Describe factors that change climates over long periods of time and cite methods that scientists have found to gather information on ancient climates.
Earth and Space Science
In prior grades students learned about a few of the methods that have made it possible to uncover the history of our planet. In grades 9-11 students learn about the major changes in Earth systems over geologic time and some of the methods used to gather evidence of those changes. Methods include observation and measurement of sediment layers, using cores drilled from the sea bottom and from ancient glaciers, and the use of radioactive isotopes. Findings of Earth history include the existence of life as early as 3.5 billion years ago and major changes in the composition of Earth’s atmosphere.
Data gathered from a variety of methods have shown that Earth has gone through a number of periods when Earth was much warmer and much colder than today.