scholarly journals 1200 years of regular outbreaks in alpine insects

2006 ◽  
Vol 274 (1610) ◽  
pp. 671-679 ◽  
Author(s):  
Jan Esper ◽  
Ulf Büntgen ◽  
David C Frank ◽  
Daniel Nievergelt ◽  
Andrew Liebhold
Keyword(s):  
Population Cycles ◽  
Temperature Reconstruction ◽  
Ice Age ◽  
European Alps ◽  
Ecological Disturbance ◽  
Maximum Latewood Density ◽  
Latewood Density ◽  
History Of ◽  
Zeiraphera Diniana ◽  
The Impact

The long-term history of Zeiraphera diniana Gn. (the larch budmoth, LBM) outbreaks was reconstructed from tree rings of host subalpine larch in the European Alps. This record was derived from 47 513 maximum latewood density measurements, and highlights the impact of contemporary climate change on ecological disturbance regimes. With over 1000 generations represented, this is the longest annually resolved record of herbivore population dynamics, and our analysis demonstrates that remarkably regular LBM fluctuations persisted over the past 1173 years with population peaks averaging every 9.3 years. These regular abundance oscillations recurred until 1981, with the absence of peak events during recent decades. Comparison with an annually resolved, millennium-long temperature reconstruction representative for the European Alps ( r =0.72, correlation with instrumental data) demonstrates that regular insect population cycles continued despite major climatic changes related to warming during medieval times and cooling during the Little Ice Age. The late twentieth century absence of LBM outbreaks, however, corresponds to a period of regional warmth that is exceptional with respect to the last 1000+ years, suggesting vulnerability of an otherwise stable ecological system in a warming environment.

scholarly journals Temperature and mineral dust variability recorded in two low-accumulation Alpine ice cores over the last millennium

2018 ◽  
Vol 14 (1) ◽  
pp. 21-37 ◽  
Author(s):  
Pascal Bohleber ◽  
Tobias Erhardt ◽  
Nicole Spaulding ◽  
Helene Hoffmann ◽  
Hubertus Fischer ◽  
...  
Keyword(s):  
Time Series ◽  
Mineral Dust ◽  
Ice Core ◽  
Ice Cores ◽  
Temperature Reconstruction ◽  
Relative Increase ◽  
Ice Age ◽  
European Alps ◽  
Stable Water Isotopes ◽  
Annual Layer

Abstract. Among ice core drilling sites in the European Alps, Colle Gnifetti (CG) is the only non-temperate glacier to offer climate records dating back at least 1000 years. This unique long-term archive is the result of an exceptionally low net accumulation driven by wind erosion and rapid annual layer thinning. However, the full exploitation of the CG time series has been hampered by considerable dating uncertainties and the seasonal summer bias in snow preservation. Using a new core drilled in 2013 we extend annual layer counting, for the first time at CG, over the last 1000 years and add additional constraints to the resulting age scale from radiocarbon dating. Based on this improved age scale, and using a multi-core approach with a neighbouring ice core, we explore the time series of stable water isotopes and the mineral dust proxies Ca2+ and insoluble particles. Also in our latest ice core we face the already known limitation to the quantitative use of the stable isotope variability based on a high and potentially non-stationary isotope/temperature sensitivity at CG. Decadal trends in Ca2+ reveal substantial agreement with instrumental temperature and are explored here as a potential site-specific supplement to the isotope-based temperature reconstruction. The observed coupling between temperature and Ca2+ trends likely results from snow preservation effects and the advection of dust-rich air masses coinciding with warm temperatures. We find that if calibrated against instrumental data, the Ca2+-based temperature reconstruction is in robust agreement with the latest proxy-based summer temperature reconstruction, including a “Little Ice Age” cold period as well as a medieval climate anomaly. Part of the medieval climate period around AD 1100–1200 clearly stands out through an increased occurrence of dust events, potentially resulting from a relative increase in meridional flow and/or dry conditions over the Mediterranean.

scholarly journals Simulated retreat of Jakobshavn Isbræ since the Little Ice Age controlled by geometry

2018 ◽  
Vol 12 (7) ◽  
pp. 2249-2266 ◽  
Author(s):  
Nadine Steiger ◽  
Kerim H. Nisancioglu ◽  
Henning Åkesson ◽  
Basile de Fleurian ◽  
Faezeh M. Nick
Keyword(s):  
Little Ice Age ◽  
Ice Age ◽  
Climate Forcing ◽  
Relative Role ◽  
Regional Warming ◽  
History Of ◽  
The Impact ◽  
Term Response

Abstract. Rapid retreat of Greenland's marine-terminating glaciers coincides with regional warming trends, which have broadly been used to explain these rapid changes. However, outlet glaciers within similar climate regimes experience widely contrasting retreat patterns, suggesting that the local fjord geometry could be an important additional factor. To assess the relative role of climate and fjord geometry, we use the retreat history of Jakobshavn Isbræ, West Greenland, since the Little Ice Age (LIA) maximum in 1850 as a baseline for the parameterization of a depth- and width-integrated ice flow model. The impact of fjord geometry is isolated by using a linearly increasing climate forcing since the LIA and testing a range of simplified geometries. We find that the total length of retreat is determined by external factors – such as hydrofracturing, submarine melt and buttressing by sea ice – whereas the retreat pattern is governed by the fjord geometry. Narrow and shallow areas provide pinning points and cause delayed but rapid retreat without additional climate warming, after decades of grounding line stability. We suggest that these geometric pinning points may be used to locate potential sites for moraine formation and to predict the long-term response of the glacier. As a consequence, to assess the impact of climate on the retreat history of a glacier, each system has to be analyzed with knowledge of its historic retreat and the local fjord geometry.

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>

Temperature reconstruction from tree-ring maximum latewood density of Qinghai spruce in middle Hexi Corridor, China

2011 ◽  
Vol 107 (3-4) ◽  
pp. 633-643 ◽  
Author(s):  
Feng Chen ◽  
Yu-jiang Yuan ◽  
Wen-shou Wei ◽  
Shu-long Yu ◽  
Zi-ang Fan ◽  
...  
Keyword(s):  
Tree Ring ◽  
Temperature Reconstruction ◽  
Hexi Corridor ◽  
Maximum Latewood Density ◽  
Latewood Density ◽  
Qinghai Spruce

scholarly journals Chemical destaining and the delta correction for blue intensity measurements of stained lake subfossil trees

2020 ◽  
Vol 17 (18) ◽  
pp. 4559-4570 ◽  
Author(s):  
Feng Wang ◽  
Dominique Arseneault ◽  
Étienne Boucher ◽  
Shulong Yu ◽  
Steeven Ouellet ◽  
...  
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Black Spruce ◽  
Temperature Reconstruction ◽  
Sodium Dithionite ◽  
Sodium Ascorbate ◽  
Maximum Latewood Density ◽  
Intensity Measurements ◽  
Latewood Density ◽  
Canadian Boreal Forest ◽  
Blue Intensity

Abstract. The stain of wood samples from lake subfossil trees (LSTs) is challenging the wide application of the blue intensity (BI) technique for millennial dendroclimatic reconstructions. In this study, we used seven chemical destaining reagents to treat samples of subfossil black spruce (Picea mariana (Mill.) B.S.P.) trees from two lakes in the eastern Canadian boreal forest. We subsequently compared latewood BI (LBI) and delta BI (DBI) time series along with conventional maximum latewood density (MXD) measured from the stained and destained samples. Results showed that the stain of our samples is most likely caused by postsampling oxidation of dissolved ferrous iron in lake sediments that penetrated into wood. Three reagents (ascorbic acid, sodium ascorbate, and sodium dithionite all mixed with ethylenediaminetetraacetic acid) could remove >90 % of Fe. However, even for the best chemical protocol, a discrepancy of about +2 ∘C compared to MXD data remained in the LBI-based temperature reconstruction due to incomplete destaining. On the contrary, the simple mathematical delta correction, DBI, was unaffected by the Fe stain and showed very similar results compared to MXD data (r>0.82) from annual to centennial timescales over the past ∼360 years. This study underlines the difficulty of completely destaining lake subfossil samples while confirming the robustness of the DBI approach. DBI data measured from stained LSTs can be used to perform robust millennial temperature reconstructions.

scholarly journals Temperature and mineral dust variability recorded in two low accumulation Alpine ice cores over the last millennium

2017 ◽  
Author(s):  
Pascal Bohleber ◽  
Tobias Erhardt ◽  
Nicole Spaulding ◽  
Helene Hoffmann ◽  
Hubertus Fischer ◽  
...  
Keyword(s):  
Time Series ◽  
Mineral Dust ◽  
Ice Core ◽  
Ice Cores ◽  
Temperature Reconstruction ◽  
Ice Age ◽  
European Alps ◽  
Annual Layer ◽  
Instrumental Temperature

Abstract. Among ice core drilling sites in the European Alps, the Colle Gnifetti (CG) glacier saddle is the only one to offer climate records back to at least 1000 years. This unique long-term archive is the result of an exceptionally low net accumulation driven by wind erosion and rapid annual layer thinning. To-date, however, the full exploitation of the CG time series has been hampered by considerable dating uncertainties and the seasonal summer bias in snow preservation. Using a new core drilled in 2013 we extend annual layer counting, for the first time at CG, over the last 1000 years and add additional constraints to the resulting age scale from radiocarbon dating. Based on this improved age scale, and using a multi-core approach with a neighboring ice core, we explore the potential for reconstructing long-term temperature variability from the stable water isotope and mineral dust proxy time series. A high and potentially non-stationary isotope/temperature sensitivity limits the quantitative use of the stable isotope variability thus far. However, we find substantial agreement comparing the mineral dust proxy Ca2+ with instrumental temperature. The temperature-related variability in the Ca2+ record is explained based on the temperature-dependent snow preservation bias combined with the advection of dust-rich air masses coinciding with warm temperatures. We show that using the Ca2+ trends for a quantitative temperature reconstruction results in good agreement with instrumental temperature and the latest summer temperature reconstruction derived from other archives covering the last 1000 years. This includes a Little Ice Age cold period as well as a medieval climate anomaly. In particular, part of the medieval climate period around 1100–1200 AD stands out through an increased occurrence of dust events, potentially resulting from a relative increase in meridional flow and dry conditions over the Mediterranean.

scholarly journals Influence of solar variability, CO<sub>2</sub> and orbital forcing between 1000 and 1850 AD in the IPSLCM4 model

2010 ◽  
Vol 6 (4) ◽  
pp. 445-460 ◽  
Author(s):  
J. Servonnat ◽  
P. Yiou ◽  
M. Khodri ◽  
D. Swingedouw ◽  
S. Denvil
Keyword(s):  
Climate Model ◽  
Internal Variability ◽  
Temperature Reconstruction ◽  
Temperature Variability ◽  
Ice Age ◽  
Last Millennium ◽  
Orbital Forcing ◽  
Temperature Reconstructions ◽  
Temperature Signal ◽  
The Impact

Abstract. Studying the climate of the last millennium gives the possibility to deal with a relatively well-documented climate essentially driven by natural forcings. We have performed two simulations with the IPSLCM4 climate model to evaluate the impact of Total Solar Irradiance (TSI), CO2 and orbital forcing on secular temperature variability during the preindustrial part of the last millennium. The Northern Hemisphere (NH) temperature of the simulation reproduces the amplitude of the NH temperature reconstructions over the last millennium. Using a linear statistical decomposition we evaluated that TSI and CO2 have similar contributions to secular temperature variability between 1425 and 1850 AD. They generate a temperature minimum comparable to the Little Ice Age shown by the temperature reconstructions. Solar forcing explains ~80% of the NH temperature variability during the first part of the millennium (1000–1425 AD) including the Medieval Climate Anomaly (MCA). It is responsible for a warm period which occurs two centuries later than in the reconstructions. This mismatch implies that the secular variability during the MCA is not fully explained by the response of the model to the TSI reconstruction. With a signal-noise ratio (SNR) estimate we found that the temperature signal of the forced simulation is significantly different from internal variability over area wider than ~5.106 km2, i.e. approximately the extent of Europe. Orbital forcing plays a significant role in latitudes higher than 65° N in summer and supports the conclusions of a recent study on an Arctic temperature reconstruction over past two millennia. The forced variability represents at least half of the temperature signal on only ~30% of the surface of the globe. This study suggests that regional reconstructions of the temperature between 1000 and 1850 AD are likely to show weak signatures of solar, CO2 and orbital forcings compared to internal variability.

scholarly journals Influence of solar variability, CO<sub>2</sub> and orbital forcing during the last millennium in the IPSLCM4 model

2010 ◽  
Vol 6 (2) ◽  
pp. 421-460
Author(s):  
J. Servonnat ◽  
P. Yiou ◽  
M. Khodri ◽  
D. Swingedouw ◽  
S. Denvil
Keyword(s):  
Climate Model ◽  
Internal Variability ◽  
Temperature Reconstruction ◽  
Temperature Variability ◽  
Ice Age ◽  
Last Millennium ◽  
Orbital Forcing ◽  
Temperature Reconstructions ◽  
Temperature Signal ◽  
The Impact

Abstract. Studying the climate of the last millennium gives the possibility to deal with a relatively well-documented climate essentially driven by natural forcings. We have performed two simulations with the IPSLCM4 climate model to evaluate the impact of Total Solar Irradiance (TSI), CO2 and orbital forcing on secular temperature variability during the preindustrial part of the last millennium. The Northern Hemisphere (NH) temperature of the simulation reproduces the amplitude of the NH temperature reconstructions over the last millennium. Using a linear statistical decomposition we evaluated that TSI and CO2 have similar contributions to secular temperature variability between 1425 and 1850 AD. They generate a temperature minimum comparable to the Little Ice Age shown by the temperature reconstructions. Solar forcing explains ~80% of the NH temperature variability during the first part of the millennium (1000–1425 AD) including the Medieval Climate Anomaly (MCA). It is responsible for a warm period which occurs two centuries later than in the reconstructions. This mismatch implies that the secular variability during the MCA is not fully explained by the response of the model to the TSI reconstruction. With a signal-noise ratio (SNR) estimate we found that the temperature signal of the forced simulation is significantly different from internal variability over area wider than ~5.106 km2, i.e. approximately the extent of Europe. Orbital forcing plays a significant role in latitudes higher than 65° N in summer and supports the conclusions of a recent study on an Arctic temperature reconstruction over past two millennia. The forced variability represents at least half of the temperature signal on only ~30% of the surface of the globe. The study of the SNR and local impacts of the forcings suggests that individual temperature reconstructions taken from random location around the Globe are potentially weakly affected by a linear response to external forcings.

scholarly journals Fire history on the California Channel Islands spanning human arrival in the Americas

2016 ◽  
Vol 371 (1696) ◽  
pp. 20150167 ◽  
Author(s):  
Mark Hardiman ◽  
Andrew C. Scott ◽  
Nicholas Pinter ◽  
R. Scott Anderson ◽  
Ana Ejarque ◽  
...  
Keyword(s):  
Radiocarbon Dating ◽  
Fire History ◽  
Ice Age ◽  
Channel Islands ◽  
Test Bed ◽  
California Channel Islands ◽  
History Of ◽  
Santa Rosa Island ◽  
Age Range ◽  
The Impact

Recent studies have suggested that the first arrival of humans in the Americas during the end of the last Ice Age is associated with marked anthropogenic influences on landscape; in particular, with the use of fire which, would have given even small populations the ability to have broad impacts on the landscape. Understanding the impact of these early people is complicated by the dramatic changes in climate occurring with the shift from glacial to interglacial conditions. Despite these difficulties, we here attempt to test the extent of anthropogenic influence using the California Channel Islands as a smaller, landscape-scale test bed. These islands are famous for the discovery of the ‘Arlington Springs Man’, which are some of the earliest human remains in the Americas. A unifying sedimentary charcoal record is presented from Arlington Canyon, Santa Rosa Island, based on over 20 detailed sedimentary sections from eight key localities. Radiocarbon dating was based on thin, fragile, long fragments of charcoal in order to avoid the ‘inbuilt’ age problem. Radiocarbon dating of 49 such fragments has allowed inferences regarding the fire and landscape history of the Canyon ca 19–11 ka BP. A significant period of charcoal deposition is identified approximately 14–12.5 ka BP and bears remarkable closeness to an estimated age range of the first human arrival on the islands. This article is part of the themed issue ‘The interaction of fire and mankind’.

scholarly journals Chemical de-staining and the delta correction for blue intensity measurements of stained lake subfossil trees

2020 ◽  
Author(s):  
Feng Wang ◽  
Dominique Arseneault ◽  
Étienne Boucher ◽  
Shulong Yu ◽  
Steeven Ouellet ◽  
...  
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Black Spruce ◽  
Temperature Reconstruction ◽  
Sodium Dithionite ◽  
Sodium Ascorbate ◽  
Maximum Latewood Density ◽  
Intensity Measurements ◽  
Latewood Density ◽  
Canadian Boreal Forest ◽  
Blue Intensity

Abstract. The stain of wood samples from lake subfossil trees (LSTs) is challenging the wide application of the blue intensity (BI) technique for millennial dendroclimatic reconstructions. In this study, we used seven chemical de-staining reagents to treat samples of subfossil black spruce (Picea mariana (Mill.) B.S.P.)) trees from two lakes in the eastern Canadian boreal forest. We subsequently compared latewood BI (LBI) and delta BI (DBI) time series along with conventional maximum latewood density (MXD) measured from the stained and de-stained samples. Results show that the stain of our samples is most likely caused by post-sampling oxidation of dissolved ferrous iron in lake sediments that penetrated into wood. Three reagents (ascorbic acid, sodium ascorbate and sodium dithionite all mixed with ethylenediaminetetraacetic acid) could remove > 90 % of Fe. However, even for the best chemical protocol, a discrepancy of about +2 °C compared to MXD data remains in the LBI-based temperature reconstruction due to incomplete de-staining. On the contrary, the simple mathematical delta correction, DBI is unaffected by Fe stain and shows very similar results compared to MXD data (r > 0.82) from annual to centennial timescales over the past ~ 360 years. This study underlines the difficulty of completely de-staining lake subfossil samples, while confirming the robustness of the DBI approach. DBI data measured from stained LSTs can be used to perform robust millennial temperature reconstructions.

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