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Going bananas for Life Cycle Assessments

If you’re a carbon nerd – those who, like us, love all things associated with carbon accounting– and have not yet picked up a copy of Mike Berners-Lee’s book ‘How Bad Are Bananas – The Carbon Footprint of Everything’, we strongly recommend you do. It will satisfy your carbon curiosity by providing you with robust insights into the carbon emissions associated with all sorts of everyday products and tasks – including bananas.

The calculations in Mike’s books are based on Life Cycle Assessments (LCAs), which are a scientific method for calculating a product or system’s environmental impact. In assessing this impact, a product or system’s Global Warming Potential (GWP) will be measured. GWP refers to the effect of the common greenhouse gases:: carbon dioxide, methane and nitrous oxides. The GWP of greenhouse gases is commonly aggregated and expressed as a carbon footprint, using the carbon equivalent unit: ‘CO2e’.

In today’s world of carbon accounting, LCAs are at the heart of almost every piece of data expressed as ‘CO2e’. Mike’s claim of having ‘the carbon footprint of everything’ shows that, in recent years, we have made much progress in assessing the carbon footprint of our products and services. Nevertheless, issues do remain when it comes to LCAs.

So, what is the problem with Life Cycle Assessments?

Problem #1: Comparing apples to bananas? Difficult comparisons

According to the Handbook on Life Cycle Assessment, the first step to measure a LCA is to define a clear functional unit (e.g. 1 banana, consumed in Singapore). This is a relatively straightforward step. The second step is to set a realistic system boundary. The boundary will determine which inputs, outputs, and processes you will be considering and quantifying (e.g. for a banana this could include various elements across its supply chain). This second step is complex and is at the heart of why it is so difficult to compare two products, even two of the same products.

Let’s go back to our trusty banana. A banana consumed in Singapore will have a significantly different LCA, and associated carbon impact, when grown and transported from Costa Rica versus China (#10 and #2 of global banana producers in 2021 respectively). Not only is the transport distance different, but the growing method and the carbon intensity of the energy used during cultivation, harvesting, processing and storage will vary from country to country. And those are just a few variables one must consider when calculating LCAs. Once we look at more technical products, like a fridge or a laptop, the added complexity of such product systems means that quite literally no two assessments are the same.

Without full transparency of what has been and has not been included in the LCAs’ calculations, it is easy to misconstrue results and wrongly draw comparative conclusions from two LCAs that on the surface look similar.

Problem #2: From seed to peel? Not the entire lifecycle

One would assume that by ‘lifecycle assessment’ we actually mean the entire lifecycle (other terms used include cradle-to-cradle farm-to-fork or farm-to-gate). Despite these terms, in practice, little attention is given to end of life treatment, often resulting in an incomplete ‘lifecycle’ analysis.

For example, the potential for reusing a product or recycling it is poorly assessed and different end-of-life processing options are rarely modelled. This prevents meaningful comparisons between different end of life treatments. The environmental and carbon impact of composting a banana peel is significantly lower compared with it ending in the landfill. Both options need to be modelled to ensure proper comparisons. These end of life treatments have much larger impacts when considering more complex products.

So, what can you do?

Here are our top tips to make sure you are properly interpretating and using LCAs:

  1. Check the author, and any sponsors, to establish legitimacy. If someone has paid for an LCA to be produced, the information used is probably not as objective as it should be.

  2. Understand the system boundary. Usually, a diagram will showcase the inputs and outputs to assist you. This will allow you to better compare different products and their carbon impact, and to understand what has or has not been included in the LCA.

  3. Make sure that end-of-life treatment has been considered and that options you are considering have been modelled. If they have not been included, you may want to do additional calculations.

  4. Ensure transparency, in particular for assumptions and methodology used.

How can xtonnes help?

Although we do not currently produce LCAs, you can measure the carbon footprints of your products on the xtonnes software. This is an integral part of your product’s environmental impact and knowing the carbon emissions associated with your products can help inform:

  • Your company’s decisions over future product lines.

  • The design of products to reduce their carbon impact.

  • End-of-life processing options to reduce associated carbon emissions.

  • Wider decarbonisation strategies and actions by visualising your products’ emissions as part of your wider organisation.

Interested in learning more about products’ footprints, get in touch with us!


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