GEOLOGY

Detailed explanation-1: -Ice cores drawn from Greenland, Antarctica, and tropical mountain glaciers show that Earth’s climate responds to changes in greenhouse gas levels. Ancient evidence can also be found in tree rings, ocean sediments, coral reefs, and layers of sedimentary rocks.

Detailed explanation-2: -Clues about the past climate are buried in sediments at the bottom of the oceans and lakes, locked away in coral reefs, frozen in glaciers and ice caps, and preserved in the rings of trees.

Detailed explanation-3: -Organisms (such as diatoms, forams, and coral) can serve as useful climate proxies. Other proxies include ice cores, tree rings, and sediment cores.

Detailed explanation-4: -Scientists do not have methods for making direct measurements of ancient climate conditions. Instead, they study indirect evidence of climate change known as proxy data.