scholarly journals Temperature-driven global sea-level variability in the Common Era

2016 ◽  
Vol 113 (11) ◽  
pp. E1434-E1441 ◽  
Author(s):  
Robert E. Kopp ◽  
Andrew C. Kemp ◽  
Klaus Bittermann ◽  
Benjamin P. Horton ◽  
Jeffrey P. Donnelly ◽  
...  
Keyword(s):  
Sea Level ◽  
20Th Century ◽  
Process Model ◽  
Tide Gauge ◽  
Semiempirical Model ◽  
Intergovernmental Panel ◽  
The Common ◽  
Global Sea Level ◽  
The 19Th Century ◽  
Common Era

We assess the relationship between temperature and global sea-level (GSL) variability over the Common Era through a statistical metaanalysis of proxy relative sea-level reconstructions and tide-gauge data. GSL rose at 0.1 ± 0.1 mm/y (2σ) over 0–700 CE. A GSL fall of 0.2 ± 0.2 mm/y over 1000–1400 CE is associated with ∼0.2 °C global mean cooling. A significant GSL acceleration began in the 19th century and yielded a 20th century rise that is extremely likely (probability P≥0.95) faster than during any of the previous 27 centuries. A semiempirical model calibrated against the GSL reconstruction indicates that, in the absence of anthropogenic climate change, it is extremely likely (P=0.95) that 20th century GSL would have risen by less than 51% of the observed 13.8±1.5 cm. The new semiempirical model largely reconciles previous differences between semiempirical 21st century GSL projections and the process model-based projections summarized in the Intergovernmental Panel on Climate Change’s Fifth Assessment Report.

scholarly journals History of cannabis and the endocannabinoid system

2020 ◽  
Vol 22 (3) ◽  
pp. 223-228
Keyword(s):  
Roman Empire ◽  
20Th Century ◽  
Endocannabinoid System ◽  
Altai Mountains ◽  
Medicinal Uses ◽  
Medicinal Use ◽  
History Of ◽  
The Common ◽  
The 19Th Century ◽  
Common Era

This article retraces the story of cannabis from the earliest contacts of humans with the plant to its subsequent global expansion, its medicinal uses, and the discovery of the endocannabinoid system in the 20th century. Cannabis was attested to around 12 000 years ago near the Altai Mountains in Central Asia, and since then, cannabis seeds have accompanied the migration of nomadic peoples. Records of the medicinal use of cannabis appear before the Common Era in China, Egypt, and Greece (Herodotus), and later in the Roman empire (Pliny the Elder, Dioscorides, Galen). In the 19th century, orientalists like Silvestre de Sacy, and Western physicians coming into contact with Muslim and Indian cultures, like O’Shaughnessy and Moreau de Tours, introduced the medicinal use of cannabis into Europe. The structure of the main psychoactive phytocannabinoid, tetrahydrocannabinol (THC), was determined in Israel by Mechoulam and Gaoni in 1964. This discovery opened the gate for many of the subsequent developments in the field of endocannabinoid system (ECS) research. The advances in the scientific knowledge of the ECS place the debate on cannabis liberalization in a new context.

scholarly journals Reassessment of 20th century global mean sea level rise

2017 ◽  
Vol 114 (23) ◽  
pp. 5946-5951 ◽  
Author(s):  
Sönke Dangendorf ◽  
Marta Marcos ◽  
Guy Wöppelmann ◽  
Clinton P. Conrad ◽  
Thomas Frederikse ◽  
...  
Keyword(s):  
Sea Level ◽  
20Th Century ◽  
Tide Gauge ◽  
Equal Proportion ◽  
Tide Gauge Records ◽  
Intergovernmental Panel ◽  
Mean Sea Level ◽  
Vertical Land Motion ◽  
Global Mean Sea Level ◽  
Global Mean

The rate at which global mean sea level (GMSL) rose during the 20th century is uncertain, with little consensus between various reconstructions that indicate rates of rise ranging from 1.3 to 2 mm⋅y−1. Here we present a 20th-century GMSL reconstruction computed using an area-weighting technique for averaging tide gauge records that both incorporates up-to-date observations of vertical land motion (VLM) and corrections for local geoid changes resulting from ice melting and terrestrial freshwater storage and allows for the identification of possible differences compared with earlier attempts. Our reconstructed GMSL trend of 1.1 ± 0.3 mm⋅y−1 (1σ) before 1990 falls below previous estimates, whereas our estimate of 3.1 ± 1.4 mm⋅y−1 from 1993 to 2012 is consistent with independent estimates from satellite altimetry, leading to overall acceleration larger than previously suggested. This feature is geographically dominated by the Indian Ocean–Southern Pacific region, marking a transition from lower-than-average rates before 1990 toward unprecedented high rates in recent decades. We demonstrate that VLM corrections, area weighting, and our use of a common reference datum for tide gauges may explain the lower rates compared with earlier GMSL estimates in approximately equal proportion. The trends and multidecadal variability of our GMSL curve also compare well to the sum of individual contributions obtained from historical outputs of the Coupled Model Intercomparison Project Phase 5. This, in turn, increases our confidence in process-based projections presented in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.

scholarly journals Greenland ice sheet contribution to sea level rise during the last interglacial period: a modelling study driven and constrained by ice core data

2013 ◽  
Vol 9 (1) ◽  
pp. 353-366 ◽  
Author(s):  
A. Quiquet ◽  
C. Ritz ◽  
H. J. Punge ◽  
D. Salas y Mélia
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Core ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Intergovernmental Panel ◽  
Orbital Configuration ◽  
Global Sea Level

Abstract. As pointed out by the forth assessment report of the Intergovernmental Panel on Climate Change, IPCC-AR4 (Meehl et al., 2007), the contribution of the two major ice sheets, Antarctica and Greenland, to global sea level rise, is a subject of key importance for the scientific community. By the end of the next century, a 3–5 °C warming is expected in Greenland. Similar temperatures in this region were reached during the last interglacial (LIG) period, 130–115 ka BP, due to a change in orbital configuration rather than to an anthropogenic forcing. Ice core evidence suggests that the Greenland ice sheet (GIS) survived this warm period, but great uncertainties remain about the total Greenland ice reduction during the LIG. Here we perform long-term simulations of the GIS using an improved ice sheet model. Both the methodologies chosen to reconstruct palaeoclimate and to calibrate the model are strongly based on proxy data. We suggest a relatively low contribution to LIG sea level rise from Greenland melting, ranging from 0.7 to 1.5 m of sea level equivalent, contrasting with previous studies. Our results suggest an important contribution of the Antarctic ice sheet to the LIG highstand.

scholarly journals Global sea level reconstruction for 1900–2015 reveals regional variability in ocean dynamics and an unprecedented long weakening in the Gulf Stream flow since the 1990s

Ocean Science ◽  
2020 ◽  
Vol 16 (4) ◽  
pp. 997-1016
Author(s):  
Tal Ezer ◽  
Sönke Dangendorf
Keyword(s):  
Sea Level ◽  
Gulf Stream ◽  
Tide Gauge ◽  
Meridional Overturning Circulation ◽  
Ocean Dynamics ◽  
South Atlantic Bight ◽  
Regional Variability ◽  
Coastal Sea ◽  
Global Sea Level

Abstract. A new monthly global sea level reconstruction for 1900–2015 was analyzed and compared with various observations to examine regional variability and trends in the ocean dynamics of the western North Atlantic Ocean and the US East Coast. Proxies of the Gulf Stream (GS) strength in the Mid-Atlantic Bight (GS-MAB) and in the South Atlantic Bight (GS-SAB) were derived from sea level differences across the GS. While decadal oscillations dominate the 116-year record, the analysis showed an unprecedented long period of weakening in the GS flow since the late 1990s. The only other period of long weakening in the record was during the 1960s–1970s, and red noise experiments showed that is very unlikely that those just occurred by chance. Ensemble empirical mode decomposition (EEMD) was used to separate oscillations at different timescales, showing that the low-frequency variability of the GS is connected to the Atlantic Multi-decadal Oscillation (AMO) and the Atlantic Meridional Overturning Circulation (AMOC). The recent weakening of the reconstructed GS-MAB was mostly influenced by weakening of the upper mid-ocean transport component of AMOC as observed by the RAPID measurements for 2005–2015. Comparison between the reconstructed sea level near the coast and tide gauge data for 1927–2015 showed that the reconstruction underestimated observed coastal sea level variability for timescales less than ∼5 years, but lower-frequency variability of coastal sea level was captured very well in both amplitude and phase by the reconstruction. Comparison between the GS-SAB proxy and the observed Florida Current transport for 1982–2015 also showed significant correlations for oscillations with periods longer than ∼5 years. The study demonstrated that despite the coarse horizontal resolution of the global reconstruction (1∘ × 1∘), long-term variations in regional dynamics can be captured quite well, thus making the data useful for studies of long-term variability in other regions as well.

scholarly journals Tide gauge location and the measurement of global sea level rise

2014 ◽  
Vol 22 (1) ◽  
pp. 179-206 ◽  
Author(s):  
Michael Beenstock ◽  
Daniel Felsenstein ◽  
Eyal Frank ◽  
Yaniv Reingewertz
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Tide Gauge ◽  
Global Sea Level

A foraminiferal proxy record of 20th century sea-level rise in the Manukau Harbour, New Zealand

2012 ◽  
Vol 63 (4) ◽  
pp. 370 ◽  
Author(s):  
Hugh R. Grenfell ◽  
Bruce W. Hayward ◽  
Ritsuo Nomura ◽  
Ashwaq T. Sabaa
Keyword(s):  
New Zealand ◽  
Salt Marsh ◽  
Sea Level Rise ◽  
Sea Level ◽  
20Th Century ◽  
Tide Gauge ◽  
Sediment Accumulation ◽  
Proxy Record ◽  
Tide Gauge Record ◽  
Tidal Salt Marsh

The present study aimed to extract a sea-level history from northern New Zealand salt-marsh sediments using a foraminiferal proxy, and to extend beyond the longest nearby tide-gauge record. Transects through high-tidal salt marsh at Puhinui, Manukau Harbour, Auckland, New Zealand, indicate a zonation of dominant foraminifera in the following order (with increasing elevation): Ammonia spp.–Elphidium excavatum, Ammotium fragile, Miliammina fusca, Haplophragmoides wilberti–Trochammina inflata, Trochamminita salsa–Miliammina obliqua. The transect sample faunas are used as a training set to generate a transfer function for estimating past tidal elevations in two short cores nearby. Heavy metal, 210Pb and 137Cs isotope analyses provide age models that indicate 35 cm of sediment accumulation since ~1890 AD. The first proxy-based 20th century rates of sea-level rise from New Zealand’s North Island at 0.28 ± 0.05 cm year–1 and 0.33 ± 0.07 cm year–1 are estimated. These are faster than the nearby Auckland tide gauge for the same interval (0.17 ± 0.1 cm year–1), but comparable to a similar proxy record from southern New Zealand (0.28 ± 0.05 cm year–1) and to satellite-based observations of global sea-level rise since 1993 (0.31 ± 0.07 cm year–1).

A 20th century acceleration in global sea-level rise

2006 ◽  
Vol 33 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
John A. Church ◽  
Neil J. White
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
20Th Century ◽  
Global Sea Level

scholarly journals Holocene and Common Era sea level changes in the Makassar Strait, Indonesia

2019 ◽  
Author(s):  
Maren Bender ◽  
Thomas Mann ◽  
Paolo Stocchi ◽  
Dominik Kneer ◽  
Tilo Schöne ◽  
...  
Keyword(s):  
Sea Level ◽  
Published Data ◽  
Glacial Isostatic Adjustment ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Isostatic Adjustment ◽  
Thousand Islands ◽  
The Common ◽  
Common Era ◽  
Spermonde Archipelago

Abstract. Indonesia is a country composed of several thousand islands, many of them small, low-lying and densely inhabited. These are, in particular, subject to high risk of inundation due to future relative sea level changes. The Spermonde Archipelago, off the coast of Southwest Sulawesi, consists of more than 100 small islands. This study presents a dataset of 24 sea-level index points from fossil microatolls, surveyed on five islands in the Spermonde Archipelago and compares these new results with published data from the same region and with relative sea level predictions from different Glacial Isostatic Adjustment (GIA) models. The newly surveyed fossil microatolls are located around the islands of Tambakulu, Suranti (both ~ 60 km offshore of Makassar city), Bone Batang and Kodingareng Keke (both located in the center of the Archipelago) and Sanrobengi (located ~ 20 km south-southwest of Makassar). Results from the near- and mid-shelf islands indicate that relative sea level between 4 to 6 ka BP was less than one meter above present sea level. The only exception to this pattern is the heavily populated island of Barrang Lompo, where we record a significant subsidence when compared to the other islands. These new results support the conclusions from a previous dataset and are relevant to constrain late Holocene ice melting scenarios. Samples from the two outer islands (Tambakulu and Suranti) yielded ages spanning the Common Era that represent, to our knowledge, the first reported for the entire Southeast Asian region.

scholarly journals Celebrating 80 years of the Permanent Service for Mean Sea Level (PSMSL)

2015 ◽  
Vol 365 ◽  
pp. 1-5
Author(s):  
L. Rickards ◽  
A. Matthwes ◽  
K. Gordon ◽  
M. Tamisea ◽  
S. Jevrejeva ◽  
...  
Keyword(s):  
Sea Level ◽  
Tide Gauge ◽  
Tide Gauge Records ◽  
International Union ◽  
Mean Sea Level ◽  
Level Change ◽  
The Mean ◽  
Set Up ◽  
The 19Th Century

Abstract. The PSMSL was established as a “Permanent Service” of the International Council for Science in 1958, but in practice was a continuation of the Mean Sea Level Committee which had been set up at the Lisbon International Union of Geodesy and Geophysics (IUGG) conference in 1933. Now in its 80th year, the PSMSL continues to be the internationally recognised databank for long-term sea level change information from tide gauge records. The PSMSL dataset consists of over 2100 mean sea level records from across the globe, the longest of which date back to the start of the 19th century. Where possible, all data in a series are provided to a common benchmark-controlled datum, thus providing a record suitable for use in time series analysis. The PSMSL dataset is freely available for all to use, and is accessible through the PSMSL website (www.psmsl.org).

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