Carbon jargon: net zero, emissions, science-based targets – what does it all mean?

Net zero, emissions, SBTIs? Carbon jargon can be complicated, and people sometimes use the same phrase to mean different things.

Our A-Z glossary will help you become familiar with common carbon and energy related terms and acronyms.

Carbon emissions and greenhouse gases

‘Carbon’ and ‘carbon emissions’ can be used as shorthand for all greenhouse gas emissions. This is because carbon dioxide is the most common greenhouse gas, however other gases such as methane also cause global warming and must be reduced.

Carbon footprint

The total amount of carbon emissions (or ‘greenhouse gases’) directly and indirectly released by a business’s activities, including in their supply chain.

Carbon footprints are also used to describe emissions associated with products or services.

Carbon Reduction Plan (CRP)

A Carbon Reduction Plan (CRP) is required when bidding for certain Government contracts, as required by PPN 06/21.

The CRP must be published on a suppliers’ website, and details their carbon footprint and confirms their commitment to achieving net-zero by 2050 at the latest.

Do a search for the GOV.UK ‘Carbon Reduction Plan Template’ to help you make your carbon reduction plan.

This template includes:

  • commitment to achieving net-zero
  • baseline emissions footprint
  • current emissions reporting
  • emissions reduction targets
  • carbon reduction projects

Circular economy

The circular economy is a system where materials never become waste. This is achieved through actions such as reuse, repair, and recycling that keep materials and products (resources) in use for longer.

Companies can also consider ways to improve the resource efficiency of their activities by designing their products to minimise waste and keep them in use at their highest value for as long as possible.

Downstream emissions

Indirect GHG emissions from logistics, use and disposal of your products. Downstream emissions also include those that are generated from activities like investing and franchising.

Dry recyclables

Dry recyclables include:

  • glass including drinks bottles and rinsed empty food jars
  • metal such as drinks cans and food tins
  • plastic such as rinsed empty food containers and bottles
  • paper such as old newspapers and envelopes
  • cardboard such as delivery boxes and packaging

Emissions baseline

An emission baseline serves as a foundation for understanding your current emissions. You can use this as a reference point against which you can measure changes in your greenhouse gas (GHG) emissions going forward.

ESG or Environmental, Social and Governance

ESG is a set of standards that measures a business’s impact on society, the environment, and the business’s ethical behaviour as well as diversity and inclusion.

Greenhouse gases (GHGs)

Greenhouse gases (GHGs) are emissions that contribute to climate change. According to a 2021 study by British Business Bank, SMEs produce around a third of all emissions in the UK.

GHGs include:

  • carbon dioxide (CO2)
  • methane (CH4)
  • nitrous oxide (N2O)
  • hydrofluorocarbons (HFCs)
  • perfluorocarbons (PFCs)
  • sulphur hexafluoride (SF6)
  • nitrogen trifluoride (NF3) 

To simplify matters, all GHGs are converted to CO2 equivalent or CO2(e) to produce a carbon footprint.

Examples of activities which contribute to GHGs are:

  • electricity from fossil fuel power stations
  • burning gas for heating
  • driving a petrol or diesel fuelled car

Green jobs

The term green skills is defined by the Green Jobs Taskforce as “employment in an activity that directly contributes to – or indirectly supports – the achievement of the UK’s net zero emissions target and other environmental goals, such as nature restoration and mitigation against climate risks”.

For example, any job in the renewables sector could be termed “green” rather than those needing “green” skills.

Green skills

The term ‘green skills’ is defined by UK Parliament as “the knowledge, abilities, values and attitudes needed to live in, develop and support a society which reduces the impact of human activity on the environment”. Examples of these skills include:

  • pollution mitigation and waste prevention
  • environmental remediation
  • sustainable procurement
  • energy generation and management

Hazardous waste

Common hazardous waste types that are unsuitable for general disposal or recycling include:

  • asbestos
  • batteries
  • chemicals, such as print toner
  • cooking oils, fats and greases
  • electrical appliances
  • fluorescent light tubes
  • fridges, freezers and air-conditioning units
  • gas bottles and canisters
  • hazardous or toxic waste
  • liquids
  • medical waste
  • mercury
  • oil, fuel and other automotive fluids
  • paints (including residues inside paint cans) and solvents
  • pesticides
  • plasterboard
  • roofing felt containing bitumen
  • solvents

Net zero

The Climate Change Act commits the UK government by law to reducing UK greenhouse gas net emissions by at least 100% of 1990 levels (net zero) by 2050.

The SME Climate Commitment defines net zero for a company as follows:

“To reach a state of net zero emissions, a company must reduce its emissions by at least 90% and counterbalance the remaining residual emissions with durable or permanent carbon removals. The term “residual” refers to emissions that cannot technically be eliminated. Such residual emissions shall not exceed 10% of baseline emissions.”

Organics recycling

Organics recycling includes food leftovers or waste generated by food preparation and garden waste.

Science-based targets

Science based targets (SBT) show how much a business’s carbon emissions need to reduce, and how quickly, to be consistent with limiting global warming to 1.5 C.

This involves calculating the amount of global emissions ‘allowed’ across different economic sectors and what a fair share would be for an individual company.

The Science Based Targets Initiative provides calculation methods and advice for firms considering this approach.

Scope 1, 2 and 3 emissions

Scope 1 

Direct emissions that from operations that are owned or controlled by the reporting company.

These include:

  • emissions from combustion in owned or controlled boilers, furnaces and vehicles
  • emissions from chemical production in owned or controlled process equipment

Scope 2 

Indirect emissions from the generation of purchased or acquired electricity, steam, heating, or cooling consumed by the reporting company.

These include the use of:

  • purchased electricity
  • steam
  • heating
  • cooling

Scope 3 

All indirect emissions that are not included in scope 2 and occur in the value chain of the reporting company, including both upstream and downstream emissions

These include the:

  • production of purchased products
  • transportation of purchased products
  • use of sold products

Overview of GHG Protocol scopes and emissions across the value chain

Source: WRI/WBCSD Corporate Value Chain (Scope 3) Accounting and Reporting Standard (opens in PDF), page 5


Sustainability is a broad term that means operating in a way that meets the needs of the current generation while not undermining future generations to meet theirs.  It can be applied to social and financial issues as well as environmental ones.

Upstream emissions

Indirect GHG emissions from purchased or acquired goods and services. Other upstream categories include business travel, employee commuting as well as emissions generated from waste leased assets.

Value chain

A value chain is a progression of activities that a business or firm performs in order to deliver goods or services of value to an end customer.

Take part in the UK Net Zero Business Census
Take part in the UK Net Zero Business Census