A report on Paleoclimatology

Palaeotemperature graphs compressed together
The oxygen content in the atmosphere over the last billion years
Sea floor core sample labelled to identify the exact spot on the sea floor where the sample was taken. Sediments from nearby locations can show significant differences in chemical and biological composition.
Timeline of glaciations, shown in blue
Changes in oxygen-18 ratios over the last 500 million years, indicating environmental change
Ice core data for the past 800,000 years (x-axis values represent "age before 1950", so today's date is on the left side of the graph and older time on the right). Blue curve is temperature, red curve is atmospheric concentrations, and brown curve is dust fluxes. Note length of glacial-interglacial cycles averages ~100,000 years.
Holocene Temperature Variations

Study of climates for which direct measurements were not taken.

- Paleoclimatology
Palaeotemperature graphs compressed together

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Overall

Reconstructions of global temperature of the past 2000 years, using composite of different proxy methods

Proxy (climate)

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Reconstructions of global temperature of the past 2000 years, using composite of different proxy methods
Ice Core sample taken from drill. Photo by Lonnie Thompson, Byrd Polar Research Center.
δ18Oair and δDice for Vostok, Antarctica ice core.
Tree rings seen in a cross section of a trunk of a tree.
Coral bleached due to changes in ocean water properties
Cyst of a dinoflagellate Peridinium ovatum
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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.

Average surface air temperatures from 2011 to 2021 compared to the 1956–1976 average. Source: NASA

Climate

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Long-term weather pattern in an area, typically averaged over 30 years.

Long-term weather pattern in an area, typically averaged over 30 years.

Average surface air temperatures from 2011 to 2021 compared to the 1956–1976 average. Source: NASA
Observed temperature from NASA vs the 1850–1900 average used by the IPCC as a pre-industrial baseline. The primary driver for increased global temperatures in the industrial era is human activity, with natural forces adding variability.

Paleoclimatology is the study of ancient climates.

Temperature record of the last 2,000 years (Chart showing the so-called Medieval Warm Period and Little Ice Age were not planet-wide phenomena)

Global temperature record

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The global temperature record shows the fluctuations of the temperature of the atmosphere and the oceans through various spans of time.

The global temperature record shows the fluctuations of the temperature of the atmosphere and the oceans through various spans of time.

Temperature record of the last 2,000 years (Chart showing the so-called Medieval Warm Period and Little Ice Age were not planet-wide phenomena)
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) and to the temperature scale derived from Vostok ice cores following Petit et al. (1999).
Temperature estimates relative to today from over 800,000 years of the EPICA ice cores in Antarctica. Today's date is on the right side of the graph.
Plot showing the variations, and relative stability, of climate during the last 12000 years.
Global average temperature datasets from NASA, NOAA, Berkeley Earth, and meteorological offices of the U.K. and Japan, show substantial agreement concerning the progress and extent of global warming: all pairwise correlations exceed [[:File:20200324 Global average temperature - NASA-GISS HadCrut NOAA Japan BerkeleyE.svg#Pairwise correlation|98%]].
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A study of the paleoclimate covers the time period from 12,000 years ago to the present.

The rocky side of a mountain creek in Costa Rica

Earth science

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Earth science or geoscience includes all fields of natural science related to the planet Earth.

Earth science or geoscience includes all fields of natural science related to the planet Earth.

The rocky side of a mountain creek in Costa Rica
A volcanic eruption is the release of stored energy from below Earth's surface.
The magnetosphere shields the surface of Earth from the charged particles of the solar wind.
(image not to scale.)
In the image above the first example their anti-parallel currents with cause them to repel. In the second example they are parallel currents which cause attraction.
Changing magnetic field through a coil of wire therefore must induce an EMF the coil which in turn causes current to flow.

Paleoclimatology

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Geologic time scale

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Representation of time based on the rock record of Earth.

Representation of time based on the rock record of Earth.

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Graphical representation of Earth's history as a spiral
Geologic time scale with proportional representation of eons/eonothems and eras/erathems. Cenozoic is abbreviated to Cz. The image also shows some notable events in Earth's history and the general evolution of life.

It is used primarily by Earth scientists (including geologists, paleontologists, geophysicists, geochemists, and paleoclimatologists) to describe the timing and relationships of events in geologic history.

NASA photo showing Earth's atmosphere at sunset, with Earth silhouetted

Atmosphere of Earth

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Layer of gases retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere.

Layer of gases retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere.

NASA photo showing Earth's atmosphere at sunset, with Earth silhouetted
Composition of Earth's atmosphere by molecular count, excluding water vapor. Lower pie represents trace gases that together compose about 0.0434% of the atmosphere (0.0442% at August 2021 concentrations ). Numbers are mainly from 2000, with and methane from 2019, and do not represent any single source.
Mean atmospheric water vapor
The mole fraction of the main constituents of the Earth's atmosphere as a function of height according to the MSIS-E-90 atmospheric model.
Earth's atmosphere Lower 4 layers of the atmosphere in 3 dimensions as seen diagonally from above the exobase. Layers drawn to scale, objects within the layers are not to scale. Aurorae shown here at the bottom of the thermosphere can actually form at any altitude in this atmospheric layer.
orbiting in the thermosphere. Because of the angle of the photo, it appears to straddle the stratosphere and mesosphere that actually lie more than 250 km below. The orange layer is the troposphere, which gives way to the whitish stratosphere and then the blue mesosphere.
Temperature trends in two thick layers of the atmosphere as measured between January 1979 and December 2005 by microwave sounding units and advanced microwave sounding units on NOAA weather satellites. The instruments record microwaves emitted from oxygen molecules in the atmosphere. Source:
Temperature and mass density against altitude from the NRLMSISE-00 standard atmosphere model (the eight dotted lines in each "decade" are at the eight cubes 8, 27, 64, ..., 729)
Rough plot of Earth's atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation, including visible light.
Distortive effect of atmospheric refraction upon the shape of the sun at the horizon.
An idealised view of three pairs of large circulation cells.
Oxygen content of the atmosphere over the last billion years

The study of historic atmosphere is called paleoclimatology.

Arctica islandica from the North Sea, prepared for investigation of growth bands for palaeoclimate reconstructions (2009)

Sclerochronology

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Study of periodic physical and chemical features in the hard tissues of animals that grow by accretion, including invertebrates and coralline red algae, and the temporal context in which they formed.

Study of periodic physical and chemical features in the hard tissues of animals that grow by accretion, including invertebrates and coralline red algae, and the temporal context in which they formed.

Arctica islandica from the North Sea, prepared for investigation of growth bands for palaeoclimate reconstructions (2009)

It is particularly useful in the study of marine paleoclimatology.

Global average temperatures show that the Medieval Warm Period was not a global phenomenon.

Medieval Warm Period

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Time of warm climate in the North Atlantic region that lasted from c. 950 to c. 1250.

Time of warm climate in the North Atlantic region that lasted from c. 950 to c. 1250.

Global average temperatures show that the Medieval Warm Period was not a global phenomenon.
Greenland ice sheet temperatures interpreted with 18O isotope from 6 ice cores (Vinther, B., et al., 2009). The data set ranges from 9690 BC to AD 1970 and has a resolution of around 20 years. That means that each data point represents the average temperature of the surrounding 20 years.
The last written records of the Norse Greenlanders are from an Icelandic marriage in 1408 but were recorded later in Iceland, at Hvalsey Church, which is now the best-preserved of the Norse ruins.
1690 copy of the 1570 Skálholt map, based on documentary information about earlier Norse sites in America.
L'Anse aux Meadows, Newfoundland, today, with a reconstruction of a Viking settlement.

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. 1200 and around c. 1600.

Temperature variations during the Holocene from a collection of different reconstructions and their average. The most recent period is on the right, but the recent warming is seen only in the inset.

Holocene climatic optimum

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Warm period that occurred in the interval roughly 9,000 to 5,000 years ago BP, with a thermal maximum around 8000 years BP.

Warm period that occurred in the interval roughly 9,000 to 5,000 years ago BP, with a thermal maximum around 8000 years BP.

Temperature variations during the Holocene from a collection of different reconstructions and their average. The most recent period is on the right, but the recent warming is seen only in the inset.
Vegetation and water bodies in northern and central Africa in the Eemian (bottom) and Holocene (top)
Milankovitch cycles.

For other past climate fluctuation, see paleoclimatology.

Foraminifera

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External shell (called a "test") of diverse forms and materials.

External shell (called a "test") of diverse forms and materials.

Earliest known illustration of a foraminifera shell, published by Robert Hooke in his 1665 book Micrographia.
Schematic diagram of a live multilocular foraminifera. 1-endoplasm, 2-ectoplasm, 3-chamber, 4-pores, 5-foramen, 6-food vacuole, 7-nucleus, 8-mitochondria, 9-granureticulose pseudopodia, 10-granules, 11- primary aperture, 12-food particle, 13-Golgi apparatus, 14-ribosomes.
Diagram of a typical foraminiferan life cycle, showing characteristic alternation of generations.
Morphs present in the foram life cycle—the megalosphere and the microsphere. The name derives from the size of the proloculus, or first chamber, and as such the microsphere has a larger overall size.
Fossil nummulitid foraminiferans showing microspheric (larger) and megalospheric individuals (smaller); Eocene of the United Arab Emirates; scale in mm
The mysterious Paleodictyon has been interpreted as a fossil xenophyophore but this remains controversial.
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A fossil test from a planktonic globigerininan foraminifera.
Neoflabellina reticulata from chalk of Rügen, Northeastern Germany. Length:1.2 mm, Age: Upper lower Maastrichtian
Thin section of a peneroplid foraminiferan from Holocene lagoonal sediment in Rice Bay, San Salvador Island, Bahamas. Scale bar 100 micrometres
Ammonia beccarii, a benthic foram from the North Sea.
Foraminifera Baculogypsina sphaerulata of Hatoma Island, Japan. Field width 5.22 mm
Foraminifera of Pag Island, Adriatic Sea -60 m, field width 5.5 mm
Foraminifera of Pag Island, Adriatic Sea -60 m, field width 5.5 mm
Foraminifera of Pag Island, Adriatic Sea -60 m, field width 5.5 mm
Foraminifera of Pag Island, Adriatic Sea -60 m, field width 5.5 mm
Foraminifera of Indian Ocean, south-eastern coast of Bali, field width 5.5 mm
Foraminifera of Indian Ocean, south-eastern coast of Bali, field width 5.5 mm
Foraminifera of Indian Ocean, south-eastern coast of Bali, field width 5.5 mm
Foraminifera in Ngapali, Myanmar, field width 5.22 mm
Foraminifera Heterostegina depressa, field width 4.4 mm

Thus, they are very useful in paleoclimatology and paleoceanography.