| Additionality | A carbon project is additional if the reduction in carbon emissions could not have occurred without carbon funding. |
| Allowance | The quantity of carbon dioxide emissions which a company or country is permitted to emit, as a result of regulation. |
| Anaerobic digester | An industrial system that converts waste products into useful energy while reducing greenhouse gas emissions. More... |
| Anthropogenic | Scientists agree that global warming is anthropogenic, meaning it is caused by humans and not part of the Earth's natural cycle. More... |
| Baseline | An estimate of the quantity of carbon that would be emitted if a carbon project was not carried out. It is essential for this estimate to be accurate. |
| Biogas | A mixture of methane and carbon dioxide which is generated by anaerobic digestion and can be burned for energy. More... |
| Biomass | Biological material such as dead plants which can be burned as fuel to generate electricity. More... |
| Carbon calculator | A feature on provider websites which helps you calculate how much carbon dioxide is emitted due to your activites. |
Carbon dioxide
(CO2) | The greenhouse gas which is responsible for most of the Earth's warming, and is generated when burning coal, oil or gas. More... |
Carbon dioxide equivalent
(CO2e) | A tonne of CO2e is a quantity of any greenhouse gas which has the same warming effect as a tonne of carbon dioxide. More... |
| Carbon neutral | An ideal in which all of a person's or organization's carbon emissions are offset, resulting in a zero carbon footprint. More... |
| Certification | A formal standard relating to the quality of a carbon project. Certification standards include the Voluntary Carbon Standard, Kyoto Clean Development Mechanism and Gold Standard. |
Clean Development Mechanism
(CDM) | Part of the Kyoto Protocol which allows rich countries to meet their carbon targets by purchasing offsets from developing countries. |
| Climate change | The series of changes to the Earth's climate which include, and are mostly caused by, global warming. More... |
| Cobenefit | An additional benefit of an offset project on top of the reduction in carbon dioxide emissions, e.g. providing employment. |
| Cost efficiency | The proportion of the money paid to a provider which goes directly to carbon offset projects. Not all providers publish this. |
| Efficient Lighting | See: Project types... |
| Environmental Buildings | See: Project types... |
Environmental Resources Trust
(ERT) | An independent non-profit organization which validates greenhouse gas reduction projects. |
| Forestation | See: Project types... |
| Fossil fuels | Fuels like coal, oil or gas which are created in the Earth from fossils. Burning fossil fuels generates carbon dioxide. More... |
| Fuel Efficiency | See: Project types... |
| Fuel Substitution | See: Project types... |
| Geothermal Power | See: Project types... |
| Global warming | The recent increase in the Earth's temperature, which is a result of human greenhouse gas emissions. More... |
Gold Standard
(GS) | A strict certification standard for carbon offsets, which goes beyond the requirements of the Kyoto Protocol. |
| Green-e | An independent program run by a non-profit which certifies and verifies renewable energy certificates (RECs). |
Greenhouse gas
(GHG) | A gas in the atmosphere which causes the Earth's warming. GHGs include carbon dioxide, methane and nitrous oxide. More... |
| Heat-Electricity Cogeneration | See: Project types... |
| Hydroelectric Power | See: Project types... |
| Industrial Methane | See: Project types... |
Joint Implementation
(JI) | Part of the Kyoto Protocol which allows rich countries to meet their carbon targets by purchasing offsets from each other. |
| Kyoto Protocol | An international agreement sponsored by the United Nations which aims to reduce human greenhouse gas emissions. |
| Leachate | Toxic water created when landfill garbage is exposed to rain. Leachate pollutes the ground and emits methane. More... |
| Leakage | A carbon project suffers from leakage if it increases carbon emissions somewhere else. For example, closing down one factory may cause a competitor's factory to ramp up production. |
| LEED | A rating system which encourages construction of buildings which require less electricity, water and fuels. More... |
| Material Substitution | See: Project types... |
| Measurement | After a project is complete, it is important to measure the quantity of greenhouse gases still emitted. This amount is subtracted from the baseline to confirm the predicted reduction. |
Methane
(CH4) | A potent greenhouse gas which is emitted by various industrial and agricultural processes. More... |
| Methane from Biomass | See: Project types... |
| Operator | The local organization which is entrusted with running a carbon offset project. |
| Permanence | If a carbon project captures and stores carbon, it must be permanent and irreversible. This issue is particularly relevant for reforestation offsets. |
| Project | A practical program which causes a reduction in carbon dioxide emissions, thus acting as a source of carbon offsets. |
| Provider | A company or non-profit organization which sells carbon offsets to individuals or businesses, and uses the money to fund projects. |
| Public Transportation | See: Project types... |
| Regulated offset | A carbon offset which a company is required to purchase by law, because it is emitting more than its allowance. |
| Renewable energy | A way of generating energy which uses up no finite resources. Examples include solar, wind and hydroelectric. More... |
Renewable Energy Certificate
(REC) | Also called Green tags, RECs represent electricity made from renewable sources. Some are resold as carbon offsets. More... |
| Sequestration | Long-term storage of carbon dioxide in the ground, plants or oceans, e.g. by reforestation. More... |
| Solar Power | See: Project types... |
| Sustainability | The ability of our systems to meet both present and future needs. Renewable energy is sustainable, fossil fuels are not. More... |
| Verification | To prevent mistakes or fraud, carbon projects should be verified by a qualified and independent third party. |
Voluntary Carbon Standard
(VCS) | A certification standard for carbon offsets which covers the basic requirements needed for a project to be valid. |
| Voluntary offset | A carbon offset which is purchased by a concerned individual or business out of choice, not as a result of regulation. |
| Wind Power | See: Project types... |
