Agriculture
The practice of preparing soil, growing crops and raising farm animals for food or other products.
Arctic
The area around the North Pole or anything related to this region.
Atmosphere
The gases and air surrounding a planet. The Earth's atmosphere includes five different layers—the troposphere, the stratosphere, the mesosphere, the ionosphere and the exosphere.
Carbon Dioxide (CO2)
A heavy, colorless gas with no smell that is made from carbon and oxygen. Carbon dioxide is also known as CO2 and it is the fourth largest gas in dry air. Plants need carbon dioxide to survive.
Climate
The record of weather and weather events throughout history. A region's climate is defined by the average daily and seasonal weather in that area.
Climate Change
Any big change in climate, such as increasing temperatures and changes in weather patterns. For example, global warming is a climate change that may have been caused by humans. Weather experts measure changes in the Earth's climate over many years and decades.
Climatology
The study of climate.
Deforestation
The cutting down of trees and forests to use the land for something else, such as building homes or to grow crops. Some climate experts think that deforestation is one cause of global warming. When trees are burned down, this releases too much carbon dioxide in the air. Also, there aren't as many trees left to absorb the carbon dioxide from the air. This higher level of carbon dioxide may result in higher temperatures.
Drought
A long period with very little or no rain.
Ecology
The study of the connections between all living things and their environment or surroundings.
Ecosystem
The complicated balance of living things and their surrounding environments and how they all work together as a "community" to keep the Earth working properly.
Environment
All the things that make up an area, including water, air, gases, land, materials, people, plants, animals and all living things.
Equator
The imaginary line that circles around the middle of the Earth from East to West. The equator is located at 0 degrees latitude, and it's the same distance from the North Pole and the South Pole. It divides the Earth into two sections
the Northern Hemisphere and the Southern Hemisphere.
Erosion
The wearing away or movement of soil or rock. Erosion is usually caused by the ocean, running water, moving ice, wind, rain or snow.
Flood
A severe weather event when rivers and streams overflow and cause water to flood into nearby areas. Floods can be caused by too much rain or snow or melting ice.
Fossil Fuel
Fuels that are formed in the Earth from plant and animal remains. This includes oil, natural gas and coal.
Fresh Water
Water that does not include salt, such as river, lake and rain water. Ocean water is salt water, not fresh water.
Glacier
A large body of ice that spreads out from land or moves slowly down a mountain, hill or valley.
Glacier Winds
Winds that blow across glaciers. Glacier winds are sometimes very strong and gust at high speeds. These winds are caused by the temperature difference between the cold air touching the glacier and the warmer air around it.
Greenhouse Effect
The process in which greenhouse gases in the atmosphere trap heat from the sun and keep Earth warm. The greenhouse effect is necessary for life on Earth, but too many gases in the atmosphere could make our planet's temperatures rise too high.
Greenhouse gas
These gases, including water vapor, carbon dioxide, ozone and methane, trap heat in the Earth's atmosphere.
Habitat
The place where a certain plant or animal naturally lives. For example, a camel's natural habitat is the desert.
Hurricane
A storm with winds that blow 74 miles per hour or more. Hurricanes occur in the North Atlantic Ocean, Caribbean Sea, Gulf of Mexico and the eastern part of the North Pacific Ocean. The same kind of storm is called a "typhoon" in the western Pacific Ocean and the Indian Ocean.
Hydrology
The study of the Earth's water and all the effects water has on and beneath the planet's surface and in the atmosphere.
Hydrologic Cycle
The constant movement of all the water on and below the Earth's surface and the atmosphere. It's also known as the water cycle.
Industrial
Relating to industries or the making of products for sale. For example, an "industrial area" is an area where there are many factories and other buildings where products are made.
Infrared
Also known as heat rays, infrared rays are given all by all hot objects. Greenhouse gases in the Earth's atmosphere, such as water vapor, ozone and carbon dioxide, can absorb or put out infrared radiation.
Methane
This colorless, odorless gas is flammable (meaning it can easily catch fire). Methane is a greenhouse gas that comes from decomposing trash and the burning of coal.
Monsoon
The seasonal shifting of winds caused by big temperature changes. Monsoons occur over large land areas and create huge amounts or rain. Monsoons are most common in eastern Asia, but they can also happen in the southwestern part of the United States.
National Climatic Data Center (NCDC)
Located in Asheville, North Carolina, this agency collects and keeps detailed records of climate information.
Nitrogen (N2)
A colorless, tasteless, odorless gas that is the main ingredient of dry air. It makes up more than 78% of air.
Oxygen (O2)
A colorless, tasteless gas with no smell that is the second biggest ingredient of dry air. Oxygen makes up almost 21% of air.
Ozone Hole
A huge decrease of ozone gases in the atmosphere over Antarctica that happens every spring. Some experts say an ozone hole may form over the Arctic, too. Scientists believe the ozone hole is caused by a chemical reaction that comes from man-made pollution combined with cloud particles and low temperatures.
Ozone Layer
A layer of the Earth's atmosphere that includes a high level of oxygen. The ozone layer helps keep ultraviolet radiation from coming to Earth. It's located about 9 ˝ to 12 ˝ miles above the Earth's surface between the troposphere and the stratosphere.
Photosynthesis
The process in which green plants and trees use energy from the sun's light to turn carbon dioxide and water into food. During this process, plants release oxygen and water into the air. Because of photosynthesis, plants are very important for removing carbon dioxide from the Earth's air and creating more oxygen for humans to breathe.
Poles/Polar
The Earth's poles, known as the North Pole and the South Pole, are at the opposite ends of the planet. Both poles are equal distance from the equator. "Polar" means anything relating to the North or South Pole. Places with polar climates are very cold, snowy and windy.
Pollutant
Particles, gases or other chemicals added to the atmosphere that are not healthy for humans, animals and the environment.
Radiation
Energy that is given off in the form of waves or rays. The type of waves are different depending on the energy source. For example, the sun gives off ultra-violet radiation and the Earth's surface gives off infrared radiation.
Solar Energy
Energy from the sun. This is also called solar radiation or short-wave radiation. Solar radiation is very important to the Earth's climate.
Subtropics/Subtropical
The region located between 35° and 40° North and South latitude just outside the tropical regions of Earth. These areas are generally warm with very mild winters and they often have hurricanes and typhoons.
Temperate Climate
An area with very obvious winter and summer seasons. Winters are generally cold and summers are warm or hot. These areas are also called the middle latitudes.
Thermal
Relating to or producing heat. For example, a thermal spring is a natural spring that is very warm or hot.
Tropics/Tropical
The tropics are located very close to the equator. Areas with tropical climates have high temperatures and lot of rain. Many rainforests are found in the tropics.
Tsunami
A huge ocean wave that is created by an underwater earthquake, landslide or volcanic eruptions. These waves can travel for thousands of miles from their original point, and they build up to large heights as they reach shallower water.
Ultraviolet
A type of ray given off by the sun, this kind of radiation helps to form the Earth's ozone layer.
Water (H2O)
A chemical compound of hydrogen and oxygen. Water can exist as a solid (ice), a liquid (water) or a gas (water vapor). Water is necessary to life on Earth.
Water Cycle
Another name for the hydrologic cycle. The constant movement of all the water on and below the Earth's surface and the atmosphere.
Weather
The conditions of the atmosphere in a certain place at a certain time. Wind, temperature, cloudiness, precipitation, atmospheric pressure and humidity are all parts of weather. Weather can change each season, every day or even by the hour in some places. Weather is not the same thing as climate. Climate is the average of weather over long periods of time. | 
