View source for Paleoclimatology and Ice Age Cycles

== Introduction ==

Paleoclimatology is the scientific study of the Earth's past climates. This field of study uses a variety of proxy methods from the Earth and life sciences to obtain data previously preserved within things such as rocks, sediments, ice sheets, tree rings, corals, shells, and microfossils. It then uses the records to determine the past states of the Earth's various climate regions and its atmospheric system. Paleoclimatology not only provides us with empirical evidence for the existence of [[Ice Age|Ice Age cycles]], but it also gives us a powerful tool to predict future climate changes.

[[Image:Detail-39623.jpg|thumb|center|A scientist examining an ice core sample.|class=only_on_mobile]]
[[Image:Detail-39624.jpg|thumb|center|A scientist examining an ice core sample.|class=only_on_desktop]]

== Paleoclimatology: An Overview ==

Paleoclimatology, a sub-discipline of [[Paleoecology|paleoecology]], is the study of changes in climate taken on the scale of the entire history of Earth. It uses a variety of techniques from geology, paleontology, geochronology, and stratigraphy to decipher the sequence and magnitude of past climate changes. The study of paleoclimatology is important for providing baseline data on natural climate variability and future climate analogs.

== Ice Age Cycles ==

An Ice Age, or glacial age, is a period of long-term reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Ice Age cycles are the result of changes in Earth's orbit and tilt, which affect the amount of summer sunlight reaching the Northern Hemisphere. These changes, known as [[Milankovitch cycles|Milankovitch cycles]], are the driving force behind cyclical animal and plant life adaptations and evolution.

== Paleoclimatological Methods ==

Paleoclimatologists employ a wide variety of techniques to deduce ancient climates. These include the study of rock types and the plants and animals that lived at the time. Other methods include the examination of microscopic organisms that lived in the oceans, the ice cores from the polar ice caps, and the study of stalactites and stalagmites in caves.

== Ice Cores and Climate Reconstruction ==

One of the most important tools in paleoclimatology is the ice core, a sample of ice taken from an ice sheet, most commonly in the polar ice caps of Antarctica, Greenland, or from high mountain glaciers elsewhere. The ice core records provide a unique contribution to our view of past climate as the bubbles within the ice capture the gas concentration of our well-mixed atmosphere while the ice itself records other properties.

== Milankovitch Cycles and Ice Ages ==

The concept of Ice Ages was first proposed by a 19th-century Swiss-American geologist, Louis Agassiz, but the explanation for their occurrence was first suggested by a Serbian mathematician, Milutin Milankovitch, in the 1920s. He proposed that variations in the Earth's orbit around the Sun (eccentricity), the tilt of the Earth's axis (obliquity), and the wobbling motion of the Earth's axis (precession) could collectively affect the amount of sunlight reaching the Earth, thus impacting its climate.

== Conclusion ==

Understanding the Earth's past climate helps us to explain how current ecosystems came to be. It also provides valuable data for testing models that predict future climate behavior. Paleoclimatology data are derived from natural sources such as tree rings, ice cores, corals, and ocean and lake sediments. These proxy climate data extend the archive of weather and climate information hundreds to millions of years.

== See Also ==

* [[Climate Change]]
* [[Geochronology]]
* [[Stratigraphy]]
* [[Paleoecology]]

[[Category:Climate History]]
[[Category:Earth Sciences]]
[[Category:Paleoclimatology]]
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