Glossary

Albedo
Albedo is the fraction of solar energy (shortwave radiation) reflected from the Earth back into space.
Aphelion
Aphelion is when the hemisphere is at the furthest point from the Sun in its orbit.
Equinox
An equinox occurs when the tilt of the Earth’s axis is inclined neither away nor towards the Sun. There are two equinoxes a year – the Spring Equinox and the Autumnal Equinox.
Geologic Time Scale
A geologic time scale is a system of chronologic measurements relating rock layers to time. This system is used by geologists, paleontologists and other earth scientists to describe the timing and relationships between events in Earth’s history.
Global Climate Change
Global climate change is change recorded over an extended length of time (decades or longer) with regards to precipitation, temperature or wind caused by natural and/or manmade factors.
Greenhouse Gases
Greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxides, and chlorofluorocarbons (CFC or "Freon"). With the exception of water vapor, increases in these greenhouse gases are produced largely by human activities. These gases let in most of the incoming solar radiation that heats Earth's surface, yet prevent part of the outgoing thermal radiation from escaping to space, thus trapping some of the surface heat energy.
Ice Ages
Ice ages refer to times in Earth's history when the surface was significantly covered by polar ice.
Insolation
Insolation is a measure of solar radiation energy received on a given surface area in a given time.
Paleoclimatologist
A paleoclimatologist is a scientist who studies climate of the past.
Perihelion
Perihelion is when a hemisphere is at its closest point to the sun in its orbit.
Positive Feedback
A feedback is the process in which changing one factor changes a second factor, and this second change in turn changes the first. A positive feedback increases the change in the first while a negative feedback reduces it.
Precession
Precession refers to a change in the orientation of the rotation axis of a rotating body.
Proxy Data
Proxy data is data derived from the natural world that scientists analyze to reconstruct past climate conditions in lieu of actual temperature or precipitation measurements.
Radiometric Dating
Radiometric dating (often called radioactive dating) is a technique used to date materials such as rocks by comparing the amounts of a naturally occurring radioactive isotope with its decay products, using known decay rates.