Author Correction: Limited capacity of tree growth to mitigate the global greenhouse effect under predicted warming.

An amendment to this paper has been published and can be accessed via a link at the top of the paper

Prominent role of volcanism in Common Era climate variability and human history

Climate reconstructions for the Common Era are compromised by the paucity of annually-resolved and absolutely-dated proxy records prior to medieval times. Where reconstructions are based on combinations of different climate archive types (of varying spatiotemporal resolution, dating uncertainty, record length and predictive skill), it is challenging to estimate past amplitude ranges, disentangle the relative roles of natural and anthropogenic forcing, or probe deeper interrelationships between climate variability and human history. Here, we compile and analyse updated versions of all the existing summer temperature sensitive tree-ring width chronologies from the Northern Hemisphere that span the entire Common Era. We apply a novel ensemble approach to reconstruct extra-tropical summer temperatures from 1 to 2010 CE, and calculate uncertainties at continental to hemispheric scales. Peak warming in the 280s, 990s and 1020s, when volcanic forcing was low, was comparable to modern conditions until 2010 CE. The lowest June–August temperature anomaly in 536 not only marks the beginning of the coldest decade, but also defines the onset of the Late Antique Little Ice Age (LALIA). While prolonged warmth during Roman and medieval times roughly coincides with the tendency towards societal prosperity across much of the North Atlantic/European sector and East Asia, major episodes of volcanically-forced summer cooling often presaged widespread famines, plague outbreaks and political upheavals. Our study reveals a larger amplitude of spatially synchronized summer temperature variation during the first millennium of the Common Era than previously recognised

The influence of decision-making in tree ring-based climate reconstructions.

Tree-ring chronologies underpin the majority of annually-resolved reconstructions of Common Era climate. However, they are derived using different datasets and techniques, the ramifications of which have hitherto been little explored. Here, we report the results of a double-blind experiment that yielded 15 Northern Hemisphere summer temperature reconstructions from a common network of regional tree-ring width datasets. Taken together as an ensemble, the Common Era reconstruction mean correlates with instrumental temperatures from 1794-2016 CE at 0.79 (p < 0.001), reveals summer cooling in the years following large volcanic eruptions, and exhibits strong warming since the 1980s. Differing in their mean, variance, amplitude, sensitivity, and persistence, the ensemble members demonstrate the influence of subjectivity in the reconstruction process. We therefore recommend the routine use of ensemble reconstruction approaches to provide a more consensual picture of past climate variability

Tree rings reveal globally coherent signature of cosmogenic radiocarbon events in 774 and 993 CE

This study was funded by the WSL-internal COSMIC project (5233.00148.001.01), the ETHZ (Laboratory of Ion Beam Physics), the Swiss National Science Foundation (SNF Grant 200021L_157187/1), and as the Czech Republic Grant Agency project no. 17-22102s.Though tree-ring chronologies are annually resolved, their dating has never been independently validated at the global scale. Moreover, it is unknown if atmospheric radiocarbon enrichment events of cosmogenic origin leave spatiotemporally consistent fingerprints. Here we measure the 14C content in 484 individual tree rings formed in the periods 770–780 and 990–1000 CE. Distinct 14C excursions starting in the boreal summer of 774 and the boreal spring of 993 ensure the precise dating of 44 tree-ring records from five continents. We also identify a meridional decline of 11-year mean atmospheric radiocarbon concentrations across both hemispheres. Corroborated by historical eye-witness accounts of red auroras, our results suggest a global exposure to strong solar proton radiation. To improve understanding of the return frequency and intensity of past cosmic events, which is particularly important for assessing the potential threat of space weather on our society, further annually resolved 14C measurements are needed.Publisher PDFPeer reviewe

Floods in Siberia: a Historical Overview

In the given work we present the information about floods on the territory of Siberia, which have taken place for the last 300 years. We consider their reasons, frequency of their distributions, territorial coverage and social consequences of these floods. For the time being, we compare the floods frequency data with the variation of the northern hemispheres annual temperatures.В работе представлена информация о наводнениях на территории Сибири за последние 300 лет. Рассматриваются причины, частота распределения, территориальный охват и социальные последствия наводнений. Проводится сопоставление данных о частоте проявлений наводнений с ходом годовых температур в Северном полушарии

Картина ледостава на реках Сибири в последние 300 лет (согласно древесно-кольцевой хронологии) как отражение изменений климата

The study represents the analysis results of the long-term time series of observation of ice breaking and freezing of the Siberian Rivers (the Ob, the Irtysh, the Yenisei, the Angara, etc.). There have been obtained statistic characteristics of the dependence of ice events dates on spring and autumn temperatures. We prove that during two last centuries there has been a steady trend towards shifting of ice-breaking moments for earlier ones and freezing dates for latter periods. We have specified common features of the variability of ice breaking and freezing periods, and there have been singled out the periods of fall in general temperature in the territory of Siberia for the last 300 years. On the basis of tree-ring chronologies data, there has been revealed a connection between the indirect indicator of summer temperatures change (tree growth) and the period of open water. The results of the work significantly enlarge the knowledge of variability of the Siberian climate for the previous centuries. Two last centuries are characterized by the steady trend of shift of ice-breaking moments towards earlier dates and those ones of freezing - towards later periods. So the long-term time series of ice events (especially the period of open water) are the indication of warming over the considerable territory of Southern Siberia, that confirms the general tendency of warming in the temperate latitudes of the Northern Hemisphere. There was found out a multi-directed trend in the ice events and long temperature-sensitive tree-ring chronologies after the 1950s. As the ice events are the consequence of physical processes, the cause of the divergence is necessary to be looked for in the biological response of trees for the climate changes or in other active biological factors of the environment. The revealed close connection between ice events and the temperature of some months gives an opportunity to use the statistical characteristics for the forecast of ice events dynamics of the Siberian Rivers, especially for the warming impacts.В работе представлены результаты анализа длительных рядов наблюдения по вскрытию и замерзанию рек на территории Сибири. Получены статистические характеристики зависимости дат ледовых явлений от весенних и осенних температур. Показано, что для двух последних столетий характерен устойчивый тренд на смещение моментов вскрытия на более ранние, а замерзания на более поздние сроки. Установлены общие черты изменчивости сроков вскрытия-замерзания и выделены периоды общего понижения температуры на территории Сибири за последние 300 лет. На основе привлечения данных древесно-кольцевых хронологий выявлена связь между косвенным индикатором изменения летних температур (приростом деревьев) и периодом открытой воды. Результаты работы существенно дополняют общие закономерности изменчивости климата Сибири за прошедшие столетия

Dendro-Chronological Dating of Constructions in the Course of Archeological Excavations of the Old-Turukhansk Site (New Mangazeya)

The article is dedicated to the dating of the Old-Turukhansk Site - a unique monument of the epoch of the Russian colonization of Siberia. In the given work we present a short review of Old Turukhansk history, results of the combined analysis of archeological, historical and dendro-chronological materials.Статья посвящена теме датирования уникального памятника эпохи русской колонизации Сибири - Старо-Туруханского городища. В работе изложена краткая история Старо- Туруханска, представлены результаты сопряженного анализ археологических, исторических и дендрохронологических материалов

A Millennium-Long Tree-Ring Chronologies Koksu and Tara on Altay

В статье представлены две новые тысячелетние древесно-кольцевые хронологии по лиственнице сибирской (Larix sibirica Ldb.) на верхней границе леса: Tara (для периода с 795 по 2011 г., Южно-Чуйский хребет) и Koksu (для периода с 588 по 2011 г., Катунский хребет). Расчет функции отклика показал, что основное воздействие на радиальный прирост древесно-кольцевой хронологии Koksu оказывают температуры июня и июля, а древесно-кольцевой хронологии Tara – только июня. Древесно-кольцевая хронология Koksu характеризуется наличием устойчивой и значимой связи с рядами наблюдений метеостанций, расположенных в Северной Монголии и Китае, т.е. она отражает изменчивость раннелетней температуры как минимум регионального масштаба. Древесно-кольцевая хронология Tara менее чувствительна к изменению летних температур и может быть пригодна для дендроиндикации геоморфологических, исторических и климатических событий (определение времени повреждения деревьев в ходе обвалов, селей, датировка древесины археологических памятников и т.п.). Анализ выявленных аномальных структур и выпавших колец на образцах позволил определить даты экстремальных событий для каждой хронологииThe work presents two new 1000-year tree-ring chronologies: Tara (AD 795-2011, the South Chui Range) and Koksu (AD 588-2011, the Katun Range). The calculation of the response function shows that the dominating factor affecting the radial growth of the tree-ring chronology Koksu is June and July temperatures and for Tara it is June temperature. The strong correlation between Koksu chronology and records of meteorological stations placed in the Northern Mongolia and China at a distance of 300 or more kilometers from the sites of sample collection illustrates that the chronology reflects summer temperature changes at least on a regional scale. At the same time Tara chronology is weakly sensitive to changes in summer temperatures and may be used for dating of geomorphologic, historical and climatic events. The analysis of abnormal structures and missing rings detected on the samples revealed the dates of extreme events for each chronolog

Floods in Siberia: a Historical Overview

In the given work we present the information about floods on the territory of Siberia, which have taken place for the last 300 years. We consider their reasons, frequency of their distributions, territorial coverage and social consequences of these floods. For the time being, we compare the floods frequency data with the variation of the northern hemispheres annual temperatures.В работе представлена информация о наводнениях на территории Сибири за последние 300 лет. Рассматриваются причины, частота распределения, территориальный охват и социальные последствия наводнений. Проводится сопоставление данных о частоте проявлений наводнений с ходом годовых температур в Северном полушарии