Let's start with the most classic one, the definition. "Life cycle assessment, or LCA, is an evaluation of the environmental impact of a product, service or system in relation to a particular function and considering all stages of its life cycle." It can also be called an ecobalance, for the cool guys among you. 

Of course, it's never as simple as a definition, there are always a million concepts behind it. And that's why we're here today, so that you can become experts in the life cycle analysis of your everyday objects and stop being fooled by GreenWashing (Well, maybe that will be the subject of a future blog too...). 

It is very difficult to make a high quality LCA, which could be certified, just as it is often difficult to arrive at an absolute and quantified assessment from A to Z expressed in a single aggregated result. One would obviously like to see this aggregate result expressed in "tons of CO2 emitted", to echo the crucial problem of global warming. We give you a first example of a product whose manufacture causes emissions of CO2 and methane (CH4), two greenhouse gases. You cannot directly add up tons of CO2 produced with polluting methane emissions. To do so, one must first convert the methane emissions into kg of CO2 equivalent emitted according to its environmental impact. In reality, one kg of CH4 corresponds to 25 kg of CO2 emitted into the air. On the other hand, it is simply impossible to add up tons of CO2 produced with tons of heavy metal emissions. This illustrates the difficulty of translating an LCA analysis into a simple result for a quick comparison between different products with identical functions.

Let's take a simple example: a screw. It's something we use often and is found in almost every piece of furniture we own. Yet you would never suspect how many processes are behind such a small and practical object. It is important to know that an LCA does not only take into account the manufacturing process, but also the extraction of raw materials, the emissions from all processes and what happens to the object at the end of its life. Here is a highly summarised outline of a life cycle of a screw.

In blue, you find the important stages in the life of our little screw. In brown or beige, the direct inputs and contributions required for each stage or for the transition between these stages are shown. Finally, on the right-hand side and in red, the raw materials that required extraction and the emissions generated are shown.

As the subject is quite topical in our society today, you probably know that any emission obviously has one or more impacts related to global warming, human health, acidification, destruction of the ozone layer, soil pollution, and so on. 

So you can use this framework to compare different screws, or screws with nails or glue: same function but different product choices. Conversely, there is no point in comparing a bamboo toothbrush with a pair of recycled plastic shoes 😄.

An LCA can be used for many things and by many people. It allows us to better control the risks and also the costs linked to the life cycle of products and activities, to identify the links in the chain from the extraction of materials to the end of life that produce the greatest impact (environmental or not), so that we can act on them as a priority. This would also enable consumers to make choices between different products according to a scientifically recognised and of course standardised approach. It allows for innovation in functionality and improvement in the quality of products and activities, anticipating market expectations and encouraging more sustainable production and consumption patterns. Finally, it can serve as a basis for product certification and also for regulatory purposes.

In the long term, when this practice is generalised, we can hope that it will help everyone to make informed product choices, to better consume with full knowledge of the facts. For us as consumers, it is a question of using it as a comparison tool: to clean my house, should I take this natural and cheap product made close to home and without packaging (in bulk), or rather this synthetic chemical product in plastic packaging and produced in Eastern Europe? Expressed like this, the choice seems easy. But how do you choose between a plastic colander made of 50% bamboo fibres and 50% recycled plastic, virtually indestructible, and a stainless steel colander, both produced in China? A comparative assessment based on an LCA will help us in this choice.

An LCA consists of 4 main steps:

1. Definition of the objectives and scope of the study

2. Analysis of the inventory

3. Environmental and societal impact assessment

4. Interpretation, which in fact takes place at every stage of the analysis process

This can be done from different angles depending on the limits you want to put on your project. However, it must remain coherent. In practice, there are 3 different LCA scopes:

- Cradle to gate: in literal translation this means from the cradle to the gate. Basically, it corresponds to the path from the extraction of the raw material to the factory gate. It therefore does not take into account all the distribution, consumption, use and end of life of the product. It is therefore not really of interest to the consumer but is important to the manufacturer. 

- Cradle to grave: this is from the cradle to the grave. Here, however, all the stages are taken into account, but the object ends up in the landfill or in incineration etc. This is also called an "open loop". 

- Cradle to cradle: it is from cradle to cradle. You have understood the trend, here it is also an LCA that takes into account all the stages up to the revalorisation of waste and the recycling of the analysed object. This is called a "closed loop". 

The minimum is to have a "cradle to grave" life cycle analysis and the best is "cradle to cradle". This avoids the displacement of polluting stages in parts of the life cycle that would not be described and thus the erroneous assumption that certain products would have no impact when their end-of-life (disposal after use) is problematic for the environment.

Anyone can try to do an LCA as there are free databases available to anyone where you can find a lot of information. However, you will not be able to quantify everything and therefore you will have to make many assumptions during your LCA. This will make it less accurate and sometimes even 50% wrong, but at least you will have an idea. As consumers, we expect a guarantee of the quality of what is done to avoid Green Washing for example (a company that "forgets" a very polluting stage of the life cycle of its product to improve its image with consumers). This is the aim of the ISO 14040 and 14044 standards, which guarantee the rigour and comparability of life cycle assessments.

There are still few ways to certify the LCAs carried out by contractors on their products, to gain credibility. For example, there are specialised offices that carry out life cycle assessments for companies on request, such as "RDC environment", a Belgian company. However, apart from ISO standards, there is no global organisation to date to verify LCAs.

There are 3 basic rules to follow when carrying out a credible life cycle assessment, i.e. to enable us to compare things that are comparable.

The first is comparability. 

The boundaries of the system under study must cover the same functional reality in the different scenarios, i.e. have the same function. Ballerinas and walking shoes, for example, do not have the same function. 

A functional unit is the quantified performance of a product system or product intended to be used as a reference unit in a life cycle assessment. This definition is taken from ISO 14044. 

The second is relevance. 

The information collected can be sorted to avoid making the analysis unnecessarily cumbersome, as not everything can be analysed. All the processes that contribute to more than X% of the mass of inputs, X% of the quantity of energy and/or X% of the emissions of a pollutant at the level of unit processes are retained, as long as the total share of neglected flows does not exceed 5%. 

The last rule: elimination of invariants.

Identical steps in different scenarios that are to be compared can be excluded provided that the reference flows are strictly equal. A reference flow is a quantity of product needed to fulfil the function that was defined when the functional unit was defined. 

When we carry out an LCA and arrive at a single score, there may be problems of simplification: starting with hundreds or even thousands of processes for an object and in the end saying that the impact on our life expectancy is that it reduces it by x days may raise questions. Indeed, to arrive at this final "score", it was necessary to make assumptions, to use certain data sources and not others, and all these choices can be discussed and contradicted. However, if we use the same methods, the same assumptions, the same data to compare two objects and see which one has a greater impact on the environment, I think that life cycle assessment is perfect!

We hope you enjoy this article and that you can interpret the results of life cycle assessments to compare objects with an awareness of the limitations of this analysis, and make better consumption choices

Please see our LCA : STAINLESS STEEL STRAWS VERSUS PLASTIC STRAWS. 

And above all, KissPlanet is preparing a large-scale review of the products offered for sale on its site. In this way, our goal of "enabling you to consume better and more knowledgeably" will become even more concrete!

Feel free to check out our other blogs on a variety of topics: salmon farming, zero waste, lacto-fermentation, essential oils, etc.

See you soon for new adventures!