Lifecycle assessments are used by some people and organisations to make some important decisions.
What we’ve aimed to do in this guide is provide an overview of why lifecycle assessments can be valuable, but also limited for various reasons.
Summary – Importance & Limitations Of Lifecycle Assessments
Lifecycle assessments can be used for measuring the footprint and potential impact of many things (products, services, activities etc.)
They can be a great way to understand the general footprint or general impact of a specific thing under specific circumstances
But, due to various limitations of lifecycle assessments, they might only be looked at as a starting point for consideration, or one of many considerations, when looking the full footprint or impact of something, and the final list of pros and cons of producing that thing or carrying out a certain activity
The Importance & Benefits Of Lifecycle Assessments
A lifecycle assessment is a great starting point for understanding the general footprint a product, service or activity may leave, and tying that footprint to a specific impact or effect.
For example, a lifecycle assessment on the carbon footprint of different animal and crop products may enable us to see which agricultural products are generally better and worse for climate change and global warming.
Additionally, some people may use this general information to decide what foods they may include more or less of in their own diet if reducing their individual carbon footprint is important to them.
The Limitations & Flaws Of Lifecycle Assessments
Making decisions based on lifecycle assessments sounds like a straightforward, simple and good idea, but unfortunately, LCAs have their limitations to consider.
These limitations may include (but aren’t limited to):
There might be limited or insufficient data available for use in the LCA, and this may mean parts of the life cycle of a product may be omitted from the LCA – for example, data may not be available on the transport and delivery of a product, and this part of the product life cycle may not make up part of the final footprint. Limited or insufficient data is caused by a range of reasons, such as data being difficult or unavailable to measure
The same type of product in a given industry may use different processes for production that lead to different footprints – for example, there is usually going to clear differences in the footprints of mostly grass fed and pasture raised beef vs. mostly grain and factory raised beef. So, the farming method in agriculture (chosen by the farmer) is an example of a production process that can change a footprint
Geographic location can change the footprint significantly – this is particularly the case in agriculture. Different regions can have different conditions for land, rain fall, water supplies, sun light, technology available, pests, and so on and so forth. All of these things can influence what can be grown in a certain location, and what the final footprint may end up being
Not all footprints are negative – for example, the water footprint of one product being higher than another is always a problem if most of that water is rain fed i.e. it is water that is always going to be naturally available no matter what vs. an irrigated water supply that has scarcity issues.
Parts of the LCA may be based on assumptions, and assumptions can differ – when calculations or data in LCA is based on specific assumptions, obviously the footprint or final figures is going to change based on different assumptions being made
An LCA may only calculate a limited number of measurables or footprints – for example, an LCA may try to calculate the environmental impact of a product by assessing carbon emissions and water use. But, the reality is, environmental impact spans across many more factors than just these, including environmental factors that we both are and aren’t aware of. Just one example of this is the use of plastic – we aren’t fully sure yet of the impact of micro and nano plastics on different areas of society. In addition, to get an idea of the full pros and cons of a particular product, we should look at it’s impact on the environment, human health, wildlife and animals, the economy, and any technological and practical considerations
The footprint or calculation in a LCA can change based on different ways of measuring it – food is a good example of this. You can look at the water footprint of different foods in total, or you can look at the footprint per gram of protein, per gram of fat, per gram of carbohydrates, or per nutritional value that that food provides. The footprint may change significantly when breaking down footprints in this way for each type of measurable
An LCA might conflict with the needs of an individual – for example, an individual might be trying to look at cutting down their carbon footprint with the foods they eat. But, that same individual might have specific nutritional requirements or health conditions that go in conflict with eating a diet that has a lower carbon footprint
There can be many more limitations than those listed above that make LCAs an imprecise way of calculating the exact footprint and impact producing something or doing something.
Examples Of Real Lifecycle Assessments
Two detailed and comprehensive examples of lifecycle assessments can be found in the following resources:
LCA Of Different Animal & Crop Products – http://static.ewg.org/reports/2011/meateaters/pdf/methodology_ewg_meat_eaters_guide_to_health_and_climate_2011.pdf
LCA Of Different Grocery Carrier Bags – https://www2.mst.dk/Udgiv/publications/2018/02/978-87-93614-73-4.pdf
Obviously these LCAs provide some fantastic data for assessing how we might consume animal and crop products when considering greenhouse gas emissions, and how we might use different types of grocery carrier bags when considering different types of environmental impacts (as well as human toxicity).
Examples Of Limitations In The Above Lifecycle Assessments
LCA Of Different Animal & Crop Products
As an example of the limitations we listed above, the EWG/CleanMetrics report on greenhouse gas emissions above did not consider the following processes related to food production (listed on page 6):
- Consumer transport to and from retail outlets
- Home storage of food products
- Production of capital goods and infrastructure (typically excluded from most LCAs and is currently excluded from standards such as PAS 2050)
- Energy required for water use in growing livestock feed (irrigation is included for alfalfa but not for corn and soybeans)
Inside their report, they list what they did include in the LCA, which was:
- Production and transport of “inputs,” the materials used to grow crops or feed animals (fertilizers, pesticides and seed for crop production; feeds for animal production)
- On-farm generation of GHG emissions (e.g., the enteric fermentation digestive process of cows, sheep and other ruminants; manure management; soil emissions from fertilizer application; etc.)
- On-farm energy use (fuel and electricity, including energy used for irrigation)
- Transportation of animals and harvested crops
- Processing (slaughter, packaging and freezing)
- Refrigeration (retail and transportation)
- Retail and consumer waste (waste before and after cooking, including served but uneaten food that is thrown away)
LCA Of Different Grocery Carrier Bags
The report consider a range of environmental impacts, and the human toxicity of using different carrier bags.
But, as far as we can see (and we might be wrong), but it doesn’t consider the impact of these bags on the release of micro plastics and nano plastics when plastic breaks down, or how plastic impacts the ocean (including marine life) beyond marine eutrophication – just as two of many examples.
Additionally, the report is mainly concerned with the environmental and human toxicity health impact of these bags, but doesn’t consider many of the economic impacts of producing, using and disposing of these bags.
On page 24 of the report, they actually list some of the limitations:
- “The present study only considers carrier bags available for purchase in Danish supermarkets in 2017. Small very lightweight plastic carrier bags , which are available in Danish supermarkets free of charge as primary packaging for loose food, were excluded from the scope of this study, since they were not included in the 94/62/EC measures. This study does not include the assessment of other types of carriers, such as personal bags or bags provided by other retailers. The report does not consider behavioural changes or consequences of introducing further economic measures. The study does not take into account economic consequences for retailers and carrier bag producers. The environmental assessment does not take into account the effects of littering”
Pages 14 and 15 list the environmental and human indicators/categories assessed in the report as:
- … “climate change, ozone depletion, human toxicity cancer and non-cancer effects, photochemical ozone formation, ionizing radiation, particulate matter, terrestrial acidification, terrestrial eutrophication, marine eutrophication, freshwater eutrophication, ecosystem toxicity, resource depletion, fossil and abiotic, and depletion of water resource”