Ablation zone


The ablation zone refers to the low-altitude area of a glacier or ice sheet below the firn line. The ablation zone often contains melt water and glacial lakes.

Accumulation zone


On a glacier, the accumulation zone is the surface area above the firn line, where snowfall accumulates. The firn is the snow left from previous years that is about to become glacial ice.



Adaptation refers to the ability of an organism, species, society or ecosystem to prepare for or adjust to change in order to survive. This may be a physical change or change in behavior.

Air pollution


Air pollution is the contamination of the air with harmful gases, dust or fumes. The introduced particulates and chemicals can cause illness, disease, and damage to all living organisms, including humans, crops, and animals.

Air quality


Air quality is the degree to which the ambient air is pollution-free, assessed by measuring a number of indicators of pollution. An air quality index (AQI) is a number used by government agencies to communicate to the public how polluted the air is currently or how polluted it is forecast to become.



Albedo (al-bee-doh) is another name for reflectivity. The albedo of a surface determines how much sunlight will be absorbed and warm the surface compared to another surface that reflects most of the light and does not change temperature. Albedo is measured on a scale from zero for no reflection of a perfectly black surface to 1 for perfect reflection of a white surface.

Annual global population growth


Annual global population growth refers to the rate of growth in a population over one year. Globally, the growth rate of the human population has been declining since peaking in 1962 and 1963, but due to medical advancements and the increase in agricultural productivity, the world's population is increasing rapidly.



The term anthropogenic is used to describe changes that relate to or result from the influence of human beings on nature.



The atmosphere is a mixture of nitrogen, oxygen, carbon dioxide, and other gases that surrounds the Earth. The atmosphere is critical to supporting life on Earth.



Biodiversity is short for biological diversity and refers to the variety of living things found in a given place—whether a small stream, an extensive desert, all the forests in the world, the ocean, or the entire planet.

Biome shifts


Biomes are climatically and geographically defined as contiguous areas with similar climatic conditions on the Earth, such as  communities of plants, animals, and are often referred to as ecosystems.



The biosphere is all the living parts of the Earth, including all ecosystems and organisms on land, in the atmosphere and hydrosphere. 

Black carbon


Black carbon warms the Earth by absorbing heat in the atmosphere and by reducing albedo, the ability to reflect sunlight, when deposited on snow and ice. Black carbon stays in the atmosphere for only several days to weeks, whereas carbon dioxide (CO2) has an atmospheric lifetime of more than 100 years.



Carbon is a naturally occurring element found in every living organism on the planet, and joins with other elements to form compounds like carbon dioxide. 

Carbon cycle


The carbon cycle is the movement and exchange of carbon through living organisms, the ocean, the atmosphere, rocks and minerals, and other parts of the Earth. Carbon moves from one place to another through various chemical, physical, geological, and biological processes.

Carbon dioxide


Carbon dioxide is a colorless, odorless greenhouse gas. It is produced naturally when dead animals or plants decay, and it is used by plants during photosynthesis. People are adding carbon dioxide into the atmosphere, mostly by burning fossil fuels such as coal, oil, and natural gas. This extra carbon dioxide is the main cause of recent climate change.

Carbon footprint


Your carbon footprint is the sum of all carbon dioxide emissions, which result from your activities in a given time frame. 

Carbon sink


A carbon sink is a forest, ocean, or other natural environment that has the ability to absorb carbon dioxide from the atmosphere and store it. 



Carbon-14 or "radiocarbon," is a radioactive isotope of carbon. Its presence in organic materials is the basis of the radiocarbon dating method used to date archaeological, geological and hydrogeological samples.



In science, the Celsius scale is used more often than the Fahrenheit scale. The Celsius scale is divided into 100 equal parts, called degrees Celsius (°C), between the freezing point and boiling point of water. This scale was invented by Anders Celsius in 1742. Celsius also based his scale on the freezing and boiling points of water. The freezing point of water on this scale is 0 degrees Celsius (0°C). The boiling point of water is 100 degrees Celsius (100°C). This thermometer scale is sometimes called the centigrade scale because there are 100 Celsius degrees between the two fixed points. 



Climate is the long-term average weather of a place, region, or planet.

Climate anomaly


An anomaly is a deviation from a typical or normal condition. A climate anomaly is the difference of a current climate compared to the past climate.

Climate change


Climate change refers to a significant change in the long-term average and patterns of climate. Recent climate change is the broader set of changes that go along with warmer temperatures, including changes in weather patterns, the oceans, ice and snow, and ecosystems around the world.



Coal is a dark-colored solid fossil fuel that can be mined from the Earth for energy. Coal is the most abundant fossil fuel produced in the United States.



Condensation is the process by which gas cools and becomes a liquid. Condensation is the opposite of evaporation and is visible when small drops of water form on a cold surface– like dew on leaves. 

Coral bleaching


Coral bleaching occurs when corals are stressed by changes in conditions such as temperature, light, or nutrients. The coral expel the symbiotic algae living in their tissues, causing them to turn completely white.

Crop yields


In agriculture, crop yield (also known as "agricultural output") refers to both the measure of the yield of a crop per unit area of land cultivated and the seed generation of the plant itself.



Cryoconite is windblown dust that gets deposited on snow, glaciers, ice sheets and icecaps. It is made up of a combination of air pollution, small rock particles, soot and microbes. The darkening color of the snow and ice absorbs more radiation and leads to faster melting. 



The cryosphere is those portions of Earth's surface where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps and ice sheets, and frozen ground (which includes permafrost).

Dengue fever


With more than one-third of the world’s population living in areas at risk for infection, dengue virus is a leading cause of illness and death in the tropics and subtropics. As many as 400 million people are infected yearly. Dengue is caused by any one of four related viruses transmitted by mosquitoes. There are not yet any vaccines to prevent infection with dengue virus and the most effective protective measures are those that avoid mosquito bites. When infected, early treatment can substantially lower the risk of medical complications and death.



Drought is a prolonged period of low rainfall and overall dryness. Droughts typically cause extensive damage to crops or prevents their successful growth.

Ecosystem services


Important benefits for people and society that arise from a healthy ecosystem, such as clean air, freshwater, food, natural disaster protection, along with recreational and cultural benefits.



An ecosystem includes all the living things (including plants, animals and organisms) and non-living parts (such as water, sun, air, climate and land) that are found in a particular area. There is a complex interaction of all these things, and each has a role in helping to sustain the system.



In biology, endemic refers to a plant or animal that is native or restricted to a certain country or area. Sometimes the plant or animal can only live in that specific location. For example, polar bears are endemic to the Arctic. 

Energy balance


Earth's energy balance describes how the incoming energy from the Sun is used and returned to space.  If incoming and outgoing energy are in balance, the Earth's temperature remains constant.

Environmental indicators


An environmental indicator is a way to identify and track changes in the environment. 

Equilibrium line


The elevation at which accumulation and melting of glacier ice are equal is known as the equilibrium line and is roughly equivalent to the snow line. It frequently varies greatly over short distances and from year to year on a specific glacier.



Evaporation is the process by which water changes from a liquid to a gas or vapor.

Extreme Ice Survey


Founded in 2007 by James Balog, the Extreme Ice Survey (EIS) is an innovative, long-term photography project that merges art and science to give a "visual voice" to the planet's changing ecosystems. EIS imagery preserves a visual legacy, providing a unique baseline—useful in years, decades and even centuries to come—for revealing how climate change and other human activity impacts the planet

Eye wall


An eye wall is the area immediately outside the eye of a hurricane or cyclone, associated with tall clouds, heavy rainfall, and high winds. This is the area where the most severe weather occurs. 



The degree Fahrenheit (oF) is the unit of temperature used by most people in the United States in describing weather. The scale derives its name from a German-born physicist, Daniel Gabriel Fahrenheit, who is recognized as having invented it. At standard Earth-atmospheric sea-level pressure, pure water freezes at 32oF and boils at +212oF.



A flood is an overflowing water beyond its normal levels, especially over what is normally dry land.

Food chain


A food chain is a series of organisms that are connected in their feeding habits. The smallest being fed upon by a larger one, which in turn feeds on a larger one, and so-on.  

Fossil fuel


Carbon or hydrocarbon-based fuels– such as natural gas, coal and oil. They are called fossil fuels because they form over long periods of time in the ground from organic material, like very old plants and animals. When burned, they release carbon dioxide. 



The geosphere is considered that portion of the Earth system that includes the Earth's interior, rocks and minerals, landforms and the processes that shape the Earth's surface. 



Geothermal energy is heat energy generated and stored at temperatures and depths below the Earth's surface. Deep wells can be drilled into underground reservoirs to tap steam and very hot water that can be brought to the surface for use in generating electricity and heating and cooling.



A glacier is a year-round mass of ice that originates on land. Glaciers are made of snow that has accumulated and compressed into ice over many years. 

Greenhouse effect


The greenhouseeffect is the process in which greenhouse gases trap heat and warm the surface of the Earth.  It is a naturally occurring process that enables Earth to maintain a warm, life-supporting climate.

Greenhouse gases


Greenhouse gases are natural or manmade gases that trap heat in the atmosphere and contribute to the greenhouse effect. 

Ground-level ozone


Ground-level ozone--what we breathe--is the main component of smog. Ozone can also be transported long distances by wind.  For this reason, even rural areas can experience high ozone levels.



A habitat is the natural home or environment of a plant, animal or organism, and is where it lives or grows.

Heat wave


A heat wave is a prolonged period of abnormally hot temperatures. 

Hotspot of biodiversity


A hotspot of biodiversity is a biogeographic region that is high in  biodiversity, meaning that it has a lot of plants and animals, and is also threatened with destruction.



A hurricane is a very strong windstorm. These storms reach the status of "hurricane" only after strengthening to very high wind speeds that are 75 mph or higher over a period of days or even weeks.



Hydrofluorocarbons (HFCs) are a type of greenhouse gas with high global warming potential. They are compounds containing only hydrogen, fluorine, and carbon atoms. They are the gases used for refrigeration and air conditioning. 



The hydrosphere is the combined mass of water found on, under, and over the surface of our planet.

Ice age


An ice age is a long-term cold period in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and mountain glaciers.

Ice caps


An ice cap is a glacier, a thick layer of ice and snow, that covers fewer than 50,000 square kilometers (19,000 square miles). Ice caps are typically dome shaped and cover surrounding topographical features. 

Ice cores


Ice cores are cylindrical, solid tubes of ice that have been removed from a glacier by drilling deep into a glacier.  These samples of ice are studied by scientists to understand what the air was like in the past by examining the tiny bubbles of air trapped in the ice as the glacier forms, sometimes over hundreds of thousands of years.  Scientists are especially interested in the amount of carbon dioxide found over time to understand climate change.

Ice sheets


Ice sheets are enormous masses of ice found only in Antarctica and Greenland. These ice sheets contain vast quantities of fresh water.

Ice shelf


An ice shelf is a thick floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface. Large ice shelves are found in Antarctica, Greenland and Canada.



Icebergs are the broken-off ends of glaciers that slide into the sea. They vary in size from small, flat “growlers” to large masses of ice that can be a mile or more across and more than 200 feet above the water.

Industrial Revolution


The Industrial Revolution was the large scale transition of civilization to new manufacturing processes that primarily depended on fossil fuels, starting around 1760 and through the early 1800's. 

Interglacial period


An interglacial period is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age

Intergovernmental Panel on Climate Change (IPCC)


The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for the assessment of climate change. It was established by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) in 1988 to provide the world with a clear scientific view on the current state of knowledge in climate change and its potential environmental and socio-economic impacts. Thousands of scientists from all over the world contribute to the work of the IPCC on a voluntary basis.

Keeling Curve


The Keeling Curve is a graph which plots the ongoing change in concentration of carbon dioxide in Earth's atmosphere since 1958. It is based on continuous measurements taken at the Mauna Loa Observatory in Hawaii that began under the supervision of Charles David Keeling.

Last Glacial Period


The last glacial period, popularly known as the Ice Age, was the most recent glacial period within the current ice age occurring during the last years of the Pleistocene, from approximately 110,000 to 12,000 years ago. During this period, there were several changes between glacier advance and retreat.

Lyme disease


Lyme disease is caused by a bacterium and is transmitted to humans through the bite of infected blacklegged ticks. Typical symptoms include fever, headache, fatigue, and a characteristic skin rash. If left untreated, infection can spread to joints, the heart, and the nervous system. Most cases of Lyme disease can be treated successfully with a few weeks of antibiotics. Steps to prevent Lyme disease include using insect repellent, removing ticks promptly, applying pesticides, and reducing tick habitat.



Malaria is a serious and sometimes fatal disease caused by a parasite that commonly infects a certain type of mosquito, which feeds on humans. People who get malaria are typically very sick with high fevers, shaking chills, and flu-like illness. Although malaria can be a deadly disease, illness and death from malaria can usually be prevented.

Metric tons


A metric ton is a unit of mass or weight in the metric system equal to 1,000 kilograms (2,205 pounds). Elephants often weight a metric ton.



Microplastics are small, toxic, non-biodegradable, plastic particles. Large concentrations of micro plastics float in the ocean and are often ingested by marine life, which are, in turn, consumed by us. 



Mitigation is the effort to reduce loss of life and property by lessening the impact of disasters. Mitigation is taking action now—before the next disaster—to reduce human and financial consequences later. Climate change mitigation generally involves reductions in human caused emissions of greenhouse gases.

Mountain glacier


Mountain glaciers, also known as "alpine glaciers", are found throughout the world's highest mountains. Some mountain glaciers, such as Alaska's Columbia Glacier, are literally rivers of ice, flowing down mountains and carving valleys.

Ocean acidification


 Our oceans' chemistry are becoming more acidic, with a decrease in the pH of the ocean caused by the uptake of carbon dioxide from the air. Ocean acidification has major impacts on ocean organisms including corals, mollusks, algae, and crustaceans, and threatening important marine food chains.

Ocean gyre


A gyre is a naturally occurring vortex of wind and currents that rotate in a clockwise direction in the northern hemisphere and counter-clockwise in the southern hemisphere. Gyres create a whirlpool effect, whose vortex moves more slowly at the center. There are 5 major gyres in the oceans worldwide. 



Organic is natural or living matter. It also refers to food, crops and meat grown or raised without chemical pesticides.



Ozone is a colorless gas with a pungent odor, having the molecular form of O3. Ozone is found in two layers of the atmosphere, the stratosphere and the troposphere.  If we breathe in ozone, it can seriously affect the human respiratory system.  

Ozone layer


The ozone layer protects life on Earth by filtering out harmful ultraviolet radiation from the sun. It begins approximately 9.3 miles above Earth and thins completely out at about 31 miles. 



Peat is an accumulation of partially decayed vegetation found in wetlands, such as swamps, bogs, moors and fens. It is highly organic natural material that can be used as a fuel source when dried. Over long periods of time, buried peat converts to lignite (clay) and then to coal.



Permafrost is soil or rock that is frozen year-round. Permafrost can be found in many parts of Alaska, northern Canada, and other countries near the Arctic Ocean.



A watt is a unit of power. Calculators and watches are typically measured in microwatts, lightening is measured in megawatts, and the sun's power is measured in petawatts. A petawatt (PW) is one of the largest units of power equal to a quadrillion (one billion million) watts per unit.



Phenology is the periodic study of plants and animal life cycle events and how these are influenced by seasonal and interannual variations in climate and habitat factors (such as elevation).



Photosynthesis is the process by which green plants use sunlight, water, and carbon dioxide to make food and other substances that they use to grow. In the process, plants release oxygen into the air.



Phytoplankton are photosynthesizing microscopic organisms that inhabit the upper sunlit layer of almost all oceans and bodies of fresh water.

Plant respiration


Plant respiration is a process of using oxygen to release the energy stored in sugars for growth, reproduction, and other life processes. 

Pleistocene epoch


The Pleistocene epoch (plī'stə-sēn' ep·och), is commonly referred to as the Ice Age and began approximately 1.6 million years ago. During that time huge sheets of ice, or glaciers, covered large portions of the earth's continents. An epoch is a time marked by an event that begins a new period or development.

Polar vortex


The polar vortex is a large region of air located in the stratosphere, rotating from west to east and circling the polar region. In the Northern Hemisphere, the axis of the rotation is generally located in the Arctic. There is also a polar vortex in the Southern Hemisphere, in which the axis of rotation is around the Antarctic continent.



Pollination is the process by which pollen is transferred from the anther (male part) to the stigma (female part) of the plant, thereby enabling fertilization and reproduction. 

Positive feedback effect


Positive feedback effect is a process in which the effects of change in a system lead to greater changes.



Precipitation is the process by which water droplets form in the atmosphere and fall to the earth as hail, mist, rain, sleet, or snow.

Renewable energies


Renewable energy is generally defined as energy that comes from resources which are naturally replenished on a human timescale, such as sunlight, wind, rain, tides and geothermal heat.



Respiration is a process in living organisms involving the production of energy, typically with the intake of oxygen and the release of carbon dioxide from the oxidation of complex organic substances.

Saffir-Simpson Wind Scale


The Saffir-Simpson Wind Scale classifies hurricanes into five categories, from 1-5, distinguished by the speed of the wind. The scale was developed in 1971 by civil engineer Herbert Saffir and meteorologist Robert Simpson and was released to the public in 1973.

Saline intrusion 


Saline or saltwater intrusion is the movement of saline, or salt, water into freshwater aquifers, which can lead to contamination of drinking water sources and other consequences.

Sea ice


Sea ice is frozen ocean water. It forms, grows, and melts in the ocean. On average, sea ice covers about 25 million square kilometers (9,652,553 square miles) of the earth, or about two-and-a-half times the area of Canada and plays a major role in ocean circulation, keeps polar regions cool, and influences global climate.



Smog is fog or haze combined with smoke and other atmospheric pollutants including ozone.



A species is a group of animals or plants that are similar and can successfully reproduce. 

Species range


A species range is the area where a particular species can be found during its lifetime. This refers to the area of land or water it can comfortably live in, including the range of temperatures it can withstand. 

Storm surge


Storm surge is an very high rise of water generated by a storm, which usually causes extreme coastal flooding when it hits land. 



In biology, symbiotic refers to any diverse organisms that live together, but in this case, the relationship is not necessarily beneficial to both. Parasites, for example, have a symbiotic relationship with their hosts, but only the parasite benefits.

Thermal expansion


Thermal expansion is 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.

Time-lapse cameras


Time-lapse photography is where a still camera takes a sequence of images of a subject at set intervals. The interval between pictures can be anything from less than a second to a day or more. When the images are played back, the interval of time is speeded up creating the look of video or movie footage. This method of photography documents change in the subject over time. 



In biology, a vector is an organism, typically a biting insect or tick, that transmits a disease or parasite from one animal or plant to another.

Water cycle


It's called the water cycle because water is always on the move! The Sun’s energy causes water to evaporate from oceans and lakes into the atmosphere. Plants and animals also release water vapor into the atmosphere as they breathe. When the atmosphere cools, water vapor condenses; making clouds that might produce rain or snow. Water has been recycled in its different forms as ice, liquid, or vapor—for more than 3.5 billion years on Earth.

Water scarcity


Water scarcity is the lack of sufficient water to meet the demands of usage within a place or region.