Climate Jargon
Simple explanations of unusual climate-related words, phrases, and acronyms.
More than 300 entries. Many have other meanings depending on context.
Most have links to their Wikipedia entry.
Click underlined letters to jump to that section
Acid rain: Rainwater that is more acidic than natural
Aerosol cooling: When tiny particles in the air cool the Earth by reflecting sunlight into space
Aerosols: Tiny particles in the air that can absorb or reflect sunlight
Afforestation: Planting trees where there was no forest before
Albedo: How much sunlight something reflects, like white Arctic ice versus dark open ocean
Alkaline: Minerals or waters that reduce acidity
Alternative energy: See renewable energy
Anaerobic: Bacteria living without oxygen, typically releasing methane
Anthracite: Hard, black, high-carbon coal
Anthropogenic: Caused by humans
Aquifer: Layer of underground rocks holding water; one place could have multiple aquifers underneath
Arable land: Land that can grow crops
Assessment Reports (AR): IPCC reports on the science and impacts of climate change
Atmospheric lifetime: How long a greenhouse gas stays in the atmosphere
Barrel (bbl): 42 gallons or about 159 liters of oil
Battery energy storage system (BESS): Large group of rechargeable batteries designed to store grid electricity for later use
Battery farm: See Battery energy storage system
Battery storage plant: See Battery energy storage system
Biochar: Charcoal made by burning wood or plants without enough air
Biodegradable: Something that can be broken down by nature
Biodiversity: Total variety of species in one area
Biofuel: Fuel made from plants or animal waste, a renewable energy source
Biomass: Total mass of living things in one area; or dead things used as fuel, like wood pellets
Biome: Large region with distinct climate, plants, and animals, like a desert or grassland
Biosphere: All life on Earth
Biotic: Living things
Bitumen: Solid oil found in oil shale and tar sand
Bituminous coal: Dense, black, soft coal with less carbon than anthracite
Black carbon: Air pollution in the form of soot
Black start: Carefully restoring power to an electric grid after a large blackout that shuts down power plants
Blackout: When part or all of an electric grid stops delivering power to customers
British thermal unit (Btu): U.S. energy unit, 1,055 Joules; 3,412 Btu is 1 kilowatt-hour
Btu/h or Btu/hr: U.S. power unit, 10,000 Btu/h is 2.9 kilowatts; sometimes confusingly abbreviated to Btu
Bunker fuel: Thick, heavy, inexpensive oil burned in ship engines
Cap and trade: When governments put a declining cap on greenhouse gas emissions, then companies buy and sell allowances under that cap
Capacity factor: Ratio of energy produced over potential, 100% or less
Carbon capture: Removing carbon dioxide released at the source
Carbon Capture and Storage (CCS): Carbon capture plus carbon sequestration
Carbon credit: See carbon offset
Carbon cycle: How carbon moves between living things, water, air, soil, and underground
Carbon dioxide (CO2): Main greenhouse gas causing global warming and climate change
Carbon dioxide equivalent (CO2e): Using global warming potential to calculate the equivalent in carbon dioxide
Carbon dioxide removal: Taking carbon dioxide out of the air
Carbon emission: Release of greenhouse gases into the air, usually carbon dioxide or methane
Carbon emission trading: Buying and selling carbon credits that decline over time
Carbon flux: Movement of carbon from one part of the carbon cycle to another
Carbon footprint: Carbon dioxide equivalent released into the air by something
Carbon intensity: Amount of carbon released per unit of fuel or energy
Carbon neutral: When greenhouse gases released equal greenhouse gases removed and stored
Carbon offset: Investing in projects that reduce, avoid, or remove greenhouse gases, making credits for sale
Carbon price: Putting a price on greenhouse gases so that a free market can reduce climate change
Carbon sequestration: Storing carbon for centuries to reduce climate change
Carbon sink: Something that removes carbon dioxide from the air, like oceans and some forests
Carbon tax: Tax on greenhouse gas emissions to encourage reductions, paying for other reductions or adapting to climate change
Carbon trading: See carbon emission trading
Carbon uptake: Carbon dioxide absorbed by plants or the ocean
CH4: Methane
Chlorofluorocarbons (CFCs): Family of chemicals that harm the ozone layer
Climate: Long-term weather patterns of a region
Climate anxiety: Anxiety created by climate change or forecasts of climate change
Climate change: Long-term changes to Earth’s climate caused by human activity, including global warming and ocean acidification
Climate change adaptation: Adjusting to the effects of climate change
Climate change denial: Denying that humans are causing climate change
Climate change feedbacks: Feedback loops that make climate change worse as the climate changes
Climate change mitigation: Actions to reduce greenhouse gases
Climate change vulnerability: How humans and nature could be harmed by climate change
Climate crisis: Urgent need for immediate action to reduce the harms of climate change
Climate emergency: See climate crisis
Climate impact: Effects of something on our climate, like burning fossil fuels
Climate lag: Delay between something that causes climate change, and actual climate changes
Climate migration: When people are forced to move because of climate change
Climate model: Simulation of our climate, typically complex software running on supercomputers
Climate refugees: People forced to move because of climate change
Climate resilience: Resist or recover quickly from climate hazards
Climate silence: Silence about climate change, based on the mistaken belief that most people don’t want to reduce climate change
Climate sensitivity: How much our climate will change after changes in greenhouse gases
Climatic zones: Areas of the Earth with similar climate, like deserts or tundra
Climatology: Scientific study of climate
CO2: Carbon dioxide
Coal mine methane: Methane released during coal mining
Coalbed methane: Methane trapped in underground coal
Coastal flooding: When dry land is covered by the ocean from a storm surge or sea level rise
Coastal inundation: See coastal flooding
Cogeneration: Using both heat and electric power from one energy source
Combined Heat and Power (CHP): See cogeneration
Conference Of Parties (COP): United Nations organization to review and carry out the Framework Convention on Climate Change
Controlled burn: Carefully setting a fire to reduce future wildfire risks
COP26: 26th meeting of the Conference of Parties, held in 2021
Community solar: Solar farms that homes and businesses can buy power from directly
Compound: Different elements held together by chemical bonds, like water is H2O
Conventional power: Electric power from non-renewable fuels, like coal, oil, natural gas, and nuclear energy
Coral bleaching: When a coral reef in hot water ejects algae living inside, turning the reef white and sometimes killing the coral
Cradle-to-grave: See life-cycle assessment
Crop residue: Leftovers after harvesting and processing a crop
Cultural burn: Traditional Native American controlled burn
Deforestation: Removing or destroying a forest
Department of Energy (DOE): Part of U.S. government in charge of energy policy and research; development of nuclear power and nuclear weapons; and nuclear waste storage
Desertification: Land turned into desert by climate change
Direct air capture (DAC): Removing carbon dioxide directly from the air
Direct emissions: Greenhouse gases released by the operations of something
Distributed generation: Small electric power systems near where the energy is used, like rooftop solar
Drought: Unusually long time without rain or snow
Dust storm: When high winds blow dry dust and sand into the air that can travel thousands of miles, causing many problems but solving others
Ecosystem: Community of living things plus their environment
El Niño–Southern Oscillation (ENSO): Global climate changes in cycles that last several years, caused by changing winds and sea surface temperatures in the Pacific Ocean; El Niño is one phase, the opposite is La Niña
Electric vehicle (EV): Vehicle powered only by electricity from a large rechargeable battery
Electricity supplier: Company that sells electricity to customers, sent over wires operated by a separate utility
Electrification: Replacing systems that burn fossil fuels with systems that use electricity
Electrolysis: Using electricity and water to make hydrogen and oxygen
Emission: Release gases or particles into the air
Energy efficiency: Using less energy to provide the same service
ENERGY STAR: EPA program to label products meeting high energy efficiency standards
Enhanced Geothermal System (EGS): Producing electric power from underground heat after drilling and fracking
Enhanced oil recovery: Removal of more oil from a well after primary and secondary recovery
Enteric fermentation: When livestock, especially cattle, produce the greenhouse gas methane as part of their digestion
Environmental Protection Agency (EPA): Part of U.S. government that protects the environment through environmental impact reports, research, education, and enforcing environmental laws
Evapotranspiration: Water evaporation plus water vapor released by plant leaves during photosynthesis
Exponential growth: Growth that doubles every time period
Extreme weather: Severe weather like heatwaves, hurricanes, floods, and droughts
Extended-Range Electric Vehicle (EREV): Electric vehicle with a fossil-fueled generator to recharge the battery
Fluorocarbons: Family of powerful greenhouse gases
Flaring: Burning unwanted gases at an oil well or refinery
Floodplain: Land covered by a river when it floods
Fossil fuel: Fuel mined or pumped from underground, like coal, oil, and natural gas
Fuel cell: Device that makes electricity using hydrogen from a tank plus oxygen from the air
Fugitive emissions: Greenhouse gas leaks, like natural gas leaking from pipelines
General Circulation Model (GCM): Computer software used to forecast climate change
Geothermal power: Electricity and heat made from underground heat
Gigatonnes: One billion metric tons
Gigatons: One billion U.S. tons, or one billion metric tons
Geographic Information System (GIS): Computerized mapping
Glacial retreat: When glaciers shrink as they melt faster than snow is added
Glacier: Dense, long-lived body of ice from unmelted snowfall, that moves downhill under its own weight
Global Warming Potential (GWP): How much heat a greenhouse gas traps compared to carbon dioxide
Green building: Building built with sustainable materials and high energy efficiency
Green power: See renewable energy
Greenhouse effect: Trapping the Sun’s heat like a greenhouse
Greenhouse gas (GHG): Gas that traps the Sun’s heat and causes global warming, mainly carbon dioxide and methane
Greenwashing: Company advertising with misleading information about its climate efforts
Groundwater: Underground water, often pumped from wells
Group of 20 (G20): Biggest economies in the world, including United States, European Union, and China
GWP-100: Global Warming Potential of a greenhouse gas over the first 100 years
GWP-20: Global Warming Potential of a greenhouse gas over the first 20 years
Habitat: Natural home or environment of a living thing
Halocarbon: Family of chemicals, some are powerful greenhouse gases that also harm the ozone layer
Heat pump: System that uses electricity to move heat from one place to another, like moving heat from cold outside air into homes
Heat wave: Days or weeks of unusually hot weather
Hybrid: Vehicle that runs on fossil fuels, with a small battery and electric motor to improve mileage
Hydrocarbon: Stuff made mostly of hydrogen and carbon, like coal, oil, natural gas, and methane
Hydroelectric power: Electricity produced from water running through turbines at a dam
Hydroelectricity: See hydroelectric power
Hydrofluorocarbons (HFCs): Family of powerful greenhouse gases
Hydrology: Science of Earth’s water on land
Hydropower: See hydroelectric power
Hydrosphere: All the water on Earth, including oceans, lakes, rivers, underground water, glaciers, clouds, and water vapor
Ice age: When most of the Earth was covered by ice sheets; the last ice age ended 11,700 years ago
Ice loss: Melting and shrinking of ocean ice, ice shelves, ice sheets, or glaciers; only melting ice sheets or glaciers add to sea level rise
Ice sheet: Ice covering a very large land area, like Greenland and Antarctica
Ice shelf: Glacier floating on the ocean but still attached to land
Independent system operator (ISO): Runs a region’s electricity grid, wholesale electricity markets, and reliability planning, separate from utilities
Indirect emissions: Greenhouse gases released by generating energy purchased, plus greenhouse gases released by suppliers and product users; Scope 2 plus Scope 3 emissions
Industrial revolution: When machines powered by fossil fuels started replacing other energy sources, starting in the 1800s
Inflation Reduction Act (IRA): Law creating tax credits and other subsidies for electric vehicles, home energy efficiency upgrades, renewable energy, and other climate actions
Infrared (IR): Heat transmitted from an object without contact, like the Sun
Inorganic compound: Combination of elements without carbon
Intergovernmental Panel on Climate Change (IPCC): United Nations body that produces reports on the science of climate change and its effects
Invasive species: Plants and animals that are not native to an area and spread fast, replacing native plants and animals
Investor-owned utility (IOU): Private company that supplies electricity, natural gas, or both
Jet stream: Fast, narrow air currents 10 kilometers or 33,000 feet high
Joule: Metric energy unit; 3,600,000 Joules is 1 Kilowatt-hour
Kilowatt-hour (kWh): 1,000 Watt-hours of electric energy
Kyoto Protocol: 1997 international treaty to reduce climate change, replaced by the Paris Agreement
Landfill: Place for solid waste disposal
Least Developed Countries (LDC): 44 developing countries with the lowest economic development
Life-cycle assessment: Measuring lifetime climate impacts
Lignite: Soft brown coal with less carbon than bituminous coal
Liquefied natural gas (LNG): Natural gas pressurized and cooled to a very low temperature, then shipped to other countries
Liquified petroleum gas (LPG): Pressurized propane and other gases from oil wells
Lithium-ion battery: Rechargeable battery that uses lithium and other chemicals
Megacity: City with a population over 10 million, like Beijing, Mexico City, and New York City
Megawatt-hour (mWh): 1 million Watt-hours of electric energy, or 1,000 kilowatt-hours
Methane (CH4): Greenhouse gas 80 times worse than carbon dioxide, major contributor to climate change
Metric ton: 1,000 kilograms or 1.1 U.S. tons
Microclimate: Climate of a small, specific place, like a beach versus a nearby mountain top
Montreal Protocol: Treaty designed to protect the ozone layer by phasing out ozone depleting substances
Nationally Determined Contribution (NDC): Under the Paris Agreement, each country commits to reduce greenhouse gases by an amount they choose
Natural gas: Fossil fuel pumped from underground that’s 95% methane
Net metering: Electric customers with solar panels getting full credit when they send power to the grid
Net zero emissions: Reducing greenhouse gas emissions plus removing greenhouse gases to reach zero
Nitrogen Oxides (NOx): Family of gases containing nitrogen and oxygen, an important part of smog, that can increase or decrease global warming
Nitrous oxide (N2O): Powerful greenhouse gas 273 times worse than carbon dioxide, also harms the ozone layer
Nonbiodegradable: Something that can’t be broken down by nature
Nonlinear: When changes in one thing cause a much larger change in something else
Nuclear power: Producing electricity using mined and refined uranium while creating radioactive waste, low in greenhouse gases
Nuclear reactor: Power plant using nuclear power to produce electricity
Ocean acidification: When the ocean absorbs too much carbon dioxide and becomes more acidic, harming plankton and shellfish
Oceanography: Science of the Earth’s oceans
Off river pumped hydro: Pumped hydro that‘s not on a river
Oil shale: Rocks containing solidified oil, producing more greenhouse gases than pumped oil
Organic compound: Contains carbon and other elements, different from organic food
Oxidize: When something combines with oxygen, like coal burning into carbon dioxide
Ozone: Rare kind of oxygen found in the ozone layer, also part of smog
Ozone Depleting Substance (ODS): Gas that reduces ozone in the ozone layer, creating the ozone hole
Ozone hole: Large area over Antarctica with much less ozone, so more ultraviolet from the Sun gets through
Ozone layer: Layer of the stratosphere with ozone that absorbs most ultraviolet from the Sun
Paris Agreement: 2016 international treaty to limit global warming to less than 2 °C (3.6 °F) above pre-industrial levels, ideally less than 1.5 °C (2.7 °F)
Particulate matter (PM): Air particles like soot and dust
Parts per billion (ppb): Number of parts of a chemical found in one billion (1,000,000,000) parts of something else
Parts per million (ppm): Number of parts of a chemical found in one million (1,000,000) parts of something else
Parts per trillion (ppt): Number of parts of a chemical found in one trillion (1,000,000,000,000) parts of something else
Passive solar: Building with windows, walls, and floors that collect and store heat from the Sun in the winter, but not in the summer
Peak oil: When worldwide oil pumping starts dropping permanently
Peatland: Wetland where dead plants build up over time and becomes a carbon sink
Per-capita emissions: Amount of greenhouse gases released per person in a country
Permafrost: Ground that stays frozen all year
Plankton: Microscopic plants and animals floating in oceans or fresh water
Photosynthesis: Plants and algae using sunlight to convert carbon dioxide and water to living tissue
Photovoltaic (PV): Special material in solar panels that converts sunlight into electricity
Phytoplankton: Microscopic algae floating in the ocean
Plug-in Hybrid Electric Vehicle (PHEV): Hybrid vehicle with a small rechargeable battery that can be plugged in
PM10: Tiny air particles 10 micrometers (0.0004 inch) or smaller, that cause disease
PM2.5: Tiny air particles 2.5 micrometers (0.0001 inch) or smaller, that penetrate deep into lungs and cause disease
Polar ice cap: Ice covering the Arctic Ocean around the North Pole, or Antarctica around the South Pole
Positive feedback loop: When one thing increases, another increases, causing the first to increase in a loop
Power Purchase Agreement (PPA): Contract to buy electricity from a company not owned by an electric utility
Pumped hydro: System that pumps water to a higher reservoir to store energy, then makes electricity when water flows through turbines to the lower reservoir
Pumped-storage hydroelectricity: See pumped hydro
Prescribed burn: See controlled burn
Radiation: Energy released by something, like sunlight from the Sun or radioactivity from nuclear fuel
Radiation budget: How much net energy the Earth gains from the Sun, changed by ice sheets, clouds, and greenhouse gases
Radioactive waste: Hazardous waste from mining, refining, and using nuclear fuel
Rainforest: Dense forest with high rainfall
Range shift: When plants or animals move to higher elevations or higher latitudes due to climate change
Reflectivity: How much something reflects sunlight
Reforestation: Planting trees in areas that used to have forests
Relative sea level rise: Sea level rise plus the local rise or fall of land
Renewable energy: Energy from natural sources that are not used up, like wind and solar
Reservoir emissions: Greenhouse gas emissions from reservoirs, created as underwater dead plants and animals decay
Residence time: See atmospheric lifetime
Retrofitting: Improving energy efficiency of older systems, like adding insulation
Rewilding: Restoring natural processes to an area, including returning missing native animals
Risk assessment: Forecasting future events that might harm something
Rooftop PV: See rooftop solar power
Rooftop solar power: Solar panels supplying electric power, mounted on a roof
Round trip efficiency: Ratio of energy out over energy in for a storage system, always less than 100%, modern rechargeable batteries are usually over 90%
Sandstorm: See dust storm
Scenario: Reasonable and simplified description of how the future could develop
Scope 1 emissions: Greenhouse gases released from operations
Scope 2 emissions: Indirect emissions from purchased energy
Scope 3 emissions: All other indirect emissions from suppliers or users of something, hard to measure
Sea level: Average ocean height at a shoreline between high tide and low tide
Sea level rise (SLR): Increase in sea level due to melting of glaciers and ice sheets, plus thermal expansion of seawater
Sea surface temperature (SST): Temperature of the ocean’s surface
Sedimentation: When particles fall to the bottom of a river, lake, or ocean, creating layers of sediment
Shale oil: Oil produced from oil shale
Short ton: One U.S. ton, 2,000 pounds or 0.91 metric tons
Small Island Developing States (SIDS): Group of 57 low-lying island nations or territories that are vulnerable to sea level rise
Small modular reactor (SMR): Small nuclear reactor built in a factory then shipped for installation
Snowpack: Seasonal buildup of slow-melting snow
Soil carbon: Carbon stored in the soil
Solar cycle: Slight changes in the Sun’s energy over 11-year cycles with minor climate effects
Solar farm: See solar power plant
Solar power plant: Group of grid-connected solar panels in one area
Solar radiation: Sunlight including infrared and ultraviolet
Steam methane reforming (SMR): Making hydrogen using natural gas and steam, while releasing greenhouse gases
Storm surge: Temporary sea level rise caused by a hurricane or storm blowing seawater toward shore
Stratosphere: Layer of the atmosphere between 20 kilometers or 65,000 feet high, and 50 kilometers or 164,000 feet
Streamflow: Volume of water passing someplace on a stream or river, often measured in cubic feet per second (cfs) or cubic meters per second
Subsidence: Land dropping relative to its surroundings, often caused by mining, or pumping underground water
Sulfate aerosols: Natural and human-made air particles containing sulfur, that reflect sunlight back into space
Sulfur dioxide (SO2): Compound created by burning some fossil fuels that creates air pollution, acid rain, and sulfate aerosols
Sulfur hexafluoride (SF6): Very powerful greenhouse gas 17,500 times worse than carbon dioxide, used in some electrical systems
Sustainable development: Meeting the needs of the present without harming the future
Tailings: Mining leftovers
Tar sand: Rocks containing solidified oil, producing more greenhouse gases than pumped oil
Temperate zone: Climate bands around the Earth that are warm in the summer, cold in the winter, and moderate in the spring and fall
Terrestrial: Dry land
Teragram: 1 trillion grams or 1 million metric tons
Thermal expansion: When warming seawater expands, adding to sea level rise
Thermal pollution: Hotter water that harms the environment
Thermohaline circulation: Ocean currents caused by changes in temperature and saltiness
Tidal power: Using ocean tides to make electricity
Tipping points: Climate thresholds that could lead to large, permanent changes
Trace gas: Less common gas found in our atmosphere, including carbon dioxide, water vapor, methane, nitrogen oxides, and ozone
Tree line: Upper elevation or upper latitude where trees stop growing
Trophic level: Position of a plant or animal in a food chain or food web
Troposphere: Lowest layer of the atmosphere up to 20 kilometers or 65,000 feet, where weather happens
Tundra: Treeless areas in the Arctic, with short growing seasons, low temperatures, and permafrost
Ultraviolet (UV): Invisible part of sunlight mostly blocked by the ozone layer, causing sunburns but needed to make Vitamin D
United Nations Framework Convention on Climate Change (UNFCCC): Structure for governments to work together on climate change
Urban heat island: City with temperatures higher than surrounding areas, because it absorbs more heat from the Sun
Utility: Private business or government agency that provides electricity or natural gas
Virtual Power Plant (VPP): Centrally managed collection of small power sources or appliances that help the electric grid
Volatile organic compound: Organic compound easily released to the air, can be a greenhouse gas, or indoor and outdoor air pollution
Volcanic ash: Tiny chunks of rock thrown into the air during volcano eruptions, eventually falling back down
Wastewater: Used water containing waste
Water cycle: How water moves around on Earth between freshwater, seawater, snow, ice, underground water, and water vapor
Water vapor: Evaporated water in the air, natural greenhouse gas that can form clouds
Wave power: Electricity from ocean waves
Weather: Conditions in the atmosphere at a specific time, like rain, wind, and temperature
Weatherization: Adding building features like weather stripping or insulation to reduce heating and cooling
Wildlife corridor: Strip of nature connecting wildlife areas separated by highways or development
Wind farm: Group of wind turbines in one area
Wind turbine: Tall machine with long fan-like blades that makes electricity when the wind blows
Zero emissions: Something that does not produce any greenhouse gases
Zooplankton: Microscopic animals floating in oceans or fresh water
100-year flood: Severe floods with a one-in-100 chance of happening in any year
About
Answering “What does that mean?” in clear, simple language.
Designed for American readers.
These are not comprehensive definitions.
Many entries have other meanings depending on context.
By Rex Sanders, CC BY-SA 4.0
Updated May 12, 2025
https://climatejargon.com