scholarly journals Volcanic climate forcing, extreme cold and the Neolithic Transition in the northern US Southwest

Antiquity ◽  
2021 ◽  
pp. 1-19
Author(s):  
R.J. Sinensky ◽  
Gregson Schachner ◽  
Richard H. Wilshusen ◽  
Brian N. Damiata

The impacts on global climate of the AD 536 and 541 volcanic eruptions are well attested in palaeoclimatic datasets and in Eurasian historical records. Their effects on farmers in the arid uplands of western North America, however, remain poorly understood. The authors investigate whether extreme cold caused by these eruptions influenced the scale, scope and timing of the Neolithic Transition in the northern US Southwest. Archaeological tree-ring and radiocarbon dates, along with settlement survey data suggest that extreme cooling generated the physical and social space that enabled early farmers to transition from kin-focused socio-economic strategies to increasingly complex and widely shared forms of social organisation that served as foundational elements of burgeoning Ancestral Pueblo societies.

2021 ◽  
pp. 1-9
Author(s):  
Feng Shi ◽  
Anmin Duan ◽  
Qiuzhen Yin ◽  
John T Bruun ◽  
Cunde Xiao ◽  
...  

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.


1988 ◽  
Vol 30 (3) ◽  
pp. 315-330 ◽  
Author(s):  
Julie M. Palais ◽  
Philip R. Kyle

The chemical composition of ice containing tephra (volcanic ash) layers in 22 sections of the Byrd Station ice core was examined to determine if the volcanic eruptions affected the chemical composition of the atmosphere and precipitation in the vicinity of Byrd Station. The liquid conductivity, acidity, sulfate, nitrate, aluminum, and sodium concentrations of ice samples deposited before, during, and after the deposition of the tephra layers were analyzed. Ice samples that contain tephra layers have, on average, about two times more sulfate and three to four times more aluminum than nonvolcanic ice samples. The acidity of ice samples associated with tephra layers is lowered by hydrolysis of silicate glass and minerals. Average nitrate, sodium, and conductivity are the same in all samples. Because much of the sulfur and chlorine originally associated with these eruptions may have been scavenged by ash particles, the atmospheric residence time of these volatiles would have been minimized. Therefore the eruptions probably had only a small effect on the composition of the Antarctic atmosphere and a negligible effect on local or global climate.


2021 ◽  
Author(s):  
Rafael Castro ◽  
Tushar Mittal ◽  
Stephen Self

<p>The 1883 Krakatau eruption is one of the most well-known historical volcanic eruptions due to its significant global climate impact as well as first recorded observations of various aerosol associated optical and physical phenomena. Although much work has been done on the former by comparison of global climate model predictions/ simulations with instrumental and proxy climate records, the latter has surprisingly not been studied in similar detail. In particular, there is a wealth of observations of vivid red sunsets, blue suns, and other similar features, that can be used to analyze the spatio-temporal dispersal of volcanic aerosols in summer to winter 1883. Thus, aerosol cloud dispersal after the Krakatau eruption can be estimated, bolstered by aerosol cloud behavior as monitored by satellite-based instrument observations after the 1991 Pinatubo eruption. This is one of a handful of large historic eruptions where this analysis can be done (using non-climate proxy methods). In this study, we model particle trajectories of the Krakatau eruption cloud using the Hysplit trajectory model and compare our results with our compiled observational dataset (principally using Verbeek 1884, the Royal Society report, and Kiessling 1884).</p><p>In particular, we explore the effect of different atmospheric states - the quasi-biennial oscillation (QBO) which impacts zonal movement of the stratospheric volcanic plume - to estimate the phase of the QBO in 1883 required for a fast-moving westward cloud. Since this alone is unable to match the observed latitudinal spread of the aerosols, we then explore the impact of an  umbrella cloud (2000 km diameter) that almost certainly formed during such a large eruption. A large umbrella cloud, spreading over ~18 degrees within the duration of the climax of the eruption (6-8 hours), can lead to much quicker latitudinal spread than a point source (vent). We will discuss the results of the combined model (umbrella cloud and correct QBO phase) with historical accounts and observations, as well as previous work on the 1991 Pinatubo eruption. We also consider the likely impacts of water on aerosol concentrations and the relevance of this process for eruptions with possible significant seawater interactions, like Krakatau. We posit that the role of umbrella clouds is an under-appreciated, but significant, process for beginning to model the climatic impacts of large volcanic eruptions.</p>


2021 ◽  
pp. SP520-2021-63
Author(s):  
L. Capra ◽  
M. Roverato ◽  
J. P. Bernal ◽  
A. Cortés

AbstractVolcán de Colima, one of the most active volcanoes in Mexico, experienced at least nine flank failures during the last 30,000 years, with catastrophic effects on the environment that implies the formation of temporary dams where lacustrine sediments accumulated for hundreds of years. These lacustrine sequences preserve an exceptional record from which to reconstruct the effect of subsequent volcanic eruptions and, eventually, contemporary environmental and climatic conditions. Here we analyze an Early Holocene lacustrine sequence, named “Gypsum King”, which accumulated in a short-lived temporary lake, likely formed by emplacement of the 10755-11230 cal. yr BP Mesa-Yerbabuena debris avalanche. Through detailed analysis of the 1.8 m thick lacustrine sequence (14C ages, sulfur content, grain size), it was possible to identify the 8.2 kyr global climate event and better constrain the Early-Holocene main sub-plinian to plinian eruptions of Volcán de Colima. The results presented here highlight the potential to explore sulfur content and abrupt change in grainsize in lacustrine sediments as additional proxies to better constrain eruptive phases in volcanic environments. Finally, the Gypsum King sequence provides the first evidence of the 8.2 kyr global climate event along the Eastern tropical Pacific Coast.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5563424


2015 ◽  
Vol 15 (13) ◽  
pp. 7523-7536 ◽  
Author(s):  
G. P. Schill ◽  
K. Genareau ◽  
M. A. Tolbert

Abstract. Ice nucleation of volcanic ash controls both ash aggregation and cloud glaciation, which affect atmospheric transport and global climate. Previously, it has been suggested that there is one characteristic ice nucleation efficiency for all volcanic ash, regardless of its composition, when accounting for surface area; however, this claim is derived from data from only two volcanic eruptions. In this work, we have studied the depositional and immersion freezing efficiency of three distinct samples of volcanic ash using Raman microscopy coupled to an environmental cell. Ash from the Fuego (basaltic ash, Guatemala), Soufrière Hills (andesitic ash, Montserrat), and Taupo (Oruanui eruption, rhyolitic ash, New Zealand) volcanoes were chosen to represent different geographical locations and silica content. All ash samples were quantitatively analyzed for both percent crystallinity and mineralogy using X-ray diffraction. In the present study, we find that all three samples of volcanic ash are excellent depositional ice nuclei, nucleating ice from 225 to 235 K at ice saturation ratios of 1.05 ± 0.01, comparable to the mineral dust proxy kaolinite. Since depositional ice nucleation will be more important at colder temperatures, fine volcanic ash may represent a global source of cold-cloud ice nuclei. For immersion freezing relevant to mixed-phase clouds, however, only the Oruanui ash exhibited appreciable heterogeneous ice nucleation activity. Similar to recent studies on mineral dust, we suggest that the mineralogy of volcanic ash may dictate its ice nucleation activity in the immersion mode.


Antiquity ◽  
2004 ◽  
Vol 78 (301) ◽  
pp. 708-710 ◽  
Author(s):  
Philippe Crombé ◽  
Mark Van Strydonck

In volume 295 of Antiquity M. Gkiasta et al. (2003) discussed the results of two sets of analysis carried out on a “new” database of radiocarbon dates: one for the whole of Europe examining the spread of the Neolithic, and one regional approach looking at the relation between Mesolithic and Neolithic dates. Although we are convinced of the potential of both approaches, we do have some major comments on the methodology.First of all the analyses were conducted on a highly incomplete database. As the authors state on their p. 48, the analysed database currently includes over 2600 samples. Many of them, however, had already been collated in Gob’s Atlas of 14C dates (1990). Although the authors have included new dates, we do not believe that this has been done very systematically. For the Belgian territory, for example, virtually all the dates used in the article were those published by Gob – 16 Mesolithic dates and 30 Neolithic dates. The authors justify this by referring to the bad state of publication and public availability of radiocarbon dates in Europe. This certainly does not hold for the Belgian territory. In the last decade over a hundred new Mesolithic and Neolithic dates have been produced, the majority published in journals available world-wide such as Radiocarbon (Van Strydonck et al. 1995; 2001a), Antiquity (Crombé et al. 2002), Archaeometry (Cauwe et al. 2002) proceedings of the international congresses such as 14C and archaeology (Crombé et al. 1999) and The Mesolithic in Europe (Crombé 1999), and the IRPA- datelists (Van Strydonck et al. 2001b; Van Strydonck et al. 2002). The authors assert that these “shortcomings” to the database probably do not affect their conclusions. This is a rash and provocative statement, which minimises all recent progress in absolute dating of the European Mesolithic and Neolithic. We believe that for the Belgian situation a hundred new dates can make a difference. In recent years, for example, these new dates have allowed a thorough revision of Mesolithic chronology (Crombé 1999; Van Strydonck et al. 2001a) and a refinement of the (early) Neolithic chronology (Jadin & Cahen 2003). This will certainly also be the case for the other study-areas in Europe.


Science ◽  
2020 ◽  
Vol 367 (6485) ◽  
pp. 1477-1481 ◽  
Author(s):  
Sylvia G. Dee ◽  
Kim M. Cobb ◽  
Julien Emile-Geay ◽  
Toby R. Ault ◽  
R. Lawrence Edwards ◽  
...  

The El Niño–Southern Oscillation (ENSO) shapes global climate patterns yet its sensitivity to external climate forcing remains uncertain. Modeling studies suggest that ENSO is sensitive to sulfate aerosol forcing associated with explosive volcanism but observational support for this effect remains ambiguous. Here, we used absolutely dated fossil corals from the central tropical Pacific to gauge ENSO’s response to large volcanic eruptions of the last millennium. Superposed epoch analysis reveals a weak tendency for an El Niño–like response in the year after an eruption, but this response is not statistically significant, nor does it appear after the outsized 1257 Samalas eruption. Our results suggest that those models showing a strong ENSO response to volcanic forcing may overestimate the size of the forced response relative to natural ENSO variability.


2019 ◽  
Vol 32 (12) ◽  
pp. 3727-3742 ◽  
Author(s):  
Mukund Gupta ◽  
John Marshall ◽  
David Ferreira

Abstract A coupled climate model with idealized representations of atmosphere, ocean, sea ice, and land is used to investigate transitions between global climate equilibria. The model supports the presence of climates with limited ice cover (Warm), a continuum of climates in which sea ice extends down into the midlatitudes and the tropics (Cold), together with a completely ice-covered earth (Snowball). Transitions between these states are triggered through volcanic eruptions, where the radiative effect of stratospheric sulfur emissions is idealized as an impulse reduction in incoming solar radiation. Snowball transitions starting from the Cold state are more favorable than from the Warm state, because less energy must be extracted from the system. However, even when starting from a Cold climate, Toba-like volcanic events (cooling of order −100 W m−2) must be sustained continuously for several decades to glaciate the entire planet. When the deep ocean is involved, the volcanic response is characterized by relaxation time scales spanning hundreds to thousands of years. If the interval between successive eruptions is significantly shorter (years to decades) than the ocean’s characteristic time scales, the cumulative cooling can build over time and initiate a state transition. The model exhibits a single hysteresis loop that connects all three climate equilibria. When starting from a Snowball, the model cannot access the Cold branch without first transitioning to an ice-free climate and completing the hysteresis loop. By contrast, a Cold state, when warmed, transitions to the Warm equilibrium without any hysteresis.


2019 ◽  
Vol 15 (2) ◽  
pp. 685-700 ◽  
Author(s):  
Olga V. Churakova (Sidorova) ◽  
Marina V. Fonti ◽  
Matthias Saurer ◽  
Sébastien Guillet ◽  
Christophe Corona ◽  
...  

Abstract. Stratospheric volcanic eruptions have far-reaching impacts on global climate and society. Tree rings can provide valuable climatic information on these impacts across different spatial and temporal scales. To detect temperature and hydroclimatic changes after strong stratospheric Common Era (CE) volcanic eruptions for the last 1500 years (535 CE unknown, 540 CE unknown, 1257 CE Samalas, 1640 CE Parker, 1815 CE Tambora, and 1991 CE Pinatubo), we measured and analyzed tree-ring width (TRW), maximum latewood density (MXD), cell wall thickness (CWT), and δ13C and δ18O in tree-ring cellulose chronologies of climate-sensitive larch trees from three different Siberian regions (northeastern Yakutia – YAK, eastern Taimyr – TAY, and Russian Altai – ALT). All tree-ring proxies proved to encode a significant and specific climatic signal of the growing season. Our findings suggest that TRW, MXD, and CWT show strong negative summer air temperature anomalies in 536, 541–542, and 1258–1259 at all studied regions. Based on δ13C, 536 was extremely humid at YAK, as was 537–538 in TAY. No extreme hydroclimatic anomalies occurred in Siberia after the volcanic eruptions in 1640, 1815, and 1991, except for 1817 at ALT. The signal stored in δ18O indicated significantly lower summer sunshine duration in 542 and 1258–1259 at YAK and 536 at ALT. Our results show that trees growing at YAK and ALT mainly responded the first year after the eruptions, whereas at TAY, the growth response occurred after 2 years. The fact that differences exist in climate responses to volcanic eruptions – both in space and time – underlines the added value of a multiple tree-ring proxy assessment. As such, the various indicators used clearly help to provide a more realistic picture of the impact of volcanic eruption on past climate dynamics, which is fundamental for an improved understanding of climate dynamics, but also for the validation of global climate models.


2020 ◽  
Author(s):  
Laura Sobral Verona ◽  
Ilana Wainer ◽  
Myriam Khodri

<p>Large volcanic eruptions can affect the global climate through changes in atmospheric and ocean circulation. Understanding the influence of volcanic eruptions on the hydroclimate over monsoon regions is of great scientific and social importance. The South America Monsoon System (SAMS) is the most important climatic feature of the continent. Both the Intertropical and the South Atlantic wind convergence zones (ITCZ and SACZ, respectively) are fundamental components of the SAMS. They show variations on a broad range of scales, dependent on complex multi-system interactions with the adjacent Atlantic Ocean and teleconnections. Also driven by the winds, the Atlantic Subtropical Cell (STC) is the link between the subduction zone in the subtropical gyre with the tropics. Hence, the STC influence equatorial sea surface temperature variability on interannual to decadal scales in the tropical Atlantic Ocean. In order to improve our understanding of the responses of the ocean-atmosphere system to the volcanic forcing, we aim to identify the dominant mechanisms of seasonal-to-interdecadal variability of the SAMS and the Atlantic STC after large Pinatubo-like (1991) and Tambora-like (1815) eruptions relying on the VolMIP model intercomparison project experiments.</p>


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