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Agriculture, forestry and land use accounts for 18 per cent of global greenhouse gas emissions. It’s an irony that a sector striving to feed the world more effectively is, by doing so, contributing to its environmental challenges. However, agriculture also has a key role to play in tackling climate change. In this article, global sustainability consultancy, Ricardo, explores some of our planet’s most pressing issues and the technologies being developed to help solve them.
The world’s population is growing by more than one per cent per year. That’s 83 million more people to feed, at a time when the Food and Agriculture Organization of the United Nations reports that nearly one in ten people in the world are exposed to severe levels of food insecurity and nearly 690 million are hungry.
The soils, water and biodiversity of our planet are under extreme strain. Ocean health is declining. According to the World Bank, these challenges are intensified by agriculture’s vulnerability to climate change including the impact of increasing temperatures, invasive plants and pests and extreme weather events. The geographical impact of such changes is unevenly distributed. Countries in the southern hemisphere are not the main originators of climate change yet suffer the greatest share of the damage.
“agriculture, forestry and land use accounts for 18 per cent of global greenhouse gas emissions”
The concept of ‘climate-smart agriculture’ encompasses crop and livestock production, forest management and fisheries. It is defined by the World Bank as an integrative approach to address the interlinked challenges of food security and climate change, with three key objectives:
- Increased productivity
- Enhanced resilience
- Reduced emissions
Achieving this ‘triple win’ was at the heart of the World Bank’s first Climate Change Action Plan from 2016-2020 as well as its update covering 2021-2025. Two years ago, 52 percent of World Bank financing in agriculture targeted climate adaption and mitigation. These actions are helping countries implement their Nationally Determined Contributions at the heart of the Paris Agreement in the agriculture sector as well as contributing to progress on Sustainable Development Goals for climate action, poverty and the eradication of hunger.
Agriculture and the land-based economy is uniquely placed to capture CO2 from the air and turn it into a wide range of foods, fibres and fuels while balancing emissions of methane and nitrous oxide from food production
Auditing for efficiency
The National Farmers’ Union (NFU) has set the goal of reaching net zero GHG emissions across the whole of agriculture in England and Wales by 2040. This is the sector’s contribution towards the UK’s ambition of net zero by 2050.
There’s no single answer to this problem, says Dave Freeman, Associate Director for the Agriculture team in Ricardo’s Energy & Environment division. This is largely because the emissions from UK farms – currently 46.3 million tonnes of carbon dioxide (CO2) equivalent a year, or one-tenth of UK greenhouse gas (GHG) emissions1 – come from multiple sources and are produced within a complex biological system.
“Unlike the rest of the economy,” Freeman explains, “only around 12 per cent of agricultural GHGs are from CO2 created by energy use, specifically combustion. On a farm, this might be using mobile and stationary machinery such as tractors or during storage.
“There are two other principal contributors to agricultural GHG emissions. Methane (CH4) accounts for 56 per cent of farming’s emissions and comes from enteric fermentation in ruminant animals – belching and farting, essentially – and from manures as they break down. The remaining 31 per cent is nitrous oxide (N2O) emanating from soil as inorganic fertiliser breaks down.2
“These latter two are particularly important due to their global warming potential. Emissions reporting standardises the impact of each gas on its climate warming potential, using CO2 as the standard unit. If one unit of CO2 causes one unit of warming, one unit of CH4 causes 25 to 28 times the impact while one unit of N2O drives between 265 and 298 times more warming than a unit of CO2.”
The starting point for a farm seeking to reduce emissions, says Freeman, is a carbon audit: “This helps to pinpoint where the emissions come from and the opportunities for their removal. While the sector is certainly a significant emitter of GHGs, it also has the potential to help mitigate climate change by acting as a carbon sink, drawing down CO2 from the atmosphere and locking it up into soil and vegetation.”
On the one hand, this means helping farmers improve productivity to obtain the same amount of food, or more, with fewer inputs and lower carbon emissions. On the other, it means increasing the amount of carbon being sequestered in soils and plants by making land use changes such as tree and hedgerow planting and peatland restoration.
“There’s plenty of evidence,” adds Freeman, “that taking steps to reduce emissions is also a good way for farmers to improve their business efficiency. Farms with a low carbon footprint are generally the most efficient because they are getting more from what they put in. Many of the steps to reduce emissions will result in lower costs, improved profitability and greater resilience to change.
“A carbon audit is more than just a tool to assess a farm’s environmental performance – it’s an audit of a farm’s overall efficiency in using resources.”
Supporting post EU transition
Britain’s departure from the European Union means the UK is no longer bound by the Common Agricultural Policy. In 2021 the Government set out plans for England to begin a seven-year transition to a new system that will reward farmers for environmental improvements alongside food production on their land.
This change, coupled with the challenges caused by COVID-19 and a number of extreme weather events, has left many farmers and land managers under stress and needing to adapt their business models. In response, the Department for Environment, Food and Rural Affairs (Defra) set up a Future Farming Resilience Fund to provide information, tools and advice during this period of change.
Ricardo was one of 19 organisations appointed by Defra to support the sector through a pilot project offering one-to-one reviews with a farm business adviser, webinars and an online resource toolbox.
“We have so far supported more than 220 farm business reviews,” says Dave Freeman, “covering the risks, opportunities and implications of future changes in terms of agricultural policy and market conditions, together with guidance on financial and business planning.
“Our approach has evolved, however, from just the technical aspects of farm management to include a focus on the impact of uncertainty on farmers’ wellbeing. We have been working with a charity, the Farming Community Network, to help farmers and their families recognise and address the signs of stress. For many, stress and uncertainty are barriers to taking positive actions such as introducing more sustainable farming practices.”
“satellite and drone technologies enable farmers to be more specific and targeted with inputs such as fertilisers”
Planning to reduce emissions
A study conducted by Ricardo on behalf of Kellogg’s3 found that up to a 60 per cent reduction in net emissions is possible by focusing on a farm’s most productive areas, with no impact on yield or financial performance.
Four options were modelled on a 550-hectare arable farm in Bedfordshire:
- Altering nitrogen management: reducing applications by 25 kilograms per hectare across the farm.
- Expanding uncultivated margins: using agri-environmental options on marginal land to increase biodiversity and bringing in two-year grass/legume rotations across whole fields.
- Introducing ‘silvo pasture’: planting trees in grassland using species such as cherry and walnut.
- Boosting renewable energy generation: increasing the number of photovoltaic solar panels and installing a biomass heating system.
While the last two options would require some upfront investment, all were being considered for this particular farm as steps towards achieving net zero. Results showed that it would be possible to reduce emissions through any or all of them.
Farming with precision
“Much of our work to reduce greenhouse gas emissions,” says Dave Freeman of Ricardo, “is based on understanding the technologies that can facilitate these reductions. Satellite and drone technologies, for example, enable farmers to be more specific and targeted with inputs such as fertilisers.
“Precision agriculture is most often associated with arable farming, but significant opportunities lie within precision livestock farming (PLF). PLF draws upon a set of electronic technologies, including cameras, sensors and feed additives, to allow automated monitoring of animals to improve their productivity, health, welfare and environmental impact. We’re all familiar with Fitbits for humans; now there are Fitbits for cows!”
From waste to energy
Carbon capture, utilisation and storage (CCUS) is a key technology in the quest for net zero. Naser Odeh, Head of Heating and Infrastructure, and Josh Dalby, Chief Engineer, at Ricardo discuss how biochar, a by-product of some biomass pyrolysis, can help improve the quality and sustainability of the food on our plates.
“a wide range of emerging applications are being developed – some of which are intended for permanent storage of the carbon”
What exactly is CCUS?
Naser Odeh: CCUS refers to a combination of technologies where carbon dioxide (CO2) is first removed from the flue gases of power generation and industrial processes or directly from the atmosphere.
It’s then either utilised in other processes onsite or compressed and transported by dedicated pipeline, by road or by ship to a location where it can be used in industry (known as carbon capture and utilisation, CCU) or injected for permanent storage in oil and gas fields or geological saline aquifers (carbon capture with permanent storage, CCS).
The various elements of the CCS chain (CO2 capture, transport and storage) are well-established and have been successfully demonstrated in industry for decades – but individually. For example, CO2 removal is an essential process in natural gas sweetening and in the chemical sectors for the production of hydrogen and ammonia. Also, CO2 injection for enhanced oil recovery is a well-established process in the oil and gas industry.
On the utilisation side, CO2 is used in the food and drink and pharmaceutical industries, for urea manufacturing, in greenhouses and much more. Also, a wide range of emerging applications are being developed – some of which are intended for permanent storage of the carbon, such as concrete curing and aggregates, while others such as synthetic fuels and e-kerosene are aimed at displacing fossil-based fuels.
The combination of CO2 removal from the atmosphere (known as direct air capture, DAC) or from the biomass process (for example, combustion or gasification) with carbon capture and permanent storage (BECCS) has the potential of achieving negative emissions – which, according to the Climate Change Committee’s sixth Carbon Budget, are essential if the UK is to meet net zero by 2050.
Such methods are known as greenhouse gas removal (GGR) technologies, which also include carbon capture via biochar from biomass pyrolysis as well as nature-based methods such as afforestation.
Why does CCUS offer such great potential in helping to meet net zero?
NO: The pathways to limit global warming to well below 2°C and preferably to 1.5°C compared to pre-industrial levels all include CCUS. There are hard-to-abate sectors where CCUS provides the only decarbonisation route or the most economically viable solution. CO2 removal from the atmosphere through DAC combined with permanent storage of the CO2 is seen as necessary to balance residual greenhouse gas emissions in 2050 from the agricultural and construction industries.
In addition, modelling by the Intergovernmental Panel on Climate Change clearly shows that BECCS is necessary for temperature rise to be limited to 1.5°C. This highlights the important role that CCUS in general and greenhouse gas removal technologies such as DAC and BECCS can play and why demonstration programmes need to be established and accelerated through the 2020s.
What can the biochar be used for?
Josh Dalby: There are several existing and emerging applications for biochar. It can be used by farmers, anaerobic digester operators and wastewater treatment sites.
Soils rich in carbon have greater physical and chemical properties for supporting plant growth. Over time, however, as a result of both natural processes and cultivation, these soil carbon pools become depleted. Adding biochar is a way to sustain the soil carbon pools and maintain productivity.
The biochar creates a layer in the soil which acts in a similar way to a domestic charcoal water filter. It holds chemicals and nutrients and prevents them leaching through to deeper levels and watercourses while improving their availability to plants. At the same time it provides an environment for microscopic organisms, bringing further improvements in soil health. This means it is much in demand in organic farming.
More productive soils also lead to greater production of biomass which, in turn, means a greater amount of CO2 being sequestered from the atmosphere. In this way, sustainable agricultural production, soil carbon management and climate change mitigation are inextricably linked.
As well as improving the fertility of soil, biochar is also used as a supplement to animal feed in livestock farming as it supresses methane emissions generated in the digestive process. This means that in regions such as Europe and North America, where meat consumption is still high, the demand for biochar is likely to continue to increase substantially.
Analysts have predicted that the global biochar market could reach $3.1 billion by 2025 and expand at a compound annual growth rate of around 14 per cent in the next decade.
When might we see this technology deployed?
JD: We have identified a site for our first demonstrator plant and our ambition is to have it running in mid-2023. Then, by focusing on smaller community-scale applications, we can deploy quickly and widely. We can operate close to the source of waste, minimising GHG emissions related to the transportation of the raw materials. And each community can benefit from the by-products.
Could the UK be at the forefront of community-scale carbon capture technology on a global stage?
NO: In terms of GGR technologies, the focus worldwide is currently on deployment on large stationary stations including power plants and industrial sites. We propose that deployment on community-scale systems also has a key role to play in CO2 removal from the atmosphere, thus helping achieve net zero targets while also developing the CO2 and biochar markets and providing communities with heat and electricity. However, such community-scale systems are still expensive and so support is needed in the early stages to reduce costs, overcome the technical challenges and develop the supply chain. This will help the UK become a leader in a technology that can be exported worldwide, with the significant emission savings making an important contribution to net zero targets.
To find out more visit: ee.ricardo.com/energy/carbon-capture-utilisation-and-storage
References
- gov.uk/government/statistics/agri-climate-report-2021/ agri-climate-report-2021#section-1-uk-agriculture-estimatedgreenhouse-gas-emissions
- gov.uk/government/statistics/final-uk-greenhouse-gasemissions-national-statistics-1990-to-2018
- wi.co.uk/arable/kelloggs-study-shows-how-arable-farms-canaim-for-net-zero
