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136-718: The Grindelwald Fluctuation occurred during the Little Ice Age , a period of cooling that occurred from the 13th to the mid 19th century; characterised by the expansion of glaciers in many parts of the world, including the Alps in Europe. It produced some of the lowest temperatures known to this holocene . The expansion of the Swiss Grindelwald glaciers during this period was likely due to a combination of factors, including volcanic activity, changes in solar radiation, and

272-454: A proglacial lake above the valley created by an ice dam as a result of the 1815 eruption of Mount Tambora , which threatened to cause a catastrophic flood when the dam broke. Perraudin attempted unsuccessfully to convert his companions to his theory, but when the dam finally broke, there were only minor erratics and no striations, and Venetz concluded that Perraudin was right and that only ice could have caused such major results. In 1821 he read

408-548: A Jacobean weather enthusiast in Bristol, chronicle some of the effects the weather Fluctuation had on agriculture and society. They specifically discuss food shortages and crop failures taking precedence throughout the area. Little Ice Age The Little Ice Age ( LIA ) was a period of regional cooling, particularly pronounced in the North Atlantic region. It was not a true ice age of global extent. The term

544-643: A climate reconstruction based on glacial length shows no great variation from 1600 to 1850 but a strong retreat thereafter. Therefore, any of several dates ranging over 400 years may indicate the beginning of the Little Ice Age: The Little Ice Age ended in the latter half of the 19th century or in the early 20th century. The 6th report of the IPCC describes the coldest period in the last millennium as: "...a multi-centennial period of relatively low temperature beginning around

680-623: A contributing factor to the Grindelwald Fluctuation. This shift in solar activity can be proved by: Overall, the evidence suggests that the amount of solar radiation reaching the Earth's surface was slightly lower during the Grindelwald Fluctuation, and this reduction in solar radiation is thought to have contributed to the expansion of the glaciers. Human activities such as deforestation and land use changes are known to negatively affect local climate patterns. William Ruddiman ,

816-526: A fertilizer that causes massive algal blooms that pulls large amounts of CO 2 out of the atmosphere. This in turn makes it even colder and causes the glaciers to grow more. In 1956, Ewing and Donn hypothesized that an ice-free Arctic Ocean leads to increased snowfall at high latitudes. When low-temperature ice covers the Arctic Ocean there is little evaporation or sublimation and the polar regions are quite dry in terms of precipitation, comparable to

952-570: A geologist and professor of forestry at an academy in Dreissigacker (since incorporated in the southern Thuringian city of Meiningen ), adopted Esmark's theory. In a paper published in 1832, Bernhardi speculated about the polar ice caps once reaching as far as the temperate zones of the globe. In Val de Bagnes , a valley in the Swiss Alps , there was a long-held local belief that the valley had once been covered deep in ice, and in 1815

1088-475: A grain-based diet. After Greenland 's climate became colder and stormier around 1250, the diet of the Norse Viking settlements there steadily shifted away from agricultural 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

1224-408: A local chamois hunter called Jean-Pierre Perraudin attempted to convert the geologist Jean de Charpentier to the idea, pointing to deep striations in the rocks and giant erratic boulders as evidence. Charpentier held the general view that these signs were caused by vast floods, and he rejected Perraudin's theory as absurd. In 1818 the engineer Ignatz Venetz joined Perraudin and Charpentier to examine

1360-416: A molten globe. In order to persuade the skeptics, Agassiz embarked on geological fieldwork. He published his book Study on Glaciers ("Études sur les glaciers") in 1840. Charpentier was put out by this, as he had also been preparing a book about the glaciation of the Alps. Charpentier felt that Agassiz should have given him precedence as it was he who had introduced Agassiz to in-depth glacial research. As

1496-550: A nonrotatory piston corer. The samples also showed volcanic activity which caused forest regeneration between 650 and 800. The instances of volcanic activity near Lake Pompal indicate varying temperatures, not a continuous coldness, during the Little Ice Age in Mesoamerica. In the North Atlantic, sediments accumulated since the end of the last ice age , which occurred nearly 12,000 years ago, show regular increases in

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1632-410: A palaeoclimatologist, proposed the hypothesis that human activity has been affecting the Earth's climate for much longer than previously thought. In particular, Ruddiman has argued that the early adoption of agriculture and land-use practices by human societies, beginning around 8,000 years ago, led to the release of significant amounts of greenhouse gases into the atmosphere, which may have contributed to

1768-544: A prize-winning paper on the theory to the Swiss Society, but it was not published until Charpentier, who had also become converted, published it with his own more widely read paper in 1834. In the meantime, the German botanist Karl Friedrich Schimper (1803–1867) was studying mosses which were growing on erratic boulders in the alpine upland of Bavaria. He began to wonder where such masses of stone had come from. During

1904-712: A regional phenomenon. Only a few years later, the Danish-Norwegian geologist Jens Esmark (1762–1839) argued for a sequence of worldwide ice ages. In a paper published in 1824, Esmark proposed changes in climate as the cause of those glaciations. He attempted to show that they originated from changes in Earth's orbit. Esmark discovered the similarity between moraines near Haukalivatnet lake near sea level in Rogaland and moraines at branches of Jostedalsbreen . Esmark's discovery were later attributed to or appropriated by Theodor Kjerulf and Louis Agassiz . During

2040-499: A result of personal quarrels, Agassiz had also omitted any mention of Schimper in his book. It took several decades before the ice age theory was fully accepted by scientists. This happened on an international scale in the second half of the 1870s, following the work of James Croll , including the publication of Climate and Time, in Their Geological Relations in 1875, which provided a credible explanation for

2176-411: A significant causal factor of the 40 million year Cenozoic Cooling trend. They further claim that approximately half of their uplift (and CO 2 "scrubbing" capacity) occurred in the past 10 million years. There is evidence that greenhouse gas levels fell at the start of ice ages and rose during the retreat of the ice sheets, but it is difficult to establish cause and effect (see the notes above on

2312-430: A tamperature nadir around 135 BP, and in south-central Alaska, mountain hemlock forests severely declined. In Glacier National Park , the last episode of glacier advance came in the late 18th and the early 19th centuries. In 1879, the famed naturalist John Muir found that Glacier Bay ice had retreated 48 miles (77 km). In Chesapeake Bay , Maryland , large temperature excursions were possibly related to changes in

2448-667: A war of succession to the Bohemian throne. Animosity between Protestants and Catholics in the Holy Roman Empire (now Germany) added fuel to the fire. It soon escalated to a huge conflict that involved all the major European powers and devastated much of Germany. When the war ended, some regions of the Holy Roman Empire had seen their population drop by as much as 70%. Early European explorers and settlers of North America reported exceptionally severe winters. In southwestern Alaska, preexisting flexibility in foraging habits among

2584-700: Is a hiatus between 1627 and 1640, which is before the main period of such subjects from the 1640s to the 1660s. That relates well with climate records for the later period. The subjects are less popular after about 1660, but that does not match any recorded reduction in severity of winters and may reflect only changes in taste or fashion. In the later period between the 1780s and 1810s, snowy subjects again became popular. Neuberger analyzed 12,000 paintings, held in American and European museums and dated between 1400 and 1967, for cloudiness and darkness. His 1970 publication shows an increase in such depictions that corresponds to

2720-524: Is also believed that an onset of disease during the Little Ice Age may have led to further depopulation. The massacre and death of indigenous populations in the Americas following the Spanish conquests, may have been a major contributor as agricultural land fell out of use and reforested. This decline in population meant that cultivated lands became unkempt, allowing for the regrowth of wild plants. This

2856-462: Is believed to be linked to a multidecennial phase of droughts in the western Mediterranean. In southwestern Europe, a negative North Atlantic oscillation (NAO) combined with increased aridity caused an increase in wind-driven sediment deposition during the LIA. In his 1995 book, the early climatologist Hubert Lamb said that in many years, "snowfall was much heavier than recorded before or since, and

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2992-578: Is estimated to potentially outweigh the orbital forcing of the Milankovitch cycles for hundreds of thousands of years. Each glacial period is subject to positive feedback which makes it more severe, and negative feedback which mitigates and (in all cases so far) eventually ends it. An important form of feedback is provided by Earth's albedo , which is how much of the sun's energy is reflected rather than absorbed by Earth. Ice and snow increase Earth's albedo, while forests reduce its albedo. When

3128-773: Is no consensus on when the Little Ice Age began, but a series of events before the known climatic minima have often been referenced. In the 13th century, pack ice began advancing southwards in the North Atlantic, as did glaciers in Greenland . Anecdotal evidence suggests expanding glaciers almost worldwide. Based on radiocarbon dating of roughly 150 samples of dead plant material with roots intact that were collected from beneath ice caps on Baffin Island and Iceland , Miller et al. (2012) state that cold summers and ice growth began abruptly between 1275 and 1300, followed by "a substantial intensification" from 1430 to 1455. In contrast,

3264-412: Is perceived to be the cause for the drop in atmospheric carbon dioxide in the sixteenth century thus exacerbating the extreme cooling period. However, of the causes, depopulation is the least significant. In historical records, the Grindelwald Fluctuation is characterised by a further drop in temperatures and more frequent cold spells throughout many parts of the world. The more notable records; written by

3400-597: Is that several factors are important: atmospheric composition , such as the concentrations of carbon dioxide and methane (the specific levels of the previously mentioned gases are now able to be seen with the new ice core samples from the European Project for Ice Coring in Antarctica (EPICA) Dome C in Antarctica over the past 800,000 years); changes in Earth's orbit around the Sun known as Milankovitch cycles ;

3536-516: Is the increased aridity occurring with glacial maxima, which reduces the precipitation available to maintain glaciation. The glacial retreat induced by this or any other process can be amplified by similar inverse positive feedbacks as for glacial advances. According to research published in Nature Geoscience , human emissions of carbon dioxide (CO 2 ) will defer the next glacial period. Researchers used data on Earth's orbit to find

3672-636: The Labours of the Months , typically placed on the calendar pages of books of hours . January and February are typically shown as snowy, as in February in the famous cycle in the Très Riches Heures du Duc de Berry , painted in 1412–1416 and illustrated below. Since landscape painting had not yet developed as an independent genre in art, the absence of other winter scenes is not remarkable. On

3808-655: The Carboniferous and early Permian periods. Correlatives are known from Argentina, also in the center of the ancient supercontinent Gondwanaland . Although the Mesozoic Era retained a greenhouse climate over its timespan and was previously assumed to have been entirely glaciation-free, more recent studies suggest that brief periods of glaciation occurred in both hemispheres during the Early Cretaceous . Geologic and palaeoclimatological records suggest

3944-683: The Himalayas are a major factor in the current ice age, because these mountains have increased Earth's total rainfall and therefore the rate at which carbon dioxide is washed out of the atmosphere, decreasing the greenhouse effect. The Himalayas' formation started about 70 million years ago when the Indo-Australian Plate collided with the Eurasian Plate , and the Himalayas are still rising by about 5 mm per year because

4080-765: The Late Ordovician and the Silurian period. The evolution of land plants at the onset of the Devonian period caused a long term increase in planetary oxygen levels and reduction of CO 2 levels, which resulted in the late Paleozoic icehouse . Its former name, the Karoo glaciation, was named after the glacial tills found in the Karoo region of South Africa. There were extensive polar ice caps at intervals from 360 to 260 million years ago in South Africa during

4216-528: The Maunder Minimum ; the most recent Grand Solar Minimum. This minimum lasted from 1645 to 1715 coinciding with the Grindelwald Fluctuation, therefore it is thought to have contributed to the expansion of glaciers, however it is not clear to what extent the changes in solar radiation affected the expansion of the Grindelwald glaciers. It is however possible that these changes in solar radiation were

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4352-482: The Pleistocene Ice Age. Because this highland is at a subtropical latitude, with four to five times the insolation of high-latitude areas, what would be Earth's strongest heating surface has turned into a cooling surface. Kuhle explains the interglacial periods by the 100,000-year cycle of radiation changes due to variations in Earth's orbit. This comparatively insignificant warming, when combined with

4488-522: The Swiss Alps were destroyed by encroaching glaciers during the mid-17th century. Canals and rivers in Great Britain and the Netherlands were frequently frozen deeply enough to support ice skating and winter festivals. As trade needed to continue during the prolonged winter often spanning 5 months, merchants equipped their boer style boats with planks and skates (runners), hence the iceboat

4624-715: The Turonian , otherwise the warmest period of the Phanerozoic, are disputed), ice sheets and associated sea ice appear to have briefly returned to Antarctica near the very end of the Maastrichtian just prior to the Cretaceous-Paleogene extinction event . The Quaternary Glaciation / Quaternary Ice Age started about 2.58 million years ago at the beginning of the Quaternary Period when

4760-546: The 15th century, with GMST averaging –0.03 [–0.30 to 0.06] °C between 1450 and 1850 relative to 1850–1900." Drangajökull , Iceland's northernmost glacier, reached its maximum extent during the LIA around 1400 CE. The Baltic Sea froze over twice, in 1303 and 1306–1307, and years followed of "unseasonable cold, storms and rains, and a rise in the level of the Caspian Sea." The Little Ice Age brought colder winters to parts of Europe and North America. Farms and villages in

4896-618: The Atlantic, increasing heat transport into the Arctic, which melted the polar ice accumulation and reduced other continental ice sheets. The release of water raised sea levels again, restoring the ingress of colder water from the Pacific with an accompanying shift to northern hemisphere ice accumulation. According to a study published in Nature in 2021, all glacial periods of ice ages over

5032-552: The Azores reflect the cooling of the LIA. Although the original designation of a Little Ice Age referred to the reduced temperature of Europe and North America, there is some evidence of extended periods of cooling outside those regions although it is not clear whether they are related or independent events. Mann states: While there is evidence that many other regions outside Europe exhibited periods of cooler conditions, expanded glaciation, and significantly altered climate conditions,

5168-818: The Bernese Oberland advocated a similar idea in a discussion with the Swiss-German geologist Jean de Charpentier (1786–1855) in 1834. Comparable explanations are also known from the Val de Ferret in the Valais and the Seeland in western Switzerland and in Goethe 's scientific work . Such explanations could also be found in other parts of the world. When the Bavarian naturalist Ernst von Bibra (1806–1878) visited

5304-463: The Chilean Andes in 1849–1850, the natives attributed fossil moraines to the former action of glaciers. Meanwhile, European scholars had begun to wonder what had caused the dispersal of erratic material. From the middle of the 18th century, some discussed ice as a means of transport. The Swedish mining expert Daniel Tilas (1712–1772) was, in 1742, the first person to suggest drifting sea ice

5440-432: The Earth's climate system. However it is believed that the Grindelwald Fluctuation began some 15 years prior to the first volcanic eruption. Solar radiation is a major driver of the Earth's climate. Changes in solar radiation can affect the temperature and precipitation patterns on Earth. During the Little Ice Age, the amount of solar radiation reaching the Earth's surface was lower than it is today due to an event known as

5576-741: The Elder painted Hunters in the Snow in Antwerp, so the mountains in the picture probably mean it was based on drawings or memories from crossing of the Alps during his trip to Rome in 1551–1552. It is one of 5 known surviving paintings, probably from a series of 6 or 12, known as “the Twelve Months”, that Breugel was commissioned to paint by a wealthy patron in Antwerp , Nicolaes Jonghelinck ( Hunters in

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5712-629: The French invasion army under Pichegru marched on the frozen rivers of the Netherlands, and the Dutch fleet was locked in the ice in Den Helder harbour. Sea ice surrounding Iceland extended for miles in every direction and closed harbors to shipping. The population of Iceland fell by half, but that may have been caused by skeletal fluorosis after the eruption of Laki in 1783. Iceland also suffered failures of cereal crops and people moved away from

5848-467: The Indo-Australian plate is still moving at 67 mm/year. The history of the Himalayas broadly fits the long-term decrease in Earth's average temperature since the mid-Eocene , 40 million years ago. Another important contribution to ancient climate regimes is the variation of ocean currents, which are modified by continent position, sea levels and salinity, as well as other factors. They have

5984-594: The Little Ice Age, which peaks between 1600 and 1649. Paintings and contemporary records in Scotland demonstrate that curling , ice skating and icesailing were popular outdoor winter sports, with curling dating to the 16th century and becoming widely popular in the mid-19th century. An outdoor curling pond constructed in Gourock in the 1860s remained in use for almost a century, but increasing use of indoor facilities, problems of vandalism, and milder winters led to

6120-603: The Little Ice Age, the East Asian Summer Monsoon (EASM) became much weaker and the summer monsoon limit (SML) migrated southeastwards. Southwestern China became significantly colder and drier as a result of the weakening of the EASM caused by the decreased pressure gradient resulting from the cooling of the southern Eurasian landmass, while northwestern China, dominated by westerlies, saw an increase in precipitation. The temperature changes were unprecedented for

6256-496: The Little Ice Age. In particular, the Little Ice Age transformed environments around the Dutch Republic and made them easier to exploit in commerce and conflict. The Dutch were resilient, even adaptive, in the face of weather that devastated neighboring countries. Merchants exploited harvest failures, military commanders took advantage of shifting wind patterns, and inventors developed technologies that helped them profit from

6392-425: The Little Ice Age. The colder climate may have caused the wood that was used in his violins to be denser than in warmer periods and to contribute to the tone of his instruments. According to the science historian James Burke , the period inspired such novelties in everyday life as the widespread use of buttons and button-holes, as well as knitting of custom-made undergarments for the better covering and insulating of

6528-667: The Little Ice Age: livestock epidemics, cows that gave too little milk, late frosts, and unknown diseases. In general, the number of witchcraft trials rose as the temperature dropped, and trials decreased when temperature increased. The peaks of witchcraft persecutions overlap with the hunger crises that occurred in 1570 and 1580, the latter lasting a decade. The trials targeted primarily poor women, many of them widows. Not everybody agreed that witches should be persecuted for weather-making, but such arguments focused primarily not upon whether witches existed but upon whether witches had

6664-544: The Medieval Warm Period: ...when viewed together, the currently available reconstructions indicate generally greater variability in centennial time scale trends over the last 1 kyr than was apparent in the TAR.... The result is a picture of relatively cool conditions in the seventeenth and early nineteenth centuries and warmth in the eleventh and early fifteenth centuries, but the warmest conditions are apparent in

6800-453: The Ming dynasty's military, such as during the 1618 Battle of Fushun . Ice age An ice age is a long period of reduction in the temperature of Earth 's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers . Earth's climate alternates between ice ages, and greenhouse periods during which there are no glaciers on

6936-489: The Ming dynasty. This period of Little Ice Age corresponded to the period's major historical events. The Jurchen people lived in Northern China and formed a tributary state to the Ming dynasty and its Wanli Emperor . From 1573 to 1620, Manchuria experienced famine caused by extreme snowfall, which depleted agriculture production and devastated the livestock population. Scholars have argued that it had been caused by

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7072-579: The North Atlantic Ocean far enough to block the Gulf Stream. Ice sheets that form during glaciations erode the land beneath them. This can reduce the land area above sea level and thus diminish the amount of space on which ice sheets can form. This mitigates the albedo feedback, as does the rise in sea level that accompanies the reduced area of ice sheets, since open ocean has a lower albedo than land. Another negative feedback mechanism

7208-539: The North Atlantic during a warming cycle may also reduce the global ocean water circulation . Such a reduction (by reducing the effects of the Gulf Stream ) would have a cooling effect on northern Europe, which in turn would lead to increased low-latitude snow retention during the summer. It has also been suggested that during an extensive glacial, glaciers may move through the Gulf of Saint Lawrence , extending into

7344-589: The Snow and the Massacre of the Innocents , are thought to have been painted around 1565. His son Pieter Brueghel the Younger (1564–1638) also painted many snowy landscapes, but according to Burroughs, he "slavishly copied his father's designs. The derivative nature of so much of this work makes it difficult to draw any definite conclusions about the influence of the winters between 1570 and 1600...". Bruegel

7480-477: The Snow being for January): none of the other four that survive show a snow-covered landscape and both The Hay Harvest (July) and The Harvesters (August) depict warm summer days. Even The Return of the Herd (thought to be the painting for November) and The Gloomy Day (known to be for February) show landscapes free of snow. Burroughs says that snowy subjects return to Dutch Golden Age painting with works by Hendrick Avercamp from 1609 onwards. There

7616-485: The Swiss Alps with his former university friend Louis Agassiz (1801–1873) and Jean de Charpentier. Schimper, Charpentier and possibly Venetz convinced Agassiz that there had been a time of glaciation. During the winter of 1836–37, Agassiz and Schimper developed the theory of a sequence of glaciations. They mainly drew upon the preceding works of Venetz, Charpentier and on their own fieldwork. Agassiz appears to have been already familiar with Bernhardi's paper at that time. At

7752-410: The U.S. National Oceanic and Atmospheric Administration , the eastern monsoon area of China was the earliest to experience the effects of the Little Ice Age, from 1560 to 1709. In the western region of China surrounding the Tibetan Plateau , the effects of the Little Ice Age lagged behind the eastern region, with significant cold periods from 1620 to 1749. As the Medieval Warm Period transitioned into

7888-525: The University of Arkansas discovered that many colonists arrived at the beginning of a seven-year drought. The droughts also decreased the Native American populations and led to conflict because of food scarcity. English colonists at Roanoke forced Native Americans of Ossomocomuck to share their depleted supplies with them. That led to warfare between the two groups, and Native American towns were destroyed. That cycle would repeat itself many times at Jamestown. The combination of fighting and cold weather also led to

8024-504: The ability to cool (e.g. aiding the creation of Antarctic ice) and the ability to warm (e.g. giving the British Isles a temperate as opposed to a boreal climate). The closing of the Isthmus of Panama about 3 million years ago may have ushered in the present period of strong glaciation over North America by ending the exchange of water between the tropical Atlantic and Pacific Oceans. Analyses suggest that ocean current fluctuations can adequately account for recent glacial oscillations. During

8160-402: The air temperature decreases, ice and snow fields grow, and they reduce forest cover. This continues until competition with a negative feedback mechanism forces the system to an equilibrium. One theory is that when glaciers form, two things happen: the ice grinds rocks into dust, and the land becomes dry and arid. This allows winds to transport iron rich dust into the open ocean, where it acts as

8296-424: The amount found in mid-latitude deserts . This low precipitation allows high-latitude snowfalls to melt during the summer. An ice-free Arctic Ocean absorbs solar radiation during the long summer days, and evaporates more water into the Arctic atmosphere. With higher precipitation, portions of this snow may not melt during the summer and so glacial ice can form at lower altitudes and more southerly latitudes, reducing

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8432-435: The amount of coarse sediment grains deposited from icebergs melting in the now-open ocean, indicating a series of 1–2 °C (2–4 °F) cooling events that recur every 1,500 years or so. The most recent cooling event was the Little Ice Age. The same cooling events are detected in sediments accumulating off Africa, but the cooling events appear to be larger: 3–8 °C (6–14 °F). δ O values from chironomid remains in

8568-553: The bay was still littered with so much floating ice that he could hide behind it in his canoe on 1 July. In the winter of 1780, New York Harbor froze, which allowed people to walk from Manhattan Island to Staten Island . The extent of mountain glaciers had been mapped by the late 19th century. In the north and the south temperate zones, Equilibrium Line Altitude (the boundaries separating zones of net accumulation from those of net ablation) were about 100 metres (330 ft) lower than they were in 1975. Southwestern Alaska experienced

8704-474: The beginning of 1837, Schimper coined the term "ice age" ( "Eiszeit" ) for the period of the glaciers. In July 1837 Agassiz presented their synthesis before the annual meeting of the Swiss Society for Natural Research at Neuchâtel. The audience was very critical, and some were opposed to the new theory because it contradicted the established opinions on climatic history. Most contemporary scientists thought that Earth had been gradually cooling down since its birth as

8840-469: The body. Chimneys were invented to replace open fires in the centre of communal halls to allow houses with multiple rooms to have the separation of masters from servants. The Little Ice Age , by the anthropologist Brian Fagan of the University of California at Santa Barbara , describes the plight of European peasants from 1300 to 1850: famines, hypothermia , bread riots and the rise of despotic leaders brutalizing an increasingly dispirited peasantry. In

8976-458: The capability to control the weather. The Catholic Church in the Early Middle Ages argued that witches could not control the weather because they were mortals, not God, but by the mid-13th century, most people agreed with the idea that witches could control natural forces. Jewish populations were also blamed for climatic deterioration during the Little Ice Age. The Western European states experienced waves of anti-Semitism , directed against

9112-495: The causes of ice ages. There are three main types of evidence for ice ages: geological, chemical, and paleontological. Geological evidence for ice ages comes in various forms, including rock scouring and scratching, glacial moraines , drumlins , valley cutting, and the deposition of till or tillites and glacial erratics . Successive glaciations tend to distort and erase the geological evidence for earlier glaciations, making it difficult to interpret. Furthermore, this evidence

9248-496: The cold. The 17th-century Dutch Golden Age therefore owed much to its people's flexibility in coping with the changing climate. Historians have argued that cultural responses to the consequences of the Little Ice Age in Europe consisted of violent scapegoating . The prolonged cold, dry periods brought drought upon many European communities and resulted in poor crop growth, poor livestock survival, and increased activity of pathogens and disease vectors. Disease intensified under

9384-488: The coldest and driest periods in northern and central China (1660–1680, 1850–1880). Scholars have argued that one of the reasons for the fall of the Ming dynasty may have been the droughts and famines that were caused by the Little Ice Age. There are debates on the start date and the periods of Little Ice Age's effects. Most scholars agree on categorizing the Little Ice Age period into three distinct cold periods: in 1458–1552, 1600–1720, and 1840–1880. According to data from

9520-409: The concentrations of greenhouse gases) may alter the climate, while climate change itself can change the atmospheric composition (for example by changing the rate at which weathering removes CO 2 ). Maureen Raymo , William Ruddiman and others propose that the Tibetan and Colorado Plateaus are immense CO 2 "scrubbers" with a capacity to remove enough CO 2 from the global atmosphere to be

9656-491: The continental ice sheets are the Greenland and Antarctic ice sheets and smaller glaciers such as on Baffin Island . The definition of the Quaternary as beginning 2.58 Ma is based on the formation of the Arctic ice cap . The Antarctic ice sheet began to form earlier, at about 34 Ma, in the mid- Cenozoic ( Eocene-Oligocene Boundary ). The term Late Cenozoic Ice Age is used to include this early phase. Ice ages can be further divided by location and time; for example,

9792-405: The continents and pack ice on the oceans would inhibit both silicate weathering and photosynthesis , which are the two major sinks for CO 2 at present." It has been suggested that the end of this ice age was responsible for the subsequent Ediacaran and Cambrian explosion , though this model is recent and controversial. The Andean-Saharan occurred from 460 to 420 million years ago, during

9928-431: The continents are in positions which block or reduce the flow of warm water from the equator to the poles and thus allow ice sheets to form. The ice sheets increase Earth's reflectivity and thus reduce the absorption of solar radiation. With less radiation absorbed the atmosphere cools; the cooling allows the ice sheets to grow, which further increases reflectivity in a positive feedback loop. The ice age continues until

10064-579: The conventional terms of "Little Ice Age" and " Medieval Warm Period " appear to have limited utility in describing trends in hemispheric or global mean temperature changes in past centuries.... [Viewed] hemispherically, the "Little Ice Age" can only be considered as a modest cooling of the Northern Hemisphere during this period of less than 1°C relative to late twentieth century levels. The IPCC Fourth Assessment Report (AR4) of 2007 discusses more recent research and gives particular attention to

10200-624: The cooling effects can last anywhere from a few years to a few decades. In 1585, the Colima volcano in Mexico erupted. 10 years later in 1595, Nevado del Ruiz erupted. Then in 1600, five years later, the Huaynaputina volcano erupted in what is known as one of the most powerful explosions to occur in the last 2500 years. These back to back major volcanic explosions can cause long-term cooling by activating “positive feedback” in different parts of

10336-540: The current glaciation, more temperate and more severe periods have occurred. The colder periods are called glacial periods , the warmer periods interglacials , such as the Eemian Stage . There is evidence that similar glacial cycles occurred in previous glaciations, including the Andean-Saharan and the late Paleozoic ice house. The glacial cycles of the late Paleozoic ice house are likely responsible for

10472-617: The deposition of cyclothems . Glacials are characterized by cooler and drier climates over most of Earth and large land and sea ice masses extending outward from the poles. Mountain glaciers in otherwise unglaciated areas extend to lower elevations due to a lower snow line . Sea levels drop due to the removal of large volumes of water above sea level in the icecaps. There is evidence that ocean circulation patterns are disrupted by glaciations. The glacials and interglacials coincide with changes in orbital forcing of climate due to Milankovitch cycles , which are periodic changes in Earth's orbit and

10608-622: The early Proterozoic Eon. Several hundreds of kilometers of the Huronian Supergroup are exposed 10 to 100 kilometers (6 to 62 mi) north of the north shore of Lake Huron, extending from near Sault Ste. Marie to Sudbury, northeast of Lake Huron, with giant layers of now-lithified till beds, dropstones , varves , outwash , and scoured basement rocks. Correlative Huronian deposits have been found near Marquette, Michigan , and correlation has been made with Paleoproterozoic glacial deposits from Western Australia. The Huronian ice age

10744-728: The existence of glacial periods during the Valanginian , Hauterivian , and Aptian stages of the Early Cretaceous. Ice-rafted glacial dropstones indicate that in the Northern Hemisphere , ice sheets may have extended as far south as the Iberian Peninsula during the Hauterivian and Aptian. Although ice sheets largely disappeared from Earth for the rest of the period (potential reports from

10880-651: The extreme weather. The colonist Ferdinando Gorges blamed the cold weather on cold ocean winds. Humphrey Gilbert tried to explain Newfoundland's icy and foggy weather by saying that the Earth drew cold vapors from the ocean and drew them west. Many others had their own theories for North America being so much colder than Europe; their observations and hypotheses offer insight on the Little Ice Age's effects in North America. An analysis of several climate proxies undertaken in Mexico's Yucatán Peninsula , which

11016-478: The famine, disease, and social unrest that they were experiencing, and they blamed the innocent. Evidence from several studies indicate that increases in violent actions against marginalized groups, which were held responsible for the Little Ice Age, overlap with the years of particularly cold, dry weather. One example of the violent scapegoating occurring during the Little Ice Age was the resurgence of witchcraft trials . Oster (2004) and Behringer (1999) argue that

11152-507: The farming communities in China. According to Coching Chu 's 1972 study, the Little Ice Age from the end of the Ming dynasty to the start of the Qing dynasty (1650–1700) was one of the coldest periods in recorded Chinese history. Many major droughts during the summer months were recorded, and significant freezing events occurred during the winter months. That greatly worsened the food supply during

11288-618: 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. Greenland was largely cut off by ice from 1410 to the 1720s. Between 1620 and 1740, the Yzeron Basin in the Massif Central of France witnessed a phase of decreased fluvial activity. This decline in fluvial activity

11424-509: The following years, Esmark's ideas were discussed and taken over in parts by Swedish, Scottish and German scientists. At the University of Edinburgh Robert Jameson (1774–1854) seemed to be relatively open to Esmark's ideas, as reviewed by Norwegian professor of glaciology Bjørn G. Andersen (1992). Jameson's remarks about ancient glaciers in Scotland were most probably prompted by Esmark. In Germany, Albrecht Reinhard Bernhardi (1797–1849),

11560-417: The geographical distribution of fossils. During a glacial period, cold-adapted organisms spread into lower latitudes, and organisms that prefer warmer conditions become extinct or retreat into lower latitudes. This evidence is also difficult to interpret because it requires: Despite the difficulties, analysis of ice core and ocean sediment cores has provided a credible record of glacials and interglacials over

11696-434: The historical warm interglacial period that looks most like the current one and from this have predicted that the next glacial period would usually begin within 1,500 years. They go on to predict that emissions have been so high that it will not. The causes of ice ages are not fully understood for either the large-scale ice age periods or the smaller ebb and flow of glacial–interglacial periods within an ice age. The consensus

11832-474: The human population (such as from the massacres by Genghis Khan , the Black Death and the epidemics emerging in the Americas upon European contact ). The Intergovernmental Panel on Climate Change Third Assessment Report (TAR) of 2001 described the areas that were affected: Evidence from mountain glaciers does suggest increased glaciation in a number of widely spread regions outside Europe prior to

11968-521: The inhabitants of that valley attributed the dispersal of erratic boulders to the glaciers, saying that they had once extended much farther. Later similar explanations were reported from other regions of the Alps. In 1815 the carpenter and chamois hunter Jean-Pierre Perraudin (1767–1858) explained erratic boulders in the Val de Bagnes in the Swiss canton of Valais as being due to glaciers previously extending further. An unknown woodcutter from Meiringen in

12104-503: The last 1.5 million years were associated with northward shifts of melting Antarctic icebergs which changed ocean circulation patterns, leading to more CO 2 being pulled out of the atmosphere . The authors suggest that this process may be disrupted in the future as the Southern Ocean will become too warm for the icebergs to travel far enough to trigger these changes. Matthias Kuhle 's geological theory of Ice Age development

12240-484: The last glacial period the sea-level fluctuated 20–30 m as water was sequestered, primarily in the Northern Hemisphere ice sheets. When ice collected and the sea level dropped sufficiently, flow through the Bering Strait (the narrow strait between Siberia and Alaska is about 50 m deep today) was reduced, resulting in increased flow from the North Atlantic. This realigned the thermohaline circulation in

12376-472: The late 17th century, agriculture had dropped off dramatically: "Alpine villagers lived on bread made from ground nutshells mixed with barley and oat flour." Historian Wolfgang Behringer has linked intensive witch-hunting episodes in Europe to agricultural failures during the Little Ice Age. The Frigid Golden Age , by the environmental historian Dagomar Degroot of Georgetown University , points out that some societies thrived, but others faltered during

12512-512: The latest Quaternary Ice Age ). Outside these ages, Earth was previously thought to have been ice-free even in high latitudes; such periods are known as greenhouse periods . However, other studies dispute this, finding evidence of occasional glaciations at high latitudes even during apparent greenhouse periods. Rocks from the earliest well-established ice age, called the Huronian , have been dated to around 2.4 to 2.1 billion years ago during

12648-483: The lower class and women were forbidden from showing their knees. Other regulations affected the wider population, such as prohibiting dancing, sexual activities and moderating food and drink intake. In Ireland, Catholics blamed the Reformation for the bad weather. The Annals of Loch Cé , in its entry for 1588, describes a midsummer snowstorm as "a wild apple was not larger than each stone of it" and blames it on

12784-461: The main religious minority in their otherwise Christian societies. There was no direct link made between Jews and the weather; they were blamed only for indirect consequences such as disease. Outbreaks of the Black Death were often blamed on Jews. In Western European cities during the 1300s, Jewish populations were murdered to stop the spread of the plague. Rumors spread that Jews were either poisoning wells themselves, or telling lepers to poison

12920-484: The most recent glacial periods, ice cores provide climate proxies , both from the ice itself and from atmospheric samples provided by included bubbles of air. Because water containing lighter isotopes has a lower heat of evaporation , its proportion decreases with warmer conditions. This allows a temperature record to be constructed. This evidence can be confounded, however, by other factors recorded by isotope ratios. The paleontological evidence consists of changes in

13056-526: The motion of tectonic plates resulting in changes in the relative location and amount of continental and oceanic crust on Earth's surface, which affect wind and ocean currents ; variations in solar output ; the orbital dynamics of the Earth–Moon system; the impact of relatively large meteorites and volcanism including eruptions of supervolcanoes . Some of these factors influence each other. For example, changes in Earth's atmospheric composition (especially

13192-459: The names Riss (180,000–130,000 years bp ) and Würm (70,000–10,000 years bp) refer specifically to glaciation in the Alpine region . The maximum extent of the ice is not maintained for the full interval. The scouring action of each glaciation tends to remove most of the evidence of prior ice sheets almost completely, except in regions where the later sheet does not achieve full coverage. Within

13328-541: The native people lent itself to high adaptability to the LIA. Both Europeans and indigenous peoples suffered excess mortality in Maine during the winter of 1607–1608, and extreme frost was meanwhile reported in the Jamestown, Virginia , settlement. Native Americans formed leagues in response to food shortages. The journal of Pierre de Troyes, Chevalier de Troyes , who led an expedition to James Bay in 1686, recorded that

13464-498: The other hand, snowy winter landscapes, particularly stormy seascapes, became artistic genres in the Dutch Golden Age painting during the coldest and stormiest decades of the Little Ice Age. Most modern scholars believe them to be full of symbolic messages and metaphors, which would have been clear to contemporary viewers. All of the famous winter landscape paintings by Pieter Bruegel the Elder , such as The Hunters in

13600-521: The past few million years. These also confirm the linkage between ice ages and continental crust phenomena such as glacial moraines, drumlins, and glacial erratics. Hence the continental crust phenomena are accepted as good evidence of earlier ice ages when they are found in layers created much earlier than the time range for which ice cores and ocean sediment cores are available. There have been at least five major ice ages in Earth's history (the Huronian , Cryogenian , Andean-Saharan , late Paleozoic , and

13736-401: The planet. Earth is currently in the ice age called Quaternary glaciation . Individual pulses of cold climate within an ice age are termed glacial periods ( glacials, glaciations, glacial stages, stadials, stades , or colloquially, ice ages ), and intermittent warm periods within an ice age are called interglacials or interstadials . In glaciology , the term ice age is defined by

13872-492: The pond being abandoned in 1963. The General Crisis of the seventeenth century in Europe was a period of inclement weather, crop failure, economic hardship, extreme intergroup violence, and high mortality linked to the Little Ice Age. Episodes of social instability track the cooling with a time lapse of up to 15 years, and many developed into armed conflicts, such as the Thirty Years' War (1618–1648). The war started as

14008-505: The population of each country. In Estonia and Finland in 1696–97, losses have been estimated at a fifth and a third of the national populations, respectively." Viticulture disappeared from some northern regions, and storms caused serious flooding and loss of life. Some of them resulted in the permanent loss of large areas of land from the Danish, German, and Dutch coasts . The violinmaker Antonio Stradivari produced his instruments during

14144-567: The presence of a "wicked, heretical, bishop in Oilfinn", the Protestant Bishop of Elphin , John Lynch . William James Burroughs analyzes the depiction of winter in paintings, as does Hans Neuberger . Burroughs asserts that it occurred almost entirely from 1565 to 1665 and was associated with the climatic decline from 1550 onwards. Burroughs claims that there had been almost no depictions of winter in art, and he "hypothesizes that

14280-542: The presence of extensive ice sheets in the northern and southern hemispheres. By this definition, the current Holocene period is an interglacial period of an ice age. The accumulation of anthropogenic greenhouse gases is projected to delay the next glacial period. In 1742, Pierre Martel (1706–1767), an engineer and geographer living in Geneva , visited the valley of Chamonix in the Alps of Savoy . Two years later he published an account of his journey. He reported that

14416-567: The reduction in weathering causes an increase in the greenhouse effect . There are three main contributors from the layout of the continents that obstruct the movement of warm water to the poles: Since today's Earth has a continent over the South Pole and an almost land-locked ocean over the North Pole, geologists believe that Earth will continue to experience glacial periods in the geologically near future. Some scientists believe that

14552-524: The resurgence was brought by the climatic decline. Prior to the Little Ice Age, witchcraft was considered an insignificant crime, and victims (the supposed witches) were rarely accused. But beginning in the 1380s, just as the Little Ice Age began, European populations began to link magic and weather-making. The first systematic witch hunts began in the 1430s, and by the 1480s, it was widely believed that witches should be held accountable for poor weather. Witches were blamed for direct and indirect consequences of

14688-469: The role of weathering). Greenhouse gas levels may also have been affected by other factors which have been proposed as causes of ice ages, such as the movement of continents and volcanism. The Snowball Earth hypothesis maintains that the severe freezing in the late Proterozoic was ended by an increase in CO 2 levels in the atmosphere, mainly from volcanoes, and some supporters of Snowball Earth argue that it

14824-547: The same conditions that unemployment and economic difficulties arose: prolonged cold, dry seasons. Disease and unemployment generated a lethal positive feedback loop. Although the communities had some contingency plans, such as better crop mixes, emergency grain stocks, and international food trade, they did not always prove effective. Communities often lashed out via violent crimes, including robbery and murder. Accusations of sexual offenses also increased, such as adultery , bestiality , and rape . Europeans sought explanations for

14960-413: The snow lay on the ground for many months longer than it does today." In Lisbon , Portugal, snowstorms were much more frequent than today, and one winter in the 17th century produced eight snowstorms. Many springs and summers were cold and wet but with great variability between years and groups of years. That was particularly evident during the "Grindelwald Fluctuation" (1560–1630); the rapid cooling phase

15096-540: The spread of diseases. The colder weather helped the parasites brought by Europeans in mosquitoes to develop faster. That in turn led to many malaria deaths among Native Americans. In 1642, Thomas Gorges wrote that between 1637 and 1645, colonists in Maine (then part of Massachusetts) experienced horrendous weather conditions. In June 1637, temperatures were so high that numerous European settlers died; travelers were forced to travel at night to stay cool. Gorges also wrote that

15232-429: The spread of ice sheets in the Northern Hemisphere began. Since then, the world has seen cycles of glaciation with ice sheets advancing and retreating on 40,000- and 100,000-year time scales called glacial periods , glacials or glacial advances, and interglacial periods, interglacials or glacial retreats. Earth is currently in an interglacial, and the last glacial period ended about 11,700 years ago. All that remains of

15368-518: The strength of the North Atlantic thermohaline circulation . Because the Little Ice Age took place during the European colonization of the Americas , it discouraged many early colonists, who had expected the climate of North America to be similar to the climate of Europe at similar latitudes. They found that North America, at least in what would become Canada and the northern United States, had hotter summers and colder winters than Europe. That effect

15504-440: The sudden decrease in population numbers. The Grindelwald Fluctuation is believed to have been partially caused by a slew of volcanic eruptions. A succession of volcanic eruptions can create a cooling effect. When a volcano erupts it releases sulphur dioxide and other aerosols into the stratosphere, which can block some of the sun's radiation from reaching the Earth's surface. Depending on the size and frequency of these eruptions,

15640-557: The summer of 1835 he made some excursions to the Bavarian Alps. Schimper came to the conclusion that ice must have been the means of transport for the boulders in the alpine upland. In the winter of 1835–36 he held some lectures in Munich. Schimper then assumed that there must have been global times of obliteration ("Verödungszeiten") with a cold climate and frozen water. Schimper spent the summer months of 1836 at Devens, near Bex, in

15776-653: The temperature drops during the Little Ice Age. Despite the lack of food production, the Wanli Emperor ordered the Jurchens to pay the same amount of tribute each year. That led to anger and sowed seeds to the rebellion against the Ming dynasty. In 1616, Jurchens established the Later Jin dynasty . Led by Hong Taiji and Nurhaci , the Later Jin dynasty moved South and achieved decisive victories in battles against

15912-481: The temperatures over land by increased albedo as noted above. Furthermore, under this hypothesis the lack of oceanic pack ice allows increased exchange of waters between the Arctic and the North Atlantic Oceans, warming the Arctic and cooling the North Atlantic. (Current projected consequences of global warming include a brief ice-free Arctic Ocean period by 2050 .) Additional fresh water flowing into

16048-547: The tilt of Earth's rotational axis. Earth has been in an interglacial period known as the Holocene for around 11,700 years, and an article in Nature in 2004 argues that it might be most analogous to a previous interglacial that lasted 28,000 years. Predicted changes in orbital forcing suggest that the next glacial period would begin at least 50,000 years from now. Moreover, anthropogenic forcing from increased greenhouse gases

16184-530: The timing and nature of these variations are highly variable from region to region, and the notion of the Little Ice Age as a globally synchronous cold period has all but been dismissed. In China, warm-weather crops such as oranges were abandoned in Jiangxi Province , where they had been grown for centuries. Also, the two periods of most frequent typhoon strikes in Guangdong coincide with two of

16320-557: The timing and the areas affected by the LIA suggested largely independent regional climate changes, rather than a globally synchronous increased glaciation. At most, there was modest cooling of the Northern Hemisphere during the period. Several causes have been proposed: cyclical lows in solar radiation , heightened volcanic activity , changes in the ocean circulation , variations in Earth's orbit and axial tilt ( orbital forcing ), inherent variability in global climate, and decreases in

16456-408: The twentieth century, including Alaska, New Zealand and Patagonia . However, the timing of maximum glacial advances in these regions differs considerably, suggesting that they may represent largely independent regional climate changes , not a globally-synchronous increased glaciation. Thus current evidence does not support globally synchronous periods of anomalous cold or warmth over this interval, and

16592-423: The twentieth century. Given that the confidence levels surrounding all of the reconstructions are wide, virtually all reconstructions are effectively encompassed within the uncertainty previously indicated in the TAR. The major differences between the various proxy reconstructions relate to the magnitude of past cool excursions, principally during the twelfth to fourteenth, seventeenth and nineteenth centuries. There

16728-438: The unusually harsh winter of 1565 inspired great artists to depict highly original images and that the decline in such paintings was a combination of the 'theme' having been fully explored and mild winters interrupting the flow of painting." Wintry scenes, which entail technical difficulties in painting, have been regularly and well handled since at least the early 15th century by artists in illuminated manuscript cycles that show

16864-497: The warming of the Earth's climate. It is difficult to accurately assess the extent of depopulation that occurred during both the 1500s and 1600s, as reliable population data from this period is limited. However it is known that this period was one of significant upheaval and change, with many regions experiencing significant population drops due to wars, plagues, famines, and natural disasters. The bubonic plague , for instance, killed between 75 and 200 million people in Europe alone. It

17000-660: The wells. To escape persecution, some Jews converted to Christianity, while others migrated to the Ottoman Empire , Italy or the Holy Roman Empire , where they experienced greater toleration. Some populations blamed the cold periods and the resulting famine and disease during the Little Ice Age on a general divine displeasure. Particular groups took the brunt of the burden in attempts to cure it. In Germany, regulations were imposed upon activities such as gambling and drinking , which disproportionately affected

17136-759: The winter of 1641–1642 was “piercingly Intolerable” and that no Englishman or Native American had ever seen anything like it. He also stated that the Massachusetts Bay had frozen as far as one could see, and that horse carriages now roamed where ships used to be. He stated that the summers of 1638 and 1639 were very short, cold, and wet, which compounded food scarcity for a few years. To make matters worse, creatures like caterpillars and pigeons fed on crops and devastated harvests. Every year about which Gorges wrote featured unusual weather patterns, including high precipitation, drought, and extreme cold or heat. Many inhabitants of North America had their own theories about

17272-528: Was a cause of the presence of erratic boulders in the Scandinavian and Baltic regions. In 1795, the Scottish philosopher and gentleman naturalist, James Hutton (1726–1797), explained erratic boulders in the Alps by the action of glaciers. Two decades later, in 1818, the Swedish botanist Göran Wahlenberg (1780–1851) published his theory of a glaciation of the Scandinavian peninsula. He regarded glaciation as

17408-483: Was aggravated by the Little Ice Age, and unpreparedness led to the collapse of many early European settlements in North America. Historians agree that when colonists settled at Jamestown , it was one of the coldest periods in the last 1000 years. Drought was also a problem in North America during the Little Ice Age, and the settlers arrived in Roanoke during the largest drought of the past 800 years. Tree ring studies by

17544-617: Was associated with more erratic weather, including increased storminess, unseasonal snowstorms, and droughts. Crop practices throughout Europe had to be altered to adapt to the shortened and less reliable growing season, and there were many years of scarcity and famine . One was the Great Famine of 1315–1317 , but that may have been before the Little Ice Age. According to Elizabeth Ewan and Janay Nugent, "Famines in France 1693–94, Norway 1695–96 and Sweden 1696–97 claimed roughly 10 percent of

17680-539: Was born. The first River Thames frost fair was in 1608 and the last in 1814. Changes to the bridges and the addition of the Thames Embankment have affected the river's flow and depth and greatly diminish the possibility of further freezes. In 1658, a Swedish army marched through Denmark and across the Great Belt to attack Copenhagen from the west. The winter of 1794–1795 was particularly harsh:

17816-625: Was caused by the elimination of atmospheric methane , a greenhouse gas , during the Great Oxygenation Event . The next well-documented ice age, and probably the most severe of the last billion years, occurred from 720 to 630 million years ago (the Cryogenian period) and may have produced a Snowball Earth in which glacial ice sheets reached the equator, possibly being ended by the accumulation of greenhouse gases such as CO 2 produced by volcanoes. "The presence of ice on

17952-429: Was caused in the first place by a reduction in atmospheric CO 2 . The hypothesis also warns of future Snowball Earths. In 2009, further evidence was provided that changes in solar insolation provide the initial trigger for Earth to warm after an Ice Age, with secondary factors like increases in greenhouse gases accounting for the magnitude of the change. The geological record appears to show that ice ages start when

18088-455: Was difficult to date exactly; early theories assumed that the glacials were short compared to the long interglacials. The advent of sediment and ice cores revealed the true situation: glacials are long, interglacials short. It took some time for the current theory to be worked out. The chemical evidence mainly consists of variations in the ratios of isotopes in fossils present in sediments and sedimentary rocks and ocean sediment cores. For

18224-543: Was introduced into scientific literature by François E. Matthes in 1939. The period has been conventionally defined as extending from the 16th to the 19th centuries, but some experts prefer an alternative time-span from about 1300 to about 1850. The NASA Earth Observatory notes three particularly cold intervals. One began about 1650, another about 1770, and the last in 1850, all of which were separated by intervals of slight warming. The Intergovernmental Panel on Climate Change Third Assessment Report considered that

18360-515: Was linked by its authors to Maya and Aztec chronicles relating periods of cold and drought, supports the existence of the Little Ice Age in the region. Another study conducted in several sites in Mesoamerica like Los Tuxtlas and Lake Pompal in Veracruz, Mexico show a decrease in human activity in the area during the Little Ice Age. That was proven by studying charcoal fragments and the amount of maize pollen taken from sedimentary samples by using

18496-526: Was suggested by the existence of an ice sheet covering the Tibetan Plateau during the Ice Ages ( Last Glacial Maximum ?). According to Kuhle, the plate-tectonic uplift of Tibet past the snow-line has led to a surface of c. 2,400,000 square kilometres (930,000 sq mi) changing from bare land to ice with a 70% greater albedo . The reflection of energy into space resulted in a global cooling, triggering

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