scholarly journals Global Climate and Sea Level: ENDURING VARIABILITY AND RAPID FLUCTUATIONS OVER THE PAST 150,000 YEARS

Oceanography ◽  
2011 ◽  
Vol 24 (2) ◽  
pp. 54-69 ◽  
Author(s):  
Yusuke Yokoyama ◽  
Tezer Esat
Keyword(s):  
Sea Level ◽  
Global Climate ◽  
The Past ◽  
And Sea Level

scholarly journals Interaction of ice sheets and climate during the past 800 000 years

2014 ◽  
Vol 10 (6) ◽  
pp. 2135-2152 ◽  
Author(s):  
L. B. Stap ◽  
R. S. W. van de Wal ◽  
B. de Boer ◽  
R. Bintanja ◽  
L. J. Lourens
Keyword(s):  
Temperature Profile ◽  
Sea Level ◽  
Climate Model ◽  
Global Climate ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Atmospheric Temperature ◽  
The Past ◽  
Long Timescales ◽  
And Sea Level

Abstract. During the Cenozoic, land ice and climate interacted on many different timescales. On long timescales, the effect of land ice on global climate and sea level is mainly set by large ice sheets in North America, Eurasia, Greenland and Antarctica. The climatic forcing of these ice sheets is largely determined by the meridional temperature profile resulting from radiation and greenhouse gas (GHG) forcing. As a response, the ice sheets cause an increase in albedo and surface elevation, which operates as a feedback in the climate system. To quantify the importance of these climate–land ice processes, a zonally averaged energy balance climate model is coupled to five one-dimensional ice sheet models, representing the major ice sheets. In this study, we focus on the transient simulation of the past 800 000 years, where a high-confidence CO2 record from ice core samples is used as input in combination with Milankovitch radiation changes. We obtain simulations of atmospheric temperature, ice volume and sea level that are in good agreement with recent proxy-data reconstructions. We examine long-term climate–ice-sheet interactions by a comparison of simulations with uncoupled and coupled ice sheets. We show that these interactions amplify global temperature anomalies by up to a factor of 2.6, and that they increase polar amplification by 94%. We demonstrate that, on these long timescales, the ice-albedo feedback has a larger and more global influence on the meridional atmospheric temperature profile than the surface-height-temperature feedback. Furthermore, we assess the influence of CO2 and insolation by performing runs with one or both of these variables held constant. We find that atmospheric temperature is controlled by a complex interaction of CO2 and insolation, and both variables serve as thresholds for northern hemispheric glaciation.

Salt marshes adjustment to anthropogenic pressures and sea-level rise

2021 ◽  
Author(s):  
A. Rita Carrasco ◽  
Katerina Kombiadou ◽  
Miguel Amado
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Salt Marshes ◽  
Anthropogenic Pressures ◽  
The Past ◽  
Ria Formosa ◽  
Sediment Loads ◽  
Human Interventions ◽  
South Portugal ◽  
And Sea Level

<p>It is predictable that salt marshes in regions, where sediment loads are high, should be stable against a broader range of relative sea level scenarios than those in sediment-poor systems. Despite extensive theoretical and laboratory studies, additional syntheses of marsh ‘persistence’ indicators under human interventions and accelerated sea-level rise rates are still needed. This study investigates the recent lateral changes occurring in lagoon-type marshes of the Ria Formosa lagoon (south Portugal) in the presence of human interventions and sea-level rise, to identify the major drivers for past marsh evolution and to estimate potential future trends. The conducted analysis assessed the past geomorphological adjustment based on imagery analysis and assessed its potential future adjustment to sea-level rise (~100 years) based on modelled land cover changes (by employing the SLAMM model within two sea-level rise scenarios).</p><p>Salt marshes in the Ria Formosa showed slow lateral growth rates over the last 70 years (<1 mm∙yr<sup>-1</sup>), with localized erosion along the main navigable channels associated with dredging activities. Higher change rates were noted near the inlets, with stronger progradation near the natural inlets of the system, fed by sediment influx pulses. Any potential influence of sea-level increase to an intensification of marsh-edge erosion in the past, could not be distinguished from human-induced pressures in the area. No significant sediment was exchanged between the salt marshes and tidal flats, and no self-organization pattern between them was observed in past. The related analysis showed that landcover changes in the salt marsh areas are likely to be more prominent in the future. The obtained results showed evidence of non-linearity in marsh response to high sea-level rise rates, which could indicate to the presence of critical thresholds and potential negative feedbacks within the system, with significant implications to marsh resilience.</p>

Beach nourishment versus sea level rise on Florida’s coasts

Shore & Beach ◽  
2020 ◽  
pp. 3-13
Author(s):  
James Houston
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
East Coast ◽  
Beach Nourishment ◽  
Shoreline Change ◽  
Intergovernmental Panel ◽  
Shoreline Changes ◽  
The Past ◽  
Equilibrium Profile ◽  
And Sea Level

Beach nourishment and sea level rise will dominate future shoreline changes on Florida’s 665 miles of sandy coast. Shoreline changes from 2020-2100 are projected along this entire coast using equilibrium profile theory that accurately predicted shoreline changes on Florida’s east coast from 1970-2017 (Houston 2019). Projections for 2020- 2100 are made assuming past rates of beach nourishment for the 30-yr period from 1988-2017 will continue and sea level will rise according to recent projections of the Intergovernmental Panel on Climate Change (IPCC) that include the latest knowledge on ice melting in Antarctica (IPCC 2019). Using the beach nourishment and sea level rise data, equilibrium profile theory is then used to predict shoreline change from 2020-2100 for each IPCC sea level rise projection. Beach nourishment is shown to produce shoreline advance seaward on average for all IPCC scenarios for both the entire Florida coast and east coast and for all scenarios except the upper confidence level of the worst scenario for the southwest and Panhandle coasts. Some of the 30 counties on these coasts will require a greater rate of nourishment than in the past to offset sea level rise for some or all of the scenarios, whereas some will offset sea level rise for all scenarios with lower nourishment rates than in the past. The annual beach nourishment volume for which a county has a shortfall or surplus in offsetting sea level rise for each IPCC scenario can be calculated with the information provided and examples are presented. The approach can be used on coasts outside Florida if beach nourishment and sea level rise are expected to dominate future shoreline change.

scholarly journals Sedimentary response to climate and sea level changes during the past ∼400 ka from borehole PRAD1-2 (Adriatic margin)

2008 ◽  
Vol 9 (9) ◽  
pp. n/a-n/a ◽  
Author(s):  
Domenico Ridente ◽  
Fabio Trincardi ◽  
Andrea Piva ◽  
Alessandra Asioli ◽  
Antonio Cattaneo
Keyword(s):  
Sea Level ◽  
Sea Level Changes ◽  
The Past ◽  
And Sea Level

scholarly journals Interaction of ice sheets and climate during the past 800 000 years

2014 ◽  
Vol 10 (3) ◽  
pp. 2547-2594
Author(s):  
L. B. Stap ◽  
R. S. W. van de Wal ◽  
B. de Boer ◽  
R. Bintanja ◽  
L. J. Lourens
Keyword(s):  
Temperature Profile ◽  
Sea Level ◽  
Time Scales ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Ice Cores ◽  
Atmospheric Temperature ◽  
The Past ◽  
Long Time ◽  
And Sea Level

Abstract. During the Cenozoic, land ice and climate have interacted on many different time scales. On long time scales, the effect of land ice on global climate and sea level is mainly set by large ice sheets on North America, Eurasia, Greenland and Antarctica. The climatic forcing of these ice sheets is largely determined by the meridional temperature profile resulting from radiation and greenhouse gas (GHG) forcing. As response, the ice sheets cause an increase in albedo and surface elevation, which operates as a feedback in the climate system. To quantify the importance of these climate-land ice processes, a zonally-averaged energy balance climate model is coupled to five one-dimensional ice-sheet models, representing the major ice sheets. In this study, we focus on the transient simulation of the past 800 000 years, where a high-confidence CO2-record from ice cores samples is used as input in combination with Milankovitch radiation changes. We obtain simulations of atmospheric temperature, ice volume and sea level, that are in good agreement with recent proxy-data reconstructions. We examine long-term climate-ice sheet interactions by a comparison of simulations with uncoupled and coupled ice sheets. We show that these interactions amplify global temperature anomalies by up to a factor 2.6, and that they increase polar amplification by 94%. We demonstrate that, on these long time scales, the ice-albedo feedback has a larger and more global influence on the meridional atmospheric temperature profile than the surface-height temperature feedback. Furthermore, we assess the influence of CO2 and insolation, by performing runs with one or both of these variables held constant. We find that atmospheric temperature is controlled by a complex interaction of CO2 and insolation, and both variables serve as thresholds for Northern Hemispheric glaciation.

Eocene-Oligocene global climate and sea-level changes: St. Stephens Quarry, Alabama

2008 ◽  
Vol 120 (1-2) ◽  
pp. 34-53 ◽  
Author(s):  
K. G. Miller ◽  
J. V. Browning ◽  
M.-P. Aubry ◽  
B. S. Wade ◽  
M. E. Katz ◽  
...  
Keyword(s):  
Sea Level ◽  
Global Climate ◽  
Sea Level Changes ◽  
And Sea Level

Global Climatic Issues in the Coastal Wider Caribbean Region

1990 ◽  
Vol 17 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Frank J. Gable ◽  
J.H. Gentile ◽  
D.G. Aubrey
Keyword(s):  
Sea Level ◽  
Global Climate ◽  
Ice Sheets ◽  
Caribbean Region ◽  
Change Analysis ◽  
Near Surface ◽  
Economic Growth And Development ◽  
The Past ◽  
Erosion Loss ◽  
Rising Sea Level

There is mounting evidence of global climate change. Analysis of near-surface temperatures over land and oceans during the past 130 years shows marked warming during the first half of this century, with relatively steady temperatures thereafter to the mid-1970s and rapid warming occurring during the 1980s. Of further significance is the fact that the warmest decade in the record is that of the 1980s, with some of the most pronounced warming occurring in the lower latitudes which include the wider Caribbean region. In the context of this study, the important consequences of this warming are the potential impacts associated with rising sea-level and the increased frequency, intensity, and seasonality, of tropical storms due to thermal expansion of the oceans, melting of land-based ice-sheets and glaciers, and local geological parameters. Within the wider Caribbean, rates of relative sea-level rise have been recently estimated at around 2.5 mm/yr. Also, meteorological changes are evident with the occurrence of unusually intense storms such as Hurricane Gilbert in 1988. Rising sea-level coupled with meteorological changes present the potential for increased coastal erosion, loss of wetlands, disappearance of special habitats such as mangroves, and destruction of coral-reef communities. These potential impacts may have a significant influence on future land-use and development practices that could alter the economic growth and development of the region not least through curtailment of tourism.

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