Glossary🔗

afforestation: Starting a forest or stand of trees in an area where there was no forest before.

AIM/CGE: An Integrated Assessment Model maintained by the National Institute for Environmental Studies, Japan.

anthropogenic: Caused by human activity

AR5: IPCC Fifth Assessment Report on Climate Change (2014)

AR6: IPCC Sixth Assessment Report on Climate Change (2021 and 2022)

BECCS: Bioenergy with carbon capture and storage. An experimental method of energy generation and technological carbon dioxide removal. BECCS entails burning biomass for energy, capturing the CO₂ emissions, storing the emissions long-term, and successfully re-growing any used biomass to result in a process that stores more carbon than it releases. BECCS relies on the success of emerging technologies and availability of sustainable sources of biomass.

biochar: A form of charcoal produced from plant matter and added to soil as a means of removing carbon dioxide from the atmosphere and adding nutrients for growing plants. Biochar operations would need to be scaled massively from current levels and steps taken to ensure biochar permanently stores carbon in the ground for it to make a significant impact on global CO₂.

biomass: Organic (carbon-based) material that comes from living organisms such as plants and can be used as fuel. Examples include wood, corn, or crop residues such as the stalks left after harvesting.

BOE (barrel of oil equivalent): A unit of energy approximately equivalent to the amount of energy generated by burning 1 barrel of oil (159 liters) or 6.12 gigajoules (GJ) of energy.

capital stock turnover: The time it takes for physical energy infrastructure (such as power plants or cars) to be retired and replaced by new, often more efficient, infrastructure.

carbon intensity: The amount of carbon dioxide emitted per amount of energy. E.g., grams of CO₂ emitted per megajoule of energy produced. Coal has the highest carbon intensity of the fossil fuels, followed by oil, then natural gas.

CCS: Carbon capture and storage. A process where CO₂ emissions, say from fossil fuel energy generation, are captured at the source and then stored in a location where the carbon will not leak into the atmosphere, such as deep underground. CCS technology is not yet commercially viable in most settings.

CDR: Carbon dioxide removal. Pulling carbon dioxide out of the atmosphere with technology (e.g., direct air capture) or via plants through photosynthesis (e.g., afforestation).

CH₄: Methane. A greenhouse gas. Methane is released from sources like cows, agriculture, natural gas drilling, and waste.

climate change: Refers to any long-term changes in Earth's weather patterns (rain, temperature, sunshine, storms, etc.) Scientists have been studying changes in the Earth’s climate over millions of years, and the data show that the weather patterns have been changing dramatically recently.

climate change adaptation: Changes made by people or plants and animals in the way things are usually done in order to respond or react to change in climate. For example, seawalls and levees are being built in many low-lying coastal cities to keep out rising tides and increased storm surge as a result of climate change.

climate sensitivity: The amount that the global surface temperature will increase in response to a doubling of CO₂ in the atmosphere.

CO₂: Carbon dioxide. A greenhouse gas that can be naturally made by living things and used by plants for photosynthesis or produced by burning fuel (gas, wood, coal, oil, etc.).

co-benefit: A positive effect of climate action that does not directly relate to climate. For example, a co-benefit of shutting down coal plants is improved air quality.

C-ROADS: Climate-Rapid Overview and Decision Support simulator created by Climate Interactive. Focuses on specific emission reduction pledges from different countries and world regions (e.g., to meet the goals of the Paris Agreement).

crop yield: The amount of food or animal feed produced per hectare of farmland, measured in kilograms/year/hectare. In En-ROADS, the crop yield is the global average productivity on land.

damage function: The estimated effect of temperature change on global economic growth. Learn more about the economic damage function and how it is modeled in En-ROADS here.

deforestation: The clearing of trees, transforming a forest into cleared land, often through burning and removing forests to make land available for crops like soybeans, corn, or palm oil.

direct air carbon capture and storage (DACCS): An experimental method of technological carbon dioxide removal where CO₂ is captured from the air with machines and stored permanently (e.g., underground). DACCS is a new industrial process that is still in development. To get a net removal benefit, the captured carbon must be stored long-term and the DACCS facility must be powered by low-carbon energy.

EIA: U.S. Energy Information Administration

EMF: Stanford Energy Modeling Forum

emissions: Making and giving off something (for example: giving off carbon dioxide gas)

En-ROADS: Energy Rapid Overview and Decision-Support climate change solutions simulator created by Climate Interactive

equity: A way of creating the conditions that enable a just and fair inclusion of everyone into a society in which all can participate, prosper, and reach their full potential. (Definition courtesy of the Partnership for Southern Equity).

exajoule: A measure of energy equal to 10¹⁸ joules

F-gases: Fluorinated gases. Synthetic (created by humans) gases that are used in industrial applications (like refrigeration, air conditioning, aerosols, foams, and manufacturing microchips) and are powerful greenhouse gases. Include HFCs, PFCs, SF₆, and Montreal gases (ozone-depleting substances controlled by the Montreal Protocol).

feedstock: Raw material used for an energy or industrial process. For bioenergy, these can be wood, waste, crops, algae, etc.

final energy consumption: Total energy consumed to meet the demand of all final end uses. For example, how much electricity a lightbulb uses or how much fuel a truck burns are measures of final energy consumption. It does not include energy lost through transmission and distribution (T&D) or inefficiencies, which, in contrast, is accounted for in primary energy demand.

fossil fuels: Coal, oil, and natural gas. Fuel derived from the remains of ancient plants and animals.

GCAM: An Integrated Assessment Model (IAM) maintained by the Pacific Northwest National Laboratory (PNNL) and Joint Global Change Research Institute (JGCRI).

GDP: Gross Domestic Product. The total value (money) of goods produced and services provided in a country during one year.

gigajoule: A measure of energy equal to 10⁹ joules.

GISTEMP: GISS Surface Temperature Analysis created by NASA. An estimate of global surface temperature change.

greenhouse gas: Any gas that absorbs radiation (heat energy) from the Earth’s surface and thus traps heat and makes the planet warmer. Anthropogenic (caused by human activity) greenhouse gases include CO₂, CH₄, N₂O, and F-gases.

Gtons: A measure of mass. Metric gigatons (10⁹ tons or 10¹² kg).

GWP: Global warming potential. The heat absorbed by a greenhouse gas in the atmosphere over a period of time as compared to the heat absorbed by an equivalent amount of CO₂.

HadCRUT5: A global dataset of historical surface temperature anomalies. Maintained by the Met Office Hadley Centre for Climate Change.

HFCs: Hydrofluorocarbons. A type of F-gas used in refrigeration and air conditioning.

HVAC: Heating, ventilation, and air conditioning

IAM: Integrated Assessment Model. A type of computer model that links economic activities with biological and geophysical dynamics to better understand how people can affect things like climate change.

IEA: International Energy Agency

IMAGE: An Integrated Assessment Model (IAM) maintained by the PBL Netherlands Environmental Assessment Agency.

IPCC: Intergovernmental Panel on Climate Change

joule: A measure of energy. Lifting an apple one meter takes about 1 joule of energy, and a liter of gasoline contains 31,536,000 joules of energy (source).

Kaya graphs: Show the drivers of growth in carbon dioxide emissions. Yoichi Kaya created the equation behind the graphs: Global Population x GDP per Capita x Energy Intensity of GDP x Carbon Intensity of Energy = CO₂ Emissions from Energy.

kWh: Kilowatt hour. A measure of energy. Equals one hour of electricity use at 1 kW power.

mature forest degradation: The harvesting of older forests for wood bioenergy or other forest products. Although the trees may not be permanently or completely lost, this disturbs the forest, releasing part of the carbon locked in the trees and soils, and reducing its capacity to remove additional carbon.

MCF: Thousand cubic feet. A unit for measuring the volume of natural gas, often used for energy measurements. Burning a thousand cubic feet of natural gas generates approximately 1.1 GJ of energy. The “M” in “MCF” is the Roman numeral for thousand.

MESSAGE-GLOBIOM: An Integrated Assessment Model (IAM) maintained by the International Institute for Applied Systems Analysis (IIASA).

multisolving: When people work together across sectors to address multiple problems with one policy or investment.

MWh: Megawatt hour. A measure of energy. Equals 1000 kWh.

N₂O: Nitrous oxide. A greenhouse gas.

NF₃: Nitrogen trifluoride. An F-gas.

NGFS: Network for Greening the Financial System. An international consortium of central banks and financial institutions. They partner with climate and economic modeling groups to create a set of climate scenarios, which were included in the recent IPCC Assessment Report (AR6 2022). Three different integrated assessment modeling teams contributed to the NGFS scenarios: PIK REMIND-MAgPIE, PNNL/JGCRI GCAM, and IIASA MESSAGEix-GLOBIOM.

Paris Agreement: International treaty signed in 2015 by 196 countries with the aim of limiting global warming “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.”

PFCs: Perfluorinated chemicals. A family of F-gases.

PM2.5: Particulate matter (tiny particles that can be inhaled) in the air of 2.5 micrometers or less in diameter. This is a category of air pollution that is associated with significant health impacts and is responsible for millions of deaths worldwide each year.

ppm: Parts per million. A common measure of CO₂ concentration in the atmosphere.

primary energy demand: Primary energy refers to the total energy from a raw energy source that is converted into consumable energy. For example, primary oil energy demand refers to the total amount of energy of crude oil that is then extracted, refined, and consumed. Primary energy is greater than final energy consumption because it accounts for inefficiencies in fuel processing, thermal conversion, and transmission and distribution (T&D).

progress ratio: The relative amount of cost reduction per doubling of cumulative production of a technology. In the case of renewable energy, the progress ratio is thought to be 20%, i.e. for every doubling of production, costs decrease by 20%. Costs come down as supply chains, business models, and production industries grow. Also known as the learning effect or learning/experience curve.

RCP: Representative concentration pathway. A greenhouse gas concentration (not emissions) pathway used by the IPCC. Shared socioeconomic pathways (SSPs) are a successor to the RCPs.

REMIND-MAgPIE: An Integrated Assessment Model (IAM) maintained by the Potsdam Institute for Climate Impact and Research (PIK).

radiative forcing (RF): The difference between energy absorbed by the Earth and energy radiated back into space. Incoming energy minus outgoing energy. When incoming energy is greater than outgoing energy, RF is positive and the planet will warm. Measured in W/m².

SF₆: Sulfur hexafluoride, an F-gas.

SSPs: Shared Socioeconomic Pathways. A set of five narratives about future social, political and economic conditions in the world that are used to create and compare climate scenarios. Learn more.

terajoule: A measure of energy equal to 10¹² joules.

thorium: A chemical element that can be used as fuel for nuclear fission, similar to uranium. Thorium fission is an experimental technology that has yet to be used in a large-scale nuclear reactor. Its use at a large scale could be modeled in En-ROADS using the New Zero-Carbon slider.

TOE (ton of oil equivalent): A unit of energy equivalent to 29.3 gigajoules (GJ). This is the amount of energy generated by burning 1 metric ton of coal.

WEO: World Energy Outlook. A yearly publication by the International Energy Agency (IEA).

WITCH-GLOBIOM: An Integrated Assessment Model maintained by the European Institute on Economics and the Environment (EIEE)