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Carbon Calculators for World Health

This blog was written for World Health Day by Dr Will James and Alexandra Dalton.

Will is a Teaching Fellow at the School of Geography, University of Leeds. He has research interests in food inequalities and dietary change.

Alex is a Data Scientist at the Consumer Data Research Centre, University of Leeds. She has research interests in consumer behaviour and sustainable diets.

Photo by NASA on Unsplash

The food we eat plays a crucial role not only for our health but also in the health of the planet. Astonishingly, over 70% of all deaths worldwide are caused by chronic diseases[1] where diet is routinely a contributing risk factor, highlighting the importance of maintaining a healthy diet and the potential benefits of dietary change. Food production also has a huge impact on the environment, accounting for 30% of all greenhouse gas emissions and requiring vast amounts of water and land. Meat production disproportionately contributes to climate change as feeding and raising animals requires substantially more energy (and emissions) than equivalent crops for direct human consumption. Furthermore, some animals produce vast quantities of methane, a potent greenhouse gas.

Changing what we eat could massively reduce these impacts, with vegetarian diets producing 37% less emissions than their non-vegetarian counterparts. The first stage of dietary change is assessing the impact of the foods we currently eat, allowing us to see where improvements can be made. Carbon calculators are an incredibly useful tool for this, providing a baseline of the emissions from our current diets and helping to suggest alternative food products. Many multinational companies are working towards labelling the emissions of their products and menu items have previously been labelled at high profile events such as the COP26 climate summit.

Carbon calculators link a database of product level emissions to the quantities of each product consumed. By aggregating the emissions of all products consumed by an individual/organisation, we are able to estimate the total carbon footprint from food. This process allows us to estimate (and thus mitigate) the impact different aspects of our lifestyle have on the environment. Calculators which focus on the carbon footprint of different foods are particularly useful to better look after the planet, since food is something that contributes massively to climate change but, whether you class yourself as a foodie or not, it is part of our lifestyle we perhaps have the most control over.

Although there are assumptions in carbon footprint calculators (e.g. the central database may not differentiate the emissions between different varieties of apples), the results will still be useful for assessing emissions from each type of product and helping to indicate areas that are particularly problematic. For example, seeing the carbon footprint difference between a chicken wing and an apple helps us all to get a grasp on how different carbon footprints really compare. By reducing our carbon footprint through eating more low-carbon meals, we can help keep the planet, and in turn humans, healthy — feeding into the aims of World Health Day!

Carbon footprint calculators are a great way to understand how we can reduce the way our food contributes to climate change. At the Consumer Data Research Centre (CDRC), we have been developing a carbon footprint calculator to evaluate the carbon footprint of school meals in Leeds.

Photo by Kelly Sikkema on Unsplash

A climate-friendly menu was recently introduced by Leeds City Council’s catering service Catering Leeds to primary schools across Leeds. The new menus offer school meals that are environmentally conscious as well as health conscious. Our calculator is the next step to look at the climate impact of these school meals in more detail.

The calculator takes a school menu and uses the recipes to generate a carbon footprint for each meal. The calculator also identifies highest emission ingredients within each recipe, to help re-design the recipes and consider changing the proportions of certain ingredients.

The project is in partnership with Leeds City Council and Catering Leeds, meaning the tool is going to be used to look at the meals they offer and to design efforts to reduce carbon emissions across the city.

The same process used to build the School Meal Calculator could easily be replicated to address other risks to our health or to the planet’s health. For example, the calculator could evaluate the healthiness, nutrients or other environmental impacts, like water footprint, of different meals in the place of carbon footprint estimates.

To really make a difference with this research, we want to make sure we win the hearts of everyone involved to look after the health of the planet. So, to extend the benefits of the school meal calculator and educate young people about their school meals, we are working with schools in Leeds to run Low-Carbon Food Workshops.

The workshops will teach young people how to make links between our food consumption and our carbon footprint and identify low carbon meals. The key messages are essentially that having more plant-based foods (e.g. fruit and vegetables) and whole foods (e.g. lentils and beans) to reduce the amount of meat will reduce the carbon footprint of most dishes whilst still ensuring that they’re tasty and filling.

As those eating school dinners every day, we wanted to make the insights from the carbon footprint calculator accessible to young people. Therefore, we are currently developing an educational online card game for kids. Each virtual school meal card has categories related to greenhouse gas emissions for different parts of the meal, which they use to try to beat their opponents' score in, helping reinforce learning from the workshop about what makes a low carbon meal.

Through the Leeds Institute for Data Analytics (LIDA), a similar process is planned for the university itself, using a carbon calculator to baseline current emissions across all their catering services. This will help to identify menu items with a high carbon footprint and suggest alternative products. This will be crucial for the university to meet its goal of being net-zero by 2030.

Photo by Tim Mossholder on Unsplash

Dietary change is a complex process and needs to be carefully managed to avoid negative secondary impacts. For example, a reduction in meat consumption may lead to a reduced intake of nutrients such as iron and zinc, where deficiency is already known to be prevalent for certain groups of the population. This is especially true in developing nations where undernutrition is often a major public health concern. Rapid and wide-scale changes in diet may also place pressure on elements of the food system, with unemployment in some sectors and a skills and labour shortage in others a possibility. It is also important to consider that any alternative products used to replace their high-emission counterparts will have their own carbon footprint, thus counterbalancing the impact of those removed to some extent. To address these issues, research is currently ongoing at the University of Leeds to assess the impacts of dietary change in terms of the environment, health and the food industry in general. This study is using detailed food diary data from over 9,000 individuals to assess their current diets and the impacts under scenarios of dietary change. Targeted policy intervention is an important tool for mitigating these negative secondary impacts. From a health perspective, this may involve targeting the highest consumers of certain products (e.g. alcohol, red meat), without penalising those who would feel little benefit from reduction consumption.

A dietary change will be required to keep humans and the planet healthy against a backdrop of climate change and environmental degradation. Reducing emissions from food will be crucial for limiting global warming to 1.5 degrees Celsius as set out by the Paris Agreement and for enabling individual organisations to meet their own net-zero commitments. Detailed knowledge of current emissions is key for this process, helping organisations to identify where best to make improvements. Carbon calculators fulfil this purpose by estimating the emissions for each individual food item. The techniques being developed at the University of Leeds will be used by Leeds City Council, the University itself and maybe beyond. World Health Day recognises the link between our health and the health of our planet, showing how carbon calculators can have an impact on both.




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