’.

This joint action reinforces the commitment of the IMF-CSIC and the Palmyra Voices Initiative to the defence of cultural heritage and the reconstruction of a post-conflict Syria.

CSIC Communication

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Method of Research

Observational study

Subject of Research

People

 

New study finds brake pad emissions can be more toxic than diesel exhaust

University of Southampton

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A study by the University of Southampton (UK) has found microscopic particles emitted from certain types of commonly fitted brake pads can be more toxic than those found in diesel vehicle exhaust.

The research shows that a higher concentration of copper in some pads is associated with increased harmful effects on sensitive cells from people’s lungs, as a result of particles being breathed in.

Exposure to pollution generated by cars, vans and lorries has long been linked to an increased risk of lung and heart disease. However, while past attention has mainly concentrated on exhaust emissions, particles are also released into the air from tyre, road and brake pad wear – emissions which are largely unregulated by legislation.

These ‘non-exhaust’ pollution sources are now responsible for the majority of vehicle particulate matter (PM) emissions in the UK and parts of Europe, with brake dust being the main contributor.

Lead author of the study, Dr James Parkin, explains that a move to electric cars is bringing the problem into sharper focus: “People generally associate pollution from cars as being from exhaust pipes and think of electric vehicles as having zero emissions. However, EVs still produce particulate matter due to friction and wear of the road, tyres, and brakes.

“We wanted to understand how different types of chemical composition of pads affect the toxicity of the particles emitted and what this might mean for the health of individuals.” 

The scientists undertook an in-depth study examining the effects on lung health of PM from four different types of brake pad with differing chemical compositions; low metallic, semi-metallic, non-asbestos organic and hybrid-ceramic. The researchers were particularly interested in the smallest particles, of PM2.5 and below (often referred to as fine PM) – 30 times smaller than the diameter of a human hair.

These tiny particles can make their way beyond the upper airways and deeper into the delicate lung air sacs, which enable the exchange of oxygen and carbon dioxide to and from the blood stream. Fine PM from a variety of different sources is associated with over four million premature deaths per year worldwide.

Brake pad particulate matter was collected using specialist equipment. In the laboratory, the Southampton team used samples of cells from the lining of the lung and exposed them to the fine particulate matter to measure its effects, such as oxidative stress, inflammation, or the death of cells.

Results showed that of the four types of brake pads, non-asbestos organic  pads were the most potent in terms of inducing inflammation and other markers of toxicity, and more toxic to human lung cells than diesel exhaust particles. Ceramic pads were the second most toxic. Importantly, both non-asbestos organic and ceramic pads contain high concentrations of copper, and later experiments to remove this copper found the PM became less toxic.

The findings, published in the journal Particle and Fibre Toxicology, suggest that a reduction of copper content in brake pads could help mitigate some of the harmful effects of vehicle particulate matter. Air pollution, including from cars, has been linked to a range of conditions, such as asthma, chronic obstructive pulmonary disease (COPD), cardiovascular diseases, dementia and idiopathic pulmonary fibrosis (scarring of the lung).

Project supervisor Professor Matthew Loxham comments: “This research has important implications for health and future policy because as we switch from diesel and petrol-powered cars to electric vehicles, non-exhaust particle emissions will remain.  Non-exhaust emissions could increase over time due to electric vehicles being heavier than combustion engine vehicles and creating greater friction.”

The researchers highlight that while electric vehicles emit no exhaust emissions they aren’t emission-free and that health effects from vehicle emissions won’t necessarily be completely removed once the fleet is fully electrified. They suggest that current legislation, which focuses on PM exhaust emissions, may be inadequate to fully mitigate the health effects of vehicles in the future.

Ends

 

Notes to Editors

1. The paper Copper‑enriched automotive brake wear particles perturb human alveolar cellular homeostasis is published in the journal Particle and Fibre Toxicology, DOI: 10.1186/s12989-024-00617-2: https://doi.org/10.1186/s12989-024-00617-2
    
2. For interviews or an embargoed copy of the paper contact Peter Franklin, Media Relations, University of Southampton. press@soton.ac.uk +44 23 8059 3212.
    
3. For more about the Faculty of Medicine at the University of Southampton visit: https://www.southampton.ac.uk/study/subjects/medicine
    
4. The University of Southampton drives original thinking, turns knowledge into action and impact, and creates solutions to the world’s challenges. We are among the top 100 institutions globally (QS World University Rankings 2025). Our academics are leaders in their fields, forging links with high-profile international businesses and organisations, and inspiring a 22,000-strong community of exceptional students, from over 135 countries worldwide. Through our high-quality education, the University helps students on a journey of discovery to realise their potential and join our global network of over 200,000 alumni. www.southampton.ac.uk

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Journal

Particle and Fibre Toxicology

DOI

10.1186/s12989-024-00617-2 

Method of Research

Experimental study

Subject of Research

Cells

Article Title

Copper‑enriched automotive brake wear particles perturb human alveolar cellular homeostasis

Article Publication Date

13-Feb-2025

 

Inconsistent reporting leads to underestimation of climate impact of methane

Companies around the world are underestimating their total greenhouse gas footprints because of inconsistent accounting standards for methane emissions, finds a new study by researchers from UCL and Imperial College London

University College London

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Companies around the world are underestimating their total greenhouse gas footprints because of inconsistent accounting standards for methane emissions, finds a new study by researchers from UCL and Imperial College London.

The new study, published in Nature Communications, found that methane emissions are being underreported by at least the equivalent of between 170 million and 3.3 billion tons of carbon over a decade, depending on the metric used in calculating the shortfall.

This means that each year, on average, companies around the world have potentially underestimated their carbon footprint by as much in total as the annual carbon emissions of the UK in 2022. This represents a significant methane emissions gap that could cost between $1.6 billion (£1.3 billion) and $40 billion (£32 billion) to fix.

Lead Author Dr Simone Cenci (UCL Bartlett School of Environment, Energy & Resources) said: “The cumulative emission gap we have documented in this work shows how important it is to standardise the reporting of methane emissions. Methane is a potent greenhouse gas and the first step towards properly addressing its effect on climate is to make sure that it’s accounted for properly. Adopting a global standard is in principle easy for companies as it essentially only requires the adjustment of a few conversion factors when calculating their greenhouse gas footprint. However, it requires global coordination as companies are currently often subject to fragmented regulations.”

Methane is a potent greenhouse gas that contributes to global warming at levels comparable to carbon dioxide. Though methane is emitted in much smaller quantities than carbon dioxide, it’s more efficient at trapping heat in the atmosphere. However, methane is also short-lived in the atmosphere, with a half-life of only about 10 years versus 120 years for carbon dioxide.

How much total heat a greenhouse gas traps is called its Global Warming Potential (GWP) and measured in CO2 equivalent units, or the amount of carbon dioxide gas that would cause the same amount of warming. Because of methane’s short lifespan, the conversion to CO2 is not straightforward and debate persists about how best to represent it in terms of carbon dioxide.

If methane’s impact is calculated over 20 years (GWP-20), it’s about 80 times more potent than carbon dioxide because that’s the timeframe before most of it has dissipated. However, gauged over 100 years (GWP-100) more of the methane has broken down so it’s only about 28 times as potent.

For companies estimating and reporting their greenhouse gas footprint, this lack of harmonization can cause confusion and inaccuracies, as there’s no legally binding guidance or consensus for which standard to use.

In this study the researchers compiled and analysed methane emissions from a sample of 2,846 representative companies across a range of economic sectors and countries. They found the conversions used by the companies are largely inconsistent with the guidelines of most current carbon accounting standards that recommend the same GWP-100 metric as the latest Intergovernmental Panel on Climate Change (IPCC) Assessment Report.

To see how much methane emissions might be underreported, the team substituted the companies’ various accounting conversions with the standard GWP-100 system suggested by the IPCC. Over the ten years from 2014 to 2023, methane emissions were underreported by the equivalent of about 170 million tons of carbon dioxide.

When they harmonised all reporting to the stricter GWP-20 standard, advocated by some climate scientists and used in some US jurisdictions, they found that over the same decade, methane emissions had been underestimated by the equivalent of about 3.3 billion tons of carbon dioxide.

The team also analysed the economic cost of correcting the underrepresented carbon footprints. Based on carbon prices from emission trading schemes across the globe, the cumulative cost to companies over the study’s ten years would total about $1.6 billion (£1.3 billion) to align all global companies with the GWP-100 standard, and about $40 billion (£32 billion) to align with the stricter GWP-20 standard. Companies in the energy, utilities and material sectors would face the biggest costs because they are the biggest industrial emitters of methane.

The authors note that even with their suggested corrections, total methane emissions are still being underestimated, as their calculations only focused on emissions directly produced by the companies they analysed. Other, downstream emissions, such as that which comes from sold products, were not included, and are likely significant contributors as well, particularly in the energy sector.

 

Notes to Editors

For more information or to speak to the researchers involved, please contact Michael Lucibella, UCL Media Relations. T: +44 (0)75 3941 0389, E: m.lucibella@ucl.ac.uk

Simone Cenci & Enrico Biffis, ‘Lack of harmonisation of greenhouse gases reporting standards and the methane emissions gap’ was published in Nature Communications on Tuesday 11 February 2025

The DOI for this paper will be https://doi.org/10.1038/s41467-025-56845-3

The paper can be found at: https://www.nature.com/articles/s41467-025-56845-3

 

About UCL – London’s Global University

UCL is a diverse global community of world-class academics, students, industry links, external partners, and alumni. Our powerful collective of individuals and institutions work together to explore new possibilities.

Since 1826, we have championed independent thought by attracting and nurturing the world's best minds. Our community of more than 50,000 students from 150 countries and over 16,000 staff pursues academic excellence, breaks boundaries and makes a positive impact on real world problems.

The Times and Sunday Times University of the Year 2024, we are consistently ranked among the top 10 universities in the world and are one of only a handful of institutions rated as having the strongest academic reputation and the broadest research impact.

We have a progressive and integrated approach to our teaching and research – championing innovation, creativity and cross-disciplinary working. We teach our students how to think, not what to think, and see them as partners, collaborators and contributors.  

For almost 200 years, we are proud to have opened higher education to students from a wide range of backgrounds and to change the way we create and share knowledge.

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Journal

Nature Communications

DOI

10.1038/s41467-025-56845-3 

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Lack of harmonisation of greenhouse gases reporting standards and the methane emissions gap

Article Publication Date

11-Feb-2025