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Reconstructions of global temperature of the past 2000 years, using composite of different proxy methods. In the study of past climates ("paleoclimatology"), climate proxies are preserved physical characteristics of the past that stand in for direct meteorological measurements [1] and enable scientists to reconstruct the climatic conditions over a longer fraction of the Earth's history.
Proxies of global climatic significance are, however, less ambiguous in paleotemperature interpretation. Marine biota have offered by far the most proxies for paleotemperature, of which the microfossils, because of their widespread, abundance and sensitive to latitudinal changes, have provided many primary important paleotemperature indicators.
Paleoclimatology (British spelling, palaeoclimatology) is the scientific study of climates predating the invention of meteorological instruments, when no direct measurement data were available. [1] As instrumental records only span a tiny part of Earth's history , the reconstruction of ancient climate is important to understand natural ...
Frank, Esper & Cook (2007) "Adjustment for proxy number and coherence in a large-scale temperature reconstruction". Hegerl et al. (2007) "Detection of human influence on a new, validated 1500–year temperature reconstruction". Juckes et al. 2007 "Millennial temperature reconstruction intercomparison and evaluation".
Reconstruction of the past 5 million years of climate history, based on oxygen isotope fractionation in deep sea sediment cores (serving as a proxy for the total global mass of glacial ice sheets), fitted to a model of orbital forcing (Lisiecki and Raymo 2005) [2] and to the temperature scale derived from Vostok ice cores following Petit et al. (1999).
Geochemical Climate Proxy: Ratio of Oxygen-18 to Oxygen-16 in calcite from deep sea sediment, and coral cores More Oxygen-18 = colder climatic periods Mass Spectrometer: ca 542,000,000 yrs BP Beryllium-10 Analysis Geochemical Climate Proxy: Ratio of Beryllium-10 to daughter isotopes in dust from ice cores
Paleoceanography makes use of so-called proxy methods as a way to infer information about the past state and evolution of the world's oceans. Several geochemical proxy tools include long-chain organic molecules (e.g. alkenones), stable and radioactive isotopes, and trace metals. [1]
The problem of changing response of some tree ring proxies to recent climate changes was first identified through research in Alaska conducted by Gordon Jacoby and Rosanne D'Arrigo. [ 3 ] [ 4 ] Keith Briffa 's February 1998 study showed that this problem was more widespread at high northern latitudes, and warned that it had to be taken into ...