Knowledge Hub

A

ALCA: See Attributional approach
Alternative scenario: See Reference scenario
As the crow flies distance: See Straight-line distance
Attributional approach: Also known as Attributional LCA and ALCA; A method for calculating avoided emissions by comparing the greenhouse gas emissions of two products that provide the same function, such as a secondhand sofa and a new sofa. Unlike the consequential approach, it covers only the physical life-cycle stages of each product and does not include market effects such as rebound effects. This makes it simpler and easier to scale, but less accurate.
Avoided emissions: Also known as Scope 4 and Comparative Impact; The difference in greenhouse gas emissions between a solution scenario, such as buying an item secondhand, and a reference scenario, such as buying the same item new. Emissions are avoided only when the solution scenario has lower emissions than the reference scenario. The term is often used for the calculation itself whatever the result.

B

Baseline scenario: See Reference scenario
Bill of materials: Also known as BoM; A list of the raw materials, components and other parts that make up an end product, with their quantities or weights.

C

Capacity utilization: See Load factor
Carbon compensation: See Carbon offsetting
Carbon dioxide equivalent: Also known as CO₂e, CO₂eq and CO₂-eq; A common unit for greenhouse gas emissions, which include several gases such as carbon dioxide, methane and nitrous oxide. It converts all of the gases into the amount of carbon dioxide that would cause the same warming. It is calculated by multiplying the mass of each gas by its global warming potential, so that the emissions can be added together as one figure.
Carbon factor: See Emission factor
Carbon footprint: Also known as GHG footprint; The total greenhouse gas emissions caused by an organization, a product or an activity, expressed in carbon dioxide equivalent (CO₂e).
Carbon intensity: The amount of greenhouse gas emissions per unit of activity or output, such as grams of CO₂e per kilometer.
Carbon offsetting: Also known as Carbon compensation; The practice of compensating for greenhouse gas emissions by paying for projects that reduce or remove emissions elsewhere, usually by buying carbon credits. The value of a carbon credit depends on whether the reduction would have happened without the project. Avoided emissions are not carbon offsets and cannot be subtracted from a company’s own greenhouse gas inventory.
CCF: See Corporate carbon footprint
Circuity: Also known as Circuity factor; The extra distance traveled when going from origin to destination, compared with the straight-line distance between them.
Circular economy: An economic system that keeps products and materials in use as long as possible, through reuse, repair, remanufacturing and recycling.
CLCA: See Consequential approach
CO₂-eq, CO₂e, CO₂eq: See Carbon dioxide equivalent
Comparative Impact: See Avoided emissions
Condition grade: See Product condition
Consequential approach: Also known as Consequential LCA, CLCA and Intervention accounting; A method for calculating avoided emissions by comparing total greenhouse gas emissions with and without a specific decision, such as buying a secondhand sofa instead of a new one. Unlike the attributional approach, it includes every process that changes as a result of the decision, including market effects such as rebound effects. This makes it more complete, but harder to apply and more dependent on assumptions about how markets and buyers respond.
Conservativeness: Also known as Conservative approach; A carbon accounting principle of choosing assumptions that tend to underestimate rather than overestimate a climate benefit when data is uncertain. For example, choosing assumptions that lead to higher generated emissions, or lower avoided emissions.
Consumer survey: Also known as Questionnaire; A questionnaire answered by the users of a service such as a marketplace, used to collect primary data on behavior that the business cannot record itself.
Consumer travel: Also known as Customer travel; Part of a delivery that's not handled by the delivery company, such as a PUDO pick-up.
Corporate carbon footprint: Also known as CCF, GHG inventory and Organizational carbon footprint; The total greenhouse gas emissions of a company over a reporting period, expressed in CO₂e. It is usually calculated in line with the GHG Protocol.
Counterfactual scenario: See Reference scenario
Cradle-to-gate: Partial LCA that covers a product’s impacts from raw material extraction up to the factory gate, before it reaches the consumer.
Cradle-to-grave: Also known as Whole life cycle; Full LCA that covers a product’s entire life cycle, from raw material extraction through manufacturing, distribution, use, and end-of-life disposal.
Creative reuse: See Upcycling
Customer travel: See Consumer travel

D

Deadstock: Also known as Unsold stock; New products that were not sold to a consumer, such as unsold inventory, overstock or discontinued lines.
Delivery van: See Light goods vehicle
Detour index: The extra distance traveled due to the delivery company’s hubs, depots and delivery rounds rather than going directly.
Direct distance: See Straight-line distance
Displaced emissions: The emissions from manufacturing new products that are avoided because a reused product takes their place, adjusted for displacement rate and remaining useful life.
Displacement rate: Also known as Replacement rate and Substitution rate; The share of secondhand purchases that replace the purchase of a new item. For example, a displacement rate of 50% means that one new item is not bought for every two secondhand items bought.
Double counting: Also known as Double claiming; In carbon accounting, counting the same emissions more than once, which makes the total impact look larger than it is. This can happen within one calculation or when several organizations claim the same impact.
Downstream emissions: Indirect emissions that occur after a company’s products or services leave its operations, such as from shipping, using and disposing of the items it sells. Under the GHG Protocol, downstream emissions are part of Scope 3, alongside upstream emissions.

E

EF: See Emission factor
Electricity mix: Also known as Electricity grid, Grid mix and Energy mix; The combination of energy sources used to generate the electricity consumed in a given area and period, such as coal, gas, nuclear, wind and solar.
Emission factor: Also known as EF, Emissions factor and Carbon factor; A factor that converts activity data, such as kilometers driven or kilograms of material produced, into GHG emissions.
End-of-life: Also known as EoL; The final stage of a product’s life cycle, when it is discarded and sent to treatment such as recycling, incineration or landfill.
Energy mix: See Electricity mix
Environmental claim: Also known as Green claim; Any message, image, label or symbol that states or implies that a product, brand or company has a positive or zero environmental impact, is less damaging than others or has improved over time. Statements about avoided emissions from buying secondhand are environmental claims.
Environmental factor: Broader factor than an emission factor that applies to more impact categories.
EoL: See End-of-life
Extrapolation: Estimating values beyond the observed data by extending past trends, for example projecting next year’s sales from historical results.

F

Fill rate: See Load factor
First mile: Also known as First leg; Initial stage of the transportation: moving goods from their point of origin to the first major waypoint in the distribution network.
Functional unit: The function of a product or service expressed as a measurable amount, which then serves as the basis of an assessment so that alternatives can be compared on equal terms. For example, one sofa used over its expected lifetime.

G

Generated emissions: The greenhouse gas emissions caused by a business, product or service. In avoided emissions calculations, the term separates the emissions a business generates from the emissions it potentially avoids. For secondhand businesses, it usually includes the corporate carbon footprint and emissions from packaging and shipping. These are included in avoided emissions calculations even if arranged by users, although such emissions often fall outside the company’s official GHG Protocol reporting.
Generic data: See Secondary data
Geodesic distance: See Straight-line distance
GHG footprint: See Carbon footprint
GHG inventory: See Corporate carbon footprint
GHG Protocol: Also known as Greenhouse Gas Protocol and GHGP; The most widely used set of standards for measuring and reporting greenhouse gas emissions, developed by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD). It includes standards for companies, products and value chains, such as the Corporate Standard used to calculate a corporate carbon footprint.
Green claim: See Environmental claim
Greenhouse Gas Protocol: See GHG Protocol
Greenwashing: Making environmental claims that are vague, exaggerated or unsupported, giving a misleading impression of a company’s or product’s environmental impact. For example, claiming to be “carbon neutral” based on avoided emissions.
Grid mix: See Electricity mix

H

Heavy goods vehicle: Also known as HGV, Truck, Lorry and Large goods vehicle; Large truck weighing above 3.5 tonnes, the kind that can be seen on the highway but not in city centers.

I

Impact category: A type of environmental problem that a life cycle assessment measures, such as climate change or water usage.
INDA: See Item not as described
Intervention accounting: See Consequential approach
ISO 14040/44: International standards for life cycle assessment: 14040 defines the framework, and 14044 sets the detailed requirements for measuring a product’s environmental impact.
Item not as described: Also known as INDA; A dispute category used by secondhand marketplaces when a buyer reports that the item received does not match its listing description.

L

Large goods vehicle: See Heavy goods vehicle
Last mile: Also known as Last leg; Last stage of the transportation: moving goods from the last major waypoint in the distribution network to their final destination.
LCA: See Life cycle assessment
LCI: See Life cycle inventory
LCIA: See Life cycle impact assessment
LCV: See Light goods vehicle
LGV: See Light goods vehicle
Life cycle assessment: Also known as LCA and Life cycle analysis; A method for quantifying the environmental impacts of a product across its life cycle, from raw materials to end-of-life, standardized by ISO 14040 and 14044.
Life cycle impact assessment: Also known as LCIA; The phase of a life cycle assessment that converts inventory flows into environmental impacts, grouped into impact categories such as climate change.
Life cycle inventory: Also known as LCI; The phase of a life cycle assessment that compiles the inputs and outputs of every process in the system, such as materials, energy, emissions and waste.
Light goods vehicle: Also known as LGV, Light commercial vehicle, LCV and Delivery van; A small truck with a weight of up to 3.5 tonnes, such as a delivery van, allowed to drive in city centers.
Line haul: See Midleg
Load factor: Also known as Capacity utilization and Fill rate; The share of a vehicle’s capacity that is actually used, measured by weight or by volume.
Location-based method: A method for calculating Scope 2 emissions, the emissions from the energy a company buys, using the average emissions of the electricity grid where the electricity is used.
Lorry: See Heavy goods vehicle

M

Market-based method: A method for calculating Scope 2 emissions, the emissions from the energy a company buys, based on the electricity it has chosen to buy through contracts or certificates, such as guarantees of origin for renewable electricity.
Marketplace: Also known as Peer-to-peer platform and Resale platform; An online platform that connects sellers and buyers, who trade with each other rather than with the platform itself.
Middle leg: See Midleg
Midleg: Also known as Middle mile, Line haul and Middle leg; The middle leg of a delivery, between the carrier’s first facility and the last sorting hub.

N

Net zero: A state in which an organization reduces its greenhouse gas emissions in line with science-based targets and neutralizes the rest with permanent carbon removals. Avoided emissions cannot be counted toward net zero.

O

Off-platform transaction: A transaction that starts on a marketplace but is completed outside it, with the buyer and seller arranging payment privately. For example, a buyer contacts a seller through the marketplace, and they meet to complete the sale in person.
On-platform transaction: A transaction that is started and completed on a marketplace, with payment made through the marketplace’s own payment system.
Organizational carbon footprint: See Corporate carbon footprint

P

Peer-to-peer platform: See Marketplace
PEF: See Product Environmental Footprint
Pick-up / drop-off point: Also known as PUDO and Pick-up and drop-off point; A store, locker or post office where a recipient can pick up a parcel or a sender can drop it off.
Pre-loved: See Secondhand
Pre-owned: See Secondhand
Primary data: Data measured or collected at the source of the emissions-generating activity.
Primary packaging: Also known as Sales packaging; Packaging in direct contact with the product that's sold to the consumer, such as a phone box or the plastic wrapping a book.
Product carbon footprint (PCF): See Product footprint
Product category: Also known as Taxonomy and Product taxonomy; A group of similar products, such as clothing, electronics or furniture, used to organize transaction data and assign footprints.
Product condition: Also known as Condition grade; The state of a secondhand item at the time of sale, often graded on marketplaces as new with tags, like new, good or fair.
Product Environmental Footprint: Also known as PEF; The European Commission’s method for measuring the life cycle environmental performance of products, covering 16 impact categories.
Product footprint: Also known as Product carbon footprint (PCF); The environmental impact of a product over its life cycle, or a defined part of it, for one or more indicators such as greenhouse gas emissions or water use.
Product return: See Return
Product taxonomy: See Product category
Proxy product: See Representative product
PUDO: See Pick-up / drop-off point

Q

Questionnaire: See Consumer survey

R

Rebound effect: An increase in consumption caused by a change that was meant to lower emissions, which reduces or cancels out the expected benefit. In the context of secondhand, this can happen when lower prices lead buyers to purchase more items than they otherwise would. Rebound effects are accounted for in the consequential approach but not in the attributional approach.
Reference scenario: Also known as Baseline scenario, Alternative scenario and Counterfactual scenario; In avoided emissions calculations, the situation that would most likely occur without the assessed solution, such as buying an item new instead of secondhand. The emissions of this scenario are compared with those of the solution scenario to show how much emissions are potentially avoided.
Remaining lifetime: See Remaining useful life
Remaining useful life: Also known as RUL, Remaining lifetime and Remaining service life; Expected duration or number of uses a product can still provide before it becomes unusable.
Replacement rate: See Displacement rate
Reporting period: Also known as Reporting year; In the context of carbon accounting the time span covered by a set of results, such as a corporate carbon footprint or avoided emissions, usually a calendar year or a fiscal year.
Representative product: Also known as Proxy product; A modeled product that stands for a group of similar items, with a typical weight, bill of materials and footprint.
Resale platform: See Marketplace
Return: Also known as Product return; An item sent back by the buyer after a purchase, for example because it does not fit or does not match its description.
Reverse logistics: The flow of goods from the consumer back towards the seller, the brand or a treatment facility, for returns, repair, refurbishment, resale or recycling.
Route factor: The extra distance traveled from origin to destination compared with the straight-line distance, caused by turns, terrain and obstacles along the way.
RUL: See Remaining useful life

S

Sales packaging: See Primary packaging
Scope 1, 2 and 3 emissions: The three categories the GHG Protocol uses to classify a company’s greenhouse gas emissions. Scope 1 covers direct emissions from sources the company owns, such as its vehicles. Scope 2 covers emissions from the energy it buys, such as electricity. Scope 3 covers all other emissions from its suppliers and customers, such as shipping and packaging.
Scope 4: See Avoided emissions
Secondary data: Also known as Generic data; Data that does not come from the specific activity being assessed, such as industry averages, life cycle inventory databases or published studies.
Secondary packaging: Packaging used for the downstream delivery, such as a cardboard box or a plastic mailer.
Secondhand: Also known as Pre-owned, Pre-loved and Used; Goods that have had at least one previous owner or user and are sold, swapped or given away for further use.
Significantly not as described: Also known as SNAD; A dispute category used by marketplaces when an item differs materially from its listing, for example when it is damaged, counterfeit or a different item.
Straight-line distance: Also known as Direct distance, Geodesic distance and As the crow flies distance; The shortest distance between two points on the surface of the Earth, ignoring roads and other transport networks.
Substitution rate: See Displacement rate
System boundary: The life-cycle stages, processes and activities included in an assessment, such as a carbon footprint or an avoided emissions calculation. Anything outside the system boundary is not counted in the results.

T

Taxonomy: See Product category
Tertiary packaging: Packaging used to handle and transport goods in bulk, such as pallets, stretch film and roll cages.
Tonne-kilometer: Also known as tkm; A unit of freight transport equal to moving one tonne of goods over one kilometer.
Traveled distance: The distance actually covered by a vehicle or a person along a transport network, as opposed to the straight-line distance.
Truck: See Heavy goods vehicle

U

Uncertainty: In carbon accounting, the degree to which a result may differ from its true value because of limitations in data, assumptions and methods.
Unsold stock: See Deadstock
Upcycling: Also known as Creative reuse; Transforming discarded materials or unwanted products into new products of higher value or quality than the original. Unlike recycling, upcycling usually keeps materials in a form close to how they were found, such as making a bag from old jeans.
Upstream emissions: Indirect emissions from a company’s supply chain, such as from producing and transporting the goods and services it buys. Under the GHG Protocol, upstream emissions are part of Scope 3.
Used: See Secondhand

W

Waste and Resources Action Programme: Also known as WRAP; A UK-based charity working on resource efficiency, waste reduction and the circular economy. Its research on reuse and textiles is often used as a data source in avoided emissions calculations for secondhand.
WBCSD: See World Business Council for Sustainable Development
Whole life cycle: See Cradle-to-grave
World Business Council for Sustainable Development: Also known as WBCSD; A Geneva-based organization of more than 250 multinational companies, led by their chief executives, that works on business sustainability. It co-developed the GHG Protocol with the World Resources Institute (WRI) and published the Guidance on Avoided Emissions.
World Resources Institute: Also known as WRI; A global non-profit research organization working on climate, energy, food, forests, water and cities. It co-developed the GHG Protocol with the World Business Council for Sustainable Development (WBCSD) and is one of the founding partners of the Science Based Targets initiative (SBTi).
WRAP: See Waste and Resources Action Programme
WRI: See World Resources Institute