Carbon Accounting Guide
Glossary of Terms
This glossary provides definitions of key terms used in carbon accounting and emissions reporting. Whether you are new to sustainability or looking to deepen your understanding, these definitions will help you navigate the language of carbon management.
Absolute Emissions
The total amount of greenhouse gas (GHG) emissions produced by an organisation, measured in tonnes of CO₂ equivalent (tCO₂e), without adjusting for factors like business growth.
Baseline Year
A reference year used as a starting point for measuring emissions and tracking reduction progress. Typically, this is the first year for which a full GHG inventory was conducted.
Carbon Dioxide Equivalent (CO₂e)
A standard unit for measuring GHG emissions, expressed in terms of the global warming potential (GWP) of carbon dioxide. This allows for comparing the impacts of different greenhouse gases on a like-for-like basis.
Carbon Footprint
The total amount of GHG emissions caused directly and indirectly by an individual, organisation, event, or product.
Carbon Neutral
A state where an organisation balances its CO₂ emissions by reducing emissions and purchasing carbon offsets to compensate for any remaining emissions.
Carbon Offset
A reduction or removal of GHG emissions made to compensate for emissions occurring elsewhere. Examples include reforestation projects or renewable energy investments.
Climate Neutral
A broader concept than carbon neutrality, encompassing all greenhouse gases and potentially addressing wider environmental impacts beyond emissions.
Downstream Emissions
GHG emissions that occur after a product or service leaves an organisation, including emissions from product use, disposal, or processing by customers.
Emissions Factor
A coefficient that converts activity data (e.g., kWh of electricity, litres of fuel) into GHG emissions. Typically expressed in kilograms or tonnes of CO₂e per unit of activity.
Fugitive Emissions
Unintentional leaks or releases of GHGs from equipment or processes, such as refrigerant leaks from HVAC systems or methane leaks during natural gas extraction.
Global Warming Potential (GWP)
A measure of how much heat a greenhouse gas traps in the atmosphere over a specific period, relative to CO₂. For example, methane (CH₄) has a GWP of 28–36 over 100 years, meaning it is 28–36 times more potent than CO₂.
Greenhouse Gases (GHGs)
Gases that trap heat in the atmosphere, contributing to the greenhouse effect. Common GHGs include:
- Carbon dioxide (CO₂)
- Methane (CH₄)
- Nitrous oxide (N₂O)
- Hydrofluorocarbons (HFCs)
- Perfluorocarbons (PFCs)
- Sulphur hexafluoride (SF₆)
- Nitrogen trifluoride (NF₃)
Net Zero
A state where an organisation reduces its GHG emissions as much as possible and balances any remaining emissions with permanent carbon removal solutions, achieving no net contribution to global warming.
Science-Based Targets (SBTs)
GHG reduction targets aligned with climate science to ensure they contribute to limiting global warming to 1.5°C or well below 2°C, as outlined in the Paris Agreement.
Scope 1 Emissions
Direct GHG emissions from sources owned or controlled by an organisation, such as fuel combustion in company vehicles or on-site energy generation.
Scope 2 Emissions
Indirect GHG emissions from the consumption of purchased electricity, steam, heating, or cooling. These emissions occur at the energy production facility.
Scope 3 Emissions
All other indirect emissions across an organisation's value chain, including emissions from suppliers, transportation, product use, and end-of-life disposal. Scope 3 often represents the largest portion of a company’s carbon footprint.
tCO₂e
An abbreviation for "tonnes of carbon dioxide equivalent," a unit used to quantify GHG emissions across different gases.
Upstream Emissions
GHG emissions that occur before a product or service reaches an organisation, including emissions from suppliers, raw material extraction, and transportation.
Value Chain
The full lifecycle of a product or service, from raw material extraction (upstream) to end use and disposal (downstream).
Verification
An independent assessment of an organisation's GHG emissions data to ensure accuracy and compliance with reporting standards.
Voluntary Carbon Market
A marketplace where organisations can purchase carbon offsets to address their emissions, typically used for achieving carbon neutrality or net zero goals.