scholarly journals Changing Expendable Bathythermograph Fall Rates and Their Impact on Estimates of Thermosteric Sea Level Rise

2008 ◽  
Vol 21 (21) ◽  
pp. 5657-5672 ◽  
Author(s):  
Susan E. Wijffels ◽  
Josh Willis ◽  
Catia M. Domingues ◽  
Paul Barker ◽  
Neil J. White ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Decadal Variability ◽  
Heat Content ◽  
Time History ◽  
Global Ocean ◽  
Fall Rate ◽  
Rate Minimum ◽  
Fall Rates

Abstract A time-varying warm bias in the global XBT data archive is demonstrated to be largely due to changes in the fall rate of XBT probes likely associated with small manufacturing changes at the factory. Deep-reaching XBTs have a different fall rate history than shallow XBTs. Fall rates were fastest in the early 1970s, reached a minimum between 1975 and 1985, reached another maximum in the late 1980s and early 1990s, and have been declining since. Field XBT/CTD intercomparisons and a pseudoprofile technique based on satellite altimetry largely confirm this time history. A global correction is presented and applied to estimates of the thermosteric component of sea level rise. The XBT fall rate minimum from 1975 to 1985 appears as a 10-yr “warm period” in the global ocean in thermosteric sea level and heat content estimates using uncorrected data. Upon correction, the thermosteric sea level curve has reduced decadal variability and a larger, steadier long-term trend.

scholarly journals Global reconstruction of historical ocean heat storage and transport

2019 ◽  
Vol 116 (4) ◽  
pp. 1126-1131 ◽  
Author(s):  
Laure Zanna ◽  
Samar Khatiwala ◽  
Jonathan M. Gregory ◽  
Jonathan Ison ◽  
Patrick Heimbach
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Heat Storage ◽  
Heat Content ◽  
Transport Processes ◽  
Sea Surface ◽  
Global Ocean ◽  
Low Latitudes ◽  
Global Coverage ◽  
Historical Coverage

Most of the excess energy stored in the climate system due to anthropogenic greenhouse gas emissions has been taken up by the oceans, leading to thermal expansion and sea-level rise. The oceans thus have an important role in the Earth’s energy imbalance. Observational constraints on future anthropogenic warming critically depend on accurate estimates of past ocean heat content (OHC) change. We present a reconstruction of OHC since 1871, with global coverage of the full ocean depth. Our estimates combine timeseries of observed sea surface temperatures with much longer historical coverage than those in the ocean interior together with a representation (a Green’s function) of time-independent ocean transport processes. For 1955–2017, our estimates are comparable with direct estimates made by infilling the available 3D time-dependent ocean temperature observations. We find that the global ocean absorbed heat during this period at a rate of 0.30 ± 0.06 W/m2 in the upper 2,000 m and 0.028 ± 0.026 W/m2 below 2,000 m, with large decadal fluctuations. The total OHC change since 1871 is estimated at 436 ± 91 ×1021 J, with an increase during 1921–1946 (145 ± 62 ×1021 J) that is as large as during 1990–2015. By comparing with direct estimates, we also infer that, during 1955–2017, up to one-half of the Atlantic Ocean warming and thermosteric sea-level rise at low latitudes to midlatitudes emerged due to heat convergence from changes in ocean transport.

scholarly journals A Holistic Framework for Evaluating Adaptation Approaches to Coastal Hazards and Sea Level Rise: A Case Study from Imperial Beach, California

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1324
Author(s):  
David Revell ◽  
Phil King ◽  
Jeff Giliam ◽  
Juliano Calil ◽  
Sarah Jenkins ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Public Trust ◽  
Adaptation Strategy ◽  
Public Benefits ◽  
Study Results ◽  
Local Risk ◽  
Over Time

Sea level rise increases community risks from erosion, wave flooding, and tides. Current management typically protects existing development and infrastructure with coastal armoring. These practices ignore long-term impacts to public trust coastal recreation and natural ecosystems. This adaptation framework models physical responses to the public beach and private upland for each adaptation strategy over time, linking physical changes in widths to damages, economic costs, and benefits from beach recreation and nature using low-lying Imperial Beach, California, as a case study. Available coastal hazard models identified community vulnerabilities, and local risk communication engagement prioritized five adaptation approaches—armoring, nourishment, living shorelines, groins, and managed retreat. This framework innovates using replacement cost as a proxy for ecosystem services normally not valued and examines a managed retreat policy approach using a public buyout and rent-back option. Specific methods and economic values used in the analysis need more research and innovation, but the framework provides a scalable methodology to guide coastal adaptation planning everywhere. Case study results suggest that coastal armoring provides the least public benefits over time. Living shoreline approaches show greater public benefits, while managed retreat, implemented sooner, provides the best long-term adaptation strategy to protect community identity and public trust resources.

Long-term legacy of delayed climate mitigation in global glacier response

2021 ◽  
Author(s):  
Fabien Maussion ◽  
Quentin Lejeune ◽  
Ben Marzeion ◽  
Matthias Mengel ◽  
David Rounce ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Greenhouse Gas ◽  
Sea Level ◽  
Climate Mitigation ◽  
Delayed Response ◽  
Glacier Change ◽  
Mountain Glaciers ◽  
Glacier Runoff ◽  
The Impact

<p>Mountain glaciers have a delayed response to climate change and are expected to continue to melt long after greenhouse gas emissions have stopped, with consequences both for sea-level rise and water resources. In this contribution, we use the Open Global Glacier Model (OGGM) to compute global glacier volume and runoff changes until the year 2300 under a suite of stylized greenhouse gas emission characterized by (i) the year at which anthropogenic emissions culminate, (ii) their reduction rates after peak emissions and (iii) whether they lead to a long-term global temperature stabilization or decline. We show that even under scenarios that achieve the Paris Agreement goal of holding global-mean temperature below 2 °C, glacier contribution to sea-level rise will continue well beyond 2100. Because of this delayed response, the year of peak emissions (i.e. the timing of mitigation action) has a stronger influence on mit-term global glacier change than other emission scenario characteristics, while long-term change is dependent on all factors. We also discuss the impact of early climate mitigation on regional glacier change and the consequences for glacier runoff, both short-term (where some basins are expected to experience an increase of glacier runoff) and long-term (where all regions are expecting a net-zero or even negative glacier contribution to total runoff), underlining the importance of mountain glaciers for regional water availability at all timescales.</p>

scholarly journals Consistency of the current global ocean observing systems from an Argo perspective

Ocean Science ◽  
2014 ◽  
Vol 10 (3) ◽  
pp. 547-557 ◽  
Author(s):  
K. von Schuckmann ◽  
J.-B. Sallée ◽  
D. Chambers ◽  
P.-Y. Le Traon ◽  
C. Cabanes ◽  
...  
Keyword(s):  
Sea Level ◽  
Heat Content ◽  
Deep Ocean ◽  
Global Ocean ◽  
Regional Variability ◽  
Tropical Ocean ◽  
Steric Sea Level ◽  
Ocean Observing ◽  
Ocean Observing Systems ◽  
Observing Systems

Abstract. Variations in the world's ocean heat storage and its associated volume changes are a key factor to gauge global warming and to assess the earth's energy and sea level budget. Estimating global ocean heat content (GOHC) and global steric sea level (GSSL) with temperature/salinity data from the Argo network reveals a positive change of 0.5 ± 0.1 W m−2 (applied to the surface area of the ocean) and 0.5 ± 0.1 mm year−1 during the years 2005 to 2012, averaged between 60° S and 60° N and the 10–1500 m depth layer. In this study, we present an intercomparison of three global ocean observing systems: the Argo network, satellite gravimetry from GRACE and satellite altimetry. Their consistency is investigated from an Argo perspective at global and regional scales during the period 2005–2010. Although we can close the recent global ocean sea level budget within uncertainties, sampling inconsistencies need to be corrected for an accurate global budget due to systematic biases in GOHC and GSSL in the Tropical Ocean. Our findings show that the area around the Tropical Asian Archipelago (TAA) is important to closing the global sea level budget on interannual to decadal timescales, pointing out that the steric estimate from Argo is biased low, as the current mapping methods are insufficient to recover the steric signal in the TAA region. Both the large regional variability and the uncertainties in the current observing system prevent us from extracting indirect information regarding deep-ocean changes. This emphasizes the importance of continuing sustained effort in measuring the deep ocean from ship platforms and by beginning a much needed automated deep-Argo network.

scholarly journals Implementing Pre-Emptive Managed Retreat: Constraints and Novel Insights

2021 ◽  
Author(s):  
Judith Lawrence ◽  
Jonathan Boston ◽  
R Bell ◽  
S Olufson ◽  
R Kool ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
First Century ◽  
Current State ◽  
Adaptation Response ◽  
Extreme Flooding ◽  
Protective Structures ◽  
Implementation Gaps ◽  
Post Disaster

Purpose of Review: Managed retreat will be inevitable where other adaptation options, such as protective structures or building restrictions, provide only temporary respite or are otherwise uneconomic, technically impractical or both. Here, we focus on the implementation of pre-emptive managed retreat, providing examples of how it can be sequenced, socialised and given the governance enablers necessary for implementation. Recent Findings: Ongoing sea-level rise during the twenty-first century and beyond poses huge adaptation challenges, especially for low-lying coastal and floodplain settlements. Settlements are already functionally disrupted from repetitive non-extreme flooding and research shows that sea-level rise will impact far more people, far sooner than previously thought, as more powerful storms, heavy rainfall and rising groundwater coincide with higher tides. To date, most examples of managed retreat have been post-disaster responses following damage and disruption. Pre-emptive managed retreat, by contrast, has yet to become a well-accepted and widely practised adaptation response. Nevertheless, there are increasing examples of research and practice on how pre-emptive managed retreat can be designed, sequenced and implemented alongside other forms of adaptation within anticipatory forms of governance. Summary: The current state of knowledge about managed retreat is reviewed and critical insights and lessons for governance and policy-making are given. Several novel examples from New Zealand are presented to address some of the implementation gaps. Goals and principles are enunciated to inform long-term adaptation strategies.

scholarly journals Delaying future sea-level rise by storing water in Antarctica

2016 ◽  
Vol 7 (1) ◽  
pp. 203-210 ◽  
Author(s):  
K. Frieler ◽  
M. Mengel ◽  
A. Levermann
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Energy Supply ◽  
Primary Energy ◽  
Ocean Water ◽  
Additional Mass ◽  
Dynamic Perspective ◽  
Primary Energy Supply ◽  
The Antarctic

Abstract. Even if greenhouse gas emissions were stopped today, sea level would continue to rise for centuries, with the long-term sea-level commitment of a 2 °C warmer world significantly exceeding 2 m. In view of the potential implications for coastal populations and ecosystems worldwide, we investigate, from an ice-dynamic perspective, the possibility of delaying sea-level rise by pumping ocean water onto the surface of the Antarctic ice sheet. We find that due to wave propagation ice is discharged much faster back into the ocean than would be expected from a pure advection with surface velocities. The delay time depends strongly on the distance from the coastline at which the additional mass is placed and less strongly on the rate of sea-level rise that is mitigated. A millennium-scale storage of at least 80 % of the additional ice requires placing it at a distance of at least 700 km from the coastline. The pumping energy required to elevate the potential energy of ocean water to mitigate the currently observed 3 mm yr−1 will exceed 7 % of the current global primary energy supply. At the same time, the approach offers a comprehensive protection for entire coastlines particularly including regions that cannot be protected by dikes.

Long-term sea-level rise implied by 1.5 °C and 2 °C warming levels

2012 ◽  
Vol 2 (12) ◽  
pp. 867-870 ◽  
Author(s):  
Michiel Schaeffer ◽  
William Hare ◽  
Stefan Rahmstorf ◽  
Martin Vermeer
Keyword(s):  
Sea Level Rise ◽  
Sea Level

scholarly journals Simulating barrier island response to sea level rise with the barrier island and inlet environment (BRIE) model v1.0

2019 ◽  
Vol 12 (9) ◽  
pp. 4013-4030 ◽  
Author(s):  
Jaap H. Nienhuis ◽  
Jorge Lorenzo-Trueba
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Barrier Island ◽  
Barrier Islands ◽  
Emergent Behavior ◽  
Tidal Inlets ◽  
Rise Rate ◽  
Ecological Importance ◽  
Alongshore Sediment Transport

Abstract. Barrier islands are low-lying coastal landforms vulnerable to inundation and erosion by sea level rise. Despite their socioeconomic and ecological importance, their future morphodynamic response to sea level rise or other hazards is poorly understood. To tackle this knowledge gap, we outline and describe the BarrieR Inlet Environment (BRIE) model that can simulate long-term barrier morphodynamics. In addition to existing overwash and shoreface formulations, BRIE accounts for alongshore sediment transport, inlet dynamics, and flood–tidal delta deposition along barrier islands. Inlets within BRIE can open, close, migrate, merge with other inlets, and build flood–tidal delta deposits. Long-term simulations reveal complex emergent behavior of tidal inlets resulting from interactions with sea level rise and overwash. BRIE also includes a stratigraphic module, which demonstrates that barrier dynamics under constant sea level rise rates can result in stratigraphic profiles composed of inlet fill, flood–tidal delta, and overwash deposits. In general, the BRIE model represents a process-based exploratory view of barrier island morphodynamics that can be used to investigate long-term risks of flooding and erosion in barrier environments. For example, BRIE can simulate barrier island drowning in cases in which the imposed sea level rise rate is faster than the morphodynamic response of the barrier island.

Middle and Late Holocene Sea-Level Changes in Eastern Maine Reconstructed from Foraminiferal Saltmarsh Stratigraphy and AMS 14C Dates on Basal Peat

1999 ◽  
Vol 52 (3) ◽  
pp. 350-359 ◽  
Author(s):  
W.Roland Gehrels
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Tidal Range ◽  
Sea Level Changes ◽  
The Past ◽  
Amplitude Fluctuations ◽  
Vertical Distributions ◽  
Low Amplitude ◽  
Long Term Trend

A relative sea-level history is reconstructed for Machiasport, Maine, spanning the past 6000 calendar year and combining two different methods. The first method establishes the long-term (103 yr) trend of sea-level rise by dating the base of the Holocene saltmarsh peat overlying a Pleistocene substrate. The second method uses detailed analyses of the foraminiferal stratigraphy of two saltmarsh peat cores to quantify fluctuations superimposed on the long-term trend. The indicative meaning of the peat (the height at which the peat was deposited relative to mean tide level) is calculated by a transfer function based on vertical distributions of modern foraminiferal assemblages. The chronology is determined from AMS 14C dates on saltmarsh plant fragments embedded in the peat. The combination of the two different approaches produces a high-resolution, replicable sea-level record, which takes into account the autocompaction of the peat sequence. Long-term mean rates of sea-level rise, corrected for changes in tidal range, are 0.75 mm/yr between 6000 and 1500 cal yr B.P. and 0.43 mm/yr during the past 1500 year. The foraminiferal stratigraphy reveals several low-amplitude fluctuations during a relatively stable period between 1100 and 400 cal yr B.P., and a sea-level rise of 0.5 m during the past 300 year.

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