Climate Jargon
Simple explanations of unusual climate-related words, phrases, and acronyms.
A climate glossary with more than 470 entries. Many have other meanings depending on context.
Most have links to their Wikipedia article.
Click the underlined letters just below to jump to that section
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About
Acid rain: Rainwater that has more acid than natural
Aerosol cooling: When tiny air particles reflect sunlight back into space and cool the Earth
Aerosols: Tiny air particles that absorb or reflect sunlight
Afforestation: Planting trees where there was no forest before
Agrivoltaics: Farming under solar panels
Albedo: See Reflectivity
Alkaline: Minerals or waters that reduce acid
Alternative energy: See Clean energy
Ammonia: Climate pollution gas 270 times worse than carbon dioxide
Anaerobic: Bacteria that live without oxygen, releasing methane instead of carbon dioxide
Anthracite: Hard, black, high-energy coal
Anthropogenic: Caused by people
Aquifer: One layer of underground rocks holding water
Arable land: Land that can grow crops
Artificial intelligence (AI): Computers and software that learns, solves problems, and delivers words, images, sounds, and videos
Assessment Reports (AR): IPCC reports on the science and damages of climate change
Atlantic Meridional Overturning Circulation (AMOC): Big Atlantic Ocean current that’s a critical part of our climate, moving heat from the equator far north and far south
Atmospheric lifetime: How long a climate pollution gas stays in the air
Atmospheric river: Long narrow band of clouds and moisture high in the air, that can fall as intense rainstorms when it reaches land
Balcony solar power: Plug-in solar panel that can hang from a balcony railing
Barrel (bbl): 42 gallons of oil
Battery Electric Vehicle (BEV): See Electric vehicle
Battery energy storage system (BESS): See Big utility battery
Battery farm: Many big utility batteries in one location
Battery storage plant: See Battery farm
Big utility battery: Utility-sized rechargeable battery in a shipping container that stores clean electricity for later use
Biochar: See Clean charcoal
Biochar carbon removal: Storing carbon dioxide for a long time by adding clean charcoal to soil
Biodegradable: Something that nature can break down
Biodiversity: Total variety of living things in one area
Biofuel: Fuel made from plants or animal waste
Biomass: Total weight 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, high-energy coal
Black carbon: Air pollution from soot
Black start: Carefully restoring power after a large blackout that shuts down power plants
Blackout: When an electric grid stops sending power
Blue hydrogen: Made from natural gas with carbon capture and storage, low climate pollution but expensive
British thermal unit (Btu): U.S. energy unit, 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: Cheap dirty oil burned in ship engines
Cap and trade: When governments put a declining cap on climate pollution, then companies buy and sell carbon credits
Capacity factor: How much electricity a power plant actually produces; a power plant that runs half the time has a 50% capacity factor
Carbon capture: Removing carbon dioxide released at the source
Carbon Capture and Storage (CCS): Carbon capture plus storing carbon dioxide for a very long time
Carbon credit: One ton of carbon dioxide or equivalent climate pollution, removed at the source or from the air
Carbon cycle: How carbon moves between living things, water, air, soil, and underground
Carbon dioxide (CO2): Main climate pollution gas causing global overheating and climate change
Carbon dioxide equivalent (CO2e): How much a gas increases global overheating compared to carbon dioxide
Carbon dioxide removal: Taking carbon dioxide out of the air to reduce climate pollution
Carbon emission: See Climate pollution
Carbon emission trading: Buying and selling carbon credits
Carbon flux: Carbon moving through the carbon cycle
Carbon footprint: How much climate pollution gets released by someone or something
Carbon intensity: Amount of climate pollution released per unit of fuel or energy
Carbon majors: Oil, natural gas, and cement companies responsible for more than half the climate pollution in the world
Carbon neutral: When climate pollution released equals carbon dioxide removed and stored
Carbon offset: When a company pays others to reduce climate pollution instead of reducing their own
Carbon price: Putting a price on climate pollution so that a free market can reduce climate change
Carbon sequestration: Storing carbon dioxide for a very long time to reduce climate change
Carbon sink: Something that naturally removes carbon dioxide from the air, like oceans, marshes, and forests
Carbon tax: When governments tax climate pollution
Carbon trading: See Carbon emission trading
Carbon uptake: Carbon dioxide absorbed by a carbon sink
CH4: See Methane
Chlorofluorocarbons (CFCs): Family of chemicals that damage the ozone layer
Clean cement: Cement made without climate pollution; regular cement makes a lot
Clean charcoal: Charcoal made from burning crop or wood waste without enough air, that can store climate pollution for thousands of years
Clean electricity: Cheaper electricity from clean energy
Clean energy: Low cost energy from the sun, wind, dams, or underground heat, that creates very little air pollution or climate pollution
Clean power: Cheaper electricity from clean energy
Clean hydrogen: Very expensive hydrogen made by using clean electricity to split water, unlikely to get cheaper
Clean tech: Technology that helps our climate, like solar panels and heat pumps
Climate: Long-term weather pattern
Climate action: Any action that helps reduce climate change or adapts to it
Climate anxiety: When someone worries a lot about climate change or forecasts of climate change
Climate change: Long-term changes to Earth’s weather caused by climate pollution, including global overheating and too much ocean acid
Climate change adaptation: Adjusting to the effects of climate change
Climate change denial: Denying that climate change is happening, or that people are causing it, or that it’s a big problem
Climate change feedbacks: Climate changes that make climate change worse
Climate change mitigation: Actions to reduce climate pollution
Climate change vulnerability: How people and nature could be hurt by climate change
Climate crisis: Urgent need for immediate action to reduce climate change
Climate coach: Someone who helps people switch to electric appliances or electric cars
Climate depression: Psychological depression caused by climate change and climate change forecasts
Climate disinformation: See Climate lies
Climate emergency: See Climate crisis
Climate engineering: See Climate modification
Climate expert syndrome (CES): When someone who knows a lot about our climate doesn’t explain stuff in plain language
Climate friendly: Better for our climate than other choices
Climate gentrification: When investors buy damaged properties after a climate disaster to turn them into expensive homes and businesses
Climate grief: Sense of loss after suffering from climate change or worrying about it
Climate guilt: Feeling guilty about making climate change worse
Climate impact: How much something damages our climate
Climate lag: Delay between something that causes climate change and actual changes to our climate
Climate lies: Lies and omissions about climate change causes, effects, and solutions
Climate migration: When climate change forces people to move
Climate misinformation: See Climate lies
Climate model: Complex computer software that forecasts climate change
Climate modification: Deliberately changing the weather to reduce climate change, very risky
Climate optimism: When someone is hopeful and confident that we can reduce climate change
Climate pollution: Gases in the air that trap the Sun’s heat and cause climate change, mainly carbon dioxide and methane, also called greenhouse gases
Climate refugees: People forced to move because of climate change
Climate resilience: Resist climate disasters and recover quickly
Climate severity index (CSI): Measures how much climate change affects temperatures; a CSI of 5 means that a high temperature happens at least 5 times more often
Climate skeptic: Someone who doesn’t believe that climate change is happening, or that people are causing it, or that it’s a big problem
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 climate pollution
Climatic zones: Areas of the Earth with similar climate, like deserts or tundra
Climatology: Scientific study of climate
CO2: See Carbon dioxide
Coal: Underground fuel that adds climate pollution when it’s mined, and when it’s burned for power or heat
Coal mine methane: Methane climate pollution from coal mining
Coalbed methane: Methane trapped in underground coal
Coastal adaptation: Making changes to the coast or how we use it, because of rising seas and extreme storms
Coastal flooding: When dry land is covered by the ocean from a storm surge or rising seas
Coastal inundation: See Coastal flooding
Cogeneration: See Combined heat and power
Combined Heat and Power (CHP): Using both heat and electric power from one energy source
Community decarbonization hub: Church that installs solar power and big batteries to provide power and shelter during disasters
Community land trust: Non-profit corporation that buys and holds land for a community in the long term, like building housing after a wildfire
Conference Of Parties (COP): United Nations organization to review and carry out the Framework Convention on Climate Change
Contrail: Long, thin clouds sometimes made by jet airplanes, might make climate change worse
Controlled burn: See Good fire
COP26: 26th meeting of the Conference of Parties, held in 2021
Community solar: Solar farms that homes and businesses can buy power from
Compound: Chemical elements held together by chemical bonds, like water is hydrogen plus oxygen
Conventional power: Electric power from coal, oil, natural gas, or 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
Cubic foot per second (cfs or ft3/sec): Measurement of streamflow, about 7.5 gallons per second
Cubic meter per second (m3/sec): Measurement of streamflow, about 264 gallons per second
Cultural burn: Traditional Native American good fire
Curtailment: Shutting down some electricity sources when too much power could damage the grid
Data center (DC): Large building with lots of computers and a fast Internet connection, that uses a lot of electricity
Decarbonization: Reducing or stopping climate pollution
Defensible space: Area around a building designed to reduce fire danger and provide a safe area for firefighters
Deforestation: Destroying a forest
Department of Energy (DOE): Part of U.S. government in charge of energy policy and research, nuclear power, nuclear weapons, and nuclear waste storage
Desalination: Removing salt from seawater to make fresh water, also called desal
Desertification: Land turning into desert because of climate change
Direct air capture (DAC): Removing carbon dioxide directly from the air
Direct emissions: Climate pollution released by the operations of something
Dirty energy: Expensive energy from coal, oil, or natural gas, that creates air pollution and climate pollution
Dirty fuel: Coal, oil, gasoline, diesel, propane, or natural gas that creates air pollution and climate pollution when it’s burned for power or heat
Disaster gentrification: When investors buy damaged properties after a disaster to turn them into expensive homes and businesses
Distributed generation: Small electric power systems near where the electricity is used, like rooftop solar panels
Domoic acid: Nerve poison released by algae during a harmful algal bloom
Drought: Unusually long time without rain or snow
Duck curve: Graph of electricity production over 24 hours, minus wind power and solar power, that looks like a side-view drawing of a floating duck
Dust storm: When high winds blow dry dust and sand into the air, can travel thousands of miles
E-bike: See Electric bicycle
Ecosystem: Community of living things plus their environment
El Niño: One phase of the El Niño–Southern Oscillation weather changes, the opposite phase is La Niña
El Niño–Southern Oscillation (ENSO): Global weather changes in cycles that last several years, caused by changing winds and sea surface temperatures in the Pacific Ocean
Electric bicycle: Bicycle that runs on an electric motor and a rechargeable battery
Electric boat: Boat that runs on electric motors and a large rechargeable battery
Electric bus: Bus that runs on electric motors and a large rechargeable battery
Electric car: Car that runs on electric motors and a large rechargeable battery
Electric grid: How most places get electricity, using power plants, storage, substations, and overhead power lines
Electric motorcycle: Motorcycle that runs on an electric motor and a large rechargeable battery
Electric school bus: School bus that runs on electric motors and a large rechargeable battery
Electric train: Train that runs on electric motors and electricity from overhead wires, or a third rail, or a large rechargeable battery, or combinations
Electric truck: Truck that runs on electric motors and a large rechargeable battery
Electric vehicle (EV): Any vehicle that runs on electric motors and a large rechargeable battery, including cars, trucks, trains, and boats
Electricity supplier: Company that sells electricity to customers, sent over wires operated by a separate power company
Electrification: Replacing systems that burn dirty fuels with systems that use electricity, like replacing a gas furnace with a heat pump
Electrolysis: Using electricity and water to make hydrogen and oxygen, very expensive
Emission: Gases or particles released into the air, like carbon dioxide, or soot from burning coal
Endangerment finding: EPA ruling that climate change threatens current and future generations
Energy efficiency: Using less energy to provide the same service
ENERGY STAR: EPA program to label products that meet high energy efficiency standards
Enhanced Geothermal System (EGS): Producing electric power from underground heat after drilling and fracking
Enhanced oil recovery: Producing more oil from a well by pumping in carbon dioxide
Enteric fermentation: When livestock, especially cattle, produce methane climate pollution during digestion
Environmental impact report (EIR): Report about a planned project, describing the good and bad effects on the environment
Environmental impact statement (EIS): See Environmental impact report
Environmental Protection Agency (EPA): Part of U.S. government that protects the environment through environmental impact reports, research, education, and enforcing environmental laws
Evaporative demand: How much water can evaporate outdoors because of dry air, high temperatures, wind, and sunlight
Evapotranspiration: Water evaporation plus water vapor released by plants
Exponential growth: Fast growth that doubles every time period
Extreme event attribution: Science of connecting climate change to extreme weather
Extreme weather: Unusual or severe weather, like heat waves, droughts, cold waves, and hurricanes
Extreme heat: See Heat wave
Extended-Range Electric Vehicle (EREV): Electric vehicle with a gasoline generator to recharge the battery
Fast charger: Electric vehicle charger much faster than a home charger
Fire hardening: Preparing buildings and areas around them to resist wildfires
Fire season: Months with higher wildfire risk
Fire weather: Hot, dry, windy days that make small wildfires more likely to grow very fast
Firestorm: When suburbs and cities burn down in large fires, often starting as wildfires
Flaring: Burning unwanted gases at an oil well or refinery
Flash drought: When a heat wave sucks more water out of plants and soil, just before a fast, much worse drought
Flash flood: Rapid flooding of low areas near creeks and rivers
Flex Alert: Official requests to use less electricity when the electric grid is overloaded
Floating wind turbine: Wind turbine that floats in the ocean, anchored to the seafloor with strong cables
Floodplain: Land covered by a river when it floods
Fluorocarbons: Family of powerful climate pollution gases
Forest thinning: Removing small trees and brush by hand or machine, to improve forest health and reduce wildfires
Fossil fuel: See Dirty fuel
Freedom of Information Act (FOIA): Law that requires release of most government documents on request
Fracking: Drilling into the ground and breaking rocks using pressurized liquids, mostly used to produce more oil and natural gas
Fuel cell: Device that makes electricity using hydrogen from a tank plus oxygen from the air
Fuel Cell Electric Vehicle (FCEV): Vehicle that uses a fuel cell to run an electric motor
Fugitive emissions: Leaks of climate pollution, like natural gas leaking from pipelines
Fusion energy: Making electricity from nuclear fusion someday, under development since the 1940s
Gas turbine: Machine that burns natural gas to make electricity
General Circulation Model (GCM): See Climate model
Geoengineering: See Climate modification
Geothermal energy: See Underground heat
Geothermal power: Clean electricity made from underground heat
Geographic Information System (GIS): Computer mapping
Gigatonnes: One billion metric tons
Gigatons: One billion U.S. tons
Glacial retreat: When glaciers shrink as they melt from climate change
Glacier: Long-lived ice field that slowly moves downhill under its own weight
Global overheating: Rapid increase in worldwide temperatures starting around 1970, also called global warming
Global warming: See Global overheating
Global Warming Potential (GWP): How much heat a gas traps compared to carbon dioxide
Good fire: Carefully setting a fire to prevent wildfires, reduce fire damage, and improve forest health
Gray hydrogen: Made from natural gas while making lots of climate pollution, expensive
Green building: Energy efficient building made with renewable or recycled materials
Green hydrogen: Made by splitting water with clean energy, very low climate pollution but very expensive
Green power: See Clean energy
Greenhouse effect: Trapping the Sun’s heat like a greenhouse
Greenhouse gas (GHG): See Climate pollution
Greenhushing: When a company keeps reducing their climate pollution, but stops talking about it
Greenwashing: When a company exaggerates its climate efforts
Groundwater: Underground water, often pumped from wells
Group of 20 (G20): Biggest economies in the world, including the United States, European Union, and China
GWP-100: Global Warming Potential of a gas over the first 100 years
GWP-20: Global Warming Potential of a gas over the first 20 years
Habitat: Natural home of a living thing
Halocarbon: Family of gases, some are powerful climate pollution that also hurts the ozone layer
Harmful algal bloom: When too much of certain kinds of algae grow in oceans or lakes, and release the nerve poison domoic acid
Heat index: Combines temperature with humidity; a heat index over 90 F is dangerous
Heat pump: Two-way air conditioner that can cool or heat a building, heat a hot water tank, or boil water for factories
Heat wave: Days or weeks of unusually hot weather
Hub home: Home that helps neighborhoods during blackouts and other disasters, with solar panels, big home batteries, and emergency supplies
Hub home captain: Someone who runs a hub home
High-voltage direct current (HVDC): Highest power transmission lines that connect electric grids thousands of miles apart, even under the ocean
Hybrid: Vehicle that runs on gasoline, with a small battery and electric motor to improve mileage
Hybrid jet: Airplane that uses both jet engines and batteries 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 climate pollution gases
Hydrogen (H2): Lightweight gas used in fuel cells to make electricity, adds climate pollution when it leaks, and usually when it’s made
Hydrogen bus: Bus that runs on hydrogen fuel cells
Hydrogen train: Train that runs on hydrogen fuel cells
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, or glaciers, but only melting glaciers add to rising seas
Ice sheet: Glaciers 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 regional electricity grid separate from power companies
Indirect emissions: Climate pollution released by all suppliers of a company and their product users, same as Scope 2 plus Scope 3 emissions
Induction range: Very efficient electric stove that uses magnetism to heat pans
Industrial revolution: When machines powered by coal, oil, and natural gas replaced other energy sources, starting about 1850
Inflation Reduction Act (IRA): Federal law with tax credits for electric vehicles, home energy upgrades, and clean energy
Infrared (IR): Heat transmitted without contact, like the Sun warming your skin
Infrastructure: Big human-built stuff, like electric grids, natural gas pipelines, roads, and buildings
Inorganic compound: Chemical compound without carbon
Intergovernmental Panel on Climate Change (IPCC): United Nations group that produces reports on the science of climate change and its effects
Invasive species: Foreign plants and animals that spread fast, replacing native plants and animals
Investor-owned utility (IOU): Private company that supplies electricity, natural gas, or both
Iron-air battery: Rechargeable battery made with iron that uses oxygen from the air
Iron fertilization: Adding iron to the ocean to increase plant growth and capture carbon dioxide
Jet stream: Fast, narrow air currents about 33,000 feet up
Joule: Tiny metric energy unit, 3,600,000 Joules is 1 Kilowatt-hour
Kilowatt-hour (kWh): 1,000 Watt-hours of electric energy, what a 10-watt light bulb uses in 100 hours, used on electric bills
King tide: Extra-high tide that happens three or four times a year in December and January
Kyoto Protocol: 1997 treaty to reduce climate change, replaced by the Paris Agreement
La Niña: One phase of the El Niño–Southern Oscillation weather changes, the opposite phase is El Niño
Landfill: Place where trash is buried
Least Developed Countries (LDC): 44 poorest countries
Levelized cost of energy (LCOE): Lifetime cost of an electricity generating system, divided by the total electricity delivered, used for comparisons
Levelized cost of storage (LCOS): Lifetime cost of an electricity storage system, divided by the total electricity delivered back to the grid, used for comparisons
LFP battery: Rechargeable battery made with lithium, iron, and phosphate, used in big utility batteries and electric vehicles
Life-cycle assessment: Measurement of climate damage caused by something, from creation to disposal
Lignite: Soft, brown, low-energy 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 iron phosphate battery: See LFP battery
Lithium NMC battery: See NMC battery
Lithium-ion battery: Rechargeable battery made with lithium and other chemicals
Managed retreat: Moving homes, businesses, roads, and utilities inland as rising seas crumble the coast
Marine darkwave: Sudden, intense undersea darkness that lasts for days or months, from storms stirring up sediment, floods washing silt and clay downstream, and algae blooms
Marine heat wave: See Ocean heat wave
Marine mammal: Air-breathing, warm-blooded animal that lives in the ocean, like whales, sea otters, and walrus
Megacity: City with more than 10 million people, 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): Climate pollution gas 80 times worse than carbon dioxide, second-worst cause of climate change
Metric ton: 1,000 kilograms or 1.1 U.S. tons
Microclimate: Climate of a small, specific place, like an ocean beach or a mountain top
Microgrid: Small electric grid that can use power from the main grid, or from local solar panels, wind turbines, and big utility batteries
Microplastics: Extremely small plastic particles
Mine tailings: Leftovers from mining, often in big piles next to the mine
Mini-split heat pump: Small heat pump designed to warm and cool 1 or 2 rooms, with pieces split betwen indoors and outdoors
Montreal Protocol: Treaty designed to protect the ozone layer by reducing gases that destroy ozone
National Interagency Coordination Center (NICC): Government group that coordinates U.S. wildfire response, and forecasts wildfire risks
Nationally Determined Contribution (NDC): Under the Paris Agreement, each country commits to reduce climate pollution by an amount they choose
Natural gas: Fuel pumped from underground, almost all methane, that adds climate pollution when it always leaks, and when it’s burned for power or heat
Neighborhood-scale decarbonization: When an entire neighborhood switches to all-electric, then permanently shuts off the natural gas supply
Net metering: When electric customers with solar panels get full credit for sending electricity to the grid
Net zero emissions: Reducing climate pollution released plus removing carbon dioxide from the air to reach zero
Nitrogen Oxides (NOx): Family of climate pollution gases that also damages the ozone layer, and create smog and acid rain
Nitrous oxide (N2O): Powerful climate pollution gas 273 times worse than carbon dioxide, that also damages the ozone layer
NMC battery: Rechargeable battery made with lithium, nickel, manganese, and cobalt, used in smartphones and electric vehicles
Not In My Back Yard (NIMBY): Local opposition to new projects, like low cost housing
Nonbiodegradable: Something that nature can't break down
Nonlinear: When changes in one thing cause a much larger change in something else
Nuclear power plant: Power plant using a nuclear reactor to make electricity
Nuclear reactor: Makes power using mined uranium while creating radioactive waste that’s dangerous for thousands of years
Ocean acidification: When the ocean absorbs too much carbon dioxide which turns into weak acid that hurts sea life
Ocean heat wave: Unusually warm sea water lasting for months
Oceanography: Science of the oceans
Off river pumped hydro: Pumped hydro that’s not on a river, with dams built on dry ground
Offshore wind farm: Group of wind turbines in the ocean or a large lake
Oil shale: Rocks containing solid oil, producing more climate pollution 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: Air layer about 15 miles up, where ozone absorbs dangerous ultraviolet light from the Sun
Pacific Decadal Oscillation (PDO): Temperature changes in the North Pacific Ocean that repeat every 10 to 30 years
Paris Agreement: International treaty to limit global overheating to less than 2 °C (3.6 °F), ideally less than 1.5 °C (2.7 °F), also called the Paris Climate Agreement
Particulate matter (PM): Air particles like soot and dust
Parts per billion (ppb): Number of parts of something found in one billion (1,000,000,000) parts of something else, like 1/2 teaspoon of oil in an Olympic swimming pool
Parts per million (ppm): Number of parts of something found in one million (1,000,000) parts of something else, like 1/2 teaspoon of oil in a large hot tub
Parts per trillion (ppt): Number of parts of something found in one trillion (1,000,000,000,000) parts of something else, like 1/2 teaspoon of oil in the New Orleans Superdome
Passive solar: Building designed to collect and store heat from the Sun in the winter, but not in the summer
Peak gas car: When gasoline car sales start dropping permanently as electric vehicle sales rise
Peak oil: When worldwide oil pumping starts dropping permanently, replaced by clean energy
Peaker plant: Natural gas power plant that runs only when demand is high, at a much higher price than other electricity sources
Peatland: Wetland where dead plants build up over time, storing carbon dioxide
Per-capita emissions: Amount of climate pollution released per person in a country
Permafrost: Ground that stays frozen all year
Photosynthesis: Plants using sunlight to convert carbon dioxide and water into new growth
Photovoltaic (PV): Special coating in solar panels that converts sunlight into electricity
Phytoplankton: Microscopic plants floating in oceans or lakes
Pineapple express: Atmospheric river that starts near Hawaii and drops lots of rain on the west coast of North America
Planetary boundaries: Tipping points that could push the whole Earth into permanent bad changes
Plankton: Microscopic plants and animals floating in oceans or lakes
Plug-in Hybrid Electric Vehicle (PHEV): Hybrid vehicle with a small rechargeable battery that can be plugged in, but also runs on gasoline
Plug-in solar: Solar panel that plugs into a normal electrical outlet
PM10: Tiny air particles that cause lung disease
PM2.5: Very tiny air particles like smoke that get 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
Positive tipping point: Where a small push can create large rapid changes that help our climate
Power grid: See Electric grid
Power Purchase Agreement (PPA): Contract to buy electricity from a company not owned by the local electric company
Power outage: See Blackout
Power station: Portable rechargeable battery with normal electric outlets
Precipitation whiplash: See Weather whiplash
Prescribed burn: See Good fire
Prescribed fire: See Good fire
Pumped hydro: Electricity storage where water is pumped uphill from one dam to another, released later through turbines to the lower dam
Pumped-storage hydroelectricity: See Pumped hydro
Radiation: Energy released by something, like sunlight from the Sun or radioactivity from nuclear fuel
Radiation budget: How much heat the Earth gets from the Sun
Radioactive waste: Hazardous waste from mining, refining, and using nuclear fuel
Rainforest: Forest with high rainfall
Red tide: See Harmful algal bloom
Reflectivity: How much something reflects sunlight
Reforestation: Planting trees in areas that used to have forests
Relative sea level rise: Rising seas plus the local rise or fall of land
Renewable energy: See Clean energy
Reservoir emissions: Climate pollution released from lakes formed by dams, made as dead plants and animals rot underwater
Residence time: See Atmospheric lifetime
Resilient: Strength and flexibility to resist damage and recover quickly
Resilience center: Community building with emergency supplies to help during blackouts and disasters
Retrofitting: Replacing old systems to improve performance, like replacing a gas heater with an electric heat pump
Rewilding: Restoring nature to an area, including native plants and animals
Rising seas: Increase in sea level caused by global overheating that melts glaciers and expands seawater
Risk assessment: Forecasting future events that might damage something
Roadmap: Clear plan for a country to switch quickly to clean energy
Rooftop PV: See Rooftop solar power
Rooftop solar power: Solar panels mounted on a roof, supplying electricity
Round trip efficiency: Efficiency of a storage system, like putting 100 kilowatt-hours into a battery, but getting 90 kilowatt-hours out, is 90% efficient
Sandstorm: See Dust storm
Scenario: Reasonable and simplified description of how the future could develop
Science Based Targets initiative (SBTi): Large global group that helps companies set climate pollution targets based on climate science
Scope 1 emissions: Climate pollution directly from a company
Scope 2 emissions: Climate pollution from purchased energy
Scope 3 emissions: Climate pollution from suppliers or users of something, hard to measure
Sea level: Average height of the ocean at a shoreline
Sea level rise (SLR): See Rising seas
Sea surface temperature (SST): Temperature of the ocean’s surface
Seawall: Concrete wall or long pile of boulders that protects the coast from damage by big waves and rising seas
Sedimentation: When particles fall to the bottom of a river, lake, or ocean
Shale oil: Oil produced from oil shale
Short ton: One U.S. ton, 2,000 pounds or 0.91 metric tons
Sinkhole: Hole or depression in land, formed by water moving or dissolving rocks and soil
Small Island Developing States (SIDS): Group of 57 low island countries that are at highest risk from rising seas
Small modular reactor (SMR): Small nuclear reactor built in a factory then shipped for installation
Smart thermostat: Thermostat with a Wi-Fi connection to the Internet
Snowpack: Snow piling up during one season
Sodium battery: Rechargeable battery made with sodium instead of lithium, used in big utility batteries, whole home batteries, and electric vehicles
Sodium-ion battery: See Sodium battery
Soil carbon: Carbon stored in the soil
Solar cell: Small thin device that converts sunlight to electricity; solar panels are covered in solar cells
Solar cycle: Slight changes in the Sun’s energy over 11-year cycles with minor climate effects
Solar farm: Large area covered with solar panels
Solar furniture: Outdoor table and bench with solar panels mounted overhead and plugs for laptops and phones
Solar panel: Panel covered in solar cells that turns sunlight into electricity
Solar power: Clean electricity made from sunlight, mostly using solar panels
Solar power plant: See Solar farm
Solar radiation: Sunlight including infrared and ultraviolet
Solar radiation management: See Solar radiation modification
Solar radiation modification (SRM): Reflecting sunlight away from the Earth to reduce global overheating
Sportswashing: When oil and gas companies advertise in sports stadiums or sponsor teams to look better
Steam methane reforming (SMR): Making hydrogen using steam and natural gas, makes a lot of climate pollution
Steam turbine: Machine that uses pressurized steam to make electricity
Storm surge: Temporary rising seas caused by a hurricane or big storm blowing seawater toward shore
Stratosphere: Atmosphere layer between 65,000 feet and 164,000 feet high
Streamflow: Volume of water passing someplace on a stream or river
Subsidence: Land dropping down, often caused by pumping underground water
Sulfate aerosols: Air particles containing sulfur that reflect sunlight back into space
Sulfur dioxide (SO2): Gas created by burning some fuels that cause air pollution, acid rain, and sulfate aerosols
Sulfur hexafluoride (SF6): Very powerful climate pollution gas 17,500 times worse than carbon dioxide
Sulfur oxides: Family of gases that cause air pollution, damage the ozone layer, and reduce global overheating
Sustainable aviation fuel (SAF): Jet fuel made from plants or animal waste
Sustainable development: Meeting the needs of the present without damaging the future
Tailings: See Mine tailings
Tar sand: Rocks containing solid oil, makes more climate pollution than pumped oil
Temperate zone: Climate bands around the Earth that are hot 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 rising seas
Thermal pollution: Hot water from power plants or factories dumped into rivers, lakes, and oceans
Thermohaline circulation: Ocean currents caused by small changes in seawater temperature and saltiness
Tidal power: Using ocean tides to make electricity
Tipping points: High global temperatures that would cause big, permanent damage
Trace gas: Less common gas found in the air, including carbon dioxide, water vapor, methane, nitrogen oxides, and ozone
Transformer: Device that converts higher voltage to lower voltage, like the can-shaped transformers on many power poles
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 65,000 feet high, 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, causes sunburns but used by our skin to make Vitamin D
Underground heat: Clean energy that can be used to heat buildings and make electricity
United Nations Framework Convention on Climate Change (UNFCCC): Structure for governments to work together on climate change
Upwelling: Wind-driven movement of cold deep seawater to the surface
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
Valley fever: Lung infection caused by breathing in certain fungus spores that grow in dry soil, mostly in the U.S. Southwest
Virtual Power Plant (VPP): Centrally managed appliances like air conditioners that can shut down or reduce power to help the electric grid
Volatile organic compound (VOC): Organic compound easily released to the air, can be climate pollution or air pollution
Volcanic ash: Tiny chunks of rock thrown into the air when a volcano erupts, falling back down in layers
Wastewater: Used water containing waste, like when you flush a toiler
Water cycle: How water moves between freshwater, seawater, snow, ice, underground water, and water vapor
Water vapor: Evaporated water in the air that can form clouds
Wave power: Electricity made from ocean waves
Weather: Conditions in the air, like temperature, humidity, wind, and rain
Weather radar: Radar system used by forecasters to find rain, snow, hail, and tornados
Weather whiplash: Rapid swings between weather extremes caused by climate change, like drought quickly followed by heavy rainfall
Weatherization: Adding building features like insulation to reduce heating and cooling needs
White hydrogen: Natural hydrogen from underground, pumped out like natural gas, expensive and rare
Whole home battery: Large battery permanently installed in a home to lower electric bills and supply power during blackouts
Wilderness myth: False belief that Native Americans did not live in or use American wilderness, so the land doesn’t need human care
Wildfire season: Months of the year with more wildfires
Wildland urban interface (WUI): Area where homes and businesses are mixed with forests
Wildlife corridor: Strip of nature connecting wildlife areas separated by highways or development
Wind farm: Group of wind turbines in one area
Wind power: Clean electricity made from wind blowing through wind turbines
Wind turbine: Tall machine with long blades like a propeller, that makes clean electricity when the wind blows
Yes in my backyard (YIMBY): Local support for new projects, like low cost housing
Zero emissions: Something that does not produce climate pollution
Zero Emissions Vehicle (ZEV): How the California Energy Commission incorrectly groups battery electric vehicles, fuel cell EVs, and plug-in hybrid EVs
Zero responder: Neighbors helping neighbors during disasters, often before first responders like firefighters can get there
Zone 0: Five feet next to a house or building that must be cleared of anything that burns, including plants, wooden fences, and mulch
Zooplankton: Microscopic animals floating in oceans or fresh water
1.5 °C: Global overheating goal from the Paris Agreement, same as 2.7 °F
100-hour battery: Big utility battery designed to supply power for several days
100-year flood: Severe floods with a one-in-100 or 1 percent chance of happening every year
1,000-year flood: Very severe floods with a one-in-1,000 or 0.1 percent chance of happening every year
2 °C: Global overheating upper limit from the Paris Agreement, same as 3.6 °F
About
Answering “What does that mean?” in clear, simple English.
Designed for American readers.
These are not comprehensive definitions.
By Rex Sanders, CC BY-SA 4.0
Updated July 15, 2026
https://climatejargon.com