scholarly journals Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly

Science ◽  
2009 ◽  
Vol 326 (5957) ◽  
pp. 1256-1260 ◽  
Author(s):  
Michael E. Mann ◽  
Zhihua Zhang ◽  
Scott Rutherford ◽  
Raymond S. Bradley ◽  
Malcolm K. Hughes ◽  
...  
Keyword(s):  
North Atlantic ◽  
Little Ice Age ◽  
Radiative Forcing ◽  
Global Climate ◽  
Ice Age ◽  
Medieval Climate Anomaly ◽  
The Past ◽  
The North ◽  
The North Atlantic Oscillation ◽  
The Tropical Pacific

Global temperatures are known to have varied over the past 1500 years, but the spatial patterns have remained poorly defined. We used a global climate proxy network to reconstruct surface temperature patterns over this interval. The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally. This period is marked by a tendency for La Niña–like conditions in the tropical Pacific. The coldest temperatures of the Little Ice Age are observed over the interval 1400 to 1700 C.E., with greatest cooling over the extratropical Northern Hemisphere continents. The patterns of temperature change imply dynamical responses of climate to natural radiative forcing changes involving El Niño and the North Atlantic Oscillation–Arctic Oscillation.

Cuban stalagmite suggests relationship between Caribbean precipitation and the Atlantic Multidecadal Oscillation during the past 1.3 ka

The Holocene ◽  
2012 ◽  
Vol 22 (12) ◽  
pp. 1405-1412 ◽  
Author(s):  
Claudia Fensterer ◽  
Denis Scholz ◽  
Dirk Hoffmann ◽  
Christoph Spötl ◽  
Jesús M Pajón ◽  
...  
Keyword(s):  
North Atlantic ◽  
Little Ice Age ◽  
Rainfall Intensity ◽  
Thermohaline Circulation ◽  
Atlantic Multidecadal Oscillation ◽  
Ice Age ◽  
The Past ◽  
The North ◽  
Southward Shift ◽  
The North Atlantic

Here we present the first high-resolution δ18O record of a stalagmite from western Cuba. The record reflects precipitation variability in the northwestern Caribbean during the last 1.3 ka and exhibits a correlation to the Atlantic Multidecadal Oscillation (AMO). This suggests a relationship between Caribbean rainfall intensity and North Atlantic sea-surface temperature (SST) anomalies. A potential mechanism for this relationship may be the strength of the Thermohaline Circulation (THC). For a weaker THC, lower SSTs in the North Atlantic possibly lead to a southward shift of the Intertropical Convergence Zone and drier conditions in Cuba. Thus, this Cuban stalagmite records drier conditions during cold phases in the North Atlantic such as the ‘Little Ice Age’. This study contributes to the understanding of teleconnections between North Atlantic SSTs and northern Caribbean climate variability during the past 1.3 ka.

Slope Water Current over the Laurentian Fan on Interannual to Millennial Time Scales

Science ◽  
1999 ◽  
Vol 286 (5439) ◽  
pp. 520-523 ◽  
Author(s):  
L. D. Keigwin ◽  
R. S. Pickart
Keyword(s):  
North Atlantic ◽  
Gulf Stream ◽  
Little Ice Age ◽  
Coupled System ◽  
Ice Age ◽  
Water Current ◽  
Sea Level Pressure ◽  
Ocean Variability ◽  
The North ◽  
The North Atlantic Oscillation

The strength and position of surface and deep currents in the slope water south of Newfoundland are thought to vary as a coupled system in relation to the dipole in atmospheric sea level pressure known as the North Atlantic oscillation (NAO). Paleoceanographic data from the Laurentian Fan, used as a proxy for sea surface temperature, reveal that surface slope waters north of the Gulf Stream experienced warming during the Little Ice Age of the 16th to 19th centuries and support the notion of an NAO-driven coupled system. The NAO may be a useful model for millennial-scale ocean variability during interglacial climate states.

scholarly journals Was the Little Ice Age more or less El Niño-like than the Medieval Climate Anomaly? Evidence from hydrological and temperature proxy data

2017 ◽  
Vol 13 (3) ◽  
pp. 267-301 ◽  
Author(s):  
Lilo M. K. Henke ◽  
F. Hugo Lambert ◽  
Dan J. Charman
Keyword(s):  
Little Ice Age ◽  
Large Scale ◽  
Global Climate ◽  
Ice Age ◽  
Medieval Climate Anomaly ◽  
Climate Anomaly ◽  
Proxy Data ◽  
The Past ◽  
Proxy Records

Abstract. The El Niño–Southern Oscillation (ENSO) is the most important source of global climate variability on interannual timescales and has substantial environmental and socio-economic consequences. However, it is unclear how it interacts with large-scale climate states over longer (decadal to centennial) timescales. The instrumental ENSO record is too short for analysing long-term trends and variability and climate models are unable to accurately simulate past ENSO states. Proxy data are used to extend the record, but different proxy sources have produced dissimilar reconstructions of long-term ENSO-like climate change, with some evidence for a temperature–precipitation divergence in ENSO-like climate over the past millennium, in particular during the Medieval Climate Anomaly (MCA; AD  ∼  800–1300) and the Little Ice Age (LIA; AD  ∼  1400–1850). This throws into question the stability of the modern ENSO system and its links to the global climate, which has implications for future projections. Here we use a new statistical approach using weighting based on empirical orthogonal function (EOF) to create two new large-scale reconstructions of ENSO-like climate change derived independently from precipitation proxies and temperature proxies. The method is developed and validated using model-derived pseudo-proxy experiments that address the effects of proxy dating error, resolution, and noise to improve uncertainty estimations. We find no evidence that temperature and precipitation disagree over the ENSO-like state over the past millennium, but neither do they agree strongly. There is no statistically significant difference between the MCA and the LIA in either reconstruction. However, the temperature reconstruction suffers from a lack of high-quality proxy records located in ENSO-sensitive regions, which limits its ability to capture the large-scale ENSO signal. Further expansion of the palaeo-database and improvements to instrumental, satellite, and model representations of ENSO are needed to fully resolve the discrepancies found among proxy records and establish the long-term stability of this important mode of climatic variability.

scholarly journals A revised chronology of key Vatnajökull (Iceland) outlet glaciers during the Little Ice Age

2005 ◽  
Vol 42 ◽  
pp. 171-179 ◽  
Author(s):  
Krista M. McKinzey ◽  
John F. Orwin ◽  
Tom Bradwell
Keyword(s):  
19Th Century ◽  
North Atlantic ◽  
Little Ice Age ◽  
Ice Age ◽  
Early 19Th Century ◽  
The North ◽  
Climate Interactions ◽  
Tephra Layers ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

AbstractGlacier fluctuations from key Vatnajökull outlets have been redated using tephrochronology coupled with two lichenometric techniques to ascertain the timing of the Little Ice Age (LIA) maximum in southeast Iceland. An updated tephrochronology for southeast Iceland (both the number of tephra layers present and their geochemical signatures) indicates a LIA maximum for both glaciers between AD 1755 and 1873. Based on a population gradient approach, lichenometrically dated moraines along the margins of Skálafellsjökull and Heinabergsjökull narrow this window to the early to mid-19th century respectively. These revised chronologies, in addition to emerging evidence from elsewhere in Iceland, support a late 18th- to early 19th-century LIA glacier maximum. In contrast, the Norwegian LIA glacial maximum is strongly centred around AD1750. This implies differing glaciological responses to secular shifts in the North Atlantic Oscillation. Such revisions to the Vatnajökull record are crucial, as accurately identifying the timing and delimiting the spatial extent of the Icelandic LIA glacier maximum will allow further light to be shed on glacier–climate interactions in the North Atlantic.

scholarly journals Higher groundwater levels in western Europe characterize warm periods in the Common Era

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Willy Tegel ◽  
Andrea Seim ◽  
Georgios Skiadaresis ◽  
Fredrik Charpentier Ljungqvist ◽  
Hans-Peter Kahle ◽  
...  
Keyword(s):  
North Atlantic ◽  
Little Ice Age ◽  
Western Europe ◽  
Full Range ◽  
Ice Age ◽  
Late Antique ◽  
Evaporative Demand ◽  
Groundwater Levels ◽  
The North ◽  
The North Atlantic Oscillation

Abstract Hydroclimate, the interplay of moisture supply and evaporative demand, is essential for ecological and agricultural systems. The understanding of long-term hydroclimate changes is, however, limited because instrumental measurements are inadequate in length to capture the full range of precipitation and temperature variability and by the uneven distribution of high-resolution proxy records in space and time. Here, we present a tree-ring-based reconstruction of interannual to centennial-scale groundwater level (GWL) fluctuations for south-western Germany and north-eastern France. Continuously covering the period of 265–2017 CE, our new record from the Upper Rhine Valley shows that the warm periods during late Roman, medieval and recent times were characterized by higher GWLs. Lower GWLs were found during the cold periods of the Late Antique Little Ice Age (LALIA; 536 to ~ 660 CE) and the Little Ice Age (LIA; between medieval and recent warming). The reconstructed GWL fluctuations are in agreement with multidecadal North Atlantic climate variability derived from independent proxies. Warm and wet hydroclimate conditions are found during warm states of the Atlantic Ocean and positive phases of the North Atlantic Oscillation on decadal scales.

scholarly journals Continental atmospheric circulation over Europe during the Little Ice Age inferred from grape harvest dates

2012 ◽  
Vol 8 (2) ◽  
pp. 577-588 ◽  
Author(s):  
P. Yiou ◽  
I. García de Cortázar-Atauri ◽  
I. Chuine ◽  
V. Daux ◽  
E. Garnier ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
North Atlantic ◽  
Little Ice Age ◽  
Ice Age ◽  
Atmospheric Flow ◽  
Climate Conditions ◽  
The Past ◽  
The North ◽  
Harvest Dates ◽  
The 19Th Century

Abstract. Estimates of climate conditions before the 19th century are based on proxy data reconstructions or sparse meteorological measurements. The reconstruction of the atmospheric circulation that prevailed during the European Little Ice Age (∼1500–1850) has fostered many efforts. This study illustrates a methodology, combining historical proxies and modern datasets to obtain detailed information on the atmospheric circulation that prevailed over the North Atlantic region during the Little Ice Age. We used reconstructions of temperature gradients over France based on grape harvest dates to infer the atmospheric circulation. We found that blocking situations were more likely in summer, inducing a continental atmospheric flow. This study advocates that the reconstructions of the past atmospheric circulation should take this regime into account.

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