The earth's climate has seen many changes in its 4.55 billion years. For example, 18,000 years ago most of Britain was covered in ice and glaciers. Although changes to the earth's climate are natural, current changes are a result of increasing human populations and activities.
When talking about climate change in relation to human activities climate change can be said to mean -
'the build-up of man-made gases in the atmosphere that trap the sun’s heat, causing changes in weather patterns around the world’.
Read More: What is Climate?