How do we know each climate has changed over the course of earth's history?

Answer 1

We know that climates have changed over Earth's history through various lines of evidence, including ice core samples, sediment cores, and fossil records. Ice cores provide trapped gas bubbles that reveal past atmospheric composition and temperatures, while sediment layers contain fossils and chemical signatures that indicate historical climate conditions. Additionally, geological features and the distribution of species offer insights into how climate shifts have influenced ecosystems over millions of years. Together, these data sources create a comprehensive picture of Earth's climatic evolution.