The Initiation of the "Little Ice Age" in Regions Round the North Atlantic

The "Little Ice Age" was the most recent period during which glaciers extended globally, their fronts oscillating about advanced positions. It is frequently taken as having started in the sixteenth or seventeenth century and ending somewhere between 1850 and 1890, but Porter (1981) pointed out that the "Little Ice Age" may 'have begun at least three centuries earlier in the North Atlantic region than is generally inferred'. The glacial fluctuations of the last millennium have been traced in the greatest detail in the Swiss Alps, where the "Little Ice Age" is now seen as starting with advances in the thirteenth century, and reaching an initial culmination in the fourteenth century. In the discussion here, evidence from Canada, Greenland, Iceland, Spitsbergen and Scandinavia is compared with that from Switzerland. Such comparisons have been facilitated by improved methods of calibrating radiocarbon dates to calendar dates and by increasing availability of evidence revealed during the current retreat phase. It is concluded that the "Little Ice Age" was initiated before the early fourteenth century in regions surrounding the North Atlantic.     

The Time Period A.D. 1400-1980 in Central Greenland Ice Cores in Relation to the North Atlantic Sector

This paper presents a review of the time period A.D. 1400-1980 based on Greenland ice cores from the central west Greenland averaged record, and from winter and summer seasonal isotopic records from the Greenland Ice Sheet Project 2 (GISP2). This time period includes the so-called "Little Ice Age". The concept of the "Little Ice Age" has evolved from the idea of a simple, centuries-long period of lower temperatures to a more complex view of temporal and spatial climatic variability. In the central Greenland ice core isotopic signals, the fifteenth and early sixteenth centuries show multi-decadal excursions above and below the mean reference. The sixteenth and mid-eighteenth to mid-nineteenth centuries are notable for decade-to-decade swings (high-low) in the isotopic signal, while multi-decadal low excursions dominate the seventeenth century. The "subdued" nature of the "Little Ice Age" isotopic signal in central Greenland is probably influenced by the North Atlantic Oscillation (NAO), which presents opposing temperature excursions between west Greenland and northern Europe. Changes in the prevailing atmospheric circulation (Iceland Low) can explain some of the spatial and temporal variability between the central Greenland isotopic records and Iceland temperature.     

The ‘Little Ice Age’ glacial expansion in western Scandinavia: summer temperature or winter precipitation?

Reconstructing the temporal and spatial climate development on a seasonal basis during the last few centuries, including the ‘Little Ice Age’, may help us better understand modern-day interplay between natural and anthropogenic climate variability. The conventional view of the climate development during the last millennium has been that it followed a sequence of a Medieval Warm Period, a cool ‘Little Ice Age’ and a warming during the later part of the 19th century and in particular during the late 20th/early 21st centuries. However, recent research has challenged this rather simple sequence of climate development. Up to the present, it has been considered most likely that the ‘Little Ice Age’ glacial expansion in western Scandinavia was due to lower summer temperatures. Data presented here, however, indicate that the main cause of the early 18th century glacial advance in western Scandinavia was mild and humid winters associated with increased precipitation and high snowfall on the glaciers.     

The "Little Ice Age" and its Geomorphological Consequences in Mediterranean Europe

Alpine glacier advances in the "Little Ice Age" took place in the decades around 1320, 1600, 1700 and 1810. They were the outcome of snowier winters and cooler summers than those of the twentieth century. Documentary records from Crete in particular, and also from Italy, southern France and southeast Spain point to a greater frequency in Mediterranean Europe's mountainous regions of severe floods, droughts and frosts at times of "Little Ice Age" Alpine glacier advances. Deluges, when more than 200 mm of rain fall within 24 hours, are most frequent on mountainous areas near the coast. An instance is given of the geomorphological consequences of a great deluge which struck the Tech valley in the eastern Pyrenees on 17 October 1940. An increased frequency of deluges, probably at times when Alpine glaciers were advancing in the "Little Ice Age" and earlier in the Holocene, in areas known to be tectonically unstable and underlain by soft sediments, could better explain the occurrence of fluvial terraces in Mediterranean Europe sometimes known as the "younger fill", than soil erosion resulting from deforestation.     

中国小冰期气候研究综述

通过对小冰期研究文献进行综述,并对已发表的小冰期温度和降水数据进行综合对比分析,探讨小冰期时期中国气候特征的区域性.结果表明,小冰期在中国地区不同区域代用指标记录中均存在,但是小冰期的起讫及持续时间具有区域差异性,温湿配置也不尽相同.小冰期的起始时间主要呈现出由西向东推移的趋势,即青藏高原最早,华北地区次之而东部地区最晚.温湿配置的差异主要体现在东部季风区小冰期时期总体上是冷干的气候环境,而西部地区气候变化则呈现冷湿的气候特征.     

Historical Climatology In Europe – The State Of The Art

This paper discusses the state of European research in historical climatology. This field of science and an overview of its development are described in detail. Special attention is given to the documentary evidence used for data sources, including its drawbacks and advantages. Further, methods and significant results of historical-climatological research, mainly achieved since 1990, are presented. The main focus concentrates on data, methods, definitions of the “Medieval Warm Period” and the “Little Ice Age”, synoptic interpretation of past climates, climatic anomalies and natural disasters, and the vulnerability of economies and societies to climate as well as images and social representations of past weather and climate. The potential of historical climatology for climate modelling research is discussed briefly. Research perspectives in historical climatology are formulated with reference to data, methods, interdisciplinarity and impacts.     

Zonal Indices for Europe 1780–1995 and Running Correlations with Temperature

Zonal circulation indices with monthly and seasonal resolutions are calculated based on gridded monthly mean sea-level pressure (SLP) reconstructed back to 1780 by Jones et al. (1999): an overall zonal index for the whole European area between 30°W and 40°E, a normalized index for the North Atlantic Oscillation (NAO), and a similar index for Central Europe. For most of the early time up to the mid-nineteenth century we get preferred negative anomalies in the NAO index for winter and preferred positive ones for summer. The turning points in cumulative anomalies - during the 1850s for winter and during the 1870s for summer - indicate a transition period in circulation modes from the "Little Ice Age" to the recent climate in Europe. Running correlations (time windows of 21 years with time steps of one year) between zonal indices and regional temperature time series from Central England, Stockholm and two Central European regions are all indicating major instationarities in these relationships with a particular decline in winter correlations around the turn from the nineteenth to the twentieth centuries. Aspects of different circulation patterns linked with these variabilities are discussed.     

Reconstruction of Nineteenth Century Summer Temperatures in Norway by Proxy Data from Farmers'Diaries

Proxy data from five farmers; diaries in the Møre, Dovre and Trøndelag regions in central Norway were used for climatic reconstruction purposes. The method chosen was "simple linear regression analysis" with the start of the grain harvest (barley or oats) as predictor and summer temperature (May – August) as predictand. Overlapping periods with modern instrumental observations (starting 1858 or later) were used for calibration of the model. The model was tested on independent data by establishing the regression on one half of the overlapping period and applying the regression on the other half. The standard deviation in the residuals varied from 0.3°C to 0.7°C and the biases of the mean values from –0.3°C to +0.3°C. Climatic reconstructions were established for the early- and mid-nineteenth century summer temperature, i.e. during the last part of what has come to be regarded as the "Little Ice Age", in this article considered to end around 1880.By use of the proxy data model, huge inhomogeneities of the "classical" Trondheim series were detected, the early nineteenth century part of the series evidently being too warm. The inhomogeneity was removed by use of adjustment terms. The adjusted series indicates that in the Trondheim region the summer temperature during the last part of the "Little Ice Age" phase was about 1°C lower than the latest 60 years. This is in serious contradiction to the classical Trondheim series.     

Tree-ring reconstructed rainfall over the southeastern U.S.A. during the medieval warm period and little ice age

A 1053-year reconstruction of spring rainfall (March-June) was developed for the southeastern United States, based on three tree-ring reconstructions of statewide rainfall from North Carolina, South Carolina, and Georgia. This regional reconstruction is highly correlated with the instrumental record of spring rainfall (r = +0.80; 1887–1982), and accurately reproduces the decade-scale departures in spring rainfall amount and variance witnessed over the Southeast during the past century. No large-magnitude centuries-long trends in spring rainfall amounts were reconstructed over the past 1053 years, but large changes in the interannual variability of spring rainfall were reconstructed during portions of the Medieval Warm Period (MWP), Little Ice Age (LIA), and the 20th century. Dry conditions persisted at the end of the 12th century, but appear to have been exceeded by a reconstructed drought in the mid-18th century. High interannual variability, including five extremely wet years were reconstructed for a 20-yr period during the late 16th and early 17th centuries, and may reflect amplified atmospheric circulation over eastern North America during what appears to have been one of the most widespread cold episodes of the Little Ice Age.     

中国气候变化的研究

总结了近10余年对中国气候变化的研究,重点对不同时间尺度的气温变化进行了分析.讨论了大暖期千年尺度气候振荡,中世纪暖期、小冰期及现代气候变暖等问题.     

Freezing of the Venetian Lagoon since the 9th century A.D. in comparision to the climate of western Europe and England

In the first part of this study, typical of historical climatology, the various sources regarding freezing of the Venetian Lagoon since the 9th century A.D., are reported and discussed. The events are related, where possible, to teleconnections. Two synoptic patterns (weather type A: northerly and D: easterly) seem to have played an important role. After having discussed the dynamics of the icing processes, the problem of comparing the data is considered, as over the centuries many works were made on the Lagoon, in order to divert the major tributaries. In fact, the hydrological regime and the physical characteristic of the Lagoon environment were changed, so that the conditions necessary for freezing were no longer the same. The series was compared with the severe winters in westtern Europe and England, in order to reconstruct the past climate of the Mediterranean region and discuss the observed secular changes in the light of the widely accepted ideas of climatic variations. The comparison shows some differences: e.g. at Venice the Medieval Climatic Optimum with the occurrence of severe winters ended earlier and the Little Ice Age was broken by a milder interval.     

Reconstruction of historical pressure patterns over Japan using two-point pressure–temperature datasets since the nineteenth century

The temperature and pressure differences between Tokyo and Nagasaki were used to reconstruct past climate conditions. January and July in each available year since the 1820s were classified into several types with characteristic sea level atmospheric pressure patterns. This results in 18 years of pre-1881 data and a continuous series thereafter. The series indicate that the warming after 1900 (after the end of the so-called Little Ice Age) and again after 1960 can at least partly be attributed to an increase in the frequency of warm circulation pattern types at the expense of cold types. The difference in nature of the shifts in circulation types that occurred in the late nineteenth century compared with that in the late twentieth centuries suggests that the mechanism behind the warming in the late nineteenth century differs from that in the late twentieth century.     

Yangtze Delta floods and droughts of the last millennium: Abrupt changes and long term memory

Summary Climate variability and flood events in the Yangtze Delta, which is a low-lying terrain prone to flood hazards, storm tides and typhoons, are studied in terms of a trend and detrended fluctuation analysis of historical records. The data used in this paper were extracted from historical records such as local annuals and chronologies from 1000–1950 and supplemented by instrumental observations since 1950. The historical data includes frequencies of floods, droughts and maritime events on a decadal basis. Flood magnitudes increase during the transition from the medieval warm interval into the early Little Ice Age. Fluctuating climate changes of the Little Ice Age, which are characterised by arid climate events, are followed by wet and cold climate conditions with frequent flood hazards. For trend analysis, the Mann-Kendall test is applied to determine the changing trends of flood and drought frequency. Flood frequency during 1000–1950 shows a negative trend before 1600 A.D. and a positive trend thereafter; drought frequency increases after 1300. The detrended fluctuation analysis of the flood and drought frequencies reveals power law scaling up to centuries; this is related to long-term memory and is similar to the river Nile floods.     

东亚地区小冰期气候的模拟

本文使用ECHO-G全球气候模式对1550～1850年的小冰期气候进行了300个模式年的模拟,着重分析了东亚地区小冰期的温度变化特征,并与目前所得到的小冰期气候重建结果进行了对比。结果表明,在考虑了太阳辐射、火山活动、CO2和CH4等主要气候影响驱动因子的条件下,较好地模拟出了东亚地区的小冰期气候特征,并与其它手段的气候重建结果相吻合,显示太阳活动和火山活动是小冰期气候形成的主要原因。     

Climatic Change and Witch-hunting: the Impact of the Little Ice Age on Mentalities

In addition to objective climatic data, subjective or social reactions can also serve as indicators in the assessment of climatic changes. Concerning the Little Ice Age the conception of witchcraft is of enormous importance. Weather-making counts among the traditional abilities of witches. During the late 14^th and 15^th centuries the traditional conception of witchcraft was transformed into the idea of a great conspiracy of witches, to explain "unnatural" climatic phenomena. Because of their dangerous nature, particularly their ability to generate hailstorms, the very idea of witches was the subject of controversial discussion around 1500. The beginnings of meteorology and its emphasis of "natural" reasons in relationship to the development of weather must be seen against the background of this demoniacal discussion. The resurgence of the Little Ice Age revealed the susceptibility of society. Scapegoat reactions may be observed by the early 1560s even though climatologists, thus far, have been of the opinion that the cooling period did not begin until 1565. Despite attempts of containment, such as the calvinistic doctrine of predestination, extended witch-hunts took place at the various peaks of the Little Ice Age because a part of society held the witches directly responsible for the high frequency of climatic anomalies and the impacts thereof. The enormous tensions created in society as a result of the persecution of witches demonstrate how dangerous it is to discuss climatic change under the aspects of morality.     

Historical climatology, <Emphasis Type="Italic">Climatic Change</Emphasis>, and implications for climate science in the twenty-first century

Historical climatology is the use of documentary evidence for the reconstruction of past climate. This paper gives a brief personal view of the development of the discipline from early times to the present day. Although several papers have been published on the importance of carefully analysing and evaluating all historical sources before they are used in climate reconstructions, several of them in Climatic Change, the use of unreliable, unanalysed data still persists. This may lead to false impressions of the climate of the past. In these times, when climate data are being used for political, as well as purely scientific ends, the cause of accuracy, as championed by Climatic Change, will best be served by emphasising, yet again, the importance of using only reliable data. A number of examples are given which illustrate these points. These include discussions on wine growing in England in medieval times, the Norse settlement of Greenland, and comments on the climate history of the past thousand years.     

Climatic and human history in Europe and Latin America: An opportunity for comparative study

Motivated by environmental concerns, a few historians have reaffirmed that history is more than relationships among people; it involves human beings interacting with their environment. Some investigators of European history have given consideration to the effects of climate variations on human history. Preliminary examination of historic documents available for Latin America suggest that a time series of climate variations could also be reconstructed for at least the last 400 years. These preliminary data suggest that the general economic and social crises that prevailed in Europe during the Little Ice Age have parallels in Latin America. Such a concurrence of economic and social trends for these regions seems to reflect the influence of the general adverse climate prevailing during this time. Clearly, an opportunity exists for historians and climatologists to reconstruct the past climate of Latin America and compare these records with other parts of the world to establish the timing, length and magnitude of climate fluctuations over periods of human history.     

SEASONAL AND ANNUAL TEMPERATURE VARIATIONS SINCE 1470 AD IN EAST CHINA

The ten-year mean anomalies of seasonal and annual temperatures were reconstructed on the basis ofhistorical documents of cold events such as severe snowing and freezing of lakes and rivers.The assorted eventswere calibrated with instrumental observations of temperature and transformed into ten-year mean anomalies.The reconstructed temperature series show predominance of cold climate in the first four hundred years of theperiod examined.The centenary seasonal temperature anomalies for the 16th to the 19th century vary between-0.1 and -0.7K.The coldest decades concentrated in the middle of 17th and 19th centuries.It provided theirrefutable evidence of the occurrence of the Little Ice Age in China.The minima of ten-year mean temperatureanomalies ranged about -1.5 to 2.0K in spring and winter.Meanwhile,the variance of ten-year mean tempera-ture was increased by more than 20％ in comparison to the 20th century.     

Secular trends in high northern latitude temperature reconstructions based on tree rings

Boreal tree-ring records from high latitude North America, Scandinavia and Russia provide baseline data reflecting long-term trends in Arctic annual temperature. Reconstructions from 1682–1968 indicate the latter part and termination of the Little Ice Age and that the northern regions are now warmer by comparison. The resulting high-resolution, extended temperature time series allows examination of underlying causes of climatic change not possible using only the instrumental record. The recent recorded data for the Arctic show recovery from the cooling in the 1950's–1960's. The overall evaluation confirms that the high northern latitudes are now in an anomalously warm state relative to the past three centuries.     

Variability of Sea-Ice Extent in Baffin Bay over the Last Millennium

Comparison of an ice core glaciochemical time-series developed from thePenny Ice Cap (PIC), Baffin Island and monthly sea-ice extent reveals astatisticallysignificant inverse relationship between changes in Baffin Bay spring sea-iceextent andPenny Ice Cap sea-salt concentrations for the period 1901–1990 AD.Empiricalorthogonal function analysis demonstrates the joint behavior between changesin PICsea-salt concentrations, sea-ice extent, and changes in North Atlanticatmosphericcirculation. Our results suggest that sea-salt concentrations in snowpreserved on thePIC reflect local to regional springtime sea-ice coverage. The PIC sea-saltrecord/sea-ice relationship is further supported by decadal and century scalecomparisonwith other paleoclimate records of eastern Arctic climate change over the last700 years. Our sea-salt record suggests that, while the turn of the century wascharacterized bygenerally milder sea-ice conditions in Baffin Bay, the last few decades ofsea-ice extentlie within Little Ice Age variability and correspond to instrumental recordsof lowertemperatures in the Eastern Canadian Arctic over the past three decades.