Environmental Science Sea Level Rise
by
Anny Cazenave
  • LAST REVIEWED: 03 June 2019
  • LAST MODIFIED: 25 October 2017
  • DOI: 10.1093/obo/9780199363445-0028

Introduction

Sea level is the height of the sea surface expressed either in a geocentric reference frame (absolute sea level) or with respect to the moving Earth’s crust (relative sea level). Absolute sea level variations result from changes in the volume of water filling ocean basins (due either to water density or mass changes), while relative sea level variations designate sea surface height changes with respect to the ground (thus accounting both for “absolute” sea level changes and ground motions). Sea level variations spread over a very broad spectrum. On geological time scales, roughly 5–100 million years ago, 330-foot-amplitude sea level changes depend primarily on tectonics processes, such as large-scale changes in the shape of ocean basins associated with seafloor spreading and midocean ridge expansion, as well as on the existence (or not) of polar ice sheets. On a 10,000–100,000-year time scale, glacial/interglacial cycles driven by changes of the Earth’s orbit and obliquity also cause about 330-foot-amplitude sea level variations. On shorter time scales, 3.3-foot-amplitude sea level changes occur in response to natural climate-forcing factors (change in solar irradiance and volcanic eruptions). Humans also influence climate, and associated sea level change is noticeable since about 1900. Sea level is a very sensitive index of climate change and variability. For example, as the ocean warms in response to global warming, seawaters expand and thus sea level rises. When mountain glaciers melt in response to increasing air temperature, sea level rises because of fresh water mass input to the oceans. Similarly, ice mass loss from the ice sheets causes sea level rise. A corresponding increase of fresh water into the oceans changes water salinity; hence, seawater density as well as ocean circulation affects sea level and its spatial variability. Finally, modification of water storage on land in response to climate variability and direct anthropogenic forcing also causes sea level to vary on interannual to multidecadal time scales. Because of the multidisciplinary character of the sea level topic, as well as enormous progress made since the late 20th century owing to new in situ and space-observing systems, the literature on the subject is vast and continually increasing. For that reason, most of the works listed in this article were published after 2000, although a few older works are also mentioned.

General Overviews

The sea level chapters of the most recent Intergovernmental Panel on Climate Change (IPCC) assessments (IPCC AR4 and IPCC AR5, Working Group I) provide extensive lists of published work on the various aspects of sea level science, including observations and contributions to modern sea level rise. These are listed in this section. In the commentary paragraphs, a number of key articles published since then, as well as a number of the most influential works, are discussed.

Observations of Paleo Sea Level

The works cited in this section provide information on paleo sea level variations on geological (million-year) time scales, during the glacial/interglacial cycles of the Quaternary, the last interglacial time, the last deglaciation, and the last few millennia. On such time scales, the main tools informing on sea level changes consist of deep-sea sediments records, fossil corals, planktonic foraminifera, geological observations of ancient shorelines, and archaeological data. Hacq and Schutter 2008; Miller, et al. 2011; Lambeck, et al. 2002; and Rohling, et al. 2004 discuss the paleo observations of sea level changes over the last few millions years. Sea level variations during the last glacial maximum and last deglaciation are addressed in Rohling, et al. 2008 and Deschamps, et al. 2012. Information on the last two millennia of sea level rise can be found in Kemp, et al. 2011; Lambeck, et al. 2004; Miller, et al. 2013; and Kopp, et al. 2015.

  • Deschamps, P., N. Durand, E. Bard, et al. 2012. Ice-sheet collapse and sea-level rise at the Bølling warming 14,600 years ago. Nature 483.7391: 559–564.

    DOI: 10.1038/nature10902Save Citation »Export Citation »

    This study reports high rates of sea level rise, up to 1.57 inches/year, lasting three hundred years or less during the last deglaciation.

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  • Hacq, B. U., and S. R. Schutter. 2008. A chronology of Paleozoic sea-level changes. Science 322.5898: 64–68.

    DOI: 10.1126/science.1161648Save Citation »Export Citation »

    Paleozoic (542 to 251 million years [Myr] ago) sea level reconstructions from analyses of sediment records in cratonic basins show long-term (order of 100 Myr) changes of roughly 330–660-foot magnitude and superimposed shorter-term oscillations of 33–330-foot amplitude.

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  • Kemp, A. C., B. Horton, J. P. Donnelly, M. E. Mann, M. Vermeer, and S. Rahmstorf. 2011. Climate related sea level variations over the past two millennia. PNAS 108.27: 11017–11022.

    DOI: 10.1073/pnas.1015619108Save Citation »Export Citation »

    Using biomarkers from the US coast of North America, this study shows that during the last two millennia, the rate of sea level rise did not exceed 0.02 inches/year until the beginning of the industrial era.

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  • Kopp, R. E., A. C. Kemp, K. Bittermann, et al. 2015. Temperature-driven global sea-level variability in the Common Era. PNAS 113.11: E1434–E1441.

    DOI: 10.1073/pnas.1517056113Save Citation »Export Citation »

    New sea level reconstruction over the past 2,500 years by using proxy data and tide gauge records.

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  • Lambeck, K., M. Anzidei, F. Antonioli, A. Benini, and A. Esposito. 2004. Sea level in Roman time in the central Mediterranean and implications for recent change. Earth and Planetary Science Letters 224.3–4: 563–575.

    DOI: 10.1016/j.epsl.2004.05.031Save Citation »Export Citation »

    Archaeological observations from the Roman fish pounds provides constraints on sea level elevation since two thousand years ago. The study shows that sea level did not rise more than 3.3 feet during that time span.

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  • Lambeck, K., T. M. Esat, and E. K. Potter. 2002. Links between climate and sea levels for the past three million years. Nature 419.6903: 199–206.

    DOI: 10.1038/nature01089Save Citation »Export Citation »

    This article reviews changes in global ice volume and sea level due to glacial and interglacial climate conditions over the past three million years, with focus on the last glacial maximum about 20,000 years ago and subsequent deglaciation.

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  • Miller, K. G., R. E. Kopp, B. P. Horton, J. V. Browning, and A. C. Kemp. 2013. A geological perspective on sea level rise and impacts along the U.S. mid-Atlantic coast. Earth’s Future 1.1: 3–18.

    DOI: 10.1002/2013EF000135Save Citation »Export Citation »

    A review on paleo, historical, and future sea level rise along the US mid-Atlantic coast.

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  • Miller, K. G., G. S. Mountain, J. D. Wright, and J. V. Browning. 2011. A 180-million-year record of sea level and ice volume variations from continental margin and deep-sea isotopic records. In Special issue on sea level. Edited by Josh Willis, Laury Miller, and Gregory Mountain. Oceanography 24.2: 40–53.

    DOI: 10.5670/oceanog.2011.26Save Citation »Export Citation »

    This article is a review of geological record constraints on rates, amplitudes, and mechanisms of sea level changes over various time scales during the last 180 Myr.

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  • Rohling, E. J., G. L. Foster, K. M. Grant, et al. 2004. Sea-level and deep-sea-temperature variability over the past 5.3 million years. Nature 508.7497: 477–482.

    DOI: 10.1038/nature13230Save Citation »Export Citation »

    This study presents a sea level reconstruction of the last 5.3 million years on the basis of sediment records from the Mediterranean Sea, showing a progressive decrease of sea level and deep-sea temperature, with a marked cooling 2.73 Myr ago and a first glaciation at 2.15 Myr ago.

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  • Rohling, E. J., K. Grant, C. H. Hemleben, et al. 2008. High rates of sea-level rise during the last interglacial period. Nature Geosciences 1.1: 38–42.

    DOI: 10.1038/ngeo.2007.28Save Citation »Export Citation »

    From well-dated fossil corals and stable oxygen isotope records from planktonic foraminifera from the Red Sea, this study refines estimates of sea level position and absolute age during the last interglacial (120,000–123,000 ago) and shows that mean sea level stood 13–20 feet higher than modern sea level, with important contribution from the Greenland ice sheet.

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Observations of Historical Sea Level over the 20th Century

Information on historical (i.e., since the beginning of the industrial era) sea level variations come from direct in situ measurements by tide gauges, located along continental coastlines and islands. Prior to the beginning of the 20th century, data are very sparse and are based on only a few long records at sites located in western Europe. The largest tide gauge database of monthly and annual mean sea level records is the Permanent Service for Mean Sea Level (PSMSL). Tide gauges measure sea level relative to the ground and hence also monitor ground motions due to tectonic and volcanic activity, subsidence due to sediment loading, oil/gas and groundwater extraction, or postglacial rebound (the viscoelastic response of the solid Earth to last deglaciation—also called glacial isostatic adjustment [GIA]). Several articles analyze data from the PSMSL to provide a historical mean sea level time series. Different processing methodologies and corrections to the data have been applied by the investigators. The most noticeable works are Douglas 2001; Peltier 2001; Jevrejeva, et al. 2006; Church and White 2011; Ray and Douglas 2011; Hay, et al. 2015; and Dangendorf, et al. 2017. Wöppelmann, et al. 2009 and Wöppelmann and Marcos 2016 discuss the impact of vertical land motions on tide gauge–based sea level reconstruction.

Satellite Altimetry and the Sea Level Record

Since the early 1990s, high-precision satellite altimetry has become the main tool for precisely and continuously measuring absolute sea level with quasiglobal coverage and a few days’ revisit time. Chelton, et al. 2001 describes the principle of satellite radar altimetry and how to derive sea surface height measurements above a reference fixed surface (typically a conventional reference ellipsoid). It also discusses all corrections to be applied to the sea surface height measurements, including drifts and bias from onboard instruments. High-precision satellite altimetry started with the launch of the TOPEX/Poseidon satellite in 1992. Since then, several other altimetry missions have been launched (Jason-1&2, Envisat, Cryosat, SARAL/AltiKa, Sentinel-3, Jason-3). Since the mid-1990s, several groups have routinely analyzed satellite altimetry data to provide a global mean sea level record and associated regional variations. While the literature on this topic is plentiful, Nerem, et al. 2010; Mitchum, et al. 2010; Ablain, et al. 2009; Ablain, et al. 2015; and Ablain, et al. 2017 provide useful information on the subject. An up-to-date altimetry-based global mean sea level rise is provided in Watson, et al. 2015 and Dieng, et al. 2017, after accounting for the TOPEX A altimeter drift. Fu and Cazenave 2001 (cited under Books) is still a reference on satellite altimetry and oceanographic applications.

  • Ablain, M., A. Cazenave, G. Valladeau, and S. Guinehut. 2009. A new assessment of the error budget of global mean sea level rate estimated by satellite altimetry over the period 1993–2008. Ocean Science 5.2: 193–201.

    DOI: 10.5194/os-5-193-2009Save Citation »Export Citation »

    A full assessment study of all sources of errors affecting the satellite altimetry system.

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  • Ablain, M., A. Cazenave, G. Larnicol, et al. 2015. Improved sea level record over the satellite altimetry era (1993–2010) from the Climate Change Initiative project. Ocean Science 11.1: 67–82.

    DOI: 10.5194/os-11-67-2015Save Citation »Export Citation »

    An update of global and regional sea level on the basis of multimission satellite altimetry.

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  • Ablain, M., J. F. Legeais, P. Prandi, et al. 2017. Satellite altimetry-based sea level at global and regional scales. In Special issue: ISSI workshop on “Integrative study of the mean sea level and its components.” Edited by A. Cazenave, N. Champollion, F. Paul, and J. Benveniste. Surveys in Geophysics 38.1: 7–31.

    DOI: 10.1007/s10712-016-9389-8Save Citation »Export Citation »

    An overview of satellite altimetry–based global and regional sea level record and associated uncertainties.

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  • Chelton, D. B., J. C. Ries, B. J. Haines, L. L. Fu, and P. S. Callahan. 2001. Satellite altimetry. In Satellite altimetry and Earth sciences: A handbook of techniques and applications. Edited by L.-L. Fu and A. Cazenave, 1–131. International Geophysics Series 69. San Diego, CA: Academic Press.

    DOI: 10.1016/S0074-6142(01)80146-7Save Citation »Export Citation »

    This book chapter is a very useful reference that describes in detail the principle of satellite altimetry for measuring sea surface height, and it discusses all corrections to be applied to the raw altimetry data.

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  • Dieng, H. B., A. Cazenave, B. Meyssignac, and M. Ablain. 2017. New estimate of the current rate of sea level rise from a sea level budget approach. Geophysical Research Letters 44.8: 3744–3751.

    DOI: 10.1002/2017GL073308Save Citation »Export Citation »

    New estimate of the global mean sea level budget over the altimetry era, using a large number of data sets and accounting for the TOPEX A altimeter drift.

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  • Mitchum, G. T., R. S. Nerem, M. A. Merrifield, and W. R. Gehrels. 2010. Modern sea-level-change estimates. In Understanding sea-level rise and variability. Edited by J. A. Church, P. L. Woodworth, T. Aarup, and W. S. Wilson, 122–142. Chichester, UK, and Hoboken, NJ: Wiley-Blackwell.

    DOI: 10.1002/9781444323276.ch5Save Citation »Export Citation »

    A review on historical sea level rise, on the basis of tide gauge measurements and satellite altimetry.

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  • Nerem, R. S., D. P. Chambers, C. Choe, and G. T. Mitchum. 2010. Estimating mean sea level change from the TOPEX and Jason altimeter missions. Marine Geodesy 33.S1: 435–446.

    DOI: 10.1080/01490419.2010.491031Save Citation »Export Citation »

    An article that estimates satellite altimetry–based sea level rise.

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  • Watson, C. S., N. J. White, J. A. Church, M. A. King, R. J. Burgette, and B. Legresy. 2015. Unabated global mean sea-level over the satellite altimeter era. Nature Climate Change 5.6: 565–568.

    DOI: 10.1038/NCLIMATE2635Save Citation »Export Citation »

    Revised estimate of the global mean sea level rise of the altimetry era, accounting for the TOPEX A altimeter drift.

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  • Woodworth, P. L., and R. Player. 2003. The permanent service for mean sea level: An update to the 21st century. Journal of Coastal Research 19.2: 287–295.

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    Reference for the PSMSL database.

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Websites

There are currently six satellite altimetry processing groups worldwide providing updated sea level data sets based on multisatellite altimetry: Altimetry Validation and Interpretation of Satellite Oceanography (AVISO, France), CU Sea Level Research Group (University of Colorado, United States), Goddard Space Flight Center (GSFC, United States), National Oceanographic and Atmospheric Administration (NOAA, United States), and Commonwealth Scientific and Industrial Research Organization (CSIRO, Australia). Satellite altimetry–based sea level products can be downloaded from the websites of these processing groups.

Causes of modern Global Mean Sea Level Changes

At interannual to decadal time scales, the main factors causing current global mean sea level rise are thermal expansion of seawaters, land ice loss, and freshwater mass exchange between oceans and land water reservoirs. These contributions vary in response to natural (internal) climate variability and to global climate change induced by anthropogenic greenhouse gas emissions. They can be quantified by using data from various observing systems. The subsections in this section list works previously assessed by the Intergovernmental Panel on Climate Change (IPCC) AR5 as well as new studies published after the IPCC AR5 deadline.

Ocean Temperature and Salinity Changes

Since the middle of the 20th century, in situ ocean temperature (and, to a lesser extent, salinity) data have been collected by various devices (e.g., expandable bathy thermographers [XBT] from ships, buoys, and moorings) (Abraham, et al. 2013), and since the first few years of the 21st century by automatic profiling floats from the Argo system, as described in Roemmich, et al. 2012. These data sets have been processed by different groups to provide gridded time series of in situ ocean temperature and salinity, useful to estimate the ocean heat content and thermal expansion (more generally on steric changes; i.e., the combined effect of ocean temperature and salinity changes). The selection of papers listed in this subsection deal with the analysis of in situ ocean temperature data collected by ships, buoys, and moorings since about 1950 (Domingues, et al. 2008; Ishii and Kimoto 2009; Levitus, et al. 2012; Lyman, et al. 2010), Argo automatic floats since about 2005 (Roemmich, et al. 2012; von Schuckmann, et al. 2014), or both (Cheng, et al. 2016). Purkey and Johnson 2010 reports on sparse temperature measurements in the deep and abyssal ocean, and Wunsch and Heimbach 2014 quantifies deep-ocean warming. Additional information can be found in IPCC AR5 (Rhein, et al. 2013). The role of ocean heat content on sea level and Earth’s energy imbalance is reviewed in von Schuckmann, et al. 2016.

  • Abraham, J. P., M. Baringer, N. L. Bindoff, et al. 2013. A review of global ocean temperature observations: Implications for ocean heat content estimates and climate change. Reviews of Geophysics 51.3: 450–483.

    DOI: 10.1002/rog.20022Save Citation »Export Citation »

    Review article describing the various observing systems (including Argo) available to estimate historical ocean warming and salinity changes. This study provides a detailed description of the various processing methodologies and their impact on estimates of ocean heat content.

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  • Cheng, L., K. E. Trenberth, M. D. Palmer, J. Zhu, and J. P. Abraham. 2016. Observed and simulated full-depth ocean heat-content changes for 1970–2005. Ocean Science 12.4: 925–935.

    DOI: 10.5194/os-12-925-2016Save Citation »Export Citation »

    A comparison of updated observations and climate models for the full-depth ocean heat content since 1970.

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  • Domingues, C. M., J. A. Church, N. J. White, et al. 2008. Improved estimates of upper-ocean warming and multi-decadal sea-level rise. Nature 453.7198: 1090–1093.

    DOI: 10.1038/nature07080Save Citation »Export Citation »

    A reconstruction of the steric sea level evolution during the previous few decades, on the basis of an empirical orthogonal functions approach.

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  • Ishii, M., and M. Kimoto. 2009. Reevaluation of historical ocean heat content variations with time-varying XBT and MBT depth bias corrections. Journal of Oceanography 65.3: 287–299.

    DOI: 10.1007/s10872-009-0027-7Save Citation »Export Citation »

    A global gridded data set of historical in situ ocean temperature and salinity.

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  • Levitus, S., J. I. Antonov, T. P. Boyer, et al. 2012. World ocean heat content and thermosteric sea level change (0–2000 m), 1955–2010. Geophysical Research Letters 39.10: L10603.

    DOI: 10.1019/2012GL051106Save Citation »Export Citation »

    An update of the world ocean heat content evolution on the basis of the World Ocean database plus additional observations. Regular updates of the integrated steric data set are available online.

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  • Lyman, J. M., S. A. Good, V. V. Gouretski, et al. 2010. Robust warming of the global upper ocean. Nature 465.7296: 334–337.

    DOI: 10.1038/nature09043Save Citation »Export Citation »

    An important article showing that despite important differences between the various estimates of ocean heat content over the previous two decades, a robust ocean warming can be detected.

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  • Lyman, J. M., and G. C. Johnson. 2014. Estimating global ocean heat content changes in the upper 1800 m since 1950 and the influence of climatology choice. Journal of Climate 27.5: 1945–1957.

    DOI: 10.1175/JCLIM-D-12-00752.1Save Citation »Export Citation »

    A reanalysis of historical (since 1950) ocean temperature measurements of the upper ocean to derive change in ocean heat content.

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  • Purkey, S. G., and G. C. Johnson. 2010. Warming of global abyssal and deep southern ocean waters between the 1990s and 2000s: Contributions to global heat and sea level rise budgets. Journal of Climate 23.23: 6336–6351.

    DOI: 10.1175/2010JCLI3682.1Save Citation »Export Citation »

    One of the few studies analyzing sparse deep and abyssal ocean temperature data, showing evidence of deep-ocean warming.

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  • Rhein, M., S. R. Rintoul, S. Aoki, et al. 2013. Observations: Ocean. In Climate change 2013: The physical science basis; Contribution of Working Group I to the fifth assessment report of the Intergovernmental Panel on Climate Change. Edited by T. F. Stocker, D. Qin, G.-K. Plattner, et al., 255–316. Cambridge, UK, and New York: Cambridge Univ. Press.

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    IPCC AR5 assessment on ocean observations.

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  • Roemmich, D., W. J. Gould, and J. Gilson. 2012. 135 years of global ocean warming between the Challenger expedition and the Argo Programme. Nature Climate Change 2.6: 425–428.

    DOI: 10.1038/nclimate1461Save Citation »Export Citation »

    A review about measurements of in situ ocean temperatures over the 20th century and before, and Argo profiling floats over the previous decade

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  • von Schuckmann, K., M. D. Palmer, K. E. Trenberth, et al. 2016. Earth’s energy imbalance: An imperative for monitoring. Nature Climate Change 6.2: 138–144.

    DOI: 10.1038/nclimate2876Save Citation »Export Citation »

    Perspective article discussing the dominant role of the oceans on storing the excess heat due to greenhouse emissions, and the different methods to monitor the Earth’s energy imbalance.

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  • von Schuckmann, K., J.-B. Sallée, D. Chambers, et al. 2014. Consistency of the current global ocean observing systems from an Argo perspective. Ocean Science 10.3: 547–557.

    DOI: 10.5194/os-10-547-2014Save Citation »Export Citation »

    This work analyzes Argo-based steric sea level data over the previous few years in a “global sea level budget” perspective.

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  • Wunsch, C., and P. Heimbach. 2014. Bidecadal thermal changes in the abyssal ocean. Journal of Physical Oceanography 44.8: 2013–2030.

    DOI: 10.1175/JPO-D-13-096.1Save Citation »Export Citation »

    The most recent review on deep-ocean warming from observation and an ocean numerical model with data assimilation.

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Websites

The ocean temperature and salinity data sets are available from several websites.

Land Ice Contribution to Sea Level

The main land ice contributions to present-day sea level come from glacier melting and ice mass loss from the Greenland and Antarctica ice sheets. The quoted works under Glaciers and Ice Sheets deal mostly with observations.

Glaciers

Being very sensitive to global warming, mountain glaciers and small ice caps retreated worldwide during the 20th century, and they continue to do so in the 21st, with significant acceleration since the early 1990s. From volume and mass balance studies of a large number of glaciers on the basis of various in situ and remote-sensing observing methods, estimates have been made of the contribution of glacier melt to sea level rise. Kaser, et al. 2006; Cogley 2009; Jacob, et al. 2012; Gardner, et al. 2013; Leclercq, et al. 2011; Marzeion, et al. 2015; and Marzeion, et al. 2017 are a selection of these estimates. Additional references can be found in IPCC AR5 (Vaughan, et al. 2013).

  • Cogley, J. C. 2009. Geodetic and direct mass balance measurements: Comparison and joint analysis. Annals of Glaciology 50:96–100.

    DOI: 10.3189/172756409787769744Save Citation »Export Citation »

    This work presents an estimate of global average mass balance of glaciers since 1950, combining different measurements approaches (direct and geodetic).

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  • Gardner, A. S., G. Moholdt, J. G. Cogley, et al. 2013. A reconciled estimate of glacier contributions to sea level rise: 2003 to 2009. Science 340.6134: 852–857.

    DOI: 10.1126/science.1234532Save Citation »Export Citation »

    An analysis that attempts to reconcile the various (dispersed) estimates of glacier mass balance and their contribution to sea level rise during the first decade of the 21st century.

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  • Jacob, T., J. Wahr, W. T. Pfeffer, and S. Swenson. 2012. Recent contributions of glaciers and ice caps to sea level rise. Nature 482.7386: 514–518.

    DOI: 10.1038/nature10847Save Citation »Export Citation »

    A reestimate of the contribution of glaciers to sea level rise during the first decade of the 21st century, on the basis of Gravity Recovery and Climate Experiment (GRACE) space gravimetry, suggesting that previous estimates have been overestimated.

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  • Kaser, G., J. G. Cogley, M. B. Dyurgerov, M. F. Meier, and A. Ohmura. 2006. Mass balance of glaciers and ice caps: Consensus estimates for 1961–2004. Geophysical Research Letters 33.19: L19501.

    DOI: 10.1029/2006GL027511Save Citation »Export Citation »

    Another work on the effect of glaciers mass balance (on the basis of observations) on sea level rise over the 1961–2004 time span.

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  • Leclercq, P. W., J. Oerlemans, and J. G. Cogley. 2011. Estimating the glacier contribution to sea-level rise for the period 1800–2005. Surveys in Geophysics 32.4–5: 519–535.

    DOI: 10.1007/s10712-011-9121-7Save Citation »Export Citation »

    Estimate of global glacier mass balance between 1800 and 2005 on the basis of change in glacier length.

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  • Marzeion, B., N. Champollion, W. Haeberli, K. Langley, P. Leclercq, and F. Paul. 2017. Observation-based estimates of global glacier mass change and its contribution to sea-level change. In Special issue: ISSI workshop on “Integrative study of the mean sea level and its components.” Edited by A. Cazenave, N. Champollion, F. Paul, and J. Benveniste. Surveys in Geophysics 38.1: 105–130.

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    An overview of global glacier mass balance and contribution to sea level.

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  • Marzeion, B., P. W. Leclercq, J. G. Cogley, and A. H. Jarosch. 2015. Brief communication: Global reconstructions of glacier mass change during the 20th century are consistent. The Cryosphere 9.6: 2399–2404.

    DOI: 10.5194/tc-9-2399-2015Save Citation »Export Citation »

    Reconstruction of global glacier mass change and associated contribution to sea level.

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  • Vaughan, D. G., J. C. Comiso, I. Allison, et al. 2013. Observations: Cryosphere. In Climate change 2013: The physical science basis; Contribution of Working Group I to the fifth assessment report of the Intergovernmental Panel on Climate Change. Edited by T. F. Stocker, D. Qin, G.-K. Plattner, et al., 317–382. Cambridge, UK, and New York: Cambridge Univ. Press.

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    IPCC AR5 assessment on land ice observations.

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Ice Sheets

Since the early 1990s, different remote-sensing observations (airborne and satellite laser and radar altimetry, interferometric synthetic aperture radar [InSAR], and, since 2002, space gravimetry from the GRACE mission) have provided important observations of the mass balance of the ice sheets (Steffen, et al. 2010). These data indicate that Greenland and West Antarctica are losing mass at an accelerated rate (Rignot, et al. 2011). Several dozen articles have been published in the early 21st century on this topic, leading to important dispersion between the various estimates of the ice sheets mass balance. Zwally and Giovinetto 2011; Shepherd, et al. 2012; Hanna, et al. 2013; and Forsberg, et al. 2017 provide an overview of the status of the question and discuss the differences obtained when using different observing systems or applying different processing methodologies. Velicogna and Wahr 2013 focuses on the use of GRACE space gravimetry to estimate the ice sheet mass balance and associated uncertainty. Pritchard, et al. 2012; Alley, et al. 2015; and Alley, et al. 2016 address the process causing accelerated ice mass loss in coastal regions of the Antarctica ice sheet. More references both on observations and processes can be found in IPCC AR5 (Vaughan, et al. 2013, cited under Glaciers).

  • Alley, R. B., S. Anandakrishnan, K. Christianson, et al. 2015. Oceanic forcing of ice-sheet retreat: West Antarctica and more. Annual Review of Earth and Planetary Sciences 43:207–231.

    DOI: 10.1146/annurev-earth-060614-105344Save Citation »Export Citation »

    A review article discussing mechanisms of ocean-ice interactions and the ice sheet response to ocean forcing.

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  • Alley, K. E., T. A. Scambos, M. R. Siegfried, and H. A. Fricker. 2016. Impacts of warm water on Antarctic ice shelf stability through basal channel formation. Nature Geoscience 9.4: 290–293.

    DOI: 10.1038/ngeo2675Save Citation »Export Citation »

    Based on different remote-sensing data, the study describes basal crevassing and ice fracturing causing ice shelf instabilities.

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  • Forsberg, R., L. Sørensen, and S. Simonsen. 2017. Greenland and Antarctica ice sheet mass changes and effects on global sea level. In Special issue: ISSI workshop on “Integrative study of the mean sea level and its components.” Edited by A. Cazenave, N. Champollion, F. Paul, and J. Benveniste. Surveys in Geophysics 38.1: 89–104.

    DOI: 10.1007/s10712-016-9398-7Save Citation »Export Citation »

    An overview of the mass balance of ice sheets and their contribution to sea level rise over the altimetry era.

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  • Hanna, E., F. J. Navarro, F. Pattyn, et al. 2013. Ice-sheet mass balance and climate change. Nature 498.7452: 51–59.

    DOI: 10.1038/nature12238Save Citation »Export Citation »

    This article (twelve authors) reviews the early-21st-century advances in monitoring from space and the mass balance of the ice sheets and discusses the processes causing the recently observed ice mass loss.

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  • Pritchard, H. D., S. R. M. Ligtenberg, H. A. Fricker, D. G. Vaughan, M. R. van den Broeke, and L. Padman. 2012. Antarctic ice-sheet loss driven by basal melting of ice shelves. Nature 484.7395: 502–505.

    DOI: 10.1038/nature10968Save Citation »Export Citation »

    This letter proposes that the main dynamical process causing accelerated ice mass at the margins of the Antarctica ice sheet is basal melting of the ice shelves.

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  • Rignot, E., I. Velicogna, M. R. van den Broeke, A. Monaghan, and J. T. M. Lenaerts. 2011. Acceleration of the contribution of the Greenland and Antarctic ice sheets to sea level rise. Geophysical Research Letters 38.5: L05503.

    DOI: 10.1029/2011gl046583Save Citation »Export Citation »

    One of the many articles showing satellite-based evidence of acceleration of ice mass loss from the Greenland and Antarctica ice sheets during the previous two decades.

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  • Shepherd, A., E. R. Ivins, A. Geruo, et al. 2012. A reconciled estimate of ice-sheet mass balance. Science 338.6111: 1183–1189.

    DOI: 10.1126/science.1228102Save Citation »Export Citation »

    This work (from forty-seven authors) examines the various space techniques (satellite altimetry, interferometry, GRACE space gravimetry) currently used to estimate the mass balance of the ice sheets, and the reasons for the very large dispersion observed in published results. Authors found that there is agreement between the various techniques within their respective uncertainties. A combination of all techniques is proposed.

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  • Steffen, K., R. H. Thomas, E. Rignot, et al. 2010. Cryospheric contributions to sea level rise and variability. In Understanding sea-level rise and variability. Edited by J. A. Church, P. L. Woodworth, T. Aarup, and S. Wilson, 177–225. Chichester, UK, and Hoboken, NJ: Wiley-Blackwell.

    DOI: 10.1002/9781444323276Save Citation »Export Citation »

    A review article on the land ice contribution to sea level.

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  • Velicogna, I., and J. Wahr. 2013. Time-variable gravity observations of ice sheet mass balance: Precision and limitations of the GRACE satellite data. Geophysical Research Letters 40.12: 3055–3063.

    DOI: 10.1002/grl.50527Save Citation »Export Citation »

    This work discusses the precision expected from the GRACE space gravimetry technique and its limitations to estimate the mass balance of the Greenland and Antarctica ice sheet.

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  • Zwally, H. J., and M. B. Giovinetto. 2011. Overview and assessment of Antarctic ice-sheet mass balance estimates: 1992–2009. Surveys in Geophysics 32.4–5: 351–376.

    DOI: 10.1007/s10712-011-9123-5Save Citation »Export Citation »

    A review of various Antarctica mass balance estimates from different space techniques over the altimetry time span.

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Land Water Storage Changes Due to Natural Climate Variability and Direct Human Activities

Change in land water storage due to natural climate variability and human activities (i.e., anthropogenic changes in the amount of water stored in soils, reservoirs, and aquifers as a result of dam building, groundwater mining, irrigation, urbanization, deforestation, etc.) is another potential contribution to sea level change. Llovel, et al. 2011; Boening, et al. 2012; Cazenave, et al. 2014; and Fasullo, et al. 2013 deal with the effect of land water changes on sea level during El Niño and La Niña events. Chao, et al. 2008; Konikow 2011; Veit and Conrad 2016; Wada, et al. 2012; Wada, et al. 2016; and Wada, et al. 2017 estimate direct human interventions on land hydrology (dam building on rivers and groundwater extraction) and associated effects on sea level. Dieng, et al. 2015 and Reager, et al. 2016 estimate the net land water contribution to sea level since 2003, using GRACE space gravimetry and a mass budget approach.

Ocean Mass Changes from Space Gravimetry since 2003

Since 2003, the data from the GRACE space gravimetry mission have provided direct estimates of ocean mass changes due to land ice melt and land water storage changes. This data set, together with in situ data of ocean temperature and salinity changes, allows studying the sea level budget since then. There are also currently several GRACE solutions from which the ocean mass can be retrieved.

Sea Level Budget for the 20th Century and the Altimetry Era

A large number of studies have tried to close the sea level budget or to compare the observed rate of sea level rise with the sum of contributions estimated independently. Gregory, et al. 2013; Church, et al. 2011; and Moore, et al. 2011 (all cited under the 20th and Early 21st Centuries) refer to the last century (for the latter, model outputs are also used) and last few decades. Sea level budget studies since the mid-1990s are numerous and regularly updated. Leuliette and Willis 2011; Chen, et al. 2013; and Llovel, et al. 2014 (all cited under Satellite Altimetry Era) and Church, et al. 2011 (cited under the 20th and Early 21st Centuries) are among the most recent (see also Church, et al. 2013, cited under General Overviews).

The 20th and Early 21st Centuries

Although information back in time about components is limited, some studies have investigated the sea level budget on a historical time scale. Church, et al. 2011 investigates the sea level and Earth’s energy budgets on the basis of available observations since 1961, while Gregory, et al. 2013; Moore, et al. 2011; and Jevrejeva, et al. 2017 attempt to close the sea level budget over the 20th century by combining data and model results.

Satellite Altimetry Era

Besides Church, et al. 2013, cited under General Overviews, additional information can be found in Leuliette and Willis 2011; Chen, et al. 2013; Leuliette and Willis 2011; Llovel, et al. 2014; Dieng, et al. 2015; and Rietbroek, et al. 2016 (see also Church, et al. 2011, cited under the 20th and Early 21st Centuries).

  • Chen, J. L., C. R. Wilson, and B. D. Tapley. 2013. Contribution of ice sheet and mountain glacier melt to recent sea level rise. Nature Geoscience 6.7: 549–552.

    DOI: 10.1038/ngeo1829Save Citation »Export Citation »

    A sea level budget study over the previous decade on the basis of satellite altimetry, Gravity Recovery and Climate Experiment (GRACE) space gravimetry, and Argo data.

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  • Chen, X., X. Zhang, J. A. Church, et al. 2017. The increasing rate of global mean sea-level rise during 1993–2014. Nature Climate Change 7.7: 492–495.

    DOI: 10.1038/NCLIMATE3325Save Citation »Export Citation »

    A new estimate of the sea level budget between 1993 and 2014. Comparing sum of components and observed sea level indicates an increase during this period in the rate of sea level rise due to increased Greenland contribution.

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  • Dieng, H., A. Cazenave, B. Meyssignac, and M. Ablain. 2017. New estimate of the current rate of sea level rise from a sea level budget approach. Geophysical Research Letters 44.8: 3744–3751.

    DOI: 10.1002/2017GL073308Save Citation »Export Citation »

    New estimate of the closure of the sea level budget between 1993 and 2015 accounting for the TOPEX A altimeter drift. As in Chen, et al. 2017, the budget approach reveals acceleration of sea level rise since the 1990s, caused by increased Greenland melting.

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  • Dieng, H. B., H. Palanisamy, A. Cazenave, B. Meyssignac, and K. von Schuckmann. 2015. The sea level budget since 2003: Inference on the deep ocean heat content. Surveys in Geophysics 36.2: 209–229.

    DOI: 10.1007/s10712-015-9314-6Save Citation »Export Citation »

    Sea level budget over the 2003–2013 time span estimated by a large number of different data sets, with inference on the deep-ocean contribution to sea level rise.

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  • Leuliette, E. W., and J. K. Willis. 2011. Balancing the sea level budget. In Special issue on sea level. Edited by Josh Willis, Laury Miller, and Gregory Mountain. Oceanography 24.2: 122–129.

    DOI: 10.5670/oceanog.2011.32Save Citation »Export Citation »

    A review article on sea level budget of the previous few years.

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  • Llovel, W., J. K. Willis, F. W. Landerer, and I. Fukumori. 2014. Deep-ocean contribution to sea level and energy budget not detectable over the past decade. Nature Climate Change 4.11: 1031–1035.

    DOI: 10.1038/NCLIMATE2387Save Citation »Export Citation »

    A study of the sea level budget over the Argo era (since 2005) dedicated to estimate the deep-ocean contribution (below 6,560 feet) to sea level rise and associated deep-ocean heat content.

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  • Rietbroek, R., S.-E. Brunnabend, J. Kusche, J. Schröter, and C. Dahle. 2016. Revisiting the contemporary sea-level budget on global and regional scales. PNAS 113.6: 1504–1509.

    DOI: 10.1073/pnas.1519132113Save Citation »Export Citation »

    Estimate of the sea level budget since 2002 from a combined analysis of satellite altimetry and space gravimetry data.

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Regional Variability in Sea Level

Satellite altimetry has revealed that sea level is not rising uniformly. In some regions (e.g., western Pacific), the rates of sea level rise are faster by a factor of up to 3 of the global mean rate. In other regions, rates are slower than the global mean (e.g., eastern Pacific). The regional variability in sea level trends is mainly due to large-scale changes in the density structure of the oceans in response to forcing factors (e.g., heat and freshwater exchange at the sea-air interface) and changes in ocean circulation. The largest regional changes in sea level trends result from ocean temperature change (i.e., from nonuniform thermal expansion), but in some regions, change in water salinity is also important. The works cited in this section refer to the regional variability in sea level, either as revealed from observations and two-dimensional sea level reconstructions (including ocean reanalyses), or from a process point of view. Articles under Observations of Spatial Trend Patterns in Sea Level and Causes discuss the various sources of regional variability, such as the climate-related factors (thermal expansion, salinity effects and internal mass redistributions, atmospheric forcing, etc.) as well as the so-called “static” effects related to the elastic/viscous response of the solid Earth to present-day land ice melt and the last deglaciation (the latter being called global isostatic adjustment or GIA). Two-Dimensional Past Sea Level Reconstructions since 1950 combining long but sparse tide gauge records with statistical information on the natural modes of ocean regional variability have appeared in the early 21st century. These provide information on regional sea level changes prior to the altimetry era. Besides ocean circulation models with or without data, assimilation also provides information on the spatial trend patterns in sea level since the late 20th century (see Ocean Reanalyses and Syntheses and Ocean Temperature and Salinity Changes). These studies show that the spatial trend patterns in sea level revealed by satellite altimetry are caused mostly by changes in the ocean circulation. Articles cited under Solid-Earth Effects on Regional Sea Level) evaluate the effects of the static effects due to past and future land ice melt on regional sea level changes.

Observations of Spatial Trend Patterns in Sea Level and Causes

The causes of the regional sea level variability and associated spatial trend patterns observed by satellite altimetry have been investigated in a number of studies. Milne, et al. 2009; Marcos, et al. 2011; and Stammer, et al. 2013 are the first reviews on this topic, reviewing all potential causes of regional sea level variability. Fukumori and Wang 2013 investigates the relative contributions of atmospheric forcing versus preexisting temperature and salinity anomalies inside the oceans to explain regional sea level trends. Timmermann, et al. 2010; Palanisamy, et al. 2015; and Merrifield and Maltrud 2011 show that higher-than-average sea level trends in the western tropical Pacific are due to trade wind intensification and associated deepening of the thermocline since 1993. Carret, et al. 2017 and Richter, et al. 2017 concern spatial trend patterns in the Arctic and North Atlantic. The roles of atmospheric forcing. associated internal climate modes, and decadal variability of the ocean circulation on spatial sea level patterns are discussed in Meyssignac, et al. 2017; Han, et al. 2017; and Sérazin, et al. 2016.

Two-Dimensional Past Sea Level Reconstructions since 1950

To get information about regional sea level variability prior to the altimetry era, reconstruction methods combining tide gauge data with representations of natural climatic modes have been developed. Hamlington, et al. 2011 and Meyssignac, et al. 2012 propose such past sea level reconstruction since 1950. Becker, et al. 2012 shows that regional sea level variability over the last six decades has caused sea level to rise three times faster than the global mean at atolls of the Tuvalu archipelago.

Ocean Reanalyses and Syntheses

In addition to past sea level reconstructions, general ocean circulation modeling without or with data assimilation (also called ocean reanalyses in the latter case) informs on past decades’ sea level variations, especially at regional scale. A number of ocean reanalyses exist in the literature. Wunsch, et al. 2007; Köhl and Stammer 2008; Carton and Giese 2008; Zhang, et al. 2007; Zuo, et al. 2017a; and Zuo, et al. 2017b are some good examples. Balmaseda, et al. 2015 provides an comparison of different ocean reanalyses.

Solid-Earth Effects on Regional Sea Level

Viscoelastic/elastic deformations of the solid Earth in response to past and ongoing land ice melt, as well as associated changes in mutual gravitational attractions between former ice bodies and water, produce regional sea level changes. Peltier 2004 and Mitrovica, et al. 2001 are pioneering works on this topic. Tamisiea and Mitrovica 2011 and Tamisiea, et al. 2014 review the solid-Earth effects on the regional variability in sea level. Spada, et al. 2013 simulates the fingerprint of future land ice loss on regional sea level, and Spada 2017 reviews expected fingerprints of past and ongoing land ice melt on regional sea level change.

  • Mitrovica, J. X., M. E. Tamisiea, J. L. Davis, and G. A. Milne. 2001. Recent mass balance of polar ice sheets inferred from patterns of global sea-level change. Nature 409.6823: 1026–1029.

    DOI: 10.1038/35059054Save Citation »Export Citation »

    A pioneering work showing that ongoing and future mass loss from land ice bodies causes regional sea level changes.

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  • Peltier, W. R. 2004. Global glacial isostasy and the surface of the ice-age Earth: The ICE-5G (VM2) model and GRACE. Annual Review of Earth and Planetary Sciences 32:111–149.

    DOI: 10.1146/annurev.earth.32.082503.144359Save Citation »Export Citation »

    This is a pioneering work on the effect of GIA on the global mean sea level.

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  • Spada, G. 2017. Glacial isostatic adjustment and contemporary sea level rise: An overview. In Special issue: ISSI workshop on “Integrative study of the mean sea level and its components.” Edited by A. Cazenave, N. Champollion, F. Paul, and J. Benveniste. Surveys in Geophysics 38.1: 153–185.

    DOI: 10.1007/s10712-016-9379-xSave Citation »Export Citation »

    An overview of past and ongoing land ice melt fingerprints and their effects on sea level.

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  • Spada, G., J. L. Bamber, and R. T. W. L. Hurkmans. 2013. The gravitationally consistent sea level fingerprint of future terrestrial ice loss. Geophysical Research Letters 40.3: 482–486.

    DOI: 10.1029/2012GL053000Save Citation »Export Citation »

    Alternative modeling work of the effect of solid-Earth deformation due to land ice melt and associated regional sea level changes.

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  • Tamisiea, M. A., C. W. Hughes, S. D. Williams, and R. M. Bingley. 2014. Sea level: Measuring the bounding surfaces of the ocean. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 372.2025: 20130336.

    DOI: 10.1098/rsta.2013.0336Save Citation »Export Citation »

    A review of sea level measurements at global and regional scales and the role of solid-Earth’s deformations and gravitational changes to explain regional variations.

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  • Tamisiea, M. E., and J. X. Mitrovica. 2011. The moving boundaries of sea level change: Understanding the origins of geographic variability. In Special issue on sea level. Edited by Josh Willis, Laury Miller, and Gregory Mountain. Oceanography 24.2: 24–39.

    DOI: 10.5670/oceanog.2011.25Save Citation »Export Citation »

    A summary of the static effects causing regional changes in sea level.

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Detection and Attribution

The phrase “detection and attribution” refers to the discrimination in a physical signal between changes due to natural (internal) variability of the climate system and changes caused by anthropogenic forcing. Direct observations from satellite altimetry and sea level reconstructions based on statistical approaches and ocean reanalyses indicate that trend patterns in thermal expansion are not stationary but fluctuate both in space and time in response to natural/internal oscillations and perturbations of the climate system, such as ENSO (El Niño–Southern Oscillation), NAO (North Atlantic Oscillation), and PDO (Pacific Decadal Oscillation). While several studies highlight the role of internal climate variability to explain the spatial trend patterns of the altimetry era (e.g., Meyssignac, et al. 2012 and Stammer, et al. 2013, the latter cited under Observations of Spatial Trend Patterns in Sea Level and Causes), a series of early-21st-century papers perform “detection/attribution” studies in order to extract from the sea level observations the fingerprint of anthropogenic forcing. Zhang and Church 2012 and Hamlington, et al. 2014 show, for example, that once the effect of the PDO (an internal mode of ocean variability in the Pacific) is removed from the observed spatial patterns, some signal remains, attributed to the response of the tropical Pacific to anthropogenic warming of the tropical Indian ocean (Han, et al. 2014). However, the question remains controversial, and the work in Palanisamy, et al. 2015 suggests that at least in the Pacific, residual regional trend patterns still reflect internal variability. This conclusion is confirmed in Bilbao, et al. 2015, except for the Southern Ocean, where the anthropogenic forcing signal may already be detectable. Detection/attribution studies applied to global mean sea level observations and steric sea level (Gleckler, et al. 2012; Slangen, et al. 2014; Marcos and Amores 2014; Becker, et al. 2014; Slangen, et al. 2016; Marcos, et al. 2017) have also suggested that anthropogenic forcing explains global mean sea level rise for most of the past decades. Fasullo, et al. 2016 suggests that the Pinatubo volcanic eruption is responsible for the slower rate of global mean sea level rise of the first decade of the altimetry era.

  • Becker, M., M. Karpytchev, and S. Lennartz-Sassinek. 2014. Long-term sea level trends: Natural or anthropogenic? Geophysical Research Letters 41.15: 5571–5580.

    DOI: 10.1002/2014GL061027Save Citation »Export Citation »

    This study provides statistical evidence that at global and regional scales, tide gauge–based sea level trends cannot be explained by natural/internal variability alone, and that 50 percent of the observed signal is anthropogenic.

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  • Bilbao, R. A. F., J. M. Gregory, and N. Bouttes. 2015. Analysis of the regional pattern of sea level change due to ocean dynamics and density change for 1993–2099 in observations and CMIP5 AOGCMs. Climate Dynamics 45.9–10: 2647–2666.

    DOI: 10.1007/s00382-015-2499-zSave Citation »Export Citation »

    Comparisons between climate models and observations suggest that most of the present-day regional variability in sea level results from internal climate variability except in the Southern Ocean, where anthropogenic forcing may explain observed sea level trends.

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  • Fasullo, J. T., R. S. Nerem, and B. Hamlington. 2016. Is the detection of accelerated sea level rise imminent? Nature: Scientific Reports 6:31245.

    DOI: 10.1038/srep31245Save Citation »Export Citation »

    This study shows that large volcanic eruptions can significantly impact the satellite record of global mean sea level change.

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  • Gleckler, P. J., B. D. Santer, C. M. Domingues, et al. 2012. Human-induced global ocean warming on multidecadal timescales. Nature Climate Change 2.7: 524–529.

    DOI: 10.1038/NCLIMATE1553Save Citation »Export Citation »

    Comparison between observations of ocean heat content and historical runs of coupled climate models allows detecting an anthropogenic fingerprint in upper-ocean temperature changes.

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  • Hamlington, B. D., M. W. Strassburg, R. R. Leben, W. Han, R. S. Nerem, and K. Y. Kim. 2014. Uncovering an anthropogenic sea-level rise signal in the Pacific Ocean. Nature Climate Change 4.9: 782–785.

    DOI: 10.1038/NCLIMATE2307Save Citation »Export Citation »

    The study suggests that spatial trend patterns observed over the altimetry era (previous twenty years) in the western tropical Pacific are only partly due to natural/internal ocean modes (e.g., the PDO) but may also include a signal related to anthropogenic warming of the tropical Indian Ocean.

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  • Han, W., G. A. Meehl, A. Hu, et al. 2014. Intensification of decadal and multi-decadal sea level variability in the western tropical Pacific during recent decades. Climate Dynamics 43.5–6: 1257–1379.

    DOI: 10.1007/s00382-013-1951-1Save Citation »Export Citation »

    This work investigates the changing sea level trend pattern in the tropical Pacific since the late 20th century and shows it cannot be totally explained by natural climate modes. Using climate experiments, the authors suggest that observed trends in sea level partly reflect the combined effects of tropical Indian Ocean (anthropogenic) warming and associated response of the tropical Pacific.

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  • Marcos, M., and A. Amores. 2014. Quantifying anthropogenic and natural contributions to thermosteric sea level rise. Geophysical Research Letters 41.7: 2502–2507.

    DOI: 10.1002/2014GL059766Save Citation »Export Citation »

    This study, based on comparisons of climate model data, suggests that a large fraction of upper-ocean thermal expansion increase since 1970 has been induced by human activities.

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  • Marcos M., B. Marzeion, S. Dangendorf, A. B. A. Slangen, H. Palanisamy, and L. Fenoglio-Marc. 2017. Internal variability versus anthropogenic forcing on sea level and its components. In Special issue: ISSI workshop on “Integrative study of the mean sea level and its components.” Edited by A. Cazenave, N. Champollion, F. Paul, and J. Benveniste. Surveys in Geophysics 38.1: 329–348.

    DOI: 10.1007/s10712-016-9373-3Save Citation »Export Citation »

    An overview of detection and attribution concerning sea level and its components.

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  • Meyssignac, B., D. Salas y Melia, M. Becker, W. Llovel, and A. Cazenave. 2012. Tropical Pacific spatial trend patterns in observed sea level: Internal variability and/or anthropogenic signature? Climate of the Past 8.2: 787–802.

    DOI: 10.5194/cp-8-787-2012Save Citation »Export Citation »

    This work, based on long control runs of climate models, suggests that the spatial trend patterns seen in the tropical Pacific by satellite altimetry mostly reflect natural/internal variability of the coupled ocean-atmosphere system.

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  • Palanisamy, H., B. Meyssignac, A. Cazenave, and T. Delcroix. 2015. Is the anthropogenic sea level fingerprint already detectable in the Pacific Ocean? Environmental Research Letters 10.8: 084024.

    DOI: 10.1088/1748-9326/10/12/124010Save Citation »Export Citation »

    The study revisits the causes of sea level trend patterns observed by satellite altimetry in the Pacific Ocean and their attribution. It concludes that the anthropogenic signal is still hidden by the internal variability.

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  • Slangen, A. B. A., J. A. Church, C. Agosta, X. Fettweis, B. Marzeion, and K. Richter. 2016. Anthropogenic forcing dominates global mean sea-level rise since 1970. Nature Climate Change 6.7: 701–706.

    DOI: 10.1038/nclimate2991Save Citation »Export Citation »

    An evaluation of the respective contributions of internal climate variability, natural forcing, and anthropogenic forcing on the different components of the historical sea level rise.

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  • Slangen, A. B. A., J. A. Church, X. Zhang, and D. Monselesan. 2014. Detection and attribution of global mean thermosteric sea level change. Geophysical Research Letters 41.16: 5951–5959.

    DOI: 10.1002/2014GL061356Save Citation »Export Citation »

    Preindustrial control runs and historical runs of coupled climate models compared with observations suggest that increased trends in ocean thermal expansion cannot be explained by natural/internal climate variability alone.

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  • Zhang, X., and J. A. Church. 2012. Sea level trends, interannual and decadal variability in the Pacific Ocean. Geophysical Research Letters 39.21: L21701.

    DOI: 10.1029/2012GL053240Save Citation »Export Citation »

    This study investigates the combined effect of different climate modes (ENSO, PDO, etc.) on sea level in the Pacific Ocean.

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Sea Level Projections over the 21st Century and Beyond

Most current (Intergovernmental Panel on Climate Change [IPCC] AR5) process-based projections for the 21st century that are based on coupled climate models indicate that sea level should be higher than it currently is by several inches, the range value depending on scenarios of future global warming, net radiative forcing, and model uncertainties. The largest contribution comes from ocean thermal expansion, followed by glaciers and the Greenland and Antarctica ice sheets (Church, et al. 2013, cited under General Overviews). However, the contribution from the Antarctica ice sheet to future sea level rise remains highly uncertain and may become dominant by 2100 and beyond (see Process-Based Sea Level Projections). Because the timing of the internal climate variability is poorly simulated by coupled climate models, current sea level projections based on the ensemble mean of a large number of model simulations suffer from significant uncertainty due to internal climate variability. Future sea level rise will not be uniform. A number of articles propose regional sea level projections for the 21st century that account for all factors causing regional sea level changes. While the largest regional changes come from ocean thermal expansion and salinity changes, factors linked to the solid-Earth response to past and future land ice melt are becoming increasingly important (see Regional Sea Level Projections). In addition to process-based models, alternative approaches (see Probabilistic Sea Level Projections) have also been proposed to estimate global mean sea level rise in the 21st century. These approaches are based on simple relationships established with past observations between observed rate of rise and mean Earth’s temperature or radiative forcing. More recently, a number of probabilistic projections based on climate modeling and expert assessment have also been developed. Improving sea level projections from global to local scales is an active area of research of primary importance for assessing future coastal impacts of sea level rise.

Process-Based Sea Level Projections

Simulations of future global mean sea level rise through using process-based climate models can be found in the IPCC AR5 for the 21st century and beyond. Lowe and Gregory 2006 helps understand the physical processes causing sea level rise. New estimates of the Antarctica ice sheets are proposed in Ritz, et al. 2015 and DeConto and Pollard 2016. Melet and Meyssignac 2015 discusses the cause of model spreading in simulating ocean thermal expansion.

  • DeConto, R. M., and D. Pollard. 2016. Contribution of Antarctica to past and future sea-level rise. Nature 531.7596: 591–597.

    DOI: 10.1038/nature17145Save Citation »Export Citation »

    This study invokes a new type of Antarctica ice sheet instability (ice cliff instability triggered by atmospheric warming) that could raise sea level by 3.3 feet in 2100 and 49 feet in 2500.

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  • Lowe, J. A., and J. M. Gregory. 2006. Understanding projections of sea level rise in a Hadley Centre coupled climate model. Journal of Geophysical Research: Oceans 111.C11: C11014.

    DOI: 10.1029/2005JC003421Save Citation »Export Citation »

    A reference work on sea level modeling using coupled climate models.

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  • Melet, A., and B. Meyssignac. 2015. Explaining the spread in global mean thermosteric sea level rise in CMIP5 climate models. Journal of Climate 28.24: 9918–9940.

    DOI: 10.1175/JCLI-D-15-0200.1Save Citation »Export Citation »

    This study investigates the causes of model spreading in simulating ocean thermal expansion and sea level.

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  • Ritz, C., T. L. Edwards, G. Durand, A. J. Payne, V. Peyaud, and R. C. A. Hindmarsh. 2015. Potential sea-level rise from Antarctic ice-sheet instability constrained by observations. Nature 528.7580: 115–118.

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    This study proposes physically plausible sea level projections up to 2200 from the Antarctica ice sheet contribution, revisiting the so-called marine ice sheet instabilities (MISI).

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Probabilistic Sea Level Projections

Since about 2005, a number of empirical projections (Rahmstorf 2007; Rahmstorf, et al. 2012; Mengel, et al. 2016) as well as probabilistic projections combining process modeling and expert assessment (Bamber and Aspinall 2013; Horton, et al. 2014; Jackson and Jevrejeva 2016; Jevrejeva, et al. 2014; Jevrejeva, et al. 2016; Kopp, et al. 2014) have also been provided.

Centennial to Millennial Projections

Very long-term (century to millennial time scales) sea level rise projections and their impact are discussed in Levermann, et al. 2013 and Clark, et al. 2016.

Regional Sea Level Projections

Several regional sea level projections, accounting for all mechanisms causing regional sea level changes, have appeared in the literature in the early 21st century (Pardaens, et al. 2010; Slangen, et al. 2012; Slangen, et al. 2014; Slangen, et al. 2017; Carson, et al. 2016). Hu and Deser 2013; Bordbar, et al. 2015; and Bilbao, et al. 2015 discuss the effect on projections of the internal variability superimposed on the anthropogenic signal.

  • Bilbao, R. A. F., J. M. Gregory, and N. Bouttes. 2015. Analysis of the regional patterns of sea level change due to ocean dynamics and density change for 1993–2099 in observations and CMIP5 AOGCMs. Climate Dynamics 45.9–10: 2647–2666.

    DOI: 10.1007/s00382-015-2499-zSave Citation »Export Citation »

    Simulations of regional patterns of sea level change in response to anthropogenic forcing during the 21st century.

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  • Bordbar, M. H., T. Martin, M. Latif, and W. Park. 2015. Effects of long-term variability on projections of twenty-first-century dynamic sea level. Nature Climate Change 5.4: 343–347.

    DOI: 10.1038/nclimate2569Save Citation »Export Citation »

    This study investigates the impact of long-term internal variability on centennial sea level projections.

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  • Carson, M., A. Köhl, D. Stammer, et al. 2016. Coastal sea level changes, observed and projected during the 20th and 21st century. Climatic Change 134.1–2: 269–281.

    DOI: 10.1007/s10584-015-1520-1Save Citation »Export Citation »

    Up-to-date regional and coastal sea level projections for the 21st century.

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  • Hu, A., and C. Deser. 2013. Uncertainty in future regional sea level rise due to internal climate variability. Geophysical Research Letters 40.11: 2768–2772.

    DOI: 10.1002/grl.50531Save Citation »Export Citation »

    This work shows that decadal variability in sea level due to natural/internal climate modes is poorly simulated by coupled climate models and significantly increases the uncertainty of long-term trend projections,

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  • Pardaens, A. K., J. M. Gregory, and J. A. Lowe. 2010. A model study of factors influencing projected changes in regional sea level over the twenty-first century. Climate Dynamics 36.9–10: 2015–2033.

    DOI: 10.1007/s00382-009-0738-xSave Citation »Export Citation »

    This work presents results about regional sea level on the basis of process-based, coupled climate modeling

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  • Slangen, A. B. A., M. Carson, C. A. Katsman, et al. 2014. Projecting twenty-first century regional sea-level changes. Climatic Change 124.1–2: 317–332.

    DOI: 10.1007/s10584-014-1080-9Save Citation »Export Citation »

    An update of the work done in Slangen, et al. 2012, using the most recent coupled climate models.

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  • Slangen, A. B. A., F. Adloff, S. Jevrejeva, et al. 2017. A review of recent updates of sea-level projections at global and regional scales. In Special issue: ISSI workshop on “Integrative study of the mean sea level and its components.” Edited by A. Cazenave, N. Champollion, F. Paul, and J. Benveniste. Surveys in Geophysics 38.1: 385–406.

    DOI: 10.1007/s10712-016-9374-2Save Citation »Export Citation »

    A review of early-21st-century sea level projections at global and regional scales in 2100 and beyond.

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  • Slangen, A. B. A., C. A. Katsman, R. S. W. van de Wal, L. L. A. Vermeersen, and R. E. M. Riva. 2012. Towards regional projections of twenty-first century sea-level change based on IPCC SRES scenarios. Climate Dynamics 38.5–6: 1191–1209.

    DOI: 10.1007/s00382-011-1057-6Save Citation »Export Citation »

    One of the first articles presenting regional sea level projections accounting for all processes (climatic and static effects) giving rise to regional sea level changes.

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  • Yin, J., S. M. Griffies, and R. J. Stouffer. 2010. Spatial variability of sea level rise in twenty-first century projections. Journal of Climate 23.17: 4585–4607.

    DOI: 10.1175/2010jcli3533.1Save Citation »Export Citation »

    This work identifies the main feature of regional variability in sea level by 2100, using a set of state-of-the-art coupled climate models.

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Coastal Impacts of Sea Level Rise

Sea level rise is a major concern for populations living in low-lying coastal regions (about 25 percent of humanity) because it will give rise to inundation, wetland loss, shoreline erosion, saltwater intrusion in surface water bodies and aquifers, and rising water tables. Future sea level rise will affect a large number of world’s largest coastal zones and megacities, as shown in Nicholls and Cazenave 2010; Nicholls, et al. 2012; Hallegatte, et al. 2013; Hanson, et al. 2011; and Nicholls, et al. 2014. Moreover, in many coastal regions of the world, the effects of rising sea level act in combination with other natural and anthropogenic factors, such as a decreased rate of fluvial sediment deposition in deltaic areas (Ericson, et al. 2006), ground subsidence due to tectonic activity or groundwater pumping, and hydrocarbon extraction. Other factors modify the shoreline morphology (due to sediment deposition in river deltas, change in coastal waves and currents, etc.) and thus interact with and amplify climate-related sea level rise (long-term trend plus regional variability). At local scale, it is still challenging to quantify future sea level rise in specific coastal regions where various factors (climate-related and non-climate-related) interact each other in very complex ways (Le Cozannet, et al. 2013; Le Cozannet, et al. 2014; Passeri, et al. 2015). The outcome of future sea level rise remains uncertain, as discussed in Hinkel, et al. 2014 and Le Cozannet, et al. 2015. Katsman, et al. 2011 is an example of projections at very local scale, useful for policymakers. Many more references are available in Wong, et al. 2014, in the Intergovernmental Panel on Climate Change (IPCC) fifth assessment report of Working Group II.

  • Ericson, J. P., C. J. Vorosmarty, S. L. Dingman, L. G. Ward, and M. Meybeck. 2006. Effective sea-level rise and deltas: Causes of change and human dimension implications. Global and Planetary Change 50.1–2: 63–82.

    DOI: 10.1016/j.gloplacha.2005.07.004Save Citation »Export Citation »

    A review of processes at work in large river deltas and their effects on relative sea level.

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  • Hallegatte, S., C. Green, R. J. Nicholls, and J. Corfee-Morlot. 2013. Future flood losses in major coastal cities. Nature Climate Change 3.9: 802–806.

    DOI: 10.1038/NCLIMATE1979Save Citation »Export Citation »

    An assessment of losses due to future sea level rise and flooding in the 136 largest coastal cities.

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  • Hanson, S., R. Nicholls, N. Ranger, et al. 2011. A global ranking of port cities with high exposure to climate extremes. Climatic Change 104.1: 89–111.

    DOI: 10.1007/s10584-010-9977-4Save Citation »Export Citation »

    This work analyzes population exposure to sea level rise at the world’s largest coastal cities for different scenarios of socioeconomic and climate changes.

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  • Hinkel, J., D. Lincke, A. T. Vafeidis, et al. 2014. Coastal flood damage and adaptation costs under 21st century sea-level rise. PNAS 111.9: 3292–3297.

    DOI: 10.1073/pnas.1222469111Save Citation »Export Citation »

    A study of coastal flood damage and adaptation costs due to future sea level rise, with detailed assessment of uncertainties both in the sea level projections and coastal response.

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  • Katsman, C. A., A. Sterl, J. J. Beersma, et al. 2011. Exploring high-end scenarios for local sea level rise to develop flood protection strategies for a low-lying delta—the Netherlands as an example. Climatic Change 109.3–4: 617–645.

    DOI: 10.1007/s10584-011-0037-5Save Citation »Export Citation »

    An example of a study quantifying a high-end scenario of future sea level rise at local scale, of usefulness to end users and policymakers.

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  • Le Cozannet, G., M. Garcin, M. Yates, D. Idier, and B. Meyssignac. 2014. Approaches to evaluate the recent impacts of sea-level rise on shoreline changes. Earth-Science Reviews 138 (November): 47–60.

    DOI: 10.1016/j.earscirev.2014.08.005Save Citation »Export Citation »

    A methodology to estimate the impact of sea level rise on shoreline changes.

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  • Le Cozannet, G., M. Garcin, L. Petitjean, et al. 2013. Exploring the relation between sea level rise and shoreline erosion using sea level reconstructions: An example in French Polynesia. In Special issue 65: International Coastal Symposium Volume 2. Journal of Coastal Research S65: 2137–2142.

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    Analysis of the respective roles of waves and sea level rise in coastal erosion of atolls in French Polynesia.

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  • Le Cozannet, G., J. Rohmer, A. Cazenave, et al. 2015. Evaluating uncertainties of future marine flooding occurrence as sea level rises. Environmental Modelling & Software 73 (November): 44–56.

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    Global sensitivity and uncertainty analysis of coastal flooding occurrence for different scenarios of sea level rise.

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  • Nicholls, R. J., and A. Cazenave. 2010. Sea-level rise and its impact on coastal zones. Science 328.5985: 1517–1520.

    DOI: 10.1126/science.1185782Save Citation »Export Citation »

    A short review on 21st-century sea level rise and impacts, suggesting that adaptation will be possible in a large number of regions.

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  • Nicholls, R. J., S. E. Hanson, J. A. Lowe, R. A. Warrick, X. Lu, and A. J. Long. 2014. Sea-level scenarios for evaluating coastal impacts. WIREs Climate Change 5.1: 129–150.

    DOI: 10.1002/wcc.253Save Citation »Export Citation »

    This study proposes a methodology to develop impact assessment and adaptation planning under different local sea level scenarios.

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  • Nicholls, R. J., N. Marinova, J. A. Lowe, et al. 2012. Sea level rise and its possible impacts given a “beyond 4°C world” in the twenty-first century. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 369.1934: 161–181.

    DOI: 10.1098/rsta-2010.0291Save Citation »Export Citation »

    A review of impacts of sea level rise during the 21st century for a temperature increase of 4°C.

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  • Passeri, D. L., S. C. Hagen, S. C. Medeiros, M. V. Bilskie, K. Alizad, and D. Wang. 2015. The dynamic effects of sea level rise on low-gradient coastal landscapes: A review. Earth’s Future 3.6: 159–181.

    DOI: 10.1002/2015EF000298Save Citation »Export Citation »

    Review article discussing the dynamic, nonlinear response of coastlines to sea level rise.

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  • Wong, P. P., I. J. Losada, J. P. Gattuso, et al. 2014. Coastal systems and low-lying areas. In Climate change 2014: Impacts, adaptation, and vulnerability; Contribution of Working Group II to the fifth assessment report of the Intergovernmental Panel on Climate Change. Edited by C. B. Field, V. R. Barros, D. J. Dokken, et al., 361–409. Cambridge, UK: Cambridge Univ. Press.

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    An assessment of coastal impacts of climate change, including sea level rise.

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Review Articles and Books

Several review articles have appeared since 2010 on modern sea level rise (global and regional scales), containing a large number of focused references. Church, et al. 2010, cited under Books, provides a collection of review articles on all aspects related to sea level (paleo, historical, and present-day observations, causes, projections, and coastal impacts). It is an excellent book from which to gain a general view about sea level.

Review Articles

Although the subject is evolving rapidly, early-21st-century review articles provide useful summaries of the most-recent results. Cazenave and Llovel 2010 and Cazenave and Le Cozannet 2014 are reviews of sea level observations and causes since the 1990s. Lambeck, et al. 2010 is an overview of paleo sea level observations and associated methodologies. Mitchum, et al. 2010 reviews sea level observations by tide gauges and satellite altimetry over the 20th century and first decade of the 21st century. Stammer, et al. 2013 is a review of all causes of regional variability in sea level, and Dieng, et al. 2015 (cited under Satellite Altimetry Era) provides an overview of different estimates of the sea level components (ocean mass and steric sea level) since 2005.

Books

A number of textbooks and overview articles gathered in books constitute a useful source of current information. Satellite Altimetry and Earth Sciences: A Handbook of Techniques and Applications (Fu and Cazenave 2001) is a textbook on the satellite altimetry techniques and corresponding applications to space oceanography. There is no equivalent text in the literature. Pirazzoli 1996 is a textbook on paleo sea level, with focus on the Mediterranean region. The book Sea Level Rise: History and Consequences (Douglas, et al. 2001) provides a series of articles on late Holocene and instrumental sea level rise. The other books cited here—Church, et al. 2010; Bengtsson, et al. 2012; and Cazenave, et al. 2017—are collections of overview articles on up-to-date sea level science.

  • Bengtsson, L., S. Koumoutsaris, R.-M. Bonnet, et al. 2012. The Earth’s cryosphere and sea level change. Space Sciences Series of ISSI 40. Dordrecht, The Netherlands, and New York: Springer.

    DOI: 10.1007/978-94-007-2063-3Save Citation »Export Citation »

    A collection of review articles on sea level and causes, with focus on the contribution from the cryosphere. Previously published in Surveys in Geophysics 32.4–5 (2011).

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  • Cazenave, A., N. Champollion, F. Paul, and J. Benveniste, eds. 2017. Integrative study of the mean sea level and its components. Space Sciences Series of ISSI 58. Cham, Switzerland: Springer.

    DOI: 10.1007/978-94-007-2063-3Save Citation »Export Citation »

    A collection of overview articles on early-21st-century sea level and its causes.

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  • Church, J. A., P. Woodworth, T. Aarup, and W. S. Wilson, eds. 2010. Understanding sea-level rise and variability. Chichester, UK, and Hoboken, NJ: Wiley-Blackwell.

    DOI: 10.1002/9781444323276Save Citation »Export Citation »

    A reference book about sea level changes (paleo, historical, and current), reviewing observations and their uncertainties, climatic and nonclimatic causes, projections for the 21st century, and coastal impacts of sea level rise.

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  • Douglas, B. C., M. S. Karney, and S. P. Leatherman, eds. 2001. Sea level rise: History and consequences. International Geophysical Series 75. San Diego, CA: Academic Press.

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    A collection of articles about sea level observations during the late Holocene and instrumental era.

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  • Fu, L.-L., and A. Cazenave, eds. 2001. Satellite altimetry and Earth sciences: A handbook of techniques and applications. International Geophysics Series 69. San Diego, CA: Academic Press.

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    A reference book on satellite altimetry and its applications in oceanography and other fields in the Earth sciences.

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  • Pirazzoli, P. A. 1996. Sea level changes: The last 20, 000 years. Chichester, UK: Wiley.

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    A reference book presenting paleo sea level observations, with focus on the Mediterranean Sea.

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