The Holocene Climate Optimum was a warm period during roughly the interval 7,000 to 5,000 years Before Present is a year numbering system, used for the far past times, relating dates to the year 1950. For example, 12,000 BP means 12,000 years before 1950. See also MYA Categories: Stub ... B.P.. This event has also been known by many other names, including: Hypisthermal, Altithermal, Climatic Optimum, Holocene Optimum, Holocene Thermal Maximum, and Holocene Megathermal.

This warm period was followed by a gradual decline until about 2,000 years ago.

• For other temperature fluctuations see: Temperature record
• For other past climate fluctuation see: Paleoclimatology is the study of climate change taken on the scale of the entire history of the earth. The beginning of Earths climate Life flourishes in the Cambrian The earths history dates back more than 4.5 billion years (Ga) which is divided roughly into 2 eons called... Paleoclimatology

Global effects

Temperature variations during the Holocene from a collection of different reconstructions and their average. Most recent period is on left.

The Holocene Climate Optimum warm event consisted of increases of up to 4 °C near the This is about the geographic meaning of North Pole. For the cities, see North Pole, Alaska and North Pole, New York. A North Pole is the northernmost point on any planet. There are various ways of defining a planets North Pole. Earths Pole, however it is defined, lies... North Pole (in one study, winter warming of 3-9°C and summer of 2-6°C in northern central Siberian federal subjects of Russia Siberia ( Russian: Сиби́рь, common English transliterations: Sibir, Sibir; possibly from the Mongolian for the calm land) is a vast region of Russia and northern Kazakhstan constituting almost all of northern Asia. It extends eastward from the Ural Mountains to... Siberia) ^{[1] (http://en.wikipedia.org/wiki/Holocene_climatic_optimum#endnote_Koshkarova2004)}. Northwestern Europe experienced warming, while there was cooling in the south. ^{[2] (http://en.wikipedia.org/wiki/Holocene_climatic_optimum#endnote_davis2003)} The average temperature change appears to have declined rapidly with latitude so that essentially no change in mean temperature is reported at low and mid latitudes. Tropical reefs tend to show temperature increases of less than 1 °C. In terms of the global average, the typical shift was probably between 0.5 and 2 °C warmer than the mid-20th century (depending on estimates of latitude dependence and seasonality in response patterns).

Sunspot activity peak 8,000 years ago. Most recent period is on left.

In the far southern hemisphere (e.g. For alternative meanings, see New Zealand (disambiguation). New Zealand is a country formed of two major islands and a number of Pacific Ocean. A common Māori name for New Zealand is Aotearoa, popularly translated as Land of the Long White Cloud. New Zealand also maintains responsibility for the... New Zealand and World map showing location of Antarctica A satellite composite image of Antarctica For the Kim Stanley Robinson novel see Antarctica (novel) Antarctica (from Greek ἀνταρκτικός, opposite the arctic) is a continent surrounding the Earths South Pole. It is the... Antarctica), the warmest period during the Holocene appears to have been roughly 8,000 to 10,500 years ago, immediately following the end of last ice age ^{[3] (http://en.wikipedia.org/wiki/Holocene_climatic_optimum#endnote_Masson2001) [4] (http://en.wikipedia.org/wiki/Holocene_climatic_optimum#endnote_Williams2004)}. By 6,000 years ago, the time normally associated with the Holocene Climatic Optimum in the Northern Hemisphere, these regions had reached temperatures similar to those existing in the modern era, and did not participate in the temperature changes of the North. However, some authors have used the term "Holocene Climatic Optimum" to describe this earlier southern warm period as well.

Milankovitch cycles

This climatic event was probably a result of predictable changes in the Earth's orbit ( This article or section should be merged with Orbital forcing Milankovitch cycles is the name given to the collective effect of changes in the Earths movements upon its climate. The eccentricity, axial tilt, and precession of the Earths orbit vary in several patterns, resulting in 100,000 year... Milankovitch cycles) and a continuation of changes that caused the end of the last Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). For the band, see Ice Age (band). An ice age is a period of long-term downturn in the temperature of Earths climate, resulting... glacial period.

The effect would have had maximum Northern Hemisphere heating 9000 years ago when axial tilt was 24° and nearest approach to the Sun ( This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. In architecture, apsis is a synonym for apse; Apogee is also the name of a video game publisher. elements of an orbit In astronomy, an apsis (plural... perihelion) was during boreal summer. The calculated Milankovitch forcing would have provided more Solar radiation is radiant energy emitted by the sun, particularly electromagnetic energy. About half of the radiation is in the visible short-wave part of the electromagnetic spectrum. The other half is mostly in the near-infrared part, with some in the ultraviolet part of the spectrum [1]. The portion... solar radiation to the Northern Hemisphere in summer, tending to cause greater heating at that time. There does seem to have been the predicted southward shift in the global band of thunderstorms called the The ITCZ, or InterTropical Convergence Zone, is a belt of low pressure girdling the globe at the equator. It is formed, as its name indicates, by the convergence of warm, moist air from the latitudes above and below the equator. This region is also known as Intertropical Front or the... Intertropical convergence zone.

However, orbital forcing would predict maximum climate response several 1000 years earlier than those observed in the Northern Hemisphere. This delay may be a result of the continuing changes in climate as the Earth emerged from the last glacial period and related to ice feedbacks. It should also be noted that different sites often show climate changes at somewhat different times and lasting for different durations. At some locations, climate changes associated with this event may have begun as early as 9000 years ago, or presisted until 4000 years before present. As noted above, the warmest interval in the far south significantly preceeded warming in the North.

Other changes

While there do not appear to have been significant temperature changes at most low latitude sites, other climate changes have been reported. These include significantly wetter conditions in World map showing location of Africa A satellite composite image of Africa Africa is the worlds second-largest continent in both area and population, after Eurasia. At about 30,244,050 km2 (11,677,240 mi2) including its adjacent islands, it covers 20.3 percent of the total land... Africa, Australia, officially the Commonwealth of Australia, is the sixth-largest country in the world, the only one to occupy an entire continent, and the largest in the region of Australasia/ Oceania. It also includes a number of secondary islands, the largest of which is Tasmania, an Australian State. Australia is... Australia and Official language Japanese Capital Tokyo Largest City Tokyo Emperor Akihito Prime Minister Junichiro Koizumi Area  - Total  - % water Ranked 60th 377,835 km² 0.8% Population  - Total ( 2004)  - Density Ranked 10th 127,333,002 337/km² GDP  - Total (PPP, 2005)  - Total (nominal)  ... Japan, and desert-like conditions in the midwestern The United States of America — also referred to as the United States, the U.S.A., the U.S., America¹, the States, or (archaically) Columbia — is a federal republic of 50 states located primarily in central North America (with the exception of two states: Alaska and Hawaii... United States. Areas around the The name Amazon may refer to several concepts: The legendary Amazons, women renowned in antiquity for their prowess in battle. The Amazon River, Amazon Rainforest, and Amazon Basin through which it flows. The river was so named because early Portuguese explorers reported having observed female warriors along its banks. Amazonas... Amazon in South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. South America is situated between the Pacific Ocean and the Atlantic Ocean. It became attached to North America only recently, geologically speaking, with the formation of the Isthmus of Panama... South America show temperature increases and drier conditions. ^{[5] (http://en.wikipedia.org/wiki/Holocene_climatic_optimum#endnote_mayle2004)}

References

1. ^ V.L. Koshkarova and A.D. Koshkarov (2004) "Regional signatures of changing landscape and climate of northern central Siberia in the Holocene". Russian Geology and Geophysics 45 (6), 672-685.
2. ^ B.A.S. Davis, S. Brewer, A.C. Stevenson, J. Guiot (2003) "The temperature of Europe during the Holocene reconstructed from pollen data". Quaternary Science Reviews 22, 1701-1716. A digital object identifier (or DOI) is a permanent identifier given to a World Wide Web file or other Internet document so that if its Internet address changes, users will be redirected to its new address. A publisher submits a DOI to a centrally-managed directory and then use the... DOI:10.1016/S0277-3791(03)00173-2  (http://dx.doi.org/10.1016/S0277-3791(03)00173-2)
3. ^ Masson, V., Vimeux, F., Jouzel, J., Morgan, V., Delmotte, M., Ciais,P., Hammer, C., Johnsen, S., Lipenkov, V.Y., Mosley-Thompson, E.,Petit, J.-R., Steig, E.J., Stievenard,M., Vaikmae, R. (2000) "Holocene climate variability in Antarctica based on 11 ice-core isotopic records". Quaternary Research 54, 348–58.
4. ^ P.W. Williams, D.N.T. King, J.-X. Zhao K.D. Collerson (2004) "Speleothem master chronologies: combined Holocene ¹⁸O and ¹³C records from the North Island of New Zealand and their paleoenvironmental interpretation". The Holocene 14 (2), 194-208.
5. ^ Francis E. Mayle, David J. Beerling, William D. Gosling, Mark B. Bush (2004) "Responses of Amazonian ecosystems to climatic and atmospheric carbon dioxide changes since the Last Glacial Maximum". Philosophical Transactions: Biological Sciences 359 (1443), 499-514. A digital object identifier (or DOI) is a permanent identifier given to a World Wide Web file or other Internet document so that if its Internet address changes, users will be redirected to its new address. A publisher submits a DOI to a centrally-managed directory and then use the... DOI:10.1098/rstb.2003.1434  (http://dx.doi.org/10.1098/rstb.2003.1434)