Some of these extinction events may have been relatively minor. Most scientists do agree there were 6 major extinction events in the 4.6 billion years history of the earth when the rates of extinction are exceptionally high. There were multiple causes for these extinctions. There also is disagreement as to what triggered specific extinction events. Climate change probably has been involved in all of the mass extinctions.
Climate change causes extinction by altering the habitats of organisms.
Changes in habitats can cause destruction of species if they are not adapted to those habitats and if they cannot move to habitats to which they are better suited. Climate changes may be caused by many events such as volcanic eruptions, asteroid impacts and changes in the rotation of the sun. Glaciation, which causes global cooling, and the creation of huge ice-sheets is a type of climate change that has played a role in mass extinctions. Evidence for this glaciation comes from glacial sediments and from the extinction of groups adapted to warm climates. Glaciation was probably a major factor in at least 3 mass extinctions - in the late Ordovician, the late Devonian and the end Permian.