Climate
A summary of the weather in a particular region over a period of at least ten years, but more commonly defined over 20 - 30 years. The climate describes both the average weather conditions (for example temperature, rain, snow and wind) in a particular region as well as the extremes.
Carbon dioxide
An important greenhouse gas, with the chemical formula CO2. After water vapour, carbon dioxide is the biggest contributor to the greenhouse effect.
Climate change
A change in the climate that can occur over various time and spatial scales, including globally. Climate change has occurred naturally throughout the Earth’s history, with numerous causes such as changes in the Earth’s orbit, fluctuations in ocean circulations and variations in the Sun’s activity.
Over recent decades, the majority of climate scientists have concluded that the current period of global climate change is real and that human activities are the main driver.
Ice age
A period of time during which the Earth’s average temperature is reduced. Polar ice caps and glaciers grow in size and global sea levels fall dramatically. The world began to emerge from the last ice age about 22,000 years ago and reached the current warm conditions about 12,000 years ago.
Feedback
A process with two interconnected factors whereby the first factor affects the second, and the change in the second factor in turn affects the first. This can either increase the rate of the process (positive feedback) or decrease it (negative feedback).
An example of a positive feedback process is the melting of ice floating on an ocean. When the local temperature increases it melts the ice and reveals the dark ocean underneath. The ocean absorbs more of the Sun’s energy than the ice, causing the local temperature to increase further and leading to even more melting.
Photosynthesis
A chemical reaction in plants which uses light from the Sun to help turn carbon dioxide and water into sugars, which plants then use as ‘food’.
Chemical weathering
The breakdown of rocks through chemical reactions. Normally the minerals within rocks react with rainwater, which is slightly acidic. The process of chemical weathering removes carbon dioxide from the air and stores it in rocks.
Meteorite
Piece of rock or metal from outer space which hits the surface of the Earth or any other planet.
