scholarly journals Reconstructing Millennial-Scale, Regional Paleoclimates of Boreal Canada during the Holocene

2009 ◽  
Vol 22 (2) ◽  
pp. 316-330 ◽  
Author(s):  
A. E. Viau ◽  
K. Gajewski
Keyword(s):  
Climate Variability ◽  
Early Holocene ◽  
Ice Age ◽  
Western Canada ◽  
Eastern Canada ◽  
The Holocene ◽  
Northern Canada ◽  
Scale Temperature ◽  
Central Canada ◽  
Millennial Scale

Abstract Regional paleoclimate reconstructions for northern Canada quantify Holocene climate variability on orbital and millennial time scales and provide a context to better understand the current global warming. The reconstructions are based on available pollen diagrams from the boreal and low Arctic zones of Canada and use the modern analog technique (MAT). Four regional reconstructions document the space–time evolution of the climate during the Holocene. Highest summer and winter temperatures anomalies are found in central Canada during the early Holocene. Eastern Canada was relatively cool in the early Holocene, whereas central Canada was warmest at that time. Labrador was relatively dry in the early to mid-Holocene during which time western Canada was relatively moist. Millennial-scale temperature variations, especially the Medieval Warm Period and Little Ice Age are seen across the continent, with some suggestion of time-transgressive changes from west to east. At the millennial scale, precipitation anomalies are of opposite signs in eastern and western Canada. The results herein indicate that modern increases in temperatures in northern Canada far exceed natural millennial-scale climate variability.

Early Holocene climate variability and the timing and extent of the Holocene thermal maximum (HTM) in northern Iceland

2006 ◽  
Vol 25 (17-18) ◽  
pp. 2314-2331 ◽  
Author(s):  
Chris Caseldine ◽  
Peter Langdon ◽  
Naomi Holmes
Keyword(s):  
Climate Variability ◽  
Early Holocene ◽  
Holocene Climate ◽  
The Holocene ◽  
Holocene Thermal Maximum ◽  
Thermal Maximum

scholarly journals Holocene biogeography of Tsuga mertensiana and other conifers in the Kenai Mountains and Prince William Sound, south-central Alaska

The Holocene ◽  
2016 ◽  
Vol 27 (4) ◽  
pp. 485-495 ◽  
Author(s):  
R Scott Anderson ◽  
Darrell S Kaufman ◽  
Edward Berg ◽  
Caleb Schiff ◽  
Thomas Daigle
Keyword(s):  
Climatic Factors ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
Early Holocene ◽  
Ice Age ◽  
Prince William Sound ◽  
Conifer Forest ◽  
The Holocene ◽  
South Central ◽  
Tsuga Mertensiana

Several important North American coastal conifers – having immigrated during the Holocene from the southeast – reach their northern and upper elevation limits in south-central Alaska. However, our understanding of the specific timing of migration has been incomplete. Here, we use two new pollen profiles from a coastal and a high-elevation site in the Eastern Kenai Peninsula–Prince William Sound region, along with other published pollen records, to investigate the Holocene biogeography and development history of the modern coastal Picea (spruce)– Tsuga (hemlock) forest. Tsuga mertensiana became established at Mica Lake (100 m elevation, near Prince William Sound) by 6000 cal. BP and at Goat Lake (550 m elevation in the Kenai Mountains) sometime after 3000 years ago. Tsuga heterophylla was the last major conifer to arrive in the region. Although driven partially by climate change, major vegetation changes during much of the Holocene are difficult to interpret exclusively in terms of climate, with periods of slow migration alternating with more rapid movement. T. mertensiana expanded slowly northeastward in the early Holocene, compared with Picea sitchensis or T. heterophylla. Difficulty of invading an already established conifer forest may account for this. We suggest that during the early Holocene, non-climatic factors as well as proximity to refugia, influenced rates of migration. Climate may have been more important after ~2600 cal. BP. Continued expansion of T. mertensiana at Goat Lake at the Medieval Climate Anomaly (MCA)–‘Little Ice Age’ (‘LIA’) transition suggests warm and wet winters. But expansion of T. mertensiana at both sites was arrested during the colder climate of the ‘LIA’. The decline was more extensive at Goat Lake, where climatic conditions may have been severe enough to reduce or eliminate the T. mertensiana population. T. mertensiana continued its expansion around Goat Lake after the ‘LIA’.

A millennium-length temperature reconstruction for the eastern Mediterranean

2020 ◽  
Author(s):  
Jan Esper ◽  
Lara Klippel ◽  
Paul J. Krusic ◽  
Oliver Konter ◽  
Christoph Raible ◽  
...  
Keyword(s):  
Central Europe ◽  
Climate Model ◽  
Eastern Mediterranean ◽  
Temperature Reconstruction ◽  
Ice Age ◽  
Temperature Trends ◽  
Latewood Density ◽  
Scale Temperature ◽  
The Mediterranean ◽  
Millennial Scale

<p>The Mediterranean has been identified as particularly vulnerable to climate change, yet a high-resolution temperature reconstruction extending back into the Medieval Warm Period is still lacking. Here we present such a record from a high-elevation site on Mt. Smolikas in northern Greece, where some of Europe’s oldest trees provide evidence of warm season temperature variability back to 730 CE. The reconstruction is derived from 192 annually resolved, latewood density series from ancient living and relict Pinus heldreichii trees calibrating at r<sub>1911-2015</sub> = 0.73 against regional July-September (JAS) temperatures. Although the recent 1985-2014 period was the warmest 30-year interval (JAS T<sub>wrt.1961-90</sub> = +0.71°C) since the 11<sup>th</sup> century, temperatures during the 9-10<sup>th</sup> centuries were even warmer, including the warmest reconstructed 30-year period from 876-905 (+0.78°C). These differences between warm periods are statistically insignificant though. Several distinct cold episodes punctuate the Little Ice Age, albeit the coldest 30-year period is centered during high medieval times from 997-1026 (-1.63°C). Comparison with reconstructions from the Alps and Scandinavia shows that a similar cold episode occurred in central Europe but was absent at northern latitudes. The reconstructions also reveal different millennial-scale temperature trends (NEur = -0.73°C/1000 years, CEur = -0.13 °C, SEur = +0.23°C) potentially triggered by latitudinal changes in summer insolation due to orbital forcing. These features, the opposing millennial-scale temperature trends and the medieval multi-decadal cooling recorded in Central Europe and the Mediterranean, are not well captured in state-of-the-art climate model simulations.</p>

Millennial-scale temperature variations in North America during the Holocene

2006 ◽  
Vol 111 (D9) ◽  
Author(s):  
A. E. Viau ◽  
K. Gajewski ◽  
M. C. Sawada ◽  
P. Fines
Keyword(s):  
North America ◽  
Temperature Variations ◽  
The Holocene ◽  
Scale Temperature ◽  
Millennial Scale

scholarly journals Effects of melting ice sheets and orbital forcing on the early Holocene warming in the extratropical Northern Hemisphere

2016 ◽  
Vol 12 (5) ◽  
pp. 1119-1135 ◽  
Author(s):  
Yurui Zhang ◽  
Hans Renssen ◽  
Heikki Seppä
Keyword(s):  
Northern Hemisphere ◽  
Spatial Patterns ◽  
Regional Differences ◽  
Climate Model ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Early Holocene ◽  
Orbital Forcing ◽  
The Holocene ◽  
Northern Canada

Abstract. The early Holocene is marked by the final transition from the last deglaciation to the relatively warm Holocene. Proxy-based temperature reconstructions suggest a Northern Hemisphere warming, but also indicate important regional differences. Model studies have analyzed the influence of diminishing ice sheets and other forcings on the climate system during the Holocene. The climate response to forcings before 9 kyr BP (referred to hereafter as kyr), however, remains not fully comprehended. We therefore studied, by employing the LOVECLIM climate model, how orbital and ice-sheet forcings contributed to climate change and to these regional differences during the earliest part of the Holocene (11.5–7 kyr). Our equilibrium experiment for 11.5 kyr suggests lower annual mean temperatures at the onset of the Holocene than in the preindustrial era with the exception of Alaska. The magnitude of this cool anomaly varied regionally, and these spatial patterns are broadly consistent with proxy-based reconstructions. Temperatures throughout the whole year in northern Canada and northwestern Europe for 11.5 kyr were 2–5 °C lower than those of the preindustrial era as the climate was strongly influenced by the cooling effect of the ice sheets, which was caused by enhanced surface albedo and ice-sheet orography. In contrast, temperatures in Alaska for all seasons for the same period were 0.5–3 °C higher than the control run, which were caused by a combination of orbital forcing and stronger southerly winds that advected warm air from the south in response to prevailing high air pressure over the Laurentide Ice Sheet (LIS). The transient experiments indicate a highly inhomogeneous early Holocene temperature warming over different regions. The climate in Alaska was constantly cooling over the whole Holocene, whereas there was an overall fast early Holocene warming in northern Canada by more than 1 °C kyr−1 as a consequence of progressive LIS decay. Comparisons of simulated temperatures with proxy records illustrate uncertainties related to the reconstruction of ice-sheet melting, and such a kind of comparison has the potential to constrain the uncertainties in ice-sheet reconstruction. Overall, our results demonstrate the variability of the climate during the early Holocene, both in terms of spatial patterns and temporal evolution.

scholarly journals Placing the Common Era in a Holocene context: millennial to centennial patterns and trends in the hydroclimate of North America over the past 2000 years

2018 ◽  
Vol 14 (5) ◽  
pp. 665-686 ◽  
Author(s):  
Bryan N. Shuman ◽  
Cody Routson ◽  
Nicholas McKay ◽  
Sherilyn Fritz ◽  
Darrell Kaufman ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Ice Age ◽  
Medieval Climate Anomaly ◽  
Climate Anomaly ◽  
The Holocene ◽  
The Past ◽  
Past 2000 Years ◽  
The Common ◽  
Common Era ◽  
Millennial Scale

Abstract. A synthesis of 93 hydrologic records from across North and Central America, and adjacent tropical and Arctic islands, reveals centennial to millennial trends in the regional hydroclimates of the Common Era (CE; past 2000 years). The hydrological records derive from materials stored in lakes, bogs, caves, and ice from extant glaciers, which have the continuity through time to preserve low-frequency ( > 100 year) climate signals that may extend deeper into the Holocene. The most common pattern, represented in 46 (49 %) of the records, indicates that the centuries before 1000 CE were drier than the centuries since that time. Principal component analysis indicates that millennial-scale trends represent the dominant pattern of variance in the southwestern US, northeastern US, mid-continent, Pacific Northwest, Arctic, and tropics, although not all records within a region show the same direction of change. The Pacific Northwest and the southernmost tier of the tropical sites tended to dry toward present, as many other areas became wetter than before. In 22 records (24 %), the Medieval Climate Anomaly period (800–1300 CE) was drier than the Little Ice Age (1400–1900 CE), but in many cases the difference was part of the longer millennial-scale trend, and, in 25 records (27 %), the Medieval Climate Anomaly period represented a pluvial (wet) phase. Where quantitative records permitted a comparison, we found that centennial-scale fluctuations over the Common Era represented changes of 3–7 % in the modern interannual range of variability in precipitation, but the accumulation of these long-term trends over the entirety of the Holocene caused recent centuries to be significantly wetter, on average, than most of the past 11 000 years.

scholarly journals Millennial-scale cyclical environment and climate variability during the Holocene in the western Mediterranean region deduced from a new multi-proxy analysis from the Padul record (Sierra Nevada, Spain)

2018 ◽  
Vol 168 ◽  
pp. 35-53 ◽  
Author(s):  
María J. Ramos-Román ◽  
Gonzalo Jiménez-Moreno ◽  
Jon Camuera ◽  
Antonio García-Alix ◽  
R. Scott Anderson ◽  
...  
Keyword(s):  
Climate Variability ◽  
Sierra Nevada ◽  
Mediterranean Region ◽  
Western Mediterranean ◽  
The Holocene ◽  
Millennial Scale

Orbital and Millennial‐Scale Cycles Paced Climate Variability During the Late Paleozoic Ice Age in the Southwestern Gondwana

2020 ◽  
Vol 21 (2) ◽  
Author(s):  
M. V. L. Kochhann ◽  
J. Cagliari ◽  
K. G. D. Kochhann ◽  
D. R. Franco
Keyword(s):  
Climate Variability ◽  
Ice Age ◽  
Late Paleozoic ◽  
Late Paleozoic Ice Age ◽  
Millennial Scale

scholarly journals Last nine-thousand years of temperature variability in Northern Europe

2009 ◽  
Vol 5 (3) ◽  
pp. 1521-1552 ◽  
Author(s):  
H. Seppä ◽  
A. E. Bjune ◽  
R. J. Telford ◽  
H. J. B. Birks ◽  
S. Veski
Keyword(s):  
Climate Variability ◽  
Ice Age ◽  
Northern Europe ◽  
Temperature Record ◽  
The Holocene ◽  
Holocene Thermal Maximum ◽  
Proxy Records ◽  
The North ◽  
Major Interest ◽  
Future Global Warming

Abstract. The threat of future global warming has generated a major interest in quantifying past climate variability on centennial and millennial time-scales. However, palaeoclimatological records are often noisy and arguments about past variability are only possible if they are based on reproducible features in several reliably dated datasets. Here we focus on the last 9000 years, explore the results of 35 Holocene pollen-based July mean and annual mean temperature reconstructions from Northern Europe by stacking them to create summary curves, and compare them with a high-resolution, summary chironomid-based temperature record and other independent palaeoclimate records. The stacked records show that the "Holocene Thermal Maximum" in the region dates to 8000 to 4800 cal yr BP and that the "8.2 event" and the "Little Ice Age" at 500–100 cal yr BP are the clearest cold episodes during the Holocene. In addition, a more detailed analysis of the last 5000 years pinpoints centennial-scale climate variability with cold anomalies at 3800–3000 and 500–100 cal yr BP, a long, warmer period around 2000 cal yr BP, and a marked warming since the mid 19th century. The colder (warmer) anomalies are associated with increased (decreased) humidity over the Northern European mainland, consistent with the modern high correlation between cold (warm) and humid (dry) modes of summer weather in the region. A comparison with the key proxy records reflecting the main forcing factors does not support the hypothesis that solar variability is the cause of the late-Holocene centennial-scale temperature changes. We suggest that the reconstructed anomalies are typical of Northern Europe and their occurrence may be related to the oceanic and atmospheric circulation variability in the North Atlantic–North-European region.

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