Medieval Warm Period

The Medieval Warm Period (MWP), also known as the Medieval Climate Optimum or the Medieval Climatic Anomaly, was a time of warm climate in the North Atlantic region that lasted from c. 950 to c. 1250.^[2] Climate proxy records show peak warmth occurred at different times for different regions, which indicate that the MWP was not a globally uniform event.^[3] Some refer to the MWP as the Medieval Climatic Anomaly to emphasize that climatic effects other than temperature were also important.^[4][5]

Global average temperatures show that the Medieval Warm Period was not a global phenomenon.^[1]

The MWP was followed by a regionally cooler period in the North Atlantic and elsewhere, which is sometimes called the Little Ice Age (LIA).

Possible causes of the MWP include increased solar activity, decreased volcanic activity, and changes in ocean circulation.^[6] Modelling evidence has shown that natural variability is insufficient on its own to explain the MWP and that an external forcing had to be one of the causes.^[7]

Research

The MWP is generally thought to have occurred from c. 950 – c. 1250, during the European Middle Ages.^[2] Some researchers divide the MWP into two phases: MWP-I, which began around 450 AD and ended around 900 AD, and MWP-II, which lasted from 1000 AD to 1300 AD; MWP-I is called the early Medieval Warm Period while MWP-II is called the conventional Medieval Warm Period.^[8] In 1965, Hubert Lamb, one of the first paleoclimatologists, published research based on data from botany, historical document research, and meteorology, combined with records indicating prevailing temperature and rainfall in England around c. 1200 and around c. 1600. He proposed, "Evidence has been accumulating in many fields of investigation pointing to a notably warm climate in many parts of the world, that lasted a few centuries around c. 1000 – c. 1200 AD, and was followed by a decline of temperature levels till between c. 1500 and c. 1700 the coldest phase since the last ice age occurred."^[9]

The era of warmer temperatures became known as the Medieval Warm Period and the subsequent cold period the Little Ice Age (LIA). However, the view that the MWP was a global event was challenged by other researchers. The IPCC First Assessment Report of 1990 discussed the "Medieval Warm Period around 1000 AD (which may not have been global) and the Little Ice Age which ended only in the middle to late nineteenth century." It stated that temperatures in the "late tenth to early thirteenth centuries (about AD 950–1250) appear to have been exceptionally warm in western Europe, Iceland and Greenland."^[10] The IPCC Third Assessment Report from 2001 summarized newer research: "evidence does not support globally synchronous periods of anomalous cold or warmth over this time frame, and the conventional terms of 'Little Ice Age' and 'Medieval Warm Period' are chiefly documented in describing northern hemisphere trends in hemispheric or global mean temperature changes in past centuries."^[11]

Global temperature records taken from ice cores, tree rings, and lake deposits have shown that the Earth may have been slightly cooler globally (by 0.03 °C) than in the early and the mid-20th century.^[12][13]

Palaeoclimatologists developing region-specific climate reconstructions of past centuries conventionally label their coldest interval as "LIA" and their warmest interval as the "MWP".^[12][14] Others follow the convention, and when a significant climate event is found in the "LIA" or "MWP" timeframes, they associate their events to the period. Some "MWP" events are thus wet events or cold events, rather than strictly warm events, particularly in central Antarctica, where climate patterns that are opposite to those of the North Atlantic have been noticed.

Global climate during the Medieval Warm Period

The nature and extent of the MWP has been marked by long-standing controversy over whether it was a global or regional event.^[15][16] In 2019, by using an extended proxy data set,^[17] the Pages-2k consortium confirmed that the Medieval Climate Anomaly was not a globally synchronous event. The warmest 51-year period within the MWP did not occur at the same time in different regions. They argue for a regional instead of global framing of climate variability in the preindustrial Common Era to aid in understanding.^[18]

North Atlantic

 

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.

See also: Tropical cyclones and climate change

Lloyd D. Keigwin's 1996 study of radiocarbon-dated box core data from marine sediments in the Sargasso Sea found that its sea surface temperature was approximately 1 °C (1.8 °F) cooler approximately 400 years ago, during the LIA, and 1700 years ago and was approximately 1 °C warmer 1000 years ago, during the MWP.^[19]

Using sediment samples from Puerto Rico, the Gulf Coast, and the Atlantic Coast from Florida to New England, Mann et al. (2009) found consistent evidence of a peak in North Atlantic tropical cyclone activity during the MWP, which was followed by a subsequent lull in activity.^[20]

Iceland

Iceland was first settled between about 865 and 930, during a time believed to be warm enough for sailing and farming.^[21][22] By retrieval and isotope analysis of marine cores and from examination of mollusc growth patterns from Iceland, Patterson et al. reconstructed a stable oxygen (δ¹⁸ O) and carbon (δ¹³ C) isotope record at a decadal resolution from the Roman Warm Period to the MWP and the LIA.^[23] Patterson et al. conclude that the summer temperature stayed high but winter temperature decreased after the initial settlement of Iceland.^[23]

Greenland

 

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.

The 2009 Mann et al. study found warmth exceeding 1961–1990 levels in southern Greenland and parts of North America during the MWP, which the study defines as from 950 to 1250, with warmth in some regions exceeding temperatures of the 1990–2010 period. Much of the Northern Hemisphere showed a significant cooling during the LIA, which the study defines as from 1400 to 1700, but Labrador and isolated parts of the United States appeared to be approximately as warm as during the 1961–1990 period.^[2] Greenlandic winter oxygen isotope data from the MWP display a strong correlation with the North Atlantic Oscillation (NAO).^[24]

 

1690 copy of the 1570 Skálholt map, based on documentary information about earlier Norse sites in America.

The Norse colonization of the Americas has been associated with warmer periods.^[25] The common theory is that Norsemen took advantage of ice-free seas to colonize areas in Greenland and other outlying lands of the far north.^[26] However, a study from Columbia University suggests that Greenland was not colonized in warmer weather, but the warming effect in fact lasted for only very briefly.^[27] c. 1000AD, the climate was sufficiently warm for the Vikings to journey to Newfoundland and to establish a short-lived outpost there.^[28]

 

L'Anse aux Meadows, Newfoundland, today, with a reconstruction of a Viking settlement.

In around 985, Vikings founded the Eastern and Western Settlements, both near the southern tip of Greenland. In the colony's early stages, they kept cattle, sheep, and goats, with around a quarter of their diet from seafood. After the climate became colder and stormier around 1250, their diet steadily shifted towards ocean sources. By around 1300, seal hunting provided over three quarters of their food.

By 1350, there was reduced demand for their exports, and trade with Europe fell away. The last document from the settlements dates from 1412, and over the following decades, the remaining Europeans left in what seems to have been a gradual withdrawal, which was caused mainly by economic factors such as increased availability of farms in Scandinavian countries.^[29]

Europe

Substantial glacial retreat in southern Europe was experienced during the MWP. While several smaller glaciers experienced complete deglaciation, larger glaciers in the region survived and now provide insight into the region's climate history.^[30] In addition to warming induced glacial melt, sedimentary records reveal a period of increased flooding, coinciding with the MWP, in eastern Europe that is attributed to enhanced precipitation from a positive phase NAO.^[31] Other impacts of climate change can be less apparent such as a changing landscape. Preceding the MWP, a coastal region in western Sardinia was abandoned by the Romans. The coastal area was able to substantially expand into the lagoon without the influence of human populations and a high stand during the MWP. When human populations returned to the region, they encountered a land altered by climate change and had to reestablish ports.^[32]

Other regions

North America

In Chesapeake Bay (now in Maryland and Virginia, United States), researchers found large temperature excursions (changes from the mean temperature of that time) during the MWP (about 950–1250) and the Little Ice Age (about 1400–1700, with cold periods persisting into the early 20th century), which are possibly related to changes in the strength of North Atlantic thermohaline circulation.^[33] Sediments in Piermont Marsh of the lower Hudson Valley show a dry MWP from 800 to 1300.^[34] In the Hammock River marsh in Connecticut, salt marshes extended 15 km farther westward than they do in the present due to higher sea levels.^[35]

Prolonged droughts affected many parts of what is now the Western United States, especially eastern California and the west of Great Basin.^[12][36] Alaska experienced three intervals of comparable warmth: 1–300, 850–1200, and since 1800.^[37] Knowledge of the MWP in North America has been useful in dating occupancy periods of certain Native American habitation sites, especially in arid parts of the Western United States.^[38][39] Aridity was more prevalent in the southeastern United States during the MWP than the following LIA, but only slightly; this difference may be statistically insignificant.^[40] Droughts in the MWP may have impacted Native American settlements also in the Eastern United States, such as at Cahokia.^[41][42] Review of more recent archaeological research shows that as the search for signs of unusual cultural changes has broadened, some of the early patterns (such as violence and health problems) have been found to be more complicated and regionally varied than had been previously thought. Other patterns, such as settlement disruption, deterioration of long-distance trade, and population movements, have been further corroborated.^[43]

Africa

The climate in equatorial eastern Africa has alternated between being drier than today and relatively wet. The climate was drier during the MWP (1000–1270).^[44] Off the coast of Africa, Isotopic analysis of bones from the Canary Islands’ inhabitants during the MWP to LIA transition reveal the region experienced a 5 °C decrease in air temperature. Over this period, the diet of inhabitants did not appreciably change, which suggests they were remarkably resilient to climate change.^[45]

Antarctica

The onset of the MWP in the Southern Ocean lagged the MWP's onset in the North Atlantic by approximately 150 years.^[46] A sediment core from the eastern Bransfield Basin, in the Antarctic Peninsula, preserves climatic events from both the LIA and the MWP. The authors noted, "The late Holocene records clearly identify Neoglacial events of the LIA and Medieval Warm Period (MWP)."^[47] Some Antarctic regions were atypically cold, but others were atypically warm between 1000 and 1200.^[48]

Pacific Ocean

Corals in the tropical Pacific Ocean suggest that relatively cool and dry conditions may have persisted early in the millennium, which is consistent with a La Niña-like configuration of the El Niño-Southern Oscillation patterns.^[49]

In 2013, a study from three US universities was published in Science magazine and showed that the water temperature in the Pacific Ocean was 0.9 degrees warmer during the MWP than during the LIA and 0.65 degrees warmer than the decades before the study.^[50]

South America

The MWP has been noted in Chile in a 1500-year lake bed sediment core,^[51] as well as in the Eastern Cordillera of Ecuador.^[52]

A reconstruction, based on ice cores, found that the MWP could be distinguished in tropical South America from about 1050 to 1300 and was followed in the 15th century by the LIA. Peak temperatures did not rise as to the level of the late 20th century, which were unprecedented in the area during the study period of 1600 years.^[53]

East Asia

Ge et al. studied temperatures in China for the past 2000 years and found high uncertainty prior to the 16th century but good consistency over the last 500 years highlighted by the two cold periods, 1620s–1710s and 1800s–1860s, and the 20th-century warming. They also found that the warming from the 10th to the 14th centuries in some regions might be comparable in magnitude to the warming of the last few decades of the 20th century, which was unprecedented within the past 500 years.^[54] Generally, a warming period was identified in China, coinciding with the MWP, using multi-proxy data for temperature. However, the warming was inconsistent across China. Significant temperature change, from the MWP to LIA, was found for northeast and central-east China but not for northwest China and the Tibetan Plateau.^[55] During the MWP, the East Asian Summer Monsoon (EASM) was the strongest it has been in the past millennium^[56] and was highly sensitive to the El Niño Southern Oscillation (ENSO).^[57] The Mu Us Desert witness increased moisture in the MWP.^[58] Peat cores from peatland in southeast China suggest changes in the EASM and ENSO are responsible for increased precipitation in the region during the MWP.^[59] However, other sites in southern China show aridification and not humidification during the MWP, showing that the MWP's influence was highly spatially heterogeneous.^[60] Modelling evidence suggests that EASM strength during the MWP was low in early summer but very high during late summer.^[61]

In far eastern Russia, continental regions experienced severe floods during the MWP while nearby islands experienced less precipitation leading to a decrease in peatland. Pollen data from this region indicates an expansion of warm climate vegetation with an increasing number of broadleaf and decreasing number of coniferous forests.^[62]

Adhikari and Kumon (2001), investigating sediments in Lake Nakatsuna, in central Japan, found a warm period from 900 to 1200 that corresponded to the MWP and three cool phases, two of which could be related to the LIA.^[63] Other research in northeastern Japan showed that there was one warm and humid interval, from 750 to 1200, and two cold and dry intervals, from 1 to 750 and from 1200 to now.^[64]

South Asia

The Indian Summer Monsoon (ISM) was also enhanced during the MWP with a temperature driven change to the Atlantic Multi-decadal Oscillation (AMO),^[65] bringing more precipitation to India.^[66] Vegetation records in Lahaul in Himachal Pradesh confirm a warm and humid MWP from 1,158 to 647 BP.^[67] Pollen from Madhya Pradesh dated to the MWP provides further direct evidence for increased monsoonal precipitation.^[68] Multi-proxy records from Pookode Lake in Kerala also reflect the warmth of the MWP.^[69]

Middle East

Sea surface temperatures in the Arabian Sea increased during the MWP, owing to a strong monsoon.^[70] During the MWP, the Arabian Sea exhibited heightened biological productivity.^[71] The Arabian Peninsula, already extremely arid in the present day, was even drier during the MWP. Prolonged drought was a mainstay of the Arabian climate until around 660 BP, when this hyperarid interval was terminated.^[72]

Oceania

There is an extreme scarcity of data from Australia for both the MWP and the LIA. However, evidence from wave-built shingle terraces for a permanently-full Lake Eyre^[73] during the 9th and the 10th centuries is consistent with a La Niña-like configuration, but the data are insufficient to show how lake levels varied from year to year or what climatic conditions elsewhere in Australia were like.

A 1979 study from the University of Waikato found, "Temperatures derived from an ¹⁸O/¹⁶O profile through a stalagmite found in a New Zealand cave (40.67°S, 172.43°E) suggested the Medieval Warm Period to have occurred between AD c. 1050 and c. 1400 and to have been 0.75 °C warmer than the Current Warm Period."^[74] More evidence in New Zealand is from an 1100-year tree-ring record.^[75]

See also

•  Global warming portal

• Classic Maya collapse – Concurrent with the Medieval Warm Period and marked by decades-long droughts
• Cretaceous Thermal Maximum – Period of climatic warming that reached its peak approximately 90 million years ago
• Description of the Medieval Warm Period and Little Ice Age in IPCC reports
• Historical climatology
• Hockey stick graph (global temperature) – Graph in climate science
• Holocene climatic optimum – Global warm period around 9,000–5,000 years ago
• Late Antique Little Ice Age – Northern Hemispheric cooling period
• Paleoclimatology – Study of changes in ancient climate

References

1. Hawkins, Ed (January 30, 2020). "2019 years". climate-lab-book.ac.uk. from the original on February 2, 2020. ("The data show that the modern period is very different to what occurred in the past. The often quoted Medieval Warm Period and Little Ice Age are real phenomena, but small compared to the recent changes.")
2. Mann, M. E.; Zhang, Z.; Rutherford, S.; et al. (2009). "Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly" (PDF). Science. 326 (5957): 1256–60. Bibcode:2009Sci...326.1256M. doi:10.1126/science.1177303. PMID 19965474. S2CID 18655276.
3. Solomon, Susan Snell; Intergovernmental Panel on Climate Change (2007). "6.6 The Last 2,000 Years". Climate change 2007: the physical science basis: contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge: Cambridge University Press for the Intergovernmental Panel on Climate Change. ISBN 978-0-521-70596-7.{{cite book}}: CS1 maint: multiple names: authors list (link) Box 6.4 2015-03-28 at the Wayback Machine
4. Bradley, Raymond S. (2003). "Climate of the Last Millennium" (PDF). Climate System Research Center.
5. Ladurie, Emmanuel Le Roy (1971). Times of Feast, Times of Famine: a History of Climate Since the Year 1000. Farrar Straus & Giroux. ISBN 978-0-374-52122-6.^{[page needed]}
6. "How does the Medieval Warm Period compare to current global temperatures?". SkepticalScience. Retrieved October 12, 2017.
7. Hunt, B. G. (11 May 2006). "The Medieval Warm Period, the Little Ice Age and simulated climatic variability". Climate Dynamics. 27 (7–8): 677–694. doi:10.1007/s00382-006-0153-5. ISSN 0930-7575. S2CID 128890550. Retrieved 5 September 2023.
8. Cronin, T.M; Dwyer, G.S; Kamiya, T; Schwede, S; Willard, D.A (March 2003). "Medieval Warm Period, Little Ice Age and 20th century temperature variability from Chesapeake Bay". Global and Planetary Change. 36 (1–2): 17–29. doi:10.1016/S0921-8181(02)00161-3. hdl:10161/6578. Retrieved 5 September 2023.
9. Lamb, H.H. (1965). "The early medieval warm epoch and its sequel". Palaeogeography, Palaeoclimatology, Palaeoecology. 1: 13–37. Bibcode:1965PPP.....1...13L. doi:10.1016/0031-0182(65)90004-0.
10. IPCC First Assessment Report Working Group 1 report, Chapter 7, Executive Summary p. 199, Climate of the Past 5,000,000 Years p. 202.
11. Folland, C.K.; Karl, T.R.; Christy, J.R.; et al. (2001). "2.3.3 Was there a "Little Ice Age" and a "Medieval Warm Period"?"". In Houghton, J.T.; Ding, Y.; Griggs, D.J.; Noguer, M.; van der Linden; Dai; Maskell; Johnson (eds.). Working Group I: The Scientific Basis. Intergovernmental Panel on Climate Change Climate Change 2001. Cambridge, United Kingdom and New York, NY, USA: Cambridge University Press. p. 881. ISBN 978-0-521-80767-8.
12. Bradley, R. S.; Hughes, MK; Diaz, HF (2003). "CLIMATE CHANGE: Climate in Medieval Time". Science. 302 (5644): 404–5. doi:10.1126/science.1090372. PMID 14563996. S2CID 130306134.
13. Crowley, Thomas J.; Lowery, Thomas S. (2000). "How Warm Was the Medieval Warm Period?". Ambio: A Journal of the Human Environment. 29: 51–54. doi:10.1579/0044-7447-29.1.51. S2CID 86527510.
14. Jones, P. D.; Mann, M. E. (2004). "Climate over past millennia". Reviews of Geophysics. 42 (2): 2002. Bibcode:2004RvGeo..42.2002J. doi:10.1029/2003RG000143.
15. Broecker, Wallace S. (23 February 2001). "Was the Medieval Warm Period Global?". Science. 291 (5508): 1497–1499. doi:10.1126/science.291.5508.1497. PMID 11234078. S2CID 17674208. Retrieved 18 June 2023.
16. Hughes, Malcolm K.; Diaz, Henry F. (March 1994). "Was there a 'medieval warm period', and if so, where and when?". Climatic Change. 26 (2–3): 109–142. Bibcode:1994ClCh...26..109H. doi:10.1007/BF01092410. S2CID 128680153. Retrieved 18 June 2023.
17. Emile-Geay, Julien; McKay, Nicholas P.; Kaufman, Darrell S.; von Gunten, Lucien; Wang, Jianghao; Anchukaitis, Kevin J.; Abram, Nerilie J.; Addison, Jason A.; Curran, Mark A.J.; Evans, Michael N.; Henley, Benjamin J. (2017-07-11). "A global multiproxy database for temperature reconstructions of the Common Era". Scientific Data. 4 (1): 170088. Bibcode:2017NatSD...470088E. doi:10.1038/sdata.2017.88. ISSN 2052-4463. PMC 5505119. PMID 28696409.
18. Neukom, Raphael; Steiger, Nathan; Gómez-Navarro, Juan José; Wang, Jianghao; Werner, Johannes P. (2019). "No evidence for globally coherent warm and cold periods over the preindustrial Common Era". Nature. 571 (7766): 550–554. Bibcode:2019Natur.571..550N. doi:10.1038/s41586-019-1401-2. ISSN 1476-4687. PMID 31341300. S2CID 198494930.
19. Keigwin, L. D. (1996). "The Little Ice Age and Medieval Warm Period in the Sargasso Sea". Science. 274 (5292): 1504–1508. Bibcode:1996Sci...274.1504K. doi:10.1126/science.274.5292.1504. PMID 8929406. S2CID 27928974.
20. Mann, Michael E.; Woodruff, Jonathan D.; Donnelly, Jeffrey P.; Zhang, Zhihua (2009). "Atlantic hurricanes and climate over the past 1,500 years". Nature. 460 (7257): 880–3. Bibcode:2009Natur.460..880M. doi:10.1038/nature08219. hdl:1912/3165. PMID 19675650. S2CID 233167.
21. Gunnar Karlsson (2000). The history of Iceland. Minneapolis, Minn.: University of Minnesota Press. ISBN 0-8166-3588-9. OCLC 42736334.
22. Lamb, H. H. (2011). Climate : present, past and future. Volume 2, Climatic history and the future. Abingdon, Oxon: Routledge. ISBN 978-0-203-80430-8. OCLC 900419132.
23. Patterson, W. P.; Dietrich, K. A.; Holmden, C.; Andrews, J. T. (2010). "Two millennia of North Atlantic seasonality and implications for Norse colonies". Proceedings of the National Academy of Sciences of the United States of America. 107 (12): 5306–10. Bibcode:2010PNAS..107.5306P. doi:10.1073/pnas.0902522107. PMC 2851789. PMID 20212157.
24. Vinther, B. M.; Jones, P. D.; Briffa, K. R.; Clausen, H. B.; Andersen, K. K.; Dahl-Jensen, D.; Johnsen, S. J. (February 2010). "Climatic signals in multiple highly resolved stable isotope records from Greenland". Quaternary Science Reviews. 29 (3–4): 522–538. Bibcode:2010QSRv...29..522V. doi:10.1016/j.quascirev.2009.11.002.
25. D'Andrea, William J.; Huang, Yongsong; Fritz, Sherilyn C.; Anderson, N. John (31 May 2011). "Abrupt Holocene climate change as an important factor for human migration in West Greenland". Proceedings of the National Academy of Sciences of the United States of America. 108 (24): 9765–9769. Bibcode:2011PNAS..108.9765D. doi:10.1073/pnas.1101708108. PMC 3116382. PMID 21628586.
26. Diamond, Jared (2005). Collapse: How Societies Choose to Fail or Succeed. New York: Penguin Books. ISBN 978-0-14-303655-5.^{[page needed]}
27. "Study Undercuts Idea That 'Medieval Warm Period' Was Global – The Earth Institute – Columbia University". earth.columbia.edu. Retrieved 7 April 2018.
28. Ingstad, Anne Stine (2001). "The Excavation of a Norse Settlement at L'Anse aux Meadows, Newfoundland". In Helge Ingstad; Anne Stine Ingstad (eds.). The Viking Discovery of America. New York: Checkmark. pp. 141–169. ISBN 978-0-8160-4716-1. OCLC 46683692.
29. Stockinger, Günther (10 January 2012). "Archaeologists Uncover Clues to Why Vikings Abandoned Greenland". Der Spiegel Online. Retrieved 12 January 2013.
30. Moreno, Ana; Bartolomé, Miguel; López-Moreno, Juan Ignacio; Pey, Jorge; Corella, Juan Pablo; García-Orellana, Jordi; Sancho, Carlos; Leunda, María; Gil-Romera, Graciela; González-Sampériz, Penélope; Pérez-Mejías, Carlos (3 March 2021). "The case of a southern European glacier which survived Roman and medieval warm periods but is disappearing under recent warming". The Cryosphere. 15 (2): 1157–1172. Bibcode:2021TCry...15.1157M. doi:10.5194/tc-15-1157-2021. hdl:10810/51794. ISSN 1994-0416. S2CID 232275176.
31. Perșoiu, Ioana; Perșoiu, Aurel (2019). "Flood events in Transylvania during the Medieval Warm Period and the Little Ice Age". The Holocene. 29 (1): 85–96. Bibcode:2019Holoc..29...85P. doi:10.1177/0959683618804632. ISSN 0959-6836. S2CID 134035133.
32. Pascucci, V.; De Falco, G.; Del Vais, C.; Sanna, I.; Melis, R. T.; Andreucci, S. (1 January 2018). "Climate changes and human impact on the Mistras coastal barrier system (W Sardinia, Italy)". Marine Geology. 395: 271–284. Bibcode:2018MGeol.395..271P. doi:10.1016/j.margeo.2017.11.002. ISSN 0025-3227.
33. . USGS. Archived from the original on 2006-06-30. Retrieved 2006-05-04.
34. . Earth Observatory News. May 19, 2005. Archived from the original on October 2, 2006. Retrieved 2006-05-04.
35. Van de Plassche, Orson; Van der Borg, Klaas; De Jong, Arie F. M. (1 April 1998). "Sea level–climate correlation during the past 1400 yr". Geology. 26 (4): 319–322. Bibcode:1998Geo....26..319V. doi:10.1130/0091-7613(1998)026<0319:SLCCDT>2.3.CO;2. Retrieved 14 July 2023.
36. Stine, Scott (1994). "Extreme and persistent drought in California and Patagonia during mediaeval time". Nature. 369 (6481): 546–549. Bibcode:1994Natur.369..546S. doi:10.1038/369546a0. S2CID 4315201.
37. Hu, F. S. (2001). "Pronounced climatic variations in Alaska during the last two millennia". Proceedings of the National Academy of Sciences of the United States of America. 98 (19): 10552–10556. Bibcode:2001PNAS...9810552H. doi:10.1073/pnas.181333798. PMC 58503. PMID 11517320.
38. Dean, Jeffrey S. (1994). "The medieval warm period on the southern Colorado Plateau". Climatic Change. 26 (2–3): 225–241. Bibcode:1994ClCh...26..225D. doi:10.1007/BF01092416. S2CID 189877071.
39. C. Michael Hogan (2008) Los Osos Back Bay, Megalithic Portal, editor A. Burnham.
40. Stahle, David W.; Cleaveland, Malcolm K. (March 1994). "Tree-ring reconstructed rainfall over the southeastern U.S.A. during the medieval warm period and little ice age". Climatic Change. 26 (2–3): 199–212. doi:10.1007/BF01092414. ISSN 0165-0009. S2CID 189878139. Retrieved 5 September 2023.
41. Benson, Larry V.; Pauketat, Timothy R.; Cook, Edward R. (2009). "Cahokia's Boom and Bust in the Context of Climate Change". American Antiquity. 74 (3): 467–483. doi:10.1017/S000273160004871X. ISSN 0002-7316. S2CID 160679096.
42. White, A. J.; Stevens, Lora R.; Lorenzi, Varenka; Munoz, Samuel E.; Schroeder, Sissel; Cao, Angelica; Bogdanovich, Taylor (19 March 2019). "Fecal stanols show simultaneous flooding and seasonal precipitation change correlate with Cahokia's population decline". Proceedings of the National Academy of Sciences of the United States of America. 116 (12): 5461–5466. Bibcode:2019PNAS..116.5461W. doi:10.1073/pnas.1809400116. ISSN 0027-8424. PMC 6431169. PMID 30804191.
43. Jones, Terry L.; Schwitalla, Al (2008). "Archaeological perspectives on the effects of medieval drought in prehistoric California". Quaternary International. 188 (1): 41–58. Bibcode:2008QuInt.188...41J. doi:10.1016/j.quaint.2007.07.007.
44. . Earth Observatory News. 2004-10-07. Archived from the original on 2006-10-04. Retrieved 2006-05-04.
45. Lécuyer, Christophe; Goedert, Jean; Klee, Johanne; Clauzel, Thibault; Richardin, Pascale; Fourel, François; Delgado-Darias, Teresa; Alberto-Barroso, Verónica; Velasco-Vázquez, Javier; Betancort, Juan Francisco; Amiot, Romain (2021-04-01). "Climatic change and diet of the pre-Hispanic population of Gran Canaria (Canary Archipelago, Spain) during the Medieval Warm Period and Little Ice Age". Journal of Archaeological Science. 128: 105336. Bibcode:2021JArSc.128j5336L. doi:10.1016/j.jas.2021.105336. ISSN 0305-4403. S2CID 233597524. Retrieved 18 June 2023.
46. Goosse, H.; Masson-Delmotte, V.; Renssen, H.; Delmotte, M.; Fichefet, T.; Morgan, V.; Van Ommen, T.; Khim, B. K.; Stenni, B. (17 March 2004). "A late medieval warm period in the Southern Ocean as a delayed response to external forcing?". Geophysical Research Letters. 31 (6): 1–5. Bibcode:2004GeoRL..31.6203G. doi:10.1029/2003GL019140. S2CID 17322719.
47. Khim, B.; Yoon, Ho Il; Kang, Cheon Yun; Bahk, Jang Jun (2002). "Unstable Climate Oscillations during the Late Holocene in the Eastern Bransfield Basin, Antarctic Peninsula". Quaternary Research. 58 (3): 234. Bibcode:2002QuRes..58..234K. doi:10.1006/qres.2002.2371. S2CID 129384061.
48. Lüning, Sebastian; Gałka, Mariusz; Vahrenholt, Fritz (15 October 2019). "The Medieval Climate Anomaly in Antarctica". Palaeogeography, Palaeoclimatology, Palaeoecology. 532: 109251. Bibcode:2019PPP...53209251L. doi:10.1016/j.palaeo.2019.109251. ISSN 0031-0182.
49. Cobb, Kim M.; Chris Charles; Hai Cheng; R. Lawrence Edwards (July 8, 2003). . The Climate of the Holocene (ICCI) 2003. Archived from the original on August 25, 2004. Retrieved 4 May 2006.
50. Rosenthal, Yair; Linsley, Braddock K.; Oppo, Delia W. (2013-11-01). "Pacific Ocean Heat Content During the Past 10,000 Years". Science. 342 (6158): 617–621. Bibcode:2013Sci...342..617R. doi:10.1126/science.1240837. ISSN 0036-8075. PMID 24179224. S2CID 140727975.
51. Fletcher, M-S.; Moreno, P.I. (16 July 2012). "Vegetation, climate and fire regime changes in the Andean region of southern Chile (38°S) covaried with centennial-scale climate anomalies in the tropical Pacific over the last 1500 years". Quaternary Science Reviews. 46: 46–56. Bibcode:2012QSRv...46...46F. doi:10.1016/j.quascirev.2012.04.016. hdl:10533/131338.
52. Ledru, M.-P.; Jomelli, V.; Samaniego, P.; Vuille, M.; Hidalgo, S.; Herrera, M.; Ceron, C. (2013). "The Medieval Climate Anomaly and the Little Ice Age in the eastern Ecuadorian Andes". Climate of the Past. 9 (1): 307–321. Bibcode:2013CliPa...9..307L. doi:10.5194/cp-9-307-2013.
53. Kellerhals, T.; Brütsch, S.; Sigl, M.; Knüsel, S.; Gäggeler, H. W.; Schwikowski, M. (2010). "Ammonium concentration in ice cores: A new proxy for regional temperature reconstruction?". Journal of Geophysical Research. 115 (D16): D16123. Bibcode:2010JGRD..11516123K. doi:10.1029/2009JD012603.
54. Ge, Q.-S.; Zheng, J.-Y.; Hao, Z.-X.; Shao, X.-M.; Wang, Wei-Chyung; Luterbacher, Juerg (2010). "Temperature variation through 2000 years in China: An uncertainty analysis of reconstruction and regional difference". Geophysical Research Letters. 37 (3): 03703. Bibcode:2010GeoRL..37.3703G. doi:10.1029/2009GL041281. S2CID 129457163. Retrieved 18 June 2023.
55. Hao, Zhixin; Wu, Maowei; Liu, Yang; Zhang, Xuezhen; Zheng, Jingyun (2020-01-01). "Multi-scale temperature variations and their regional differences in China during the Medieval Climate Anomaly". Journal of Geographical Sciences. 30 (1): 119–130. doi:10.1007/s11442-020-1718-7. ISSN 1861-9568. S2CID 209843427.
56. Zhou, XiuJi; Zhao, Ping; Liu, Ge; Zhou, TianJun (24 September 2011). "Characteristics of decadal-centennial-scale changes in East Asian summer monsoon circulation and precipitation during the Medieval Warm Period and Little Ice Age and in the present day". Chinese Science Bulletin. 56 (28–29). doi:10.1007/s11434-011-4651-4. ISSN 1001-6538.
57. Zhang, Zhenqiu; Liang, Yijia; Wang, Yongjin; Duan, Fucai; Yang, Zhou; Shao, Qingfeng; Liu, Shushuang (15 December 2021). "Evidence of ENSO signals in a stalagmite-based Asian monsoon record during the medieval warm period". Palaeogeography, Palaeoclimatology, Palaeoecology. 584: 110714. Bibcode:2021PPP...58410714Z. doi:10.1016/j.palaeo.2021.110714. S2CID 239270259. Retrieved 8 July 2023.
58. Liu, Xiaokang; Lu, Ruijie; Jia, Feifei; Chen, Lu; Li, Tengfei; Ma, Yuzhen; Wu, Yongqiu (5 March 2018). "Holocene water-level changes inferred from a section of fluvio-lacustrine sediments in the southeastern Mu Us Desert, China". Quaternary International. 469: 58–67. doi:10.1016/j.quaint.2016.12.032. Retrieved 23 September 2023.
59. Sun, Jia; Ma, Chunmei; Zhou, Bin; Jiang, Jiawei; Zhao, Cheng (2021). "Biogeochemical evidence for environmental and vegetation changes in peatlands from the middle Yangtze river catchment during the medieval warm period and little ice Age". The Holocene. 31 (10): 1571–1581. Bibcode:2021Holoc..31.1571S. doi:10.1177/09596836211025966. ISSN 0959-6836. S2CID 237010950.
60. Chu, Peter C.; Li, Hong-Chun; Fan, Chenwu; Chen, Yong-Heng (11 December 2012). "Speleothem evidence for temporal–spatial variation in the East Asian Summer Monsoon since the Medieval Warm Period". Journal of Quaternary Science. 27 (9): 901–910. doi:10.1002/jqs.2579. ISSN 0267-8179. S2CID 9727512. Retrieved 23 September 2023.
61. Kamae, Youichi; Kawana, Toshi; Oshiro, Megumi; Ueda, Hiroaki (4 August 2017). "Seasonal modulation of the Asian summer monsoon between the Medieval Warm Period and Little Ice Age: a multi model study". Progress in Earth and Planetary Science. 4 (1): 1–13. doi:10.1186/s40645-017-0136-7. ISSN 2197-4284.
62. Razjigaeva, Nadezhda G.; Ganzey, Larisa A.; Bazarova, Valentina B.; Arslanov, Khikmatulla A.; Grebennikova, Tatiana A.; Mokhova, Ludmila M.; Belyanina, Nina I.; Lyaschevskaya, Marina S. (10 June 2019). "Landscape response to the Medieval Warm Period in the South Russian Far East". Quaternary International. The 3rd ASQUA Conference (Part II). 519: 215–231. Bibcode:2019QuInt.519..215R. doi:10.1016/j.quaint.2018.12.006. ISSN 1040-6182. S2CID 134246491. Retrieved 18 June 2023.
63. Adhikari, D. P.; Kumon, F. (2001). "Climatic changes during the past 1300 years as deduced from the sediments of Lake Nakatsuna, central Japan". Limnology. 2 (3): 157. doi:10.1007/s10201-001-8031-7. S2CID 20937188.
64. Yamada, Kazuyoshi; Kamite, Masaki; Saito-Kato, Megumi; Okuno, Mitsuru; Shinozuka, Yoshitsugu; Yasuda, Yoshinori (June 2010). "Late Holocene monsoonal-climate change inferred from Lakes Ni-no-Megata and San-no-Megata, northeastern Japan". Quaternary International. 220 (1–2): 122–132. Bibcode:2010QuInt.220..122Y. doi:10.1016/j.quaint.2009.09.006. Retrieved 8 July 2023.
65. Naidu, Pothuri Divakar; Ganeshram, Raja; Bollasina, Massimo A.; Panmei, Champoungam; Nürnberg, Dirk; Donges, Jonathan F. (2020-01-28). "Coherent response of the Indian Monsoon Rainfall to Atlantic Multi-decadal Variability over the last 2000 years". Scientific Reports. 10 (1): 1302. Bibcode:2020NatSR..10.1302N. doi:10.1038/s41598-020-58265-3. ISSN 2045-2322. PMC 6987308. PMID 31992786.
66. Naidu, Pothuri Divakar; Ganeshram, Raja; Bollasina, Massimo A.; Panmei, Champoungam; Nürnberg, Dirk; Donges, Jonathan F. (28 January 2020). "Coherent response of the Indian Monsoon Rainfall to Atlantic Multi-decadal Variability over the last 2000 years". Scientific Reports. 10 (1): 1302. Bibcode:2020NatSR..10.1302N. doi:10.1038/s41598-020-58265-3. ISSN 2045-2322. PMC 6987308. PMID 31992786.
67. Rawat, Suman; Gupta, Anil K.; Sangode, S. J.; Srivastava, Priyeshu; Nainwal, H.C. (15 April 2015). "Late Pleistocene–Holocene vegetation and Indian summer monsoon record from the Lahaul, Northwest Himalaya, India". Quaternary Science Reviews. 114: 167–181. doi:10.1016/j.quascirev.2015.01.032. Retrieved 23 September 2023.
68. Quamar, M. F.; Chauhan, M. S. (19 March 2014). "Signals of Medieval Warm Period and Little Ice Age from southwestern Madhya Pradesh (India): A pollen-inferred Late-Holocene vegetation and climate change". Quaternary International. Holocene Palynology and Tropical Paleoecology. 325: 74–82. doi:10.1016/j.quaint.2013.07.011. ISSN 1040-6182. Retrieved 23 September 2023.
69. Veena, M.P.; Achyuthan, Hema; Eastoe, Christopher; Farooqui, Anjum (19 March 2014). "A multi-proxy reconstruction of monsoon variability in the late Holocene, South India". Quaternary International. 325: 63–73. doi:10.1016/j.quaint.2013.10.026. Retrieved 23 September 2023.
70. Gupta, Anil K.; Anderson, David M.; Overpeck, Jonathan T. (23 January 2003). "Abrupt changes in the Asian southwest monsoon during the Holocene and their links to the North Atlantic Ocean". Nature. 421 (6921): 354–357. doi:10.1038/nature01340. ISSN 1476-4687. S2CID 4304234.
71. Agnihotri, Rajesh; Dutta, Koushik; Bhushan, Ravi; Somayajulu, B. L. K (15 May 2002). "Evidence for solar forcing on the Indian monsoon during the last millennium". Earth and Planetary Science Letters. 198 (3): 521–527. doi:10.1016/S0012-821X(02)00530-7. ISSN 0012-821X. Retrieved 30 September 2023.
72. Kalman, Akos; Katz, Timor; Hill, Paul; Goodman-Tchernov, Beverly (21 March 2020). "Droughts in the desert: Medieval Warm Period associated with coarse sediment layers in the Gulf of Aqaba-Eilat, Red Sea". Sedimentology. 67 (6): 3152–3166. doi:10.1111/sed.12737. S2CID 216335544. Retrieved 18 June 2023.
73. Allen, Robert J. (1985). The Australasian Summer Monsoon, Teleconnections, and Flooding in the Lake Eyre Basin. Royal Geographical Society of Australasia, S.A. Branch. ISBN 978-0-909112-09-7.^{[page needed]}
74. Wilson, A. T.; Hendy, C. H.; Reynolds, C. P. (1979). "Short-term climate change and New Zealand temperatures during the last millennium". Nature. 279 (5711): 315. Bibcode:1979Natur.279..315W. doi:10.1038/279315a0. S2CID 4302802.
75. Cook, Edward R.; Palmer, Jonathan G.; d'Arrigo, Rosanne D. (2002). "Evidence for a 'Medieval Warm Period' in a 1,100 year tree-ring reconstruction of past austral summer temperatures in New Zealand". Geophysical Research Letters. 29 (14): 12. Bibcode:2002GeoRL..29.1667C. doi:10.1029/2001GL014580. S2CID 34033855.

Further reading

• Fagan, Brian (2000). The Little Ice Age: How Climate Made History, 1300–1850. Basic Books. ISBN 978-0-465-02272-4.
• Fagan, Brian (2009). The Great Warming: Climate Change and the Rise and Fall of Civilizations. Bloomsbury Publishing. ISBN 9781596913929.
• Lamb, Hubert (1995). Climate, History, and the Modern World: Second Edition. Routledge.
• Staff members at NOAA Paleoclimatology (19 May 2000). The "Medieval Warm Period". A Paleo Perspective...on Global Warming. NOAA Paleoclimatology. {{cite book}}: External link in |author= (help)

External links

 

Wikimedia Commons has media related to Medieval Warm Period.

• HistoricalClimatology.com, further links, resources, and relevant news, updated 2016
• Climate History Network
• at the American Geophysical Union