How can scientists know what happened to Earth's climate hundreds of thousands of years ago?

Clues about the past climate are buried in sediments at the bottom of the oceans, locked away in coral reefs, frozen in glaciers and ice caps, and preserved in the rings of trees. Each of these natural recorders provides scientists with information about temperature, precipitation, and more.

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But if scientists want to know what Earth's climate was like hundreds of thousands to millions of years ago, they study sediment cores and ice cores. Sediment cores come from the bottoms of lakes or the ocean floor. Ice cores are drilled from deep — sometimes miles — below the surface of the ice in places like Antarctica.

and after water is usually warmed by the sun the water temperature raises and then evaporates .