Multidecadal climate oscillations during the past millennium driven by volcanic forcing

Science ◽  
2021 ◽  
Vol 371 (6533) ◽  
pp. 1014-1019
Author(s):  
Michael E. Mann ◽  
Byron A. Steinman ◽  
Daniel J. Brouillette ◽  
Sonya K. Miller
Keyword(s):  
Past Research ◽  
Atlantic Multidecadal Oscillation ◽  
Oscillatory Behavior ◽  
Time Varying ◽  
Sulfate Aerosols ◽  
Climate Oscillations ◽  
The Past ◽  
Volcanic Forcing ◽  
Climate Noise ◽  
Past Millennium

Past research argues for an internal multidecadal (40- to 60-year) oscillation distinct from climate noise. Recent studies have claimed that this so-termed Atlantic Multidecadal Oscillation is instead a manifestation of competing time-varying effects of anthropogenic greenhouse gases and sulfate aerosols. That conclusion is bolstered by the absence of robust multidecadal climate oscillations in control simulations of current-generation models. Paleoclimate data, however, do demonstrate multidecadal oscillatory behavior during the preindustrial era. By comparing control and forced “Last Millennium” simulations, we show that these apparent multidecadal oscillations are an artifact of pulses of volcanic activity during the preindustrial era that project markedly onto the multidecadal (50- to 70-year) frequency band. We conclude that there is no compelling evidence for internal multidecadal oscillations in the climate system.

Volcanoes and ENSO over the Past Millennium

2008 ◽  
Vol 21 (13) ◽  
pp. 3134-3148 ◽  
Author(s):  
Julien Emile-Geay ◽  
Richard Seager ◽  
Mark A. Cane ◽  
Edward R. Cook ◽  
Gerald H. Haug
Keyword(s):  
El Niño ◽  
El Nino ◽  
Volcanic Eruptions ◽  
Explosive Volcanism ◽  
The Past ◽  
El Niño Event ◽  
Volcanic Forcing ◽  
El Niño Events ◽  
Past Millennium ◽  
El Nino Events

Abstract The controversial claim that El Niño events might be partially caused by radiative forcing due to volcanic aerosols is reassessed. Building on the work of Mann et al., estimates of volcanic forcing over the past millennium and a climate model of intermediate complexity are used to draw a diagram of El Niño likelihood as a function of the intensity of volcanic forcing. It is shown that in the context of this model, only eruptions larger than that of Mt. Pinatubo (1991, peak dimming of about 3.7 W m−2) can shift the likelihood and amplitude of an El Niño event above the level of the model’s internal variability. Explosive volcanism cannot be said to trigger El Niño events per se, but it is found to raise their likelihood by 50% on average, also favoring higher amplitudes. This reconciles, on one hand, the demonstration by Adams et al. of a statistical relationship between explosive volcanism and El Niño and, on the other hand, the ability to predict El Niño events of the last 148 yr without knowledge of volcanic forcing. The authors then focus on the strongest eruption of the millennium (A.D. 1258), and show that it is likely to have favored the occurrence of a moderate-to-strong El Niño event in the midst of prevailing La Niña–like conditions induced by increased solar activity during the well-documented Medieval Climate Anomaly. Compiling paleoclimate data from a wide array of sources, a number of important hydroclimatic consequences for neighboring areas is documented. The authors propose, in particular, that the event briefly interrupted a solar-induced megadrought in the southwestern United States. Most of the time, however, volcanic eruptions are found to be too small to significantly affect ENSO statistics.

scholarly journals Discrepancies between the modeled and proxy-reconstructed response to volcanic forcing over the past millennium: Implications and possible mechanisms

2013 ◽  
Vol 118 (14) ◽  
pp. 7617-7627 ◽  
Author(s):  
Michael E. Mann ◽  
Scott Rutherford ◽  
Andrew Schurer ◽  
Simon F.B. Tett ◽  
Jose D. Fuentes
Keyword(s):  
The Past ◽  
Volcanic Forcing ◽  
Past Millennium

Exploring the Boundaries of the Number–Temporal Order Association

2015 ◽  
Vol 62 (3) ◽  
pp. 198-205 ◽  
Author(s):  
Dana Ganor-Stern
Keyword(s):  
Embodied Cognition ◽  
Mental Representation ◽  
Temporal Order ◽  
Past Research ◽  
Numerical Comparison ◽  
Negative Number ◽  
Comparison Task ◽  
Negative Numbers ◽  
The Past

Past research has shown that numbers are associated with order in time such that performance in a numerical comparison task is enhanced when number pairs appear in ascending order, when the larger number follows the smaller one. This was found in the past for the integers 1–9 ( Ben-Meir, Ganor-Stern, & Tzelgov, 2013 ; Müller & Schwarz, 2008 ). In the present study we explored whether the advantage for processing numbers in ascending order exists also for fractions and negative numbers. The results demonstrate this advantage for fraction pairs and for integer-fraction pairs. However, the opposite advantage for descending order was found for negative numbers and for positive-negative number pairs. These findings are interpreted in the context of embodied cognition approaches and current theories on the mental representation of fractions and negative numbers.

HURRICANE FREQUENCY NEAR CHESAPEAKE BAY DURING THE PAST MILLENNIUM

2019 ◽  
Author(s):  
Michael Toomey ◽  
◽  
Nicole D'Entremont ◽  
Emma Armstrong ◽  
Thomas Cronin ◽  
...  
Keyword(s):  
Chesapeake Bay ◽  
The Past ◽  
Past Millennium

scholarly journals Creating Price Indexes for Measuring Productivity in Mental Health Care

2001 ◽  
Vol 4 (1) ◽  
Author(s):  
Susan H. Busch ◽  
Ernst R. Berndt ◽  
Richard G. Frank
Keyword(s):  
Mental Health ◽  
Health Care ◽  
Major Depression ◽  
Price Index ◽  
Time Varying ◽  
Measurement Issues ◽  
The Past ◽  
Price Indexes ◽  
Treatment Technologies ◽  
New Treatment

Economists have long suggested that to be reliable, a preferred medical care price index should employ time-varying weights to measure outcomes-adjusted changes in the price of treating an episode of illness. In this article, we report on several years of research developing alternative indexes for the treatment of the acute phase of major depression, for the period 1991–1996. The introduction of new treatment technologies in the past two decades suggests well-known measurement issues may be prominent in constructing such a price index.We report on the results of four successively re

scholarly journals Conceptualizing histories of multispecies entanglements: Ancient pathogen genomics and the case of Borrelia recurrentis

2021 ◽  
pp. 146960532199394
Author(s):  
Venla Oikkonen
Keyword(s):  
East Africa ◽  
Ancient Dna ◽  
Relapsing Fever ◽  
Borrelia Recurrentis ◽  
The Past ◽  
Cultural Implications ◽  
Past Millennium

This article explores the conceptual and cultural implications of using pathogen ancient DNA (aDNA) collected in archaeological contexts to understand the past. More specifically, it examines ancient pathogen genomics as a way of conceptualizing multispecies entanglements. The analysis focuses on the 2018 sequencing of Borrelia recurrentis bacteria retrieved from a medieval graveyard in Oslo, Norway. B. recurrentis is associated with louse-borne relapsing fever (LBRF), known to have killed several million people in Europe during the past millennium, and it is still encountered in parts of East Africa. The article demonstrates that while aDNA research often foregrounds multispecies entanglements, its epistemic tools cannot easily address the ontological blurriness of pathogens and their embeddedness in vibrant material processes. The article draws on feminist posthumanities work on microbes and materiality to highlight conceptual openings that a theorization of ancient pathogens could engender.

scholarly journals Climate and environmental changes during the past millennium in central western Guizhou, China as recorded by Stalagmite ZJD-21

2011 ◽  
Vol 40 (6) ◽  
pp. 1111-1120 ◽  
Author(s):  
Tz-Shing Kuo ◽  
Zi-Qi Liu ◽  
Hong-Chun Li ◽  
Nai-Jung Wan ◽  
Chuan-Chou Shen ◽  
...  
Keyword(s):  
Environmental Changes ◽  
The Past ◽  
Western Guizhou ◽  
Past Millennium

scholarly journals Supporting Restoration Decisions through Integration of Tree-Ring and Modeling Data: Reconstructing Flow and Salinity in the San Francisco Estuary over the Past Millennium

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2139
Author(s):  
Paul H. Hutton ◽  
David M. Meko ◽  
Sujoy B. Roy
Keyword(s):  
San Francisco ◽  
Tree Ring ◽  
San Francisco Estuary ◽  
Salinity Intrusion ◽  
Estuarine Ecosystem ◽  
Freshwater Flow ◽  
The Past ◽  
Decadal Scale ◽  
Tree Ring Data ◽  
Past Millennium

This work presents updated reconstructions of watershed runoff to San Francisco Estuary from tree-ring data to AD 903, coupled with models relating runoff to freshwater flow to the estuary and salinity intrusion. We characterize pre-development freshwater flow and salinity conditions in the estuary over the past millennium and compare this characterization with contemporary conditions to better understand the magnitude and seasonality of changes over this time. This work shows that the instrumented flow record spans the range of runoff patterns over the past millennium (averaged over 5, 10, 20 and 100 years), and thus serves as a reasonable basis for planning-level evaluations of historical hydrologic conditions in the estuary. Over annual timescales we show that, although median freshwater flow to the estuary has not changed significantly, it has been more variable over the past century compared to pre-development flow conditions. We further show that the contemporary period is generally associated with greater spring salinity intrusion and lesser summer–fall salinity intrusion relative to the pre-development period. Thus, salinity intrusion in summer and fall months was a common occurrence under pre-development conditions and has been moderated in the contemporary period due to the operations of upstream reservoirs, which were designed to hold winter and spring runoff for release in summer and fall. This work also confirms a dramatic decadal-scale hydrologic shift in the watershed from very wet to very dry conditions during the late 19th and early 20th centuries; while not unprecedented, these shifts have been seen only a few times in the past millennium. This shift resulted in an increase in salinity intrusion in the first three decades of the 20th century, as documented through early records. Population growth and extensive watershed modification during this period exacerbated this underlying hydrologic shift. Putting this shift in the context of other anthropogenic drivers is important in understanding the historical response of the estuary and in setting salinity targets for estuarine restoration. By characterizing the long-term behavior of San Francisco Estuary, this work supports decision-making in the State of California related to flow and salinity management for restoration of the estuarine ecosystem.

Modulation of the relationship between summer temperatures in the Qinghai–Tibetan Plateau and Arctic over the past millennium by external forcings

2021 ◽  
pp. 1-9
Author(s):  
Feng Shi ◽  
Anmin Duan ◽  
Qiuzhen Yin ◽  
John T Bruun ◽  
Cunde Xiao ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Global Climate ◽  
Volcanic Eruptions ◽  
Warm Period ◽  
Temperature Correlation ◽  
The Past ◽  
External Forcings ◽  
Centennial Variation ◽  
Summer Temperatures ◽  
Past Millennium

Abstract The Qinghai–Tibetan Plateau and Arctic both have an important influence on global climate, but the correlation between climate variations in these two regions remains unclear. Here we reconstructed and compared the summer temperature anomalies over the past 1,120 yr (900–2019 CE) in the Qinghai–Tibetan Plateau and Arctic. The temperature correlation during the past millennium in these two regions has a distinct centennial variation caused by volcanic eruptions. Furthermore, the abrupt weak-to-strong transition in the temperature correlation during the sixteenth century could be analogous to this type of transition during the Modern Warm Period. The former was forced by volcanic eruptions, while the latter was controlled by changes in greenhouse gases. This implies that anthropogenic, as opposed to natural, forcing has acted to amplify the teleconnection between the Qinghai–Tibetan Plateau and Arctic during the Modern Warm Period.

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