Climates have sometimes changed abruptly in the past as a result of changes in the earth's crust, such as volcanic eruptions or impacts of huge rocks from space.
(Climates; have changed abruptly; T:in the past; as a result of changes in the earth's crust, such as volcanic eruptions or impacts of huge rocks from space; T:sometimes)
Climates
have changed abruptly
T:in the past as a result of changes in the earth's crust, such as volcanic eruptions or impacts of huge rocks from space T:sometimes