Life Cycle Assessments (LCAs): What They Are, How To Do One, Limitations, & Eco Impact At Different Stages

In the guide below, we discuss the following points:

– What a life cycle assessment (LCA) is 

– How to do a life cycle assessment

– Examples of life cycle assessments for different products, services and activities

– The environmental impact at different stages of the product lifecycle for several different products, and, potential solutions to reduce impact at different stages

– The potential importance of life cycle assessments

– Potential limitations of life cycle assessments


Summary – Life Cycle Assessments

What Are Life Cycle Assessments?

Different reports have different definition of what a LCA is

However, a general definition might be that a life cycle assessment is a tool that attempts to quantify the impact or footprint of something over it’s entire life cycle (from sourcing materials, up to disposal, re-use, or even decomposition), or at a particular stage of it’s life cycle

This impact or footprint is usually expressed in the form of some type of indicator, such as water used (i.e. the water footprint), waste generated, or some type of other indicator

Several indicators may be quantified and expressed in the one life cycle assessment


How To Do A Life Cycle Assessment

– Different Indicators

One indicator, or different indicators can be assessed within a life cycle assessment

For example, water use, carbon emissions, and waste generation are just a few examples of indicators that could be tracked and quantified over the life cycle of something

Human health indicators can also be measured, as well as economic, wild life and other indicators.


– Specifying What Makes Up A LCA

A LCA should specify:

What data was included and excluded/omitted

What assumptions were made for the assessment (just one example of this is the number of times a piece of clothing is assumed to be worn before being thrown out and buying new clothing)

What formulas were used


– Variables To Different Lifecycle Assessments

Different life cycle assessments may produce different conclusions or express different findings depending on these variables

This is especially the case when considering that every product, company, and supply chain has different variables to consider


Entire Lifecycle vs Single Stage Of A Lifecycle

The entire lifecycle of something can be analysed, or one specific stage in the lifecycle can be analysed (e.g. the production stage, the usage/operation stage, and so on)


Stage Of A Product’s Lifecycle With The Most Environmental Impact

Different products have different outputs and impacts at each stage of their life cycle.

This means that changes at different stages of different products’ life cycles may lead to a greater potential to reduce impact at a particular stage. 

Generally, products that don’t use fuel, electricity/energy, or consumables during use/operation have the most environmental impact during product manufacture

An example of a product of this nature might be a T Shirt

There might be a few exceptions to this though, such as a smart phone, where ‘An iPhone X has a 79 kg CO2e total greenhouse gas emissions … 80% comes from production, 17% from customer use, 2% from transport and 1% from recycling (

But, other products like vehicles, appliances and electrical items, or printers (that need ink and toner), might have a higher environmental impact at the product usage stage i.e. the consumption and operation stage (one example is a car where about 86% of carbon emissions happen during the combustion of petroleum based fuels during driving)

This might be especially accurate once you take into consideration replacements (of batteries and parts), cleaning, use of electricity or fuel, and other maintenance and consumption.

For example, mentions that in terms of GHG emissions: ‘… [for Conventional internal combustion vehicles,] around 81% of the [GHG] emissions [come] directly from burning the petrol, 13% from extraction and transportation, and around 6% from refining’

Some products, especially more raw products like certain metals, may have a heavy impact at the material sourcing and fabrication stage, due to the extraction (and mining), refining and fabrication processes of ores and metals using so much energy

Farmed foods like meat may also have a heavier impact at the farming and processing stage compared to the consumption stage

In the guide below, we look at three examples of different products in regards to environmental impact at each stage, and also potential areas for improvement.


Potential Importance Of Life Cycle Assessments

Life cycle assessments more of a tool used to estimate the footprint or impact of something, and are not definitive

However, they may be able to provide some type of guide as to how sustainable or eco friendly something is, according to certain indicators

This data may indicate how that thing, if it’s a product or activity for example, impacts issues in society such as global water issues, some type of waste pollution, or something else

When LCAs are carried out on two different products or activities using the same LCA processes and methods, these products and activities can be compared to one another in some ways

LCAs can also be used in isolation, or alongside other tools, to get a better idea of the true impact of something

Lastly, LCAs have the benefit of being able to break down impact by life cycle stage (in addition to the entire life cycle)

Identifying stages that have the most environmental impact for a particular product or thing can be one potential way to make improvements to products that lead to more eco friendly products and processes

But, all changes and improvements usually involve trade offs to consider, such as cost, efficiency, performance, aesthetics, and so on.


Potential Limitations Of Lifecycle Assessments

LCAs can have various limitations.

Challenges with obtaining certain data, omitting certain factors or making certain exclusion, and only measuring specific indicators, can all be examples of limitations. 

Due to these limitations and others, LCAs might only be a starting point for consideration when assessing the sustainability or eco impact of specific things, and not a definitive tool.


What Is A Life Cycle Assessment?

A ‘Life Cycle Assessment’ is also referred as a LCA

It is a concept or tool that can be used to quantify the footprint of a particular product, service, activity, or thing (like a city, country, company, or something else)

It can be used to analyse specific stages of a lifecycle, or the entire lifecycle

It can use one specific indicator, or several indicators

It’s an estimation, and not considered to be definitive


Examples Of Stages Of A Lifecycle

Examples of stages of a LCA include sourcing, manufacture, consumption and disposal


Examples of the stages of a car, and a unit of electricity are as follows:

– A Car

A car is made up of materials that have to be sourced and/or refined (such as steel, rubber, plastic, leather, foam, etc).

A car is then manufactured, including not only the body of the car, but different parts like the tires.

A car is then driven and needs to be maintained – including re-fuelling, servicing, repairs, modification, cleaning, and so on

A car then reaches the end of it’s life at some point, and make go to the scrap heap.


– A Unit Of Electricity

Electricity can be sourced from different energy sources, with one being coal

Coal has to first be mined

Coal might then be refined

Coal is then combusted for energy at a coal power plant

Coal energy then has to be converted to electricity, travel through the power grid, and can then be used in buildings and at home


Examples Of Indicators Measured In A LCA

Indicator examples of a LCA include carbon emissions, water use, land use, and more

As one example, the water footprint of a product or thing can be measured.


How To Do A Lifecycle Assessment

Lifecycle assessments can be very short and simple, or much more comprehensive, detailed and complex.

In general, the components or steps of a basic LCA may include the following:


– Pick one or multiple products to do a LCA on

For example, if the focus on different types of carry bags, a LCA might be done on just a plastic bag, but it could also be done on light plastic bags, heavy duty plastic bags, composite bags, and so on.


– Specify the stages included in the LCA

The stages could include any stage from sourcing and/or extracting materials, to disposal, re-use or decomposition

But, examples of other stages might include refining materials, manufacturing/processing, transport and delivery, retail, consumption, and so on

For foods and fibres, there would also be consideration for the agricultural stage (growing and harvesting)

Different products have different stages


– Specifying the measurable or indicator being measured or quantified

For example, carbon emissions, water consumption, land use, emission of specific air pollution contaminants, generation of waste material or substances from production, can all be measured or quantified in different ways

These indicators can be broken down by the specific stage, but also quantified for the entire lifecycle


– Specifying the formulas, assumptions, inclusions and exclusions used and accounted for in the LCA

This enables others to see how the data was formulated

It also allows comparison between LCAs where variables and factors present in the LCA is comparable to another

As one example, the LCA might include data on production, consumption and disposal, but not material sourcing or refining.

This should be highlighted in the LCA summary

Additionally, the LCA may be on a specific product or material in a specific industry, in a specific country or State, using a specific method of production – these variables and factors should be detailed (as production in a different country, using different methods of production may produce different results and data)


– Other

At this point, there are several things that can be done with LCA data.

One thing that might be done is interpreting how the life cycle impacts different issues.

For example, the impact of carbon emissions on climate change, the impact of water consumption on fresh water supplies or water scarcity, the impact of air contaminants on air pollution and associated human health issues and air pollution related mortality rates, the impact generating and dumping production waste into the ocean, and so on.


Examples Of Lifecycle Assessments

Two detailed and comprehensive examples of lifecycle assessments can be found in the following resources:


– LCA Of Different Animal & Crop Products 

Refer to the resource in the resources list


– LCA Of Different Grocery Carrier Bags

Refer to the resource in the resources list


– Other

We’ve also looked at the different stages of the bottle life cycle for different bottle materials in this guide.


Potential Limitations In The Above Life Cycle Assessment Examples

EWG/CleanMetrics LCA Report Of Different Animal & Crop Products

In the report, there are certain inclusions and exclusions made.


[The inclusions listed are:]

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)


[On page 6, they mention they excluded the following processes related to food production:]

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) resource LCA Report Of Different Grocery Carrier Bags

This report considers 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 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”


What Stage Of A Product’s Life Cycle Has The Most Environmental Impact?

Below are examples of how different products have different environmental impacts at different stages of their life cycle.

Knowing this information is helpful when trying to understand what stage to focus on to potentially achieve the highest level of environmental impact reduction, or coming up with more effective solutions to reduce impact.


3 Different Product Life Cycle Examples

Car Navigation System

Car Navigation System (



Printers (


Clothing (In Sweden)

T Shirt (


How The 3 Product Life Cycles Differ At Each Stage In Terms Of Environmental Impact

Car Navigation System

Life cycle assessment measures CO2 emissions at each stage.

Those results found that emissions were greatest at the ‘Use’ stage because the navigation system consumed power at this stage.


The full CO2 emission totals at each stage were:

Manufacture Of Material – 35,219 (grams of CO2 emissions)

Assembly Of Parts – 13,555

Shipment – 1,246

Use – 139,087 (110,847 came from an electrical origin, and 28,240 from a weight origin) 

Waste – 29



Life cycle assessment measures global warming-causing emissions at each stage of the product life cycle for two different Kyocera printer models.

Emissions were greatest at the ‘Material Manufacturing’ stage for both, but were followed closely by ‘Usage’


The full CO2 emission totals at each stage for the older TASKalfa 256i were:

Material Manufacturing – 291 (CO2 equivalent in kg)

Product Manufacturing – 86

Distribution – 12

Usage (electricity) – 145

Usage (consumables, like toner) – 121

Disposal – 2


The full CO2 emission totals at each stage for the newer and improved TASKalfa 2510i are:

Material Manufacturing – 276 (CO2 equivalent in kg)

Product Manufacturing – 32

Distribution – 11

Usage (electricity) – 100

Usage (consumables, like toner) – 121

Disposal – 2

(Overall 115 CO2 equivalent kg of reduction)


The emissions reduction from the first model to the second model was 115 CO2 equivalent kgs, or, a 17% total emissions reduction


Clothing (In Sweden)

Life cycle assessment measures climate impact generated by Swedes during various stages of the clothing lifecycle:

Production – 70%

Distribution – 4%

Consumer Transport (to and from the store) – 22%

Laundry – 3%

Disposal – 1%


Variables for clothing include duration of wear, features of the fibres, printing and other treatments done to the fabric, number of washes.


How There May Be Potential To Improve A Stage, Or Stages, Of Product Life Cycles

Improvements being made or made in the above examples include:

– Car Navigation System

Alpine states they are ‘working to reduce the energy consumption (through reduction of number of parts), size, and weight of our products.’


– Printers

The emissions reduction from the first model to the second model printer was 115 CO2 equivalent kgs, or, a 17% total emissions reduction.

Kyocera ‘developed [their] own unique controller technology for managing power consumption, and achieved a major reduction of 30%’


– Clothing

The number of times consumers wear a garment before throwing it out, how greatly spin dyeing can reduce water use compared to wet dyeing, or how much smaller the carbon footprint of fabric made from dissolved wood cellulose is, compared to cotton – are all important variables to decrease environmental impact of clothing (


These are good examples of how companies (and third parties or even consumers) can be most effective with trying to make products more environmentally friendly, by identifying the key stages with the most environmental impact or harm, and focussing on solutions to reduce or eliminate that impact.

Although, there is sometimes trade offs to consider, such as cost, efficiency, performance, aesthetics, and so on.


The Importance & Benefits Of Life Cycle Assessments

A life cycle assessment can be one tool for understanding the impact of something.

That impact may be on a specific issue like water scarcity, waste pollution, or resource management, just as a few examples.

It may also relate to a specific area of society like the environment, the economy, human health, animals and wildlife, and so on.

Similar life cycle assessments can be compared against one another, meaning products can be compared against one another.

LCAs can also be used in conjunction with other assessment tools to gain a better understanding of a particular product or thing.

They also enables us to see at what stage a product or thing has the most impact, and least impact.


Potential Limitations Of Life Cycle Assessments

Making decisions based on life cycle assessments sounds like a straightforward idea, but unfortunately, LCAs have their limitations to consider.

This means LCAs aren’t definitive, but rather a just a tool that can provide general data, and therefore a guide only.

Limitations to consider with LCAs include but aren’t limited to:


– Every product, service, activity or thing has it’s own variables and individual factors to consider

Including what that thing is, how it’s made (with what processes), what it’s made of (the specific materials), where materials are sourced from, where it’s made (geography and climate can play a big role in agriculture for example), what it’s used for, how it’s used, how long it’s used for, and more.


– 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.

This can sometimes be the case in some specific countries where data is difficult to obtain.


– The same type of product in a specific industry may use different processes for production that leads 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 in the LCA.


– 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 measureables 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









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