Paleoclimatology

Paleoclimatology uses a variety of proxy methods from the Earth and life sciences to obtain data previously preserved within rocks, sediments, boreholes, ice sheets, tree rings, corals, shells, and microfossils.

In the study of past climates ("paleoclimatology"), climate proxies are preserved physical characteristics of the past that stand in for direct meteorological measurements and enable scientists to reconstruct the climatic conditions over a longer fraction of the Earth's history.

Paleoclimatology (in British spelling, palaeoclimatology) is the study of climates for which direct measurements were not taken.

Paleoclimatology is the study of ancient climates.

Scientists can get a grasp of long term climate by studying sedimentary rock going back billions of years.

The study of the sequence of sedimentary rock strata is the main source for an understanding of the Earth's history, including palaeogeography, paleoclimatology and the history of life.

;Corals (see also sclerochronology)

It is particularly useful in the study of marine paleoclimatology.

Paleoclimatology uses a variety of proxy methods from the Earth and life sciences to obtain data previously preserved within rocks, sediments, boreholes, ice sheets, tree rings, corals, shells, and microfossils.

In 1965 Hubert Lamb, one of the first paleoclimatologists, published research based on data from botany, historical document research and meteorology, combined with records indicating prevailing temperature and rainfall in England around c.

Paleoclimatology uses a variety of proxy methods from the Earth and life sciences to obtain data previously preserved within rocks, sediments, boreholes, ice sheets, tree rings, corals, shells, and microfossils.

The growth rings allow geologists to construct year-by-year chronologies, a form of incremental dating, which underlie high-resolution records of past climatic and environmental changes using geochemical techniques.

Climatic geomorphology is of limited use to study recent (Quaternary, Holocene) large climate changes since there are seldom discernible in the geomorphological record.

The Quaternary subdivisions were defined based on biostratigraphy instead of paleoclimate.

On a longer time scale, the rock record may show signs of sea level rise and fall, and features such as "fossilised" sand dunes can be identified.

Paleoclimatologists can track sea level by examining the rocks deposited along coasts that are very tectonically stable, like the east coast of North America.

The geological record, however, shows a continually relatively warm surface during the complete early temperature record of Earth with the exception of one cold glacial phase about 2.4 billion years ago.

Older time periods are studied by paleoclimatology.

Paleoclimatology uses a variety of proxy methods from the Earth and life sciences to obtain data previously preserved within rocks, sediments, boreholes, ice sheets, tree rings, corals, shells, and microfossils.

These are used for dating in a manner similar to dendrochronology, and such techniques are used in combination with dendrochronology, to plug gaps and to extend the range of the seasonal data available to archaeologists and paleoclimatologists.

The scientific study field of paleoclimatology began to further take shape in the early 19th century, when discoveries about glaciations and natural changes in Earth's past climate helped to understand the greenhouse effect.

Paleoclimatologists consider variations in carbon dioxide concentration to be a fundamental factor influencing climate variations over this time scale.

The early basic carbon isotopy (isotope ratio proportions) was very much in line with what is found today, suggesting that the fundamental features of the carbon cycle were established as early as 4 billion years ago.

Other workers have used oxygen isotope ratios to reconstruct historical atmospheric temperatures, making them important tools for paleoclimatology.

The next atmosphere, consisting largely of nitrogen, carbon dioxide, and inert gases, was produced by outgassing from volcanism, supplemented by gases produced during the late heavy bombardment of Earth by huge asteroids.

The 15 N: 14 N ratio is commonly used in stable isotope analysis in the fields of geochemistry, hydrology, paleoclimatology and paleoceanography, where it is called δ 15 N.

Massive deposits of tillites and anomalous isotopic signatures are found, which gave rise to the Snowball Earth hypothesis.

In geochemistry, paleoclimatology and paleoceanography this ratio is called δ 13 C.

Thus, they are very useful in paleoclimatology and paleoceanography.

The fact that it is not perfectly in line with the 30% lower solar radiance (compared to today) of the early Sun has been described as the "faint young Sun paradox".

Overwash deposits in atolls, coastal lakes, marshes or reef flats are the most important paleoclimatological evidence of tropical cyclone strikes; when storms hit these areas currents and waves can overtop barriers, erode these and other beach structures and lay down deposits in the water bodies behind barriers.

The relatively warm local minimum between Jurassic and Cretaceous goes along with an increase of subduction and mid-ocean ridge volcanism due to the breakup of the Pangea supercontinent.

These are important factors on how flood basalts influenced paleoclimate.

Paleoceanographic research is also intimately tied to paleoclimatology.

James Hansen suggested that humans emit CO 2 10,000 times faster than natural processes have done in the past.

In a 2007 paper, Hansen discussed the potential danger of "fast-feedback" effects causing ice sheet disintegration, based on paleoclimate data.