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Large volcanic eruptions are one of the dominant perturbations to global and regional atmospheric temperatures on timescales of years to decades. Discrepancies remain, however, in the estimated magnitude and persistence of the surface temperature cooling caused by volcanic eruptions, as characterized by paleoclimatic proxies and climate models. We investigate these discrepancies in the context of large tropical eruptions over the Last Millennium using two state‐of‐the‐art data assimilation products, the Paleo Hydrodynamics Data Assimilation product (PHYDA) and the Last Millennium Reanalysis (LMR), and simulations from the National Center for Atmospheric Research Community Earth System Model‐Last Millennium Ensemble (NCAR CESM‐LME). We find that PHYDA and LMR estimate mean global and hemispheric cooling that is similar in magnitude and persistence once effects from eruptions occurring in short succession are removed. The estimates also compare well to Northern‐Hemisphere reconstructions based solely or partially on tree‐ring density, which have been proposed as the most accurate proxy estimates of surface cooling due to volcanism. All proxy‐based estimates also agree well with the magnitude of the mean cooling simulated by the CESM‐LME. Differences remain, however, in the spatial patterns of the temperature responses in the PHYDA, LMR, and the CESM‐LME. The duration of cooling anomalies also persists for several years longer in the PHYDA and LMR relative to the CESM‐LME. Our results demonstrate progress in resolving discrepancies between proxy‐ and model‐based estimates of temperature responses to volcanism, but also indicate these estimates must be further reconciled to better characterize the risks of future volcanic eruptions.

 

A pesar de la abundancia de desperdicios de talla líticos en los sitios precerámicos de las tierras bajas mayas, rara vez se han estudiado con gran detalle. Los desperdicios de talla de sílex de Caye Coco y Fred Smith, dos sitios del período Arcaico en el drenaje de Freshwater Creek en el norte de Belice, se analizaron para evaluar estrategias de obtención de materia prima lítica, producción de herramientas de piedra y uso de herramientas. Los análisis tecnológicos y de las huellas de uso de los desperdicios de talla demuestran que los habitantes de los sitios adquirieron la mayor parte de su piedra para herramientas de la zona de sílex del norte de Belice (NBCZ) y se basaron en la percusión de martillo duro para producir muchas lascas para su uso como herramientas no especializadas y algunas herramientas bifaciales y unifaciales simples. Aunque se demuestran patrones similares de adquisición de ambos sitios, existen algunas diferencias, incluida la reducción bipolar en Caye Coco. Según el análisis de las huellas de uso, los desperdicios de talla en el sitio de la isla de Caye Coco se utilizaron principalmente para trabajar madera, conchas, materiales de contacto duro y excavar tierra. En la costa de Fred Smith, la mayor parte las huellas de uso es consistente con trabajar madera, plantas y materiales de contacto duro, así como con excavar la tierra. Para ambos sitios, los análisis sugieren la creciente importancia de una estrategia de subsistencia hortícola con movilidad reducida y dependencia de algunos cultivos que se produjeron localmente. 

Large tropical volcanic eruptions can affect the climate of many regions on Earth, yet it is uncertain how the largest eruptions over the past millennium may have altered Earth’s hydroclimate. Here, we analyze the global hydroclimatic response to all the tropical volcanic eruptions over the past millennium that were larger than the Mount Pinatubo eruption of 1991. Using the Paleo Hydrodynamics Data Assimilation product (PHYDA), we find that these large volcanic eruptions tended to produce dry conditions over tropical Africa, Central Asia and the Middle East and wet conditions over much of Oceania and the South American monsoon region. These anomalies are statistically significant, and they persisted for more than a decade in some regions. The persistence of the anomalies is associated with southward shifts in the Intertropical Convergence Zone and sea surface temperature changes in the Pacific and Atlantic oceans. We compare the PHYDA results with the stand-alone model response of the Community Earth System Model (CESM)-Last Millennium Ensemble. We find that the proxy-constrained PHYDA estimates are larger and more persistent than the responses simulated by CESM. Understanding which of these estimates is more realistic is critical for accurately characterizing the hydroclimate risks of future volcanic eruptions. 

Abstract The fourth millennium b.p. in the Maya lowlands provides an interesting case, with mobile, aceramic peoples documented, while ceramic-using villagers lived in other parts of Mesoamerica. Rather than ask why ceramic containers and village life took so long to reach the Maya lowlands, the question can be inverted to posit that a mixed horticultural-foraging adaptation was so effective that it persisted longer than elsewhere. I propose that the so-called 4.2 ka b.p. event was the ultimate cause of increased sedentism and the first adoption of ceramic containers in a limited number of regions of Mesoamerica. My musings are grounded in the comparisons of data from the Soconusco region of southern Mexico and evidence from northern Belize at Colha and Pulltrouser Swamp, as well as the Freshwater Creek drainage. I assume that proximate behavior must account for local adaptations and different rates of change in each region of Mesoamerica. Therefore, regional adaptation in northern Belize during the Late Archaic period provides the evidence with which to reconstruct local adaptation. Excavations and regional reconnaissance document a distinctive orange soil horizon at Progresso Lagoon associated with patinated chert tools and an absence of ceramics. Stone tool assemblages from the preceramic components of three sites in the region indicate a spatial separation of tool use and resharpening at island versus shore. Starch grains recovered from these stone tools indicate that preceramic peoples in northern Belize harvested maize and several other domesticated plant species. These data are consistent with local paleoenvironmental studies that document an extended period of horticultural activity during the fifth and fourth millennia b.p. prior to the adoption of ceramics. Lithic assemblages and associated dietary information from multiple sites provide glimpses of the data necessary to reconstruct Late Archaic period adaptation from a single locale. Such data will be required to understand the proximate causes for the transition to a more settled, village life. 

In this paper, I discuss what is known of the Late Archaic occupation in northern Belize. The second millennium BC is the “Early Formative” for most of Mesoamerica but the subsistence and residential adaptation of the Maya lowlands residents up until ~1100 BC consisted of mixed foraging-horticulturalists with no ceramic containers or permanent villages. This means that an “Archaic” strategy persisted in the Maya area for almost a thousand years longer than elsewhere in Mesoamerica. I review evidence from the site of San Estevan where first ceramic-using (i.e., Swasey phase) villagers are documented with little evidence of their predecessors. Next, I review evidence of Archaic-period occupation on the west shore of Progresso Lagoon where maize, squash and chili peppers were cultivated by mobile foragers. Finally, I present plans to thoroughly document and date the second and third millennium BC occupation of Progresso Lagoon and explore how the global climatic change impacted the adaptation of forager-horticulturalists.