NSES Content Standard F Science in Personal and Social Perspectives: Changes in environments Grades K-4, page 140 Some environmental changes occur slowly, and others occur rapidly. Students should understand the different consequences of changing environments in small increments over long periods as compared with changing environments in large increments over short periods.

Benchmark 4B The Physical Setting: The Earth
Grades 6-8, page 69
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. Even relatively small changes in atmospheric or ocean content can have widespread effects on climate if the change lasts long enough.

Benchmark 4C The Physical Setting: Processes that Shape the Earth
Grades 6-8, page 73
Some changes in the earth's surface are abrupt (such as earthquakes and volcanic eruptions) while other changes happen very slowly (such as uplift and wearing down of mountains). The earth's surface is shaped in part by the motion of water and wind over very long times, which act to level mountain ranges.