🏌️1. Goal and Scope Definition

Yook's approach at a glance:

  1. Yook conducts streamlined Life Cycle Assessments with a focus on the products' global warming potential (GWP 100) -IPCC 2021- measured in Kg CO2e.

  2. The products’ life cycle is analyzed on a cradle-to-gate basis, meaning that upstream activities, production, transport, and packaging are included while distribution, use, and end-of-life are excluded from the analysis.

  3. We conduct attributional LCAs and apply cut-off allocation or the PEF Circular Footprint Formula (CFF) if applicable.

  4. Our methodology follows the GHG Protocol Product Standard and follows sector-specific guidelines, for example, the EU PEFCR. In addition, we can follow sector-specific guidelines, for example, the EU PEFCR, or apply sector-specific requirements, for example for differentiating FLAG- from non-FLAG emissions or to be able to use the data for CBAM reporting

In the LCA journey, the first step is to define a clear goal and scope for the analysis.

As there is no single source of truth for LCA, the first phase, Goal and Scope Definition, plays an important role and determines the cooking recipe depending on the objectives.

Different LCA approaches can be applied depending on the objectives and data availability.

Some areas to consider are:

  • Depth of the analysis: screening LCA for hotspot analysis, or would you like product-level insights?

  • Scope and limitations: cradle-to-gate LCA with a single impact focus on global warming or cradle-to-grave with multiple indicators?

  • Compliance: Choose regulations and standards to follow. This will directly affect the modeling of the product.

LCA approaches

The least complex but also the least granular approach is the spend-based carbon footprint calculation, using monetary emission factors depending on the product category.

The activity-based approach can be applied to enhance the assessment. This assessment is based on the physical flows within the product system boundaries. As the first step, the average data from databases can be used. In the following step, the results can be enriched by using supplier-specific data.

Let's dive into each approach:

The spend-based calculation uses general emission factors (EFs) and only considers a product's price and category. The relevant emission factors indicate [Kg CO2e/EUR spend]. As the required input data is mainly accessible, the assessment is relatively easy.

However, some disadvantages are:

  • No possibility to account for differences in one product category

  • Price or spending is not a sufficient proxy for climate impact due to the volatility of CO2e results because of externalities (e.g., inflation, price reductions)

    • When a price discount is offered, the PCF decreases, though it´s the same product

    • Higher-priced goods, e.g., luxury brands and sustainable options, result in a higher product carbon footprint compared to low-priced products

The activity-based calculation is more complex but also as more accurate. Depending on the granularity of the study, three methods are available :

  • The average-data approach uses industry-specific default data for a defined product category. In this approach, the granularity depends on the available industry and product category average data.

  • The supplier-specific approach requires specific, primary data along a product's supply chain to conduct an LCA. This method helps to determine the precise environmental impact of a specific product.

  • The hybrid approach combines the methods mentioned above, using a mix of supplier-specific data whenever available and average data to fill gaps.

Curious to learn more? This scientific article provides more detailed insights into each of these approaches.

Functional unit

The functional unit specifies the unit of analysis for the LCA study, such as one kilogram of product, one kilometer of transportation, or one hour of service. It defines the reference quantity against which all inputs and outputs are measured and compared.

At Yook, the functional unit is specified as one product.

Environmental impact indicators

Environmental impact indicators are essential components of LCA, as they provide a structured framework for quantifying and assessing the environmental burdens across different stages of a product's life cycle.

Here are the key environmental impact indicators commonly measured in LCA studies:

IndicatorWhat does it mean

Global Warming Potential (GWP)

Measures the potential of greenhouse gas emissions to contribute to global warming over a specified time horizon, typically 100 years.

It is expressed in terms of carbon dioxide equivalents (CO2e) and encompasses emissions of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and other greenhouse gases.

Acidification Potential

Quantifies the potential for sulfur dioxide (SO2) emissions and nitrogen oxides (NOx) to acidify the environment, leading to acid rain. It assesses the impacts on soil, water bodies, and vegetation, which can harm ecosystems.

Eutrophication Potential

Evaluates the potential for nutrient emissions, such as nitrogen (N) and phosphorus (P), to cause eutrophication in water bodies. Excessive nutrient levels promote algae growth, leading to oxygen depletion and ecological imbalance in aquatic ecosystems.

Ozone Depletion Potential

Measures the potential of substances, such as chlorofluorocarbons (CFCs) and halons, to deplete the ozone layer in the stratosphere. Ozone depletion increases the harmful UV radiation reaching the Earth's surface, posing risks to human health and ecosystems.

Human Toxicity Potential

Evaluates the potential for substances to cause harm to human health through various exposure pathways, including ingestion, inhalation, and dermal contact. It considers both acute and chronic toxicity effects and helps prioritize substances based on their hazardous properties.

Ecotoxicity Potential

Assesses the potential for substances to cause harm to ecosystems and non-human organisms, including aquatic and terrestrial species. It considers the toxicity of substances to different organisms and ecosystems, helping identify environmentally sensitive areas.

Land Use

Quantify the amount of land occupied or transformed by a product or process, including direct land use (e.g., agriculture, infrastructure) and indirect land use (e.g., habitat destruction). They help assess the impacts on biodiversity, ecosystem services, and land availability.

Water use

Assesses the consumption of water resources.

By integrating these indicators into LCA studies, stakeholders can identify hotspots, prioritize improvement opportunities, and promote sustainable decision-making to minimize environmental impacts.

At Yook, we are currently calculating carbon footprints. We focus on the climate change impact category, which measures the global warming potential (GWP 100).

Whenever possible, we constantly use updated emission factors from reliable databases and primary data. We constantly use updated emission factors from reliable databases and primary data whenever possible.

Note: Additional environmental impact categories might have relevant effects and can lead to trade-offs or unwanted burden shifting.

System boundary

The system boundary includes all life cycle stages of the product, process, or service, from raw material extraction and production, distribution, use, and end-of-life disposal (cradle to grave).

  • Raw Material Acquisition: Includes activities such as resource extraction, agricultural production, and material processing.

  • Manufacturing: Encompasses all processes involved in the production of goods or the provision of services, including assembly, fabrication, and packaging.

  • Distribution and Transportation: Involves the transportation of the raw materials, components, and finished products between different stages of the supply chain and to end-users.

  • Use: Covers the operational use of the product or service by consumers, including energy consumption, maintenance, and product performance.

  • End of life: Addresses the disposal, recycling, or recovery of materials and energy at the end of the product's life cycle, including waste management and recycling processes.

In some studies, the boundaries can be to the gate of the distribution (cradle to gate). At Yook, our current model is cradle-to-gate. This means we include all upstream and core activities while the downstream activities are excluded.

Here is an example of a product system with cradle-to-gate system boundaries.


Allocation refers to assigning environmental burdens or benefits among multiple co-products or processes within a life cycle system.

Allocation is necessary when a product system yields more than one product or service simultaneously or when a process produces the desired product and by-products or co-products.

According to ISO 14040/44, there are three choices in the case of multi-output processes:

  • Avoid allocation by system expansion: Employing this strategy, particularly in consequential Life Cycle Assessment (LCA), helps to sidestep the complexities associated with allocation.

  • Physical relationships allocation: Allocation factor based on dry mass or volume of the co-products: Simplifying the process, this method ensures a fair distribution of environmental impacts across the system based on the physical properties of the co-products.

  • Allocation by other relationships (e.g., economic): Use the price of the co-products to determine allocation factor: By considering economic factors, such as the price of co-products, this approach offers a straightforward and transparent method for determining allocation, enhancing the accuracy and reliability of LCA assessments.

Now, we are getting a bit deeper into LCA Theory. But let's start smoothly:

One case is when multiple products are interconnected or share standard processes. In such cases, also called multi-output processes, it can be challenging to precisely attribute the environmental impacts to a specific product.

Example is:

A sheep produces wool and sheep milk.
To calculate the PCF of 1kg wool, the environmental impact of sheep husbandry needs to be shared between milk and wool.

Another case is the recycling process.

Regarding recycled materials, we also have two interlinked products: The virgin material recycled in its end-of-life phase and the resulting recyclate. This raises two questions that require an allocation decision:

  1. which material bears the burden of the recycling process? Is the virgin material in the End of Life (EOL) phase or the recyclate in the material phase?

  2. how is the burden of virgin material extraction allocated? Is it only to the virgin material, or is a portion also allocated to the recyclate?

There are some alternatives as the solution.

Burdens or credits associated with materials from previous or subsequent life cycles are not considered.

For example, scrap input to the production process is considered to be free of burdens, but equally, no credit is received for scrap available for recycling at end-of-life.

Hence this approach rewards the use of recycled content but does not reward end-of-life recycling.

Attributional versus Consequential LCA

Alright! Now that we know about multi-output processes and allocation, let's head over to the next topic: Attributional versus Consequential LCA.

Imagine a scenario where a company is evaluating the environmental impact of replacing conventional plastic packaging with a biodegradable alternative made from agricultural by-products.

Attributional LCA

  • The analysis would focus on comparing the direct environmental impacts of producing the two types of packaging over the life cycle (raw materials, production, etc.) for both packaging types.

  • Result: The LCA might show differences in carbon impacts between the two materials.

Consequential LCA

  • The analysis would go beyond the immediate impacts and consider the broader consequences of the material switch.

  • This assessment accounts for potential changes in market behaviors and technology adoption

  • Result: It would provide an understanding of the overall carbon impact due to market changes.

Here is a comparison of these two approaches:

Attributional LCAConsequential LCA

Environmental impact in its current state

Environmental impact of changes

Inputs and outputs are attributed to a product.

Activities are linked. Thus, the product system adapts to changes.

Direct and indirect impacts associated with the production, use, and end-of-life of a product

Includes indirect effects beyond the direct system boundaries and considers the consequences of decisions

Analysis of product environmental impact and product optimization within specific system boundaries

Broader analysis such as market changes or policy decisions e.g. changes in market prices and subsequent effects

You might wonder what is the most relevant method for your product. Currently, there is not a single LCA standard applicable across all product categories. Therefore, facilitating easy comparison of LCAs does not exist. Instead, there are numerous guidelines, standards, handbooks, and sector-specific initiatives, which can be daunting to navigate.

At Yook, we diligently monitor regulations within each industry sector and employ the widely accepted methodologies available.

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