1.5°C limit
a target set in the Paris Climate Agreement, in which Countries committed to “holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels”. 

Carbon credit
financial unit representing the reduction or removal of one tonne of CO2e from the atmosphere. It is generated through the development of mitigation projects that follow precise methodologies and international standards and is certified by an external accreditation programme (e.g. Verified Carbon Standards-VCS, Gold Standard). It can be used in carbon neutral, net-zero or climate positive corporate strategies as a tool to offset emissions (see “Offsetting”) and contribute to mitigation initiatives that fall outside a company’s value chain . Carbon credits are stored and retired in a third-party registry officially recognised by the certification standards.

Carbon footprint
the sum of the greenhouse gas (GHG) emissions of a system. It is part of Life Cycle Assessment (LCA) to quantify the environmental impacts associated with a product/process/activity.

Carbon Neutrality 
condition in which anthropogenic emissions of carbon dioxide into the atmosphere are balanced by equal offsets, removals or absorptions over a given period of time. Sometimes used as a synonym for “Climate Neutrality”, from which it differs in the range of climate-altering factors considered: only carbon dioxide (CO2) in the case of Carbon Neutrality, all GHGs and other relevant biogeophysical changes due to human activities in the case of Climate Neutrality. At the corporate level, companies can reach Carbon Neutrality through purchasing carbon credits (see Carbon credit) or other compensation activities (see Offsetting).

Climate Positive
characteristic of an activity or of a target that combines abatement of emissions in line with the 1.5°C target (science-based), removal (or neutralisation) of residual emissions, and offsetting during the transition, to a greater extent than necessary to achieve net-zero emissions (see Net-zero emissions). Term still being defined, sometimes used as a synonym for Carbon Negative.

CO2 equivalent
a unit of measurement that makes it possible to weigh the emissions of different greenhouse gases with different climate-changing effects. The amount of CO2 equivalent is calculated by multiplying the mass of a given greenhouse gas by its global warming potential (GWP).

Direct emissions
emissions produced by sources owned or controlled by the company or entity being studied. 

Global Warming Potential (GWP) > Potenziale di riscaldamento globale
a factor expressing the contribution to the greenhouse effect of a GHG with respect to carbon dioxide (whose reference potential is 1), over a given period of time.

Greenhouse Gases (GHG)
gaseous constituents present in the atmosphere capable of retaining part of the infra-red component of solar radiation that strikes the Earth. The main greenhouse gases are: carbon dioxide (CO2); methane (CH4); nitrogen monoxide (N2O); hydro fluorocarbons (HFCs); fluorocarbons (PFCs); and sulphur hexafluoride (SF6). Also called “Climate Change Gases”. 

Indirect emissions
emissions that are a consequence of the operations of the company or entity being studied, but which occur from sources owned or controlled by external parties. They include emissions due to the production of purchased and used energy (Scope 2) and other emissions due to activities upstream or downstream of the operations of the company or entity under study (Scope 3). 

Mitigation hierarchy
a term borrowed from natural resource management disciplines and practices. It involves four main steps, in order of priority: avoid, reduce, restore, compensate. Applied to the context of climate strategies, it means prioritising the elimination and reduction of emission sources over offsetting or neutralising measures.

Nature-based Solutions (NBS)
activities that help address climate change (e.g. by removing CO2 from the atmosphere) through the conservation, restoration and sustainable management of natural and anthropic ecosystems, providing additional benefits for biodiversity conservation. This category includes, for example, the protection of primary forests and coastal ecosystems (e.g. mangroves), reforestation, and agricultural soil regeneration practices.

Negative emission technologies (NETs) or practices
activities that remove carbon dioxide (CO2) from the Earth’s atmosphere, in addition to the removal which occur through carbon cycle natural processes, and store it permanently or for a sufficiently long period of time. They include NBS activities such as reforestation and ecosystem restoration, as well as emerging technologies such as carbon capture and storage. Also called “Carbon Dioxide Removal” (CDR) activities.

Net-zero emissions
the condition in which anthropogenic emissions of all greenhouse gases into the atmosphere are balanced by equal removals or absorptions over a given period of time. As described in the Paris Climate Agreement, “a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases”.  According to the current standards, setting net-zero corporate targets means reducing emissions in the value chain consistently with the 1.5°C path and neutralizing the impact of any residual emissions through the removal of an equivalent volume of CO2.

The action that entirely or partly compensate emissions remained unabated in a company, product or service value chain, through investments in activities that reduce or remove an equivalent amount of emissions and that are developed outside the boundaries of the organisation (or of a particular product or service system).  Such investments often take the form of the purchase of carbon credits (see Carbon credit). Similar to the concept of insetting, from which it differs according to where the compensation takes place with respect to the boundaries of the activity to be compensated: insetting projects are projects to reduce emissions (in a measurable and certifiable way) within the supply chain of the company or the communities associated with it. In more recent developments (eg SBTi), the term “Offsetting” is associated and superseded by the concept of “Beyond Value Chain Mitigation”.

Radiative Force Index
Aviation emissions are calculated by multiplying the great circle distance by the appropriate emissions factor, a Radiative Forcing Index (RFI) of 1.9 and up uplift factor of 1.09. The RFI is used to incorporate non-CO2 warming effects and the uplift factor is added to take into account non-direct routes (i.e. not along the straight line great circle distances between destinations) and delays/circling.

Science-based target
emission reduction targets aligned with the best available scientific knowledge to meet the commitments made in the Paris Agreement: to limit global warming to well below 2°C compared to pre-industrial levels and to continue efforts to limit warming to 1.5°C (see 1.5°C limit). 


This Glossary is based on the work carried out by Carbonsink in partnership with UN Global Compact Network Italy as part of the Position Paper “Italian Business and Decarbonization: a just and inclusive transition” (hyperlink: It includes a selection of the main concepts and definitions currently used in communication concerning the climate transition, chosen according to criteria of relevance, transversality and complexity. This Glossary captures the state of the art of the current situation and is open to being extended and updated in response to future developments and the best available knowledge. 



United Nations Framework Convention on Climate Change (UNFCCC)

Intergovernmental Panel on Climate Change (IPCC)

Science Based Targets initiative (SBTi)

Greenhouse Gas Protocol

Voluntary Carbon Market Integrity Initiative (VCMI)