Which do scientists study to determine air temperature at the time it was formed?
To determine the air temperature at the time it was formed, scientists study various types of proxies or indirect evidence from the past. These proxies include:
1. Ice Cores: Scientists extract ice cores from glaciers or polar ice caps, representing layers of frozen water accumulated over thousands of years. By studying the isotopic composition of the ice, as well as air bubbles trapped within, scientists can estimate the past air temperature.
2. Tree Rings: By examining tree rings, scientists can determine the age of the tree and analyze its growth patterns. The width of tree rings can provide insights into past climatic conditions, including air temperature during each growth season.
3. Sediments: Sediments from lakes, oceans, or other bodies of water can preserve various fossilized remains, such as pollen, diatoms, and foraminifera. By analyzing these indicators, scientists can deduce historical climate conditions, including air temperature.
4. Coral Reefs: Coral skeletons contain bands that can be used to estimate the temperature of the water in which the coral grew. Since the growth of corals is dependent on temperature, scientists can infer the air temperature during that time period.
5. Historical Records: Old weather records, diaries, and other written accounts can provide valuable clues about past climates. Information contained in these records can be used to reconstruct air temperature at the time it was formed.
By analyzing these different proxies, scientists can develop a comprehensive understanding of past air temperatures and their variations over time.