scholarly journals Tracking Long-Term Changes in Global Sea Level Extremes

Eos ◽  
2016 ◽  
Author(s):  
Sarah Stanley
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Large Scale ◽  
Long Term Changes ◽  
Global Sea Level

Large-scale climate change may drive trends in extreme sea level events.

Long-term changes in the geographic distribution and population structures of Osilinus lineatus (Gastropoda: Trochidae) in Britain and Ireland

2007 ◽  
Vol 87 (2) ◽  
pp. 537-545 ◽  
Author(s):  
N. Mieszkowska ◽  
S.J. Hawkins ◽  
M.T. Burrows ◽  
M.A. Kendall
Keyword(s):  
Climate Change ◽  
Geographic Distribution ◽  
Climate Warming ◽  
Global Climate Change ◽  
Large Scale ◽  
Global Climate ◽  
Range Limits ◽  
Long Term Changes ◽  
Population Structures

Since the rate of global climate change began to accelerate in the 1980s, the coastal seas of Britain have warmed by up to 1°C. Locations close to the northern range edges of a southern trochid gastropod Osilinus lineatus in Britain previously surveyed in the 1950s and 1980s were resurveyed during 2002–2004 to determine whether changes in the success of near-limit populations had occurred during the period of climate warming. Between the 1980s and the 2000s, the range limits had extended by up to 55 km. Populations sampled over a latitudinal extent of 4 degrees from northern limits towards the centre of the range showed synchronous increases in abundance throughout the years sampled, suggesting a large-scale factor such as climate was driving the observed changes. These increases in abundance and changes in range limits are likely to have occurred via increased recruitment success in recent years.

Periodically forced self-organization in the long-term evolution of planktic foraminifera

2001 ◽  
Vol 38 (2) ◽  
pp. 293-308 ◽  
Author(s):  
Andreas Prokoph ◽  
Anthony D Fowler ◽  
R Timothy Patterson
Keyword(s):  
Sea Level ◽  
Logistic Map ◽  
Late Eocene ◽  
Self Organization ◽  
Extinction Data ◽  
Sea Level Fluctuations ◽  
Global Sea Level ◽  
Extinction Events ◽  
The Impact

Wavelet transform and other signal analysis techniques suggest that the planktic foraminiferal (PF) long-term evolutionary record of the last 127 Ma can be attributed to complex periodic and nonlinear patterns. Correlation of the PF extinction pattern with other geological series favors an origin of the ~30 Ma periodicity and self-organization by quasi-periodic mantle-plume cycles that in turn drive episodic volcanism, CO2-degassing, oceanic anoxic conditions, and sea-level fluctuations. Stationary ~30 Ma periodicity and a weak secular trend of ~100 Ma period are evident in the PF record, even without consideration of the mass extinction at the K–T boundary. The 27–32 Ma periodicity in the impact crater record and lows in the global sea-level curve, respectively, are ~6.5 Ma and ~2.3 Ma out of phase with PF-extinction data, although major PF-extinction events correspond to the bolide impacts at the K–T boundary and in late Eocene. Another six extinction events correspond to abrupt global sea-level falls between the late Albian and early Oligocene. Self-organization in the PF record is characterized by increased radiation rates after major extinction events and a steady number of baseline species. Our computer model of long-term PF evolution replicates this SO pattern. The model consists of output from the logistic map, which is forced at 30 Ma and 100 Ma frequencies. The model has significant correlations with the relative PF-extinction data. In particular, it replicates singularities, such as the K–T event, nonstationary 2.5–10 Ma periodicities, and phase shifts in the ~30 Ma periodicity of the PF record.

scholarly journals Long-term changes in oxygen depletion in a small temperate lake: effects of climate change and eutrophication

2011 ◽  
Vol 57 (2) ◽  
pp. 278-289 ◽  
Author(s):  
BRIAN FOLEY ◽  
IAN D. JONES ◽  
STEPHEN C. MABERLY ◽  
BRIAN RIPPEY
Keyword(s):  
Climate Change ◽  
Oxygen Depletion ◽  
Temperate Lake ◽  
Long Term Changes

scholarly journals What can we learn from long-term groundwater data to improve climate change impact studies?

2011 ◽  
Vol 8 (4) ◽  
pp. 7621-7655 ◽  
Author(s):  
S. Stoll ◽  
H. J. Hendricks Franssen ◽  
R. Barthel ◽  
W. Kinzelbach
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Climate Change Impact ◽  
Large Scale ◽  
Climate Models ◽  
Groundwater Resources ◽  
Groundwater Dynamics ◽  
Impact Studies ◽  
Change Impact

Abstract. Future risks for groundwater resources, due to global change are usually analyzed by driving hydrological models with the outputs of climate models. However, this model chain is subject to considerable uncertainties. Given the high uncertainties it is essential to identify the processes governing the groundwater dynamics, as these processes are likely to affect groundwater resources in the future, too. Information about the dominant mechanisms can be achieved by the analysis of long-term data, which are assumed to provide insight in the reaction of groundwater resources to changing conditions (weather, land use, water demand). Referring to this, a dataset of 30 long-term time series of precipitation dominated groundwater systems in northern Switzerland and southern Germany is collected. In order to receive additional information the analysis of the data is carried out together with hydrological model simulations. High spatio-temporal correlations, even over large distances could be detected and are assumed to be related to large-scale atmospheric circulation patterns. As a result it is suggested to prefer innovative weather-type-based downscaling methods to other stochastic downscaling approaches. In addition, with the help of a qualitative procedure to distinguish between meteorological and anthropogenic causes it was possible to identify processes which dominated the groundwater dynamics in the past. It could be shown that besides the meteorological conditions, land use changes, pumping activity and feedback mechanisms governed the groundwater dynamics. Based on these findings, recommendations to improve climate change impact studies are suggested.

scholarly journals Rising Sea Level, Receding Boundaries and Freezing Baselines in a Warming Climate

2019 ◽  
pp. 1-7
Author(s):  
Emojong Amai Mercy ◽  
Eliud Garry Michura
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Future Climate Change ◽  
Maritime Boundary ◽  
Climate Change Effect ◽  
Global Sea Level ◽  
Comprehensive Framework ◽  
Maritime Boundary Delimitation ◽  
International Boundaries

This paper discusses the less publicised but far from less significant, an issue of how the international community’s approach to maritime boundary delimitation will be impacted by climate change resulting in sea level rise with coastal lands submerging affecting the international boundaries and impacting on biodiversity and human survival in the future. The climate change effect is already creating pressure on international law regardless of the direction that the law of the sea takes in remedying this dilemma. It is quite apparent that global disputes and conflicts are arising and solutions are needed urgently. The climate change and the consequent global sea level rise are widely touted to submerge islands and coastlines without discrimination. The international community has been relatively slow to react to what could pose an unprecedented threat to human civilisation.  The policies that have been applied have arguably been reactive and not proactive.  In future climate change may develop other by-products which may not be understood at this moment and may require a proactive approach. Further discussion of the merits of the potential paths is ideal in ensuring that appropriate and well thought-out resolutions are negotiated. Regardless of the outcome, the thorough debate is required to ensure the correct decision is made and that the balancing act between fulfilling states' interests and achieving a meaningful result does not become detrimental to the solidity and the enforceability of the outcome. There is a need to establish a comprehensive framework for ocean governance for management and long-term development and sustainability.

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.

Limited subduction of water to mid-upper mantle depths predicted by the phase assemblages in hydrated peridotites with natural chemical composition at high-PT conditions

2021 ◽  
Author(s):  
Nestor Cerpa ◽  
Diane Arcay ◽  
José Alberto Padrón-Navarta
Keyword(s):  
Experimental Data ◽  
Sea Level ◽  
Subduction Zones ◽  
Thermal State ◽  
Water Flux ◽  
Geochemical Evolution ◽  
Hydrous Minerals ◽  
Global Sea Level ◽  
Global Water

<p>The water exchange between the Earth’s surface and the deep interior is a prime process for the geochemical evolution of our planet and its dynamics. The degassing of water from the mantle takes place through volcanism whereas mantle regassing occurs through the subduction of H<sub>2</sub>O chemically bound to hydrous minerals. The (im)balance between degassing and regassing controls the budget of surficial liquid water over geological timescales, i.e, the long-term global sea level. Continental freeboard constraints show that the mean-sea level has remained relatively constant in the last 540 Ma (changes less than about 100 m), thus suggesting a limited imbalance. However, thermopetrological models of water fluxes at present-day subduction zones predict that regassing exceeds degassing by about 50% which, if extrapolated to the past, would have induced a drop inconsistent with the estimations of the long-term sea-level. We have made the case that these inconsistencies arise from thermodynamic predictions for the hydrated lithospheric mantle mineralogy that are poorly constrained at a high pressure (P) and temperature (T). In our study, we thus have revised the global-water flux calculations in subduction zones using petrological constraints on post-antigorite assemblages from recent laboratory experimental data on natural peridotites under high-PT conditions [e.g. Maurice et al, 2018].</p><p>We model the thermal state of all present-day mature subduction zones along with petrological modeling using the thermodynamic code Perple_X and the most updated version of the thermodynamic database of Holland and Powell [2011]. For the modeling of peridotite, we build a hybrid phase diagram that combines thermodynamic calculations at moderate PT and experimental data at high PT (> 6 GPa- 600˚C). Our updated thermopetrological model reveals that the hydrated mantle efficiently dehydrates upon the breakdown of the hydrous aluminous-phase E before reaching 250 km in all but the coldest subduction zones. Further subducting slab dehydration is expected between 300-350 km depths, regardless of its thermal state, as a result of lawsonite breakdown in the gabbroic crust. Overall, we predict that present-day global water retention in subducting plates beyond a depth of 350 km barely exceeds the estimations of mantle degassing for average thicknesses of subducting serpentinized mantle subducting at the trenches of up to 6 km. Finally, our models quantitatively support the steady-state sea level scenario over geological times.</p><p> </p><p>Maurice, J., Bolfan-Casanova, N., Padrón-Navarta, J. A., Manthilake, G., Hammouda, T., Hénot, J. M., & Andrault, D. (2018). The stability of hydrous phases beyond antigorite breakdown for a magnetite-bearing natural serpentinite between 6.5 and 11 GPa. <em>Contributions to Mineralogy and Petrology</em>, 173(10), 86.</p><p>Holland, T. J. B., & Powell, R. (2011). An improved and extended internally consistent thermodynamic dataset for phases of petrological interest, involving a new equation of state for solids. <em>Journal of Metamorphic Geology</em>, 29(3), 333-383.</p>

Vulnerability of coastal areas to increased aquifer saturation due to climate change

2021 ◽  
Author(s):  
Alexandre Gauvain ◽  
Ronan Abhervé ◽  
Jean-Raynald de Dreuzy ◽  
Luc Aquilina ◽  
Frédéric Gresselin
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Large Scale ◽  
Regional Scale ◽  
Drainage System ◽  
Hydrological Regime ◽  
Coastal Areas ◽  
Western Coast ◽  
Study Sites ◽  
The Impact

<p>Like in other relatively flat coastal areas, flooding by aquifer overflow is a recurring problem on the western coast of Normandy (France). Threats are expected to be enhanced by the rise of the sea level and to have critical consequences on the future development and management of the territory. The delineation of the increased saturation areas is a required step to assess the impact of climate change locally. Preliminary models showed that vulnerability does not result only from the sea side but also from the continental side through the modifications of the hydrological regime.</p><p>We investigate the processes controlling these coastal flooding phenomena by using hydrogeological models calibrated at large scale with an innovative method reproducing the hydrographic network. Reference study sites selected for their proven sensitivity to flooding have been used to validate the methodology and determine the influence of the different geomorphological configurations frequently encountered along the coastal line.</p><p>Hydrogeological models show that the rise of the sea level induces an irregular increase in coastal aquifer saturations extending up to several kilometers inland. Back-littoral channels traditionally used as a large-scale drainage system against high tides limits the propagation of aquifer saturation upstream, provided that channels are not dominantly under maritime influence. High seepage fed by increased recharge occurring in climatic extremes may extend the vulnerable areas and further limit the effectiveness of the drainage system. Local configurations are investigated to categorize the influence of the local geological and geomorphological structures and upscale it at the regional scale.</p>

3. Evidence for climate change

2014 ◽  
pp. 29-45
Author(s):  
Mark Maslin
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Greenhouse Gases ◽  
Sea Level ◽  
Arctic Sea Ice ◽  
Weather Patterns ◽  
Recent Climate ◽  
Arctic Sea ◽  
Global Sea Level ◽  
Very High

‘Evidence for climate change’ considers both past and recent climate change through changes in temperature, precipitation, and relative global sea level to show that significant changes in climate have been recorded. These include a 0.85°Celsius (C) increase in average global temperatures over the last 150 years, sea-level rise of over 20 cm, significant shifts in the seasonality and intensities of precipitation, changing weather patterns, and significant retreat of Arctic sea ice and nearly all continental glaciers. The IPCC 2013 report states that the evidence for global warming is unequivocal and that there is very high confidence that this warming is due to human emissions of greenhouse gases.

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