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Abrupt Climate Change:

Sudden (on the order of decades), large changes in some major component of the climate system, with rapid, widespread effects.


Adjustment or preparation of natural or human systems to a new or changing environment which moderates harm or exploits beneficial opportunities.


Planting of new forests on lands that historically have not contained forests.


Alternative Energy: 
Energy derived from nontraditional sources (e.g., compressed natural gas, solar, hydroelectric, wind).


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Gas or liquid fuel made from plant material (biomass).  Includes wood, wood waste, wood liquors, peat, railroad ties, wood sludge, spent sulfite liquors, agricultural waste, straw, tires, fish oils, tall oil, sludge waste, waste alcohol, municipal solid waste, landfill gases, other waste, and ethanol blended into motor gasoline.


Biomass Energy:

Biomass is simply material from plants and animals; when these materials are burned, their stored energy is released as heat.  Plants absorb energy from the sun through photosynthesis, which creates their stored energy.  When biomass is burned, it releases carbon dioxide and plants take it out of the atmosphere and use it to grow their leaves, flowers, branches, and stems.  Many different kinds of biomass, such as wood chips, corn, and some types of garbage, are used to produce electricity.


Some types of biomass can be converted into liquid fuels called biofuels that can power cars, trucks, and tractors. Leftover food products like vegetable oils and animal fats can create biodiesel, while corn, sugarcane, and other plants can be fermented to produce ethanol.


The part of the Earth system comprising all ecosystems and living organisms, in the atmosphere, on land (terrestrial biosphere) or in the oceans (marine biosphere), including derived dead organic matter, such as litter, soil organic matter and oceanic detritus.


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Carbon Capture & Underground Storage:

diagram of carbon capture underground storage
Most of the planet’s electricity is generated at large power plants that burn coal and other fossil fuels that add lots of carbon dioxide to the atmosphere. It will likely be many decades before we can get most of our electricity from renewable resources that emit little or no carbon dioxide. In the meantime, scientists are developing ways to capture carbon dioxide from power plants and factories and safely store it underground so that it can't go into the atmosphere.


Carbon Dioxide:

A type of greenhouse gas that is emitted into the atmosphere; it is the most important greenhouse gas that is emitted by human activities.

chart of carbon Dioxide in the atmosphere
Carbon Footprint: 

carbon dioxide emissions from people activities
The total amount of greenhouse gases that are emitted into the atmosphere each year by a person, family, building, organization, or company. A persons carbon footprint includes greenhouse gas emissions from fuel that an individual burns directly, such as by heating a home or riding in a car. It also includes greenhouse gases that come from producing the goods or services that the individual uses, including emissions from power plants that make electricity, factories that make products, and landfills where trash gets sent.


Climate in a narrow sense is usually defined as the "average weather," or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands of years. The classical period is 3 decades, as defined by the World Meteorological Organization (WMO). These quantities are most often surface variables such as temperature, precipitation, and wind. Climate in a wider sense is the state, including a statistical description, of the climate system.


Climate Change:

climate change
A long-term change in the state of the climate; it can also include gradual and/or abrupt changes in the frequencies and intensities of extreme events.


Climate Variability:

climate variability
Variations of the climate, which is part of long-term climate change (variable temperatures are a natural part of the climate).

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Those practices or processes that result in the conversion of forested lands for non-forest uses.  Deforestation contributes to increasing carbon dioxide concentrations for two reasons: 1) the burning or decomposition of the wood releases carbon dioxide; and 2) trees that once removed carbon dioxide from the atmosphere in the process of photosynthesis are no longer present.


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Ecological Threshold:

The point at which there is an abrupt change in an ecosystem quality, property, or phenomenon, or where small changes in one or more external conditions produce large and persistent responses in an ecosystem.


Any natural unit or entity including living and non-living parts that interact to produce a stable system through cyclic exchange of materials.  Also, an ecosystem can refer to the animals, plants, and the microorganisms that live in one place, as well as the environmental conditions that support them.


Ecosystem Services:

Products and services provided by ecosystems, such as: food, fuel, timber, water, clean air, and medicines.  It also includes less material benefits, such as regulation of local climate conditions and aesthetic value or cultural identity.


The release of a substance (usually a gas when referring to the subject of climate change) into the atmosphere.


Enhanced Greenhouse Effect: 
The concept that the natural greenhouse effect has been enhanced by increased atmospheric concentrations of greenhouse gases (such as CO2 and methane) emitted as a result of human activities. These added greenhouse gases cause the earth to warm.


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Food Web:

Made up of predators and prey that interact in a habitat or ecosystem.


Fossil Fuel: 
A general term for organic materials formed from decayed plants and animals that have been converted to crude oil, coal, natural gas, or heavy oils by exposure to heat and pressure in the earth's crust over hundreds of millions of years.


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Global Average Temperature: 
An estimate of Earths mean surface air temperature averaged over the entire planet.


Global Warming: 
The recent and ongoing global average increase in temperature near the Earth’s surface.


Global Warming Potential: 
A measure of the total energy that a gas absorbs over a particular period of time (usually 100 years), compared to carbon dioxide.


Geothermal Energy:

Deep inside the Earth, the temperature gradually gets warmer the deeper you go; this is a result of the inside of the Earth being full of heat.  This heat is called geothermal energy.


Geothermal Heat Pumps:

geothermal heat pump
Tap into heat close to the Earth’s surface to heat water or provide heat for buildings.

Geothermal Power Plants:

These power plants drill wells 1 or 2 miles deep into the Earth to pump steam or hot water to the surface.  They use heat from deep inside the Earth to generate steam to make electricity. 

geothermal power plants


Greenhouse Effect: 
Trapping and build-up of heat in the atmosphere (troposphere) near the Earth’s surface. Some of the heat flowing back toward space from the Earth's surface is absorbed by water vapor, carbon dioxide, ozone, and several other gases in the atmosphere and then reradiated back toward the Earth’s surface. If the atmospheric concentrations of these greenhouse gases rise, the average temperature of the lower atmosphere will gradually increase.


Greenhouse Gases:

climate connections
A natural part of the atmosphere that traps the sun’s energy and maintains the earth’s surface temperature (around 15 degrees Celsius) through the natural process called the greenhouse effect.


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Heat Waves: 
A prolonged period of excessive heat, often combined with excessive humidity.

Substances containing only hydrogen and carbon. Fossil fuels are made up of hydrocarbons.


Hydroelectric Dam:

diagram of the operation of a hydroelectric dam
Captures energy from the movement of a river. Dam operators control the flow of water and the amount of electricity produced. Dams create reservoirs (large bodies of calm water) behind them, which can be used for recreation, wildlife sanctuaries, and sources of drinking water.


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Indirect Emissions: 
Indirect emissions from a building, home or business are those emissions of greenhouse gases that occur as a result of the generation of electricity used in that building. These emissions are called "indirect" because the actual emissions occur at the power plant which generates the electricity, not at the building using the electricity.


Industrial Revolution: 
A period of rapid industrial growth with far-reaching social and economic consequences, beginning in England during the second half of the 18th century and spreading to Europe and later to other countries including the United States. The industrial revolution marks the beginning of a strong increase in combustion of fossil fuels and related emissions of carbon dioxide.


Infrared Radiation: 
Infrared radiation consists of light whose wavelength is longer than the red color in the visible part of the spectrum, but shorter than microwave radiation. Infrared radiation can be perceived as heat. The Earth’s surface, the atmosphere, and clouds all emit infrared radiation, which is also known as terrestrial or long-wave radiation. In contrast, solar radiation is mainly short-wave radiation because of the temperature of the Sun.


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Land waste disposal site in which waste is generally spread in thin layers, compacted, and covered with a fresh layer of soil each day.


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landfill methane capture
A type of greenhouse gas that is emitted into the atmosphere; it is released mainly from the livestock enteric fermentation (digestive process) and paddy rice farming (flooded land used for growing semiaquatic rice).  Methane is also the main ingredient in natural gas; methane can be captured from landfills, and can in turn, be burned to produce electricity, heat buildings, or power garbage trucks. Capturing methane before it gets into the atmosphere also helps reduce the effects of climate change.


A human intervention to reduce the human impact on the climate system; it includes strategies to reduce greenhouse gas sources and emissions and enhancing greenhouse gas sinks.

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Natural Disasters are categorized into three groups:

Biological Disasters- epidemics & insect infestation

Climate-related Disasters- floods, wave surges, storms, droughts, wildfires, extreme temperatures, landslides and avalanches

Geophysical Disasters- earthquakes, tsunamis, and volcanic eruptions


Natural Gas: 
Underground deposits of gases consisting of 50 to 90 percent methane (CH4) and small amounts of heavier gaseous hydrocarbon compounds such as propane (C3H8) and butane (C4H10).


Nitrogen Cycle: 
The natural circulation of nitrogen among the atmosphere, plants, animals, and microorganisms that live in soil and water. Nitrogen takes on a variety of chemical forms throughout the nitrogen cycle, including nitrous oxide (N2O) and nitrogen oxides (NOx).


Nitrous Oxide:

A type of greenhouse gas that is emitted into the atmosphere; it is emitted mainly by soils due to the use of fertilizers.


Nuclear Energy:

The energy made from splitting atoms (nuclear fission) that takes place in nuclear power plants.


Nuclear Fission:

The process of making energy from splitting atoms apart to make electricity.


Nuclear Power Plants:

diagram of a nuclear power plant
Nuclear power plants do not burn fossil fuels, and therefore, do not produce greenhouse gases; what nuclear power plants do produce is radioactive waste that has to be handled and disposed of properly to protect people and the environment.


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Ocean Acidification: 
Increased concentrations of carbon dioxide in sea water causing a measurable increase in acidity (i.e., a reduction in ocean pH). This may lead to reduced calcification rates of calcifying organisms such as corals, mollusks, algae and crustaceans.

diagram of ocean acidification


To chemically transform a substance by combining it with oxygen.


Ozone, the triatomic form of oxygen (O3), is a gaseous atmospheric constituent. In the troposphere, it is created by photochemical reactions involving gases resulting both from natural sources and from human activities (photochemical smog). In high concentrations, tropospheric ozone can be harmful to a wide range of living organisms. Tropospheric ozone acts as a greenhouse gas. In the stratosphere, ozone is created by the interaction between solar ultraviolet radiation and molecular oxygen (O2). Stratospheric ozone plays a decisive role in the stratospheric radiative balance. Depletion of stratospheric ozone, due to chemical reactions that may be enhanced by climate change, results in an increased ground-level flux of ultraviolet (UV-) B radiation.


Ozone Layer: 
The layer of ozone that begins approximately 15 km above Earth and thins to an almost negligible amount at about 50 km, shields the Earth from harmful ultraviolet radiation from the sun. The highest natural concentration of ozone (approximately 10 parts per million by volume) occurs in the stratosphere at approximately 25 km above Earth. The stratospheric ozone concentration changes throughout the year as stratospheric circulation changes with the seasons. Natural events such as volcanoes and solar flares can produce changes in ozone concentration, but man-made changes are of the greatest concern.


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Perennially (continually) frozen ground that occurs where the temperature remains below 0°C for several years.

permafrost in Alaska's Seward Peninsula


The timing of natural events, such as flower blooms and animal migration, which is influenced by changes in climate. Phenology is the study of such important seasonal events. Phenological events are influenced by a combination of climate factors, including light, temperature, rainfall, and humidity.


The process by which plants take CO2 from the air (or bicarbonate in water) to build carbohydrates, releasing O2 in the process. There are several pathways of photosynthesis with different responses to atmospheric CO2 concentrations.


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Energy transfer in the form of electromagnetic waves or particles that release energy when absorbed by an object. 


Collecting and reprocessing a resource so it can be used again. An example is collecting aluminum cans, melting them down, and using the aluminum to make new cans or other aluminum products.


Planting of forests on lands that have previously contained forests but that have been converted to some other use.


Renewable Energy: 
Energy resources that are naturally replenishing such as biomass, hydro, geothermal, solar, wind, ocean thermal, wave action, and tidal action.


The process whereby living organisms convert organic matter to CO2, releasing energy and consuming O2.


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The impact caused from increased incidence of an extreme high sea level.


Solar Energy:

diagram of Photovoltaic cells

The light and heat that come from the sun.  People can harness the sun’s energy in multiple ways to create energy in different contexts, such as: sunlight into electricity (photovoltaic cells); heat from the sun to make hot water or steam (solar thermal technology); and letting sun shine through windows to heat the inside of a building (passive solar heating).

Solar Radiation: 
Radiation emitted by the Sun. It is also referred to as short-wave radiation. Solar radiation has a distinctive range of wavelengths (spectrum) determined by the temperature of the Sun.


Region of the atmosphere between the troposphere and mesosphere, having a lower boundary of approximately 8 km at the poles to 15 km at the equator and an upper boundary of approximately 50 km. Depending upon latitude and season, the temperature in the lower stratosphere can increase, be isothermal, or even decrease with altitude, but the temperature in the upper stratosphere generally increases with height due to absorption of solar radiation by ozone.



A factor that reduces the health or productivity of an ecosystem (i.e. causes stress).


The downward settling of the Earth's crust relative to its surroundings. 


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Thermal Expansion: 
The increase in volume (and decrease in density) that results from warming water. A warming of the ocean leads to an expansion of the ocean volume, which leads to an increase in sea level.


Tidal Power:

A type of water energy that captures the energy of flowing waters with the help of turbines as tides rush in and out of coastal areas.


Trace Gas: 
Any one of the less common gases found in the Earth's atmosphere. Nitrogen, oxygen, and argon make up more than 99 percent of the Earth's atmosphere. Other gases, such as carbon dioxide, water vapor, methane, oxides of nitrogen, ozone, and ammonia, are considered trace gases. Although relatively unimportant in terms of their absolute volume, they have significant effects on the Earth's weather and climate.


The lowest part of the atmosphere from the surface to about 10 km in altitude in mid-latitudes (ranging from 9 km in high latitudes to 16 km in the tropics on average) where clouds and "weather" phenomena occur. In the troposphere temperatures generally decrease with height.


A treeless, level, or gently undulating plain characteristic of the Arctic and sub-Arctic regions characterized by low temperatures and short growing seasons.


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Ultraviolet Radiation (UV): 
The energy range just beyond the violet end of the visible spectrum. Although ultraviolet radiation constitutes only about 5 percent of the total energy emitted from the sun, it is the major energy source for the stratosphere and mesosphere, playing a dominant role in both energy balance and chemical composition. Most ultraviolet radiation is blocked by Earth's atmosphere, but some solar ultraviolet penetrates and aids in plant photosynthesis and helps produce vitamin D in humans. Too much ultraviolet radiation can burn the skin, cause skin cancer and cataracts, and damage vegetation.


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The degree to which a system is susceptible to, or unable to cope with, adverse effects of climate change, including climate variability and extremes. Vulnerability is a function of the character, magnitude, and rate of climate variation to which a system is exposed; its sensitivity; and its adaptive capacity.


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Water that has been used and contains dissolved or suspended waste materials.


Water Vapor: 
The most abundant greenhouse gas, it is the water present in the atmosphere in gaseous form. Water vapor is an important part of the natural greenhouse effect. While humans are not significantly increasing its concentration through direct emissions, it contributes to the enhanced greenhouse effect because the warming influence of greenhouse gases leads to a positive water vapor feedback. In addition to its role as a natural greenhouse gas, water vapor also affects the temperature of the planet because clouds form when excess water vapor in the atmosphere condenses to form ice and water droplets and precipitation.


Wave Power:

A type of water energy that captures energy from waves on the surface of the ocean using a special buoy or other floating device.


Atmospheric condition at any given time or place. It is measured in terms of such things as wind, temperature, humidity, atmospheric pressure, cloudiness, and precipitation. In most places, weather can change from hour-to-hour, day-to-day, and season-to-season. Climate in a narrow sense is usually defined as the "average weather", or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years. The classical period is 30 years, as defined by the World Meteorological Organization (WMO). These quantities are most often surface variables such as temperature, precipitation, and wind. Climate in a wider sense is the state, including a statistical description, of the climate system. A simple way of remembering the difference is that climate is what you expect (e.g. cold winters) and 'weather' is what you get (e.g. a blizzard).


Wind Energy:

Using the wind to create energy in the form of: windmills – to grind grain and pump water; and wind turbines – to make electricity.

diagram of wind energy


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United States Environmental Protection Agency (EPA) 2013 A Student’s Guide to Global Climate Change., accessed April 3, 2014.

United States Environmental Protection Agency (EPA)2013 Climate Change: Ecosystems., accessed April 3, 2014.

United States Environmental Protection Agency (EPA) 2013 Glossary of Climate Change Terms., accessed March 27, 2014

Heather Heffner

Last Updated: October 04, 2016