The global climate has been changing since time began and will continue to change into the future. However, since around 1950 there has been a dramatic increase in global temperatures. This increase is known as global warming.
The Earth's average temperature has changed over the last 500,000 years. There are times when global climate is warmer (interglacial phases) and times when it has been cooler (glacial phases), when there have been ice ages.
The last major cold period was known as the Pleistocene. It started 2.6 million years ago and ended just 10,000 years ago. Since then, conditions have been warmer. This current warm phase is known as the Holocene. The Holocene and Pleistocene are part of the Quaternary Period of Earth's history.