Question

Complete the paragraph to describe how scientists obtain information about past climates.



Glaciologists, geochemists, and climatologists study ice layers to learn about past climates. Distinct ice layers are caused by
. When studying ice layers, scientists use
to measure isotopes of certain gases. These gases reveal the
at the time when the ice layers were formed.

Answer 1

Glaciologists, geochemists, and climatologists study ice layers to learn about past climates. Distinct ice layers are caused by seasonal changes in snowfall and by varying amounts of dust, ash and melt, which create annual bands. When studying ice layers, scientists use mass spectrometers (often isotope‑ratio mass spectrometry) to measure isotopes of certain gases and of the ice itself. These gases and isotopes reveal the past atmospheric composition and temperatures at the time when the ice layers were formed.