scholarly journals Low-resolution Australasian palaeoclimate records of the last 2000 years

2017 ◽  
Author(s):  
Bronwyn C. Dixon ◽  
Jonathan J. Tyler ◽  
Andrew M. Lorrey ◽  
Ian D. Goodwin ◽  
Joëlle Gergis ◽  
...  
Keyword(s):  
Climate Variability ◽  
A Priori ◽  
High Quality ◽  
Bayesian Techniques ◽  
The Past ◽  
Past 2000 Years ◽  
Dating Methods ◽  
The Common ◽  
Common Era ◽  
Australasian Region

Abstract. Non-annually resolved palaeoclimate records in the Australasian region were compiled to facilitate investigations of decadal to centennial climate variability over the past 2000 years. A total of 661 lake/wetland, geomorphic, marine, and speleothem records were identified and then assessed against a set of a priori criteria based on temporal resolution, record length, dating methods, and confidence of the proxy-climate relationship over the Common Era. A high quality subset of 22 records across Australasia met the criteria and they are endorsed for subsequent analyses. New chronologies based on progressive Bayesian techniques were constructed for the high quality records to ensure a consistent approach to age modelling and quantification of age uncertainties. Chronological uncertainty was the primary reason why records did not meet the selection criteria. Despite present limitations, existing proxies and reconstruction techniques that successfully capture climate variability in the region show potential to address spatial gaps and expand the range of climate variables covering the last 2000 years from the Australasian region.

scholarly journals Low-resolution Australasian palaeoclimate records of the last 2000 years

2017 ◽  
Vol 13 (10) ◽  
pp. 1403-1433 ◽  
Author(s):  
Bronwyn C. Dixon ◽  
Jonathan J. Tyler ◽  
Andrew M. Lorrey ◽  
Ian D. Goodwin ◽  
Joëlle Gergis ◽  
...  
Keyword(s):  
Climate Variability ◽  
Accumulation Rate ◽  
A Priori ◽  
Data Availability ◽  
Bayesian Techniques ◽  
Tephra Layers ◽  
The Common ◽  
The Arid Regions ◽  
Common Era ◽  
Australasian Region

Abstract. Non-annually resolved palaeoclimate records in the Australasian region were compiled to facilitate investigations of decadal to centennial climate variability over the past 2000 years. A total of 675 lake and wetland, geomorphic, marine, and speleothem records were identified. The majority of records are located near population centres in southeast Australia, in New Zealand, and across the maritime continent, and there are few records from the arid regions of central and western Australia. Each record was assessed against a set of a priori criteria based on temporal resolution, record length, dating methods, and confidence in the proxy–climate relationship over the Common Era. A subset of 22 records met the criteria and were endorsed for subsequent analyses. Chronological uncertainty was the primary reason why records did not meet the selection criteria. New chronologies based on Bayesian techniques were constructed for the high-quality subset to ensure a consistent approach to age modelling and quantification of age uncertainties. The primary reasons for differences between published and reconstructed age–depth models were the consideration of the non-singular distribution of ages in calibrated 14C dates and the use of estimated autocorrelation between sampled depths as a constraint for changes in accumulation rate. Existing proxies and reconstruction techniques that successfully capture climate variability in the region show potential to address spatial gaps and expand the range of climate variables covering the last 2000 years in the Australasian region. Future palaeoclimate research and records in Australasia could be greatly improved through three main actions: (i) greater data availability through the public archiving of published records; (ii) thorough characterisation of proxy–climate relationships through site monitoring and climate sensitivity tests; and (iii) improvement of chronologies through core-top dating, inclusion of tephra layers where possible, and increased date density during the Common Era.

scholarly journals Millennial-to-centennial patterns and trends in the hydroclimate of North America over the past 2000 years

2017 ◽  
Author(s):  
Bryan N. Shuman ◽  
Cody Routson ◽  
Nicholas McKay ◽  
Sherilyn Fritz ◽  
Darrell Kaufman ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Ice Age ◽  
The Arctic ◽  
Medieval Period ◽  
The Past ◽  
Past 2000 Years ◽  
Annual Range ◽  
The Common ◽  
Common Era ◽  
Millennial Scale

Abstract. A synthesis of 93 hydrologic records from across North and Central America, and adjacent tropical and Arctic islands, reveals centennial to millennial trends in the regional hydroclimates of the Common Era (CE; past 2000 years). The hydrological records derive from materials stored in lakes, bogs, caves, and ice from extant glaciers, which have the continuity through time to preserve low-frequency (> 100 year) climate signals that may not be well represented by other shorter-lived archives, such as tree-ring chronologies. The most common pattern, represented in 46 (49 %) of the records, indicates that the centuries before 1000 CE were drier than the centuries since that time. Principal components analysis indicates that millennial-scale trends represent the dominant pattern of variance in the southwest and northeast U.S., the mid-continent, Pacific Northwest, the Arctic, and the tropics, although not all records within a region show the same direction of change. The Pacific Northwest, Greenland, and the southernmost tier of the tropical sites tended to dry toward present, as many other areas became wetter than before. Twenty-two records (24 %) indicate that the Medieval period (800–1300 CE) was drier than the Little Ice Age (1400–1900 CE), but in many cases the difference was part of the longer millennial-scale trend, and, in 25 records (27 %), the Medieval period represented a pluvial (wet) phase. Where quantitative records permitted a comparison, we found that centennial-scale fluctuations over the Common Era represented changes of 3–7 % of the modern inter-annual range of variability in precipitation, but the accumulation of these long-term trends over the entirety of the Holocene caused recent centuries to be significantly wetter, on average, than most of the past 11 000 years.

scholarly journals Placing the Common Era in a Holocene context: millennial to centennial patterns and trends in the hydroclimate of North America over the past 2000 years

2018 ◽  
Vol 14 (5) ◽  
pp. 665-686 ◽  
Author(s):  
Bryan N. Shuman ◽  
Cody Routson ◽  
Nicholas McKay ◽  
Sherilyn Fritz ◽  
Darrell Kaufman ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Ice Age ◽  
Medieval Climate Anomaly ◽  
Climate Anomaly ◽  
The Holocene ◽  
The Past ◽  
Past 2000 Years ◽  
The Common ◽  
Common Era ◽  
Millennial Scale

Abstract. A synthesis of 93 hydrologic records from across North and Central America, and adjacent tropical and Arctic islands, reveals centennial to millennial trends in the regional hydroclimates of the Common Era (CE; past 2000 years). The hydrological records derive from materials stored in lakes, bogs, caves, and ice from extant glaciers, which have the continuity through time to preserve low-frequency ( > 100 year) climate signals that may extend deeper into the Holocene. The most common pattern, represented in 46 (49 %) of the records, indicates that the centuries before 1000 CE were drier than the centuries since that time. Principal component analysis indicates that millennial-scale trends represent the dominant pattern of variance in the southwestern US, northeastern US, mid-continent, Pacific Northwest, Arctic, and tropics, although not all records within a region show the same direction of change. The Pacific Northwest and the southernmost tier of the tropical sites tended to dry toward present, as many other areas became wetter than before. In 22 records (24 %), the Medieval Climate Anomaly period (800–1300 CE) was drier than the Little Ice Age (1400–1900 CE), but in many cases the difference was part of the longer millennial-scale trend, and, in 25 records (27 %), the Medieval Climate Anomaly period represented a pluvial (wet) phase. Where quantitative records permitted a comparison, we found that centennial-scale fluctuations over the Common Era represented changes of 3–7 % in the modern interannual range of variability in precipitation, but the accumulation of these long-term trends over the entirety of the Holocene caused recent centuries to be significantly wetter, on average, than most of the past 11 000 years.

Advancing community-led research into the climate of the Common Era

2021 ◽  
Author(s):  
Sarah S. Eggleston ◽  
Steven Phipps ◽  
Oliver Bothe ◽  
Helen V. McGregor ◽  
Belen Martrat ◽  
...  
Keyword(s):  
Climate Science ◽  
Global Changes ◽  
Present Climate ◽  
The Third ◽  
The Past ◽  
Third Phase ◽  
The Common ◽  
Common Era ◽  
Scientific Questions ◽  
New Phase

<p>The past two thousand years is a key interval for climate science. This period encompasses both the era of human-induced global warming and a much longer interval when changes in Earth’s climate were governed principally by natural drivers and unforced variability. Since 2009, the Past Global Changes (PAGES) 2k Network has brought together hundreds of scientists from around the world to reconstruct and understand the climate of the Common Era using open and collaborative approaches to palaeoclimate science, including virtual meetings. The third phase of the network will end in December 2021. Here we highlight some key outputs of PAGES 2k and present the major themes and scientific questions emerging from recent surveys of the community. We explore how these might boost a new phase of PAGES 2k or a successor project(s). This year we will further reach out to the community through Town Hall consultations, vEGU and other meetings, and a PAGES 2k global webinar series. The aim of these activities is to foster development of post-2021 community-led PAGES initiatives that connect past and present climate.</p>

INTRODUCTION TO THE NEW SERIES: UNCOMMON “COMMON SENSE”

2007 ◽  
Vol 4 (1) ◽  
pp. 45-49
Author(s):  
Akinobu Kuroda
Keyword(s):  
East Asia ◽  
Opposite Direction ◽  
Common Sense ◽  
High Quality ◽  
Short Supply ◽  
Modern Times ◽  
The Past ◽  
The People ◽  
The World ◽  
The Common

The common sense of modern times was not always “common” in the past. For example, if it is true that inflation is caused by an oversupply of money, a short supply of money must cause deflation. However logical that sounds, though, it has not been so uncommon in history that rising prices were recognized as being caused by a scarcity of currency. Even in the same period, a common idea prevailing in one historical area was not always common in another; rather, it sometimes appeared in quite the opposite direction. It is likely that the idea that a government gains from bad currencies, while traders appreciate good ones, is popular throughout the world. In the case of China, however, its dynasties sometimes intentionally issued high-quality coins without regard to their losses. East Asia shared the idea that cheap currency harms the state, while an expensive currency harms the people. This is in considerable contrast with a common image in other regions that authorities gained profits from seigniorage.

Centennial-scale climate variability during the past 2000 years on the central Tibetan Plateau

The Holocene ◽  
2015 ◽  
Vol 25 (6) ◽  
pp. 892-899 ◽  
Author(s):  
Xiumei Li ◽  
Jie Liang ◽  
Juzhi Hou ◽  
Wenjing Zhang
Keyword(s):  
Tibetan Plateau ◽  
Climate Variability ◽  
The Past ◽  
Central Tibetan Plateau ◽  
Past 2000 Years

2000 years of marine primary productivity in the Eastern Tropical North Pacific

2020 ◽  
Author(s):  
Christina Treinen-Crespo ◽  
Jose Carriquiry ◽  
Julio Villaescusa ◽  
Elisabet Repiso-Terrones
Keyword(s):  
High Resolution ◽  
Climate Variability ◽  
Primary Productivity ◽  
North Pacific ◽  
Biogenic Silica ◽  
Change Scenario ◽  
The Past ◽  
Past 2000 Years ◽  
Increasing Trend ◽  
Marine Primary Productivity

<p>Changes in marine primary productivity (MPP) over the 21st century are expected to occur under the prevailing climate change scenario. For better understanding of past climate variability, we reconstructed MPP at high resolution (~1-2 years) for the past 2000 years analyzing biogenic silica and total organic carbon (TOC %) on a sediment core collected from Soledad Basin (25°N, 112°W), Baja  California, Mexico. Located in the Eastern Tropical North Pacific, this suboxic basin is ideal for palaeoceanographic reconstructions due to its high sedimentation rate (2 mm/year), which allow us to reconstruct past changes in the ocean and climate at high resolution. Our results show an increasing trend in the variability of MPP for the past 2000 years: biogenic silica content does not show a well-defined trend, but rather it is dominated by strong multidecadal and prominent centennial-scale cycles while TOC (%) shows a slight increasing trend towards the present, starting at least 2000 years ago. Spectral analysis confirms the presence of multidecadal to centennial cycles. These results will be discussed in the context of the Anthropocene and natural climate variability.</p>

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