Paleoclimatology studies the entire history of the Earth with respect to the changes in climate which have occurred over this time span - since the beginning of time. Paleoclimatology uses a variety of proxy methods from the Earth to obtain data which is preserved within rocks, sediments, ice sheets, tree rings, corals, shells and microfossils. It uses these records to determine the past states of the Earth’s various climate regions and its atmospheric system.
Paleoclimatologists can employ a wide variety of techniques to deduce ancient climates. They can use glaciers and tree rings for example to recognize changes in the atmosphere. Air trapped within fallen snow becomes encased in tiny bubbles as the snow is compressed into the ice of the glacier. This air is valuable with looking at the composition of the air for each time period. Trees also respond to changes in climate by speeding up or slowing down growth. Tree ring records can be used to produce information regarding precipitation, temperature, hydrology and fire in that area.
The first atmosphere was found to consist of gases in the solar nebula. This is primarily hydrogen. The second atmosphere formed consisted mostly of nitrogen, carbon dioxide, water vapor and other gases. This atmosphere was produced by outgassing from volcanoes. The third atmosphere formed is Earth’s current atmosphere. It is made up mostly of nitrogen and oxygen, but has other trace elements. These discoveries have been made through the study of paleoclimatology.
Title Image Credit: Geograph. (2014). TL1948: tree rings. Retrieved from http://www.geograph.org.uk/photo/3424463