How did they measure temperature in the past?

Answer 1

They estimate it based on the thickness of sedimentation, the types of gases found in glaciers, the thickness of annual snowfall in glacier samples, and what kind of plant or animal life is found in different layers of sedimentation.

Answer 2

In the past, temperature was measured using instruments such as Mercury or alcohol thermometers. These thermometers relied on the expansion and contraction of liquids with changes in temperature to provide a reading. Other methods included using thermoscopes or temperature scales based on observable phenomena like the freezing and boiling points of water.