Every term. Zero pretending.

1.5°C goal

The Paris Agreement aim of pursuing efforts to limit global warming to 1.5°C above pre-industrial levels.

Abatement cost

The cost of avoiding a unit of greenhouse gas emissions relative to a defined alternative.

Absolute emissions

The total quantity of greenhouse gases emitted within a defined scope and period.

Activity data

Information about an activity used to estimate greenhouse gas emissions.

Additionality

The requirement that an intervention creates a result beyond what would otherwise have occurred.

Afforestation

Establishment of forest on land that has not recently been forested under the relevant definition.

Albedo

The fraction of incoming sunlight a surface reflects.

Anaerobic decomposition

Breakdown of organic matter by microorganisms in the absence of oxygen.

Anaerobic digestion

A managed biological process that breaks down organic material without oxygen.

Anthropogenic methane

Methane emissions caused by human activity.

Atmospheric lifetime

A measure of how long a substance remains in the atmosphere before removal or chemical transformation.

Audit trail

A chronological record that allows actions and changes to be followed.

Avoided emissions

Emissions estimated not to occur compared with a defined counterfactual scenario.

Base year

A historical period used as the reference for tracking change.

Baseline scenario

A reference description of what would happen without the assessed intervention.

Behaviour change

A change in what people do, influenced by capabilities, opportunities and motivations.

Beyond value chain mitigation

Mitigation activities supported outside a company's own value chain.

Biodiversity

The variety of life, including diversity within species, between species and across ecosystems.

Biogas

A gas mixture created through biological breakdown of organic matter, usually rich in methane and CO₂.

Biogenic methane

Methane produced from recently living organic material through biological processes.

Biomethane

Methane-rich gas made by upgrading biogas to remove CO₂ and other unwanted components.

Blue carbon

Carbon stored in coastal and marine ecosystems, often referring to mangroves, tidal marshes and seagrasses.

Buffer pool

A reserve of credits intended to address specified reversal risks within a programme.

Bystander effect

The tendency for each person to be less likely to help when others who could also act are present.

Calibration

Comparison of an instrument's readings with an appropriate reference under specified conditions.

Carbon allowance

A unit granting permission to emit a specified amount under an emissions trading scheme.

Carbon budget

The cumulative amount of CO₂ compatible with a stated warming limit and probability under specified assumptions.

Carbon capture and storage

Capture of CO₂ from a source, transport and storage intended to isolate it from the atmosphere.

Carbon credit

A tradable unit issued under a programme, commonly representing one tonne of CO₂e reduction or removal.

Carbon dioxide

A gas with the chemical formula CO₂, released by processes including respiration, fossil fuel combustion and land-use change.

Carbon dioxide equivalent

A common unit that expresses different greenhouse gases relative to CO₂ using a selected emissions metric.

Carbon dioxide removal

Human activity that takes CO₂ from the atmosphere and stores it in a reservoir.

Carbon footprint

The greenhouse gas emissions associated with an activity, product, person or entity across a defined boundary.

Carbon neutral

A state in which the CO₂ emissions attributed to a person, organisation, product or activity are balanced by CO₂ removals over a stated period.

Carbon offsetting

Using reductions or removals outside an activity's boundary to compensate for its emissions.

Carbon pricing

Policies that attach an explicit price to greenhouse gas emissions.

Carbon registry

A system recording carbon projects, unit issuance, transfers and final use.

Carbon sink

A process or reservoir that takes up more carbon than it releases over a stated period.

Carbon stock

The amount of carbon stored in a reservoir at a given time.

Carbon tax

A tax linked to the carbon content of fuels or greenhouse gas emissions.

Citizen participation

Involvement of members of the public in decisions that affect them.

Climate adaptation

Adjustment to actual or expected climate effects to reduce harm or take advantage of opportunities.

Climate agency

The capacity to make choices and take actions that influence climate-related outcomes.

Climate anxiety

Distress or worry associated with climate change and its consequences.

Climate change

A lasting change in the average state or variability of the climate, observed over decades or longer.

Climate fatalism

The belief that damaging climate outcomes are inevitable or that action cannot alter them.

Climate fatigue

A commonly used description of weariness or disengagement around repeated climate messages or demands.

Climate feedback

A process triggered by a climate change that then strengthens or weakens the original response.

Financial resources directed towards mitigation or adaptation activities.

Climate justice

An approach examining how climate causes, impacts and responses distribute rights, responsibilities and opportunities.

Climate literacy

Understanding climate processes, human influences and the options for responding.

Climate mitigation

Human intervention that reduces greenhouse gas emissions or increases their removal from the atmosphere.

Climate model

A mathematical representation of the climate system used to investigate its behaviour and possible responses.

Climate neutral

A state in which human activities have no net effect on the climate system, counting all greenhouse gases and land-surface effects such as albedo.

Climate positive

A marketing term for claims that an organisation or product removes or compensates for more greenhouse gas than it emits.

Climate projection

A simulated future response of the climate system to an assumed emissions or concentration pathway.

Climate resilience

The capacity to cope with climate-related disturbances while maintaining or adapting essential functions.

Climate sensitivity

A measure of the temperature response to a change in radiative forcing.

Climate tipping point

A threshold beyond which a change can become self-sustaining or lead to a different state of a system.

Climate variability

Fluctuations in climate conditions around their average over different spatial and temporal scales.

Co-benefit

A beneficial effect beyond the primary objective of an intervention.

Collective action

Coordinated activity by people working towards a shared objective.

Collective efficacy

A group's belief that its joint effort can achieve a desired outcome.

Community energy

Energy activity organised with meaningful community participation, ownership or benefit.

Compliance carbon market

A market created by a legal system that requires regulated participants to meet emissions obligations.

Composting

Managed decomposition of organic material in the presence of oxygen.

Conference of the Parties

The governing meeting of parties to an international convention.

Conflict of interest

A situation in which another interest could influence a person's professional judgement or responsibilities.

Constructive hope

Hope grounded in an honest view of a problem together with a realistic sense of what people can do about it.

Contribution claim

A statement that an organisation has funded climate action outside its own value chain without counting it against its own emissions.

Counterfactual

A reasoned account of what would have happened under different conditions.

Credit retirement

The permanent removal of a carbon credit from circulation for a stated use.

Credit vintage

The period in which a credited reduction or removal occurred, as defined by a programme.

CSRD

The Corporate Sustainability Reporting Directive, an EU law requiring companies in scope to publish sustainability information under common European standards.

Decarbonisation

Reduction of carbon emissions associated with an activity or economy.

Deforestation

Conversion of forest to another land use.

Demand-side mitigation

Changes in service demand and the ways services are provided that reduce emissions.

Destruction efficiency

The proportion of a target substance destroyed by treatment.

Diffusion of responsibility

The weakening of each person's sense of duty to act when responsibility is shared across a large group.

Direct air capture

A process that separates CO₂ directly from ambient air.

Double counting

Counting the same emission reduction or removal more than once in ways that undermine the intended accounting rules.

Ecosystem

A community of living organisms interacting with one another and with their physical environment.

Ecosystem services

The contributions ecosystems make to human wellbeing.

Electrification

Replacing a process powered by another energy source with one using electricity.

Emission factor

A coefficient used to estimate emissions from a unit of activity.

Emission reduction

A decrease in greenhouse gas emissions relative to a stated reference.

Emissions intensity

Greenhouse gas emissions per unit of an activity, output or economic measure.

Emissions inventory

A structured account of greenhouse gas sources and quantities within a stated boundary and period.

Employee engagement

Employees' involvement and connection with workplace activities or goals.

Empowering Consumers Directive

Directive (EU) 2024/825, which amends EU consumer law concerning environmental claims and related practices.

Energy conservation

Reducing energy use through changes in behaviour or service demand.

Energy efficiency

Providing a given service using less energy.

Energy storage

Technologies or methods that hold energy for later use.

Environmental claim

A statement or representation about an environmental attribute or effect.

Environmental stewardship

Responsible care for the natural environment through decisions and practice.

EU Emissions Trading System

An EU cap-and-trade system regulating emissions from covered activities.

Flaring

Combustion of a gas stream in a device designed to burn it.

Forest degradation

A decline in a forest's condition or capacity to provide ecological functions without complete conversion to another land use.

Fossil fuel

A fuel formed from ancient organic matter over geological timescales.

Fossil methane

Methane originating from carbon stored in geological deposits over long periods.

Free-rider problem

The incentive to benefit from a shared good, such as a stable climate, while leaving the cost of providing it to others.

Fugitive emissions

Unintended releases of gas from equipment, infrastructure or other sources.

Gas collection efficiency

The proportion of generated gas successfully captured by a collection system.

Gas composition

The proportions of substances present in a gas mixture.

Gas flow rate

The volume or mass of gas passing a point per unit of time.

Generic environmental claim

A broad environmental statement whose specification is not clearly and prominently provided on the same medium under EU rules.

Global Methane Pledge

A voluntary international initiative in which participating countries aim for a collective cut in methane emissions from human activity.

Global stocktake

The Paris Agreement process for assessing collective progress towards its goals.

Global warming

The long-term rise in global surface temperature, commonly measured against a pre-industrial baseline.

Global warming potential

A metric comparing the integrated radiative effect of equal-mass gas emissions over a chosen period, relative to CO₂.

Green Claims Directive

The name commonly used for a separate EU legislative proposal on substantiating and communicating explicit environmental claims.

Greenhouse effect

Warming of the surface and lower atmosphere caused by gases that absorb and emit infrared radiation.

Greenhouse gas

An atmospheric gas that absorbs and emits infrared radiation at wavelengths relevant to Earth's energy balance.

Greenwashing

Communication that creates a misleading impression of environmental performance.

GWP100

Global warming potential evaluated over one hundred years after a pulse emission.

GWP20

Global warming potential evaluated over twenty years after a pulse emission.

Heat pump

A device that uses energy to move heat from one place to another.

Independent assurance

A review performed by a party sufficiently separate from the activity being assessed.

Informed consent

A freely made decision based on adequate understanding of the relevant information.

IPCC

The Intergovernmental Panel on Climate Change, the UN body that assesses published research on climate change for governments.

Just transition

A transition that seeks fair treatment and decent opportunities for workers and communities affected by economic change.

Landfill cover

Material placed over waste to manage exposure, water infiltration and gas movement.

Landfill gas

A mixture of gases produced as organic material decomposes in a landfill.

Landfill methane

Methane formed when food, paper, wood and other organic waste decompose without oxygen inside a landfill.

Leak detection and repair

A programme for identifying leaks, prioritising repairs and checking whether the fixes worked.

Leakage

An increase in emissions outside a project's boundary caused by the project itself.

Learned helplessness

A pattern in which repeated experience of having no control leads people to stop trying, even after options for action appear.

Life-cycle assessment

A method for assessing environmental burdens across stages of a product or service's life.

Loss and damage

Harm associated with climate impacts that goes beyond or occurs despite mitigation and adaptation responses.

Maladaptation

An adaptation response that increases climate risk or vulnerability, now or later.

Materiality

The significance of information for a defined assessment or decision.

Measurement uncertainty

The quantified or described doubt associated with a measurement result.

Measurement, reporting and verification (MRV)

A system for measuring emissions or actions, reporting the results and checking them against defined criteria.

A greenhouse gas with the formula CH₄ and the main component of natural gas.