Why Measure the Carbon Footprint of Vineyards?

In 2020, with global temperatures rising at unprecedented levels and a marked increase in extreme weather events, climate change is being perceived as a major challenge. The Intergovernmental Panel on Climate Change (IPCC) estimates that global average temperatures are rising at 0.2°C every decade, and, if this rate continues, we are likely to reach 1.5°C above pre-industrial levels by 2030. This change will have an irreversible impact across all industries, including wine production: for instance, it is predicted that many quality wine growing areas of Spain will only be suitable for bulk wine within the next 30 years. The Paris Agreement aims to keep the global average temperature within 2°C above pre-industrial levels and is pursuing efforts to limit it to 1.5°C; this has encouraged the UK government to pursue a net zero target by 2050, and the National Farmers Union to set Achieving Net Zero as a goal for UK farming by 2040.

Greenhouse gas (GHG) emissions are defined as the increase in concentration of certain gases in the atmosphere, through the activities of human beings. The main greenhouse gases are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF6); but carbon dioxide, methane and nitrous oxide account for nearly 90% of all man-made greenhouse gas emissions. Commonly referred to as the “Greenhouse Effect”, greenhouse gases trap heat reflected off the Earth’s surface, causing the planet to increase in temperature. Our carbon footprint is the measure of greenhouse gas emissions we are producing: this can be used to compare emissions ranging from a national level all the way down to an individual vineyard.

While many of us want to do our bit and reduce our greenhouse gas emissions, without a starting point it is impossible to set measurable goals. In addition to reducing sources of GHGs, there are many opportunities to offset these emissions with interventions such as planting cover crops and hedgerows and minimising soil tilling. Initiatives like Four Parts Per Thousand aim to revitalise the agriculture industry by utilising its potential for forming carbon sinks, which can help us to solve this global crisis.

Aside from the desire to protect our environment, there are several more commercial reasons for measuring, then working to reduce your GHG emissions and overall carbon footprint. The first is that, by reducing conventional machinery usage, you can directly reduce your fuel costs. Furthermore, by moving to an Integrated Crop Management approach; for instance by ensuring that nitrogen-based fertilisers are used efficiently, you can directly reduce the cost of materials. The second benefit is that, from a marketing point of view, showing an honest interest in carbon footprinting has a clear benefit and could lead to increases in sales, particularly from young wine consumers, if promoted. We also need to bear in mind that UK Government regulation on carbon emissions in agriculture will come sooner or later. It will be related to farm payments (public money for public goods). Be prepared or be forced to change!

Ho do other industries do this?

The term ‘carbon footprint’ is widely used for measuring the amount of greenhouse gas emissions associated with commercial and consumption activity. There are currently a number of methodologies for calculating carbon footprints, including the Greenhouse Gas Protocol, produced by the World Resources Institute and World Business Council for Sustainable Development, and a standard produced by the International Organisation for Standardisation, ISO 14064. Both of these methods use life-cycle analysis techniques and measure corporate or project greenhouse gas emissions rather than a per product carbon footprint. As a result of increased public understanding of climate change, there is increasing consumer demand to encourage producers of goods and services to adopt a method of measuring and clearly labelling the carbon footprint of individual retail products and services. The Carbon Trust is currently trialling a carbon label that shows the carbon content of a product in grams as well as a signal of the producer’s commitment to lowering their products’ carbon footprint. To support the label, Carbon Trust has developed a carbon footprint methodology, drawing heavily on the life-cycle assessment techniques outlined in the GHG Protocol, BSI PAS2050 and ISO 14064.

Different wine producing regions have adapted varying forms of carbon tracking. The Australian Wine Research Institute uses an Excel spreadsheet with emissions classified into three different ‘Scopes’:

Scope 1: Direct emissions that arise from within the bounds of your operation. These include fuel use, energy use, manufacturing process activity, or on-site waste disposal.

Scope 2: Indirect emissions that occur in the wider economy as a consequence of an organisation’s activity. The most important indirect emissions come from electricity generation.

Scope 3: Indirect emissions from other sources include the manufacture and disposal of packaging, transport, and the sale and consumption of wine.

Their calculator focuses on Scope 1 and 2, but does not tackle the Scope 3 emissions. AWRI also provides a training course to further understand the impact of wine manufacturing.

Sustainable Winegrowing New Zealand doesn’t currently require its members to measure their carbon footprint, but it has a strong focus on climate change, and has adopted a carboNZero Certification, overseen by Landcare New Zealand, one of the eight Crown Research Institutes. Meanwhile, in California, spurred on by the passage of the Global Warming Solutions Act 2006, 73 researchers at University of California, Berkeley, and the California Air Resources Board have also begun investigating the creation of a viable carbon label using assessment techniques comparable to those developed by the UK’s Carbon Trust. The Office Internationale de la Vigne et du vin (OIV) has published an excellent inventory of factors concerning GHG emissions and sequestrations in Greenhouse gases accounting in the vine and wine sector.

New Zealand carboNZero certification
The WineGB Carbon Calculator

A sub-group from the SWGB Workgroup considered several options, which could be grouped into two types of carbon footprint calculator: a bespoke spreadsheet, such as the Australian Wine Carbon Calculator, and a web-based system, such as that used by the Cool Farm Tool. After working on this subject for several weeks, we decided that the latter option is better for us, as it makes sense to go with an established tool, which conforms to international protocols, is regularly updated, and already includes complex areas like carbon sequestration. Unfortunately, all the existing carbon calculating tools are quite complicated to use, and don’t concern themselves with wine production.

The chosen proposal was from The Farm Carbon Toolkit Company, as they have a free carbon calculating tool that is very comprehensive, their website full of useful information, and they were very responsive to the need to adapt their tool to the UK wine industry. Sponsored by a generous donation from WineGB South East, SWGB has been working with them to make their tool more relevant. In particular, we have constructed a bespoke landing page where WineGB members can register, and gain instructions (including a video!), on how to use their Calculator. As you can see from this site, the next step is to download and complete a data collection sheet, which takes quite a bit of time, but makes it much easier to fill in the tool itself. The list is very comprehensive; the first time you fill it in, you might want to focus on the ‘Minimum Standard’ requirements (as opposed to ‘Best Practice’). Once you have created a new report, this will take you to the ‘Data Entry’ page, where you can use the data from the spreadsheet to fill in every relevant category. There are helpful hints throughout the data entry section to help you, and, as you go along, you can immediately see the results in terms of Carbon Dioxide equivalent (CO2e) in tonnes per year, in a diagram that will look something like the one here.

If you click on either a segment in the chart, or an item in the list, a pop-up will illustrate the exact item, emission and percentage of the total emissions. You can edit or delete any item in the list at any time. This function, along with the category emissions, not only gives you an excellent overview of how your carbon footprint is stacking up, but also enables the WineGB Carbon Calculator to act as a decision-making tool. For example, you could start a new report and make some comparisons on the impact of planting some new woodland; using a new electric vehicle; building your soil organic matter...there are lots of options available. Once you have completed the data entry, click on ‘View Report’. Note that you can toggle back and forth between the ‘Report’ and ‘Data Entry’ area at any time. The report gives you three levels of detail: ‘Summary’, ‘Detailed Summary’ and ‘Full Results’, offering you varying levels of detail and analysis of the carbon footprint of your business.

Carbon Footprint live results table

The main idea of the Calculator is help you make positive changes to reduce your carbon footprint, year on year. From the Calculator, you will be able to see the carbon hotspots on your vineyard (and winery). There are lots of opportunities to cut emissions in all sectors, and to increase carbon sequestration in the soils and biomass on your vineyard, and the land surrounding your winery. Carbon sequestration offers huge potential to ‘offset’ your vineyard emissions, and is going to be a clear policy direction for farming subsidies in coming years. In ‘Full Results’ you’ll see links to detailed advice, information and resources for farmers and growers to reduce their emissions or increase sequestration in specific areas. Farm Carbon Consultancy also offers consultancy and training to farmers and organisations who want more in-depth support. It’s very important to both reduce emissions and increase sequestration together. It’s the same principle as ensuring you insulate a house before fixing solar panels to the roof.

Once you have completed your carbon footprint, repeat it on an annual basis in order to understand how you’re progressing. Keeping up this process makes you look at your business in a different way; hopefully you will always be looking at opportunities to reduce emissions and increase sequestration. WineGB Members seeking SWGB Certification will need to go through this process every year, then formulate a strategy to reduce their carbon footprint every three years, when they present themselves for audit.

Sequestering carbon in the vineyard

Carbon sequestration is the capture of carbon dioxide from the atmosphere. This gas is absorbed by plants through photosynthesis, and can then be stored long-term in woody biomass and soils. Agriculture and forestry are the only industries that can sequester more carbon than they emit, offering a huge opportunity to contribute to the global aim of reducing our global carbon emissions.

Vineyards have great potential to be net carbon sinks, because of the perennial nature of the crop and the lack of cultivation. However, some systems will be sequestering more carbon than others, therefore understanding your carbon footprint is really important. Vines themselves sequester 2.84 tonnes of carbon dioxide per hectare per year, which is approximately a third of one UK person’s total annual carbon footprint. Carbon is stored in the woody biomass, and some carbon is assimilated into the soil via the root system. It’s worth noting that if you burn the prunings from vines, a lot of that carbon is released back into the atmosphere, which is why this practice is prohibited for those seeking SWGB Scheme Certification. On the other hand, mulching or composting the prunings could raise your soil organic matter (SOM). If your SOM rises, via whatever management change, by 0.05% in a year, it will sequester an extra 4.47 tonnes of carbon dioxide per hectare.

Hedges can sequester anything between 4.40 and 7.20 tonnes of carbon dioxide per hectare per year, depending largely on their management system. Essentially, the larger the hedge, the more carbon it captures, so if you can leave your hedges to grow up and out, and cut less frequently, they will absorb more carbon. This should also provide better bird nesting opportunities. Woodland can sequester anything from one tonne to over 25 tonnes of carbon dioxide per hectare per year, depending on age and species. Trees that are roughly 15 to 35 years old suck in carbon at the highest rate, with deciduous trees slightly outperforming conifers, but conifers starting at an earlier age. Note that trees of 100 years or more continue to sequester carbon, albeit at a lower rate. All this is taken into account when calculating your carbon footprint using the WineGB Carbon Calculator.

Soil management is perhaps the best opportunity to increase carbon sequestration in the vineyard, but first you need to measure your SOM levels across your fields. The Farm Carbon Calculator Company have a detailed guide on how to do this called Testing soils for organic matter. There are two main areas to focus on: reducing the potential for SOM to be lost, and maximising carbon gains. To reduce losses, ensure that cultivations are minimised, or preferably eliminated (apart from prior to establishment). If they do need to be undertaken, make sure that they are shallow and of minimum frequency, as, when soil is cultivated, this disturbance introduces a sudden flush of oxygen to the deeper layers of the soil, which stimulates the soil microbiology, resulting in a loss of carbon. Bare soil will also likely lose carbon, so best to cover it with weed control fabrics or natural mulches like woodchip or compost.

After losses are minimised, try to maximise your carbon gains by ensuring that organic materials are frequently added into the system. This could be achieved by spreading woodchip and/or compost where possible, and paying attention to your alleys. It could even be beneficial to reseed some alleys with different grass mixes, as well as adding some legumes. Expert advice from a seed merchant could be beneficial. Allow grasses to grow longer to assimilate more carbon, whilst reducing fuel use through mowing. Field margins are also an opportunity to grow much deeper rooting grass and legume species, which can increase carbon sequestration and biodiveristy, without affecting the growth of vines. Remember that soils higher in organic matter often have improved biodiversity (above and below ground), better water retention and drainage, are more fertile and sequester carbon. A win-win approach!

Albury Organic Vineyard Poppies
Reducing carbon dioxide and GHG emissions

First it should be noted that grape and wine production are not major contributors to climate change compared with, say, cement manufacturing, aluminium production, transport or electricity generation from coal. However, their impact is not immaterial, and the sector is very much subject to consumer trends towards more sustainable patterns of consumption. It is therefore useful to consider some ways that vinegrowers can reduce their footprint.

The analysis of the carbon footprint of wine shows that carbon emissions from vineyards contribute a relatively small share of the overall carbon footprint of a bottle of wine; glass bottles make the largest contribution. However, from a consumer perspective, the vineyard is emblematic of wine production, so a low carbon (and local) status could provide an attractive marketing message for UK producers.

The primary sources of carbon emissions on a vineyard are from energy consumption (electricity and fuel) and nitrous oxide emissions from fertiliser use. Electricity use on a vineyard is usually associated with pumping for water irrigation and so is unlikely to contribute in the UK context, though some growers are looking to use electricity in frost protection systems. Other energy use is of diesel or other fossil fuels, associated with machinery used for spraying, harvesting, soil preparation, transportation and other vineyard operations. Vineyard owners are already amply incentivised to reduce these emissions as it represents a significant cost to production. Such emissions can be reduced two ways: use less, or change the power source, so the first message is to drive less and use less diesel, but what alternatives exist for changing fuel? In passenger cars, there has been a significant trend towards battery-powered electric vehicles (BEVs) or hybrid vehicles, which have a lower footprint, even when including the greater ‘upstream’ emissions associated with battery production. At present, the uptake of electric tractors in agriculture has been very limited, due to a lack of charging infrastructure, high cost, low range and recharging downtime. Electric farming vehicles are probably an innovation for the medium term and perhaps a more realistic next step for vineyard owners is to consider fast charging points for public visitors (where local electricity load allows) and moving to BEVs or hybrids for their business passenger vehicles.

The second largest emitter at farm level is the use of nitrogen-based fertilisers, as these can result in large amounts of nitrous oxide emissions. Nitrous oxide is 300 times more potent as a greenhouse gas than carbon dioxide. Organic fertiliser may also generate significant emissions due to the fuel used in its transportation, and synthetic fertiliser requires energy use in its production. Other sources of vineyard emissions relate to waste disposal, wastewater processing and trellis materials. All these are accounted for in the WineGB Carbon Calculator. In some cases, vineyard waste can be turned into sources of power: biofuel can be produced from woodchips and pomace.

In 2008, Torres, the largest wine producer in Spain, committed to reducing the carbon footprint per bottle of its wine. The innovations it introduced include:

  • Five acres photovoltaic solar array on the roof of its main warehouse, plus a boiler that burns the prunings from its vineyards and other organic wastes, contributing 15% of its overall energy use and reducing gas consumption by 95%;
  • Water reservoirs: recycling and treatment of water on-site, storage of water for summer irrigation, drip control irrigation;
  • 80% of vehicles are electric or hybrid, including an electric-solar train for visitors;
  • Using an innovative technology to capture and use the CO2 from the fermentation of grapes;
  • A programme of ‘insetting’; reforesting its own areas of Spain and Chile.

For more information see www.torresearth.com

By 2018, it had reduced its footprint by 28% per bottle. Maybe the UK wine industry can achieve similar results?


The WineGB Carbon Calculator: Webinar

To find out more about the WineGB Carbon Calculator, and how to use it, watch the video of a webinar held on 10th June 2020 with Jonathan Smith, from the Farm Carbon Toolkit, Ian Behling and Emily Dawson from Ricardo (the auditors of the SWGB Scheme) and Morgan Jones from Carbon Trust.

For further questions on the carbon calculator please email [email protected].