An extended Arctic proxy temperature database for the past 2,000 years

McKay, Nicholas P.; Kaufman, Darrell S.

doi:10.1038/sdata.2014.26

Cited by 128 publications

(172 citation statements)

References 68 publications

(90 reference statements)

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“…clusions reached previously in Shi et al (2012), Hanhijärvi et al (2013), andKaufmann (2014). At the same time, in contrast to other reconstructions (notably Hanhijärvi et al, 2013) the Roman times around the first and second century CE do not show up as particularly warm in the circum-Arctic mean, which is also reflected in the analyses presented in section 4.2.…”

contrasting

confidence: 42%

Spatio-temporal variability of Arctic summer temperatures over the past two millennia: an overview of the last major climate anomalies

Werner

Divine

Ljungqvist

et al. 2017

Preprint

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Abstract.In this article, the first spatially resolved millennium-long summer (June-August) temperature reconstruction over the Arctic and Subarctic domain (north of 60• N) is presented. It is based on a set of 54 annually dated temperature sensitive proxy archives of various types, mainly from the updated and revised PAGES2k database supplemented with 6 new recently published proxy records. As a major novelty, an extension of the Bayesian BARCAST climate field (CF) reconstruction technique provides 5 a means to treat climate archives with dating uncertainties. In total 1400 realisations of the temperature CF were generated, enabling further analyses to be carried out in a probabilistic framework. The new seasonal CF reconstruction for the Arctic region can be shown to be skilful for the majority of the terrestrial nodes. The decrease in the proxy data density back in time however limits the analyses in the spatial domain to the period after 750 CE, while the spatially averaged reconstruction covers the entire time interval of 1-2002 CE. The analysis of basic features of the reconstructed seasonal CF focuses on the regional 10 expression of past major climate anomalies in order to uncover the potential of the new product for studying Common Era temperature variability in the region.The long-term, centennial to millennial, evolution of the reconstructed temperature is in good agreement with a general pattern that was inferred in recent studies for the Arctic and its sub-regions. On the pan-Arctic scale the reconstruction shows a cooling trend which is, however, statistically insignificant and the estimated magnitude of the millennial scale cooling is three

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contrasting

confidence: 42%

Spatio-temporal variability of Arctic summer temperatures over the past two millennia: an overview of the last major climate anomalies

Werner

Divine

Ljungqvist

et al. 2017

Preprint

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“…To compare global surface ocean and global land temperature trends, we calculate a terrestrial composite of nonmarine reconstructions 7,25 (Terrestrial 2k composite; Supplementary Section 9), ensuring that independent data sets are used to determine marine and terrestrial signals. The Terrestrial 2k composite shows a cooling trend qualitatively similar to the Ocean2k SST synthesis over the 801-1800 ce interval, the interval with the highest availability of SST reconstruction data and model simulations ( Fig.…”

Section: Comparisons With Simulations and Terrestrial Datamentioning

confidence: 99%

Robust global ocean cooling trend for the pre-industrial Common Era

et al. 2015

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International audienceKnowledge of natural climate variability is essential to better constrain the uncertainties in projections of twenty-first-century climate change 1–5. The past 2,000 years (2 kyr) have emerged as a critical interval in this endeavour, with sufficient length to characterize natural decadal-to-centennial scale change, known external climate forcings 6 and with distinctive patterns of spatiotemporal temperature variations 7. However, reconstructions for the full 2 kyr interval are not available for the global ocean, a primary heat reservoir 8 and an important regulator of global climate on longer timescales 9–11. Here we present a global ocean sea surface temperature (SST) synthesis (Ocean2k SST synthesis) spanning the Common Era, which shows a cooling trend that is similar, within uncertainty, to that simulated by realistically forced climate models for the past millennium. We use the simulations to identify the climate forcing(s) consistent with reconstructed SST variations during the past millennium. The oceans mediate the response of global climate to natural and anthropogenic forcings. Yet for the past 2,000 years — a key interval for understanding the present and future climate response to these forcings — global sea surface temperature changes and the underlying driving mechanisms are poorly constrained. Here we present a global synthesis of sea surface temperatures for the Common Era (ce) derived from 57 individual marine reconstructions that meet strict quality control criteria. We observe a cooling trend from 1 to 1800 ce that is robust against explicit tests for potential biases in the reconstructions. Between 801 and 1800 ce, the surface cooling trend is qualitatively consistent with an independent synthesis of terrestrial temperature reconstructions, and with a sea surface temperature composite derived from an ensemble of climate model simulations using best estimates of past external radiative forcings. Climate simulations using single and cumulative forcings suggest that the ocean surface cooling trend from 801 to 1800 ce is not primarily a response to orbital forcing but arises from a high frequency of explosive volcanism. Our results show that repeated clusters of volcanic eruptions can induce a net negative radiative forcing that results in a centennial and global scale cooling trend via a decline in mixed-layer oceanic heat content

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“…Most temperature reconstructions include different types of archives and proxies (Moberg et al, 2005;Mann et al, 2009;Kaufman et al, 2009;Ljungqvist, 2010;Marcott et al, 2013) and some studies focused on a single paleoclimate archive type and/or area (e.g., McGregor et al, 2015, for oceans;Weissbach et al, 2016, for ice core; Wilson et al, 2016, for tree rings). In the Arctic and subarctic area • N), several multi-proxy reconstructions of temperatures encompassing the last 2 millennia were published on a global (PAGES 2k Consortium, 2013;McKay and Kaufman, 2014;Werner et al, 2017) and regional scale (Hanhijärvi et al, 2013). The annual resolution of these reconstructions allows the study of the climate variability from low frequencies (i.e., millennial and multi-centennial fluctuations) to high frequencies such as decadal variations.…”

Section: Introductionmentioning

confidence: 99%

Climate variability in the subarctic area for the last 2 millennia

et al. 2018

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Abstract.To put recent climate change in perspective, it is necessary to extend the instrumental climate records with proxy data from paleoclimate archives. Arctic climate variability for the last 2 millennia has been investigated using statistical and signal analyses from three regionally averaged records from the North Atlantic, Siberia and Alaska based on many types of proxy data archived in the Arctic 2k database v1.1.1. In the North Atlantic and Alaska, the major climatic trend is characterized by long-term cooling interrupted by recent warming that started at the beginning of the 19th century. This cooling is visible in the Siberian region at two sites, warming at the others. The cooling of the Little Ice Age (LIA) was identified from the individual series, but it is characterized by wide-range spatial and temporal expression of climate variability, in contrary to the Medieval Climate Anomaly. The LIA started at the earliest by around AD 1200 and ended at the latest in the middle of the 20th century. The widespread temporal coverage of the LIA did not show regional consistency or particular spatial distribution and did not show a relationship with archive or proxy type either. A focus on the last 2 centuries shows a recent warming characterized by a well-marked warming trend parallel with increasing greenhouse gas emissions. It also shows a multidecadal variability likely due to natural processes acting on the internal climate system on a regional scale. A ∼ 16-30-year cycle is found in Alaska and seems to be linked to the Pacific Decadal Oscillation, whereas ∼ 20-30-and ∼ 50-90-year periodicities characterize the North Atlantic climate variability, likely in relation with the Atlantic Multidecadal Oscillation. These regional features are probably linked to the sea ice cover fluctuations through ice-temperature positive feedback.

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An extended Arctic proxy temperature database for the past 2,000 years

Cited by 128 publications

References 68 publications

Spatio-temporal variability of Arctic summer temperatures over the past two millennia: an overview of the last major climate anomalies

Spatio-temporal variability of Arctic summer temperatures over the past two millennia: an overview of the last major climate anomalies

Robust global ocean cooling trend for the pre-industrial Common Era

Climate variability in the subarctic area for the last 2 millennia

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