Past Sea Level Changes Part One

Credits: Phil Woodworth Past sea level changes Part One

Svetlana Jevrejeva National Oceanography Centre, Liverpool, UK [email protected] Outline

• Sea level changes from geological records • Instruments for the measurement of sea level • Tide gauge records, Data Centres, Specific data sets • Sea level observing systems (networks) • Interpretation of observations, synthesis of the data- global sea level rise, reconstructions • Sea level budget • Short conclusion Sea level changes from geological records

http://www.ncdc.noaa.gov/paleo/ctl/clisci100k.html Sea level changes during the Late Holocene

AR5 IPCC, 2013. Chapter 5, Figure 5.17 How unusual is the current sea level rate of change?

AR5 IPCC, 2013. Chapter 5, FAQ5.2 Global sea level rise since 1700

Figure 13.27, AR5 IPCC ( 2013)

Sea Level Expansion Glaciers Greenland Antarctica Land Water Climate Change

1712 – Steam engine by Thomas Newcomen (industrial use of coal)

1938 - Using records from 147 weather stations around the world, British engineer Guy Callendar shows that temperatures had risen over the previous century, link to the CO2 concentrations, suggesting that increase in CO2 caused the warming

1972 - First UN environment conference (chemical pollution, atomic bomb testing - no climate change), in Stockholm

1975 - US scientist Wallace Broecker puts the term "global warming" into the public domain in the title of a scientific paper

12 Dec 2015 – Paris Agreement on climate change (195 nations) Why do we make sea level measurements What do we measure?

Coastal protection (extreme sea levels)

Navigation (tide /shallow waters)

Vertical land movement Instruments for the Measurement of Sea Level

Automatic tide gauge at Port Protection, Prince of www.bidstonobservatory.org.uk/tide-gauges/ Wales Island, Alaska, 1915. Photo from NOAA Photo Library

www.climate.gov/news-features/climate-tech/reading-between-tides- 200-years-measuring-global-sea-level Instruments for the Measurement of Sea Level

IOC manual Two large stilling wells at Holyhead in North Wales, UK Instruments for the Measurement of Sea Level

GPS for time Geostatic satellite antenna

Tube for acoustic sensor Electronics box

A NOAA water level monitoring station with an acoustic sensor on Dauphin Island, Alabama. A small GPS antenna enables precise timekeeping—not elevation tracking— and a second antenna transmits data to geostationary Radar gauge in Liverpool satellites. Photo courtesy Morgan McHugh The main limitation of tide gauge data

Specific limitations: 1) Geographical locations 2) Vertical land movement/benchmark GPS at tide gauge locations

King et al, 2012 Globally: 90% of tide gauge locations are not covered by GPS observations Remote measurements

IOC manual Summary of commonly used methods for measuring sea level

Category Type Wave averaging Accuracy Advantage Disadvantage

Surface Tide pole By eye 0.02-0.10m Inexpensive, Effort, workforce following Easy to make Float Stilling well 0.01-0.05m Robust Needs vertical structure, high maintanance

Fixed sensors Acoustic Multiple 0.005-0.01m Robust, low Needs vertical structure reflection samples cost, low maintenance

Radar reflection Pressure Hydrodynamics 0.01m No vertical Density and wave corrections, high and multiple structure is maintance samples needed

Remote Satellite Empirical 0.01m Systematic Expensive, specialist use only, multiple adjustment global corrections, misses local storms, does not coverage sample near the coast IOC Manual http://www.psmsl.org/train_and_info/training/manuals/manual_14_final_21_09_06.pdf Tide gauge data

1. Permanent Service for Mean Sea Level (PSMSL) 2. National data centres, Local Authorities 3. Global Observing Sea Level System (GLOSS) 4. Data for Geophysical signals (e.g. SONEL) 5. Specific tide gauge data sets (e.g. high frequency data)

! Please acknowledge use of any data in your publications Permanent Service for Mean Sea Level (PSMSL)

From PSMSL, www.psmsl.org Evolution of the PSMSL dataset RLR (Datum Controlled) Dataset

From PSMSL, www.psmsl.org Sea level measurements in Arctic

Henry et al, 2012. Regions not covered by satellite altimetry

Blue – active after 2006

White- discontinued since 2006 Longer RLR Records

From PSMSL, www.psmsl.org Historical data

Number of the tide gauge measurements available since 1807

Since 1900

From PSMSL, www.psmsl.org www.psmsl.org Land movement signals SONEL http://www.sonel.org/-Sea-level-trends-.html Local vertical land movement

King et al, 2012 Global Sea Level Observing System (GLOSS)

GLOSS is a programme of the IOC and WMO with primary aim to increase quantity and quality of data to PSMSL

High Frequency data

1) GLOSS Delayed Mode Higher Frequency (DM HF) Data Sets

• British Oceanographic Data Centre (BODC) https://www.bodc.ac.uk/data/hosted_data_systems/sea_level/international/

• University of Hawaii Sea Level Center (UHSLC), http://uhslc.soest.hawaii.edu/

2) GLOSS Fast Mode Higher Frequency Data Sets, at the UHSLC

3) IOC Operational Status and Quick Inspection, Sea Level Monitoring Facility http://www.ioc-sealevelmonitoring.org/

4) National and International Data Centres http://www.psmsl.org/links/programmes/ IOC Operational Status and Quick Inspection, Sea Level Monitoring Facility http://www.ioc-sealevelmonitoring.org/ Associated data sets (GIA, as an example)

GIA models are available from several scientists:

• Richard Peltier (University of Toronto) has made available his ICE-5G (VM2) and ICE-5G (VM4), ICE 6G relative sea level predictions http://www.psmsl.org/train_and_info/geo_signals/gia/peltier/index.php

• Jerry Mitrovica (Harvard University) • Kurt Lambeck (Australian National University) • Giorgio Spada Free Associate Professor of Physics of the Earth, DiSPeA, Urbino University, Italy Use of the tide gauge data sets

TAR IPCC (2001): “… Based on tide gauge data, the rate of global average sea level rise during the 20th century is in the range 1.0 to 2.0 mm/yr, with a central value of 1.5 mm/yr (as with other ranges of uncertainty, it is not implied that the central value is the best estimate).

Estimates of the 20th century sea level rise from “selected” locations

Buenos Aires 1987 Balboa 1996 Cristobal 1980 Quequen 1982

Douglas, 1997 Estimates of the 20th century sea level rise from “selected” locations

Douglas, 1997 Table 1. From Douglas, 1997

ICE 3G

San Francisco 1.5 -0.1 (-0.4) 1.6 (1.9) ICE 5G, [Peltier, 2004] Santa Monica 1.4 0 (-0.7) 1.4 (2.1) La Jolla 2.1 -0.1 (-0.6) 2.2 (2.7) San Diego 2.1 -0.1 (-0.6) 2.2 (2.7) 1.8 (2.4) Estimates of the 20th century sea level rise

Douglas, 1997

Figure 3.13, AR5 IPCC, chapter 3 Reconstructions (Virtual station)

Regional average wpacific

Individual tide gauge records Jevrejeva et al., 2014 Binomial tree to illustrate the ‘virtual station’ stacking method. Top-node represents the regional average, bottom nodes the tide gauge records, and rest of nodes are virtual stations. Grinsted et al., 2007 Estimates of the 20th century sea level rise

AR4 IPCC (2007): “…For the 20th century, the average rate was 1.7 ± 0.5 mm/yr, consistent with the TAR estimate of 1 to 2 mm/yr”.

AR5 IPCC (2013): “It is very likely that the mean rate was 1.7 [1.5 to 1.9] mm/ yr between 1901 and 2010 for a total sea level rise of 0.19 [0.17 to 0.21] m. Between 1993 and 2010, the rate was very likely higher at 3.2 [2.8 to 3.6] mm/yr; similarly high rates likely occurred between 1930 and 1950”. New estimate of global sea level rise by Hay et al., 2015

Time series of GMSL for the period 1900–2010.

CC Hay et al. Nature 000, 1-4 (2015) doi:10.1038/nature14093 New estimate of sea level rise from Dangendorf et al., 2017 Short summary

Tide gauge observations, observational networks and data sets • Since 1700 instrumental records provide information about sea level rise and variability • In addition to climate related application, tide gauges are used for Tsunami and storm surges warning systems, Satellite altimetry calibration; Navigation (including tidal predictions) Civil engineering, coastal defences, survey and others.

Data • Monthly mean sea level data – PSMSL/global; National authorities/local • GLOSS, High- frequency (IOC, University of Hawaii Sea Level Centre, British Oceanographic Data Centre • GPS data for GLOSS and PSMSL - SONEL References

Handbook of Sea-Level Research edited by Ian Shennan, Antony J. Long, Benjamin P. Horton

IOC Manual http://www.psmsl.org/train_and_info/training/manuals/manual_14_final_21_09_06.pdf

Reconstructions ( Data from http://www.psmsl.org/products/reconstructions/) Global Sea Level Reconstruction by Church and White, GRL 2006, with an update in 2011. Global Sea Level Reconstruction 1807-2002 by Jevrejeva et al., JGR 2006. Global Sea Level Reconstruction 1700-2002 by Jevrejeva et al., GRL 2008. 1900-2009 Global Sea Level Reconstruction from Ray and Douglas, Prog. Oceanogr. 2011. Global Sea Level Reconstruction 1807-2010 by Jevrejeva et al., GPC 2014.

Reconstructions Hay CC, Morrow E, Kopp RE, Mitrovica JX (2015) Probabilistic reanalysis of twentieth century sea-level rise. Nature 517:481–484. (Data are available from Nature)

Dangendorf, S, M Marcos, G Wöppelmann, CP Conrad, T Frederikse, R. Riva (2017) Reassessment of 20th century global mean sea level rise, Proceedings of the National Academy of Sciences, 201616007. Credits: Aslak Grinsted

Part TWO

Understanding of past sea level changes

Svetlana Jevrejeva National Oceanography Centre, Liverpool, UK Outline

• Motivation for understanding of the past sea level changes • Sea level budget Motivation

May 14, 2002, Proceedings of the National Academy of Sciences (PNAS)

Twentieth century sea level: An enigma Walter Munk

“….Sea level is important as a metric for climate change as well as in its own right. We are in the uncomfortable position of extrapolating into the next century without understanding the last.” Sea flood damage costs with the sea level rise by 2100

Global sea floods cost, Global sea floods cost, % Sea flood cost for China, % of Million US$ per year of GDP (global) GDP (China)

1.5 degree

RCP8.5

RCP8.5J14

China, flood cost in 2100 US$ 3.4 trillion per year (5.8 % GDP) with warming of 1.5 degree (0.5 m sea level rise) US$ 4.6 trillion per year (7.8% GDP) with RCP8.5 (0. 8 m sea level rise) Jevrejeva et al., 2018 US$ 8.5 trillion per year (14 % GDP) with RCP8.5J14 (1.8 m sea level rise) Sea level budget

S- sea level T- thermal expansion of the ocean Mg- mass loss from glaciers Gis – Greenland ice sheet Ais- Antartcica ice sheet

Snc- None climatic component Sea level budget since 1993

From A. Cazenave, http://www.psmsl.org/about_us/news/2013/workshop_2013/talks/02_PSMSL_Liverpool_28Oct2013_WEB.pdf www.aviso.org www.psmsl.org

www.lienss.univ-larochelle.fr www.ukargo.net

Observations since 1993 Estimated contributors to sea level rise over the 20th century (in cm)

Sea level components Low Best High estimate Thermal expansion 2 4 6 Glaciers 1.5 4 7 Greenland ice sheet 1 2.5 4 Antarctic ice sheet -5 0 5 TOTAL -0.5 10.5 22 Observed 10 15 20

FAR IPCC report (1990) Main components of sea level budget in AR4 IPCC

1961-2003

1993-2003

IPCC AR4 (2007) 39% Main components of sea level budget in AR5 IPCC

AR5 IPCC (2013) Could we close the 20th century budget ?

Gregory et al, 2013 Could we close the budget?

Min= 0.45 mm/yr Max= 1.88 mm/yr

Greenland 0.6mm/yr, Mitrovica et al, 2001

Based on table 2 from Gregory et al, 2013 Sea level budget

Gregory et al, 2013 Sea level budget since 1800s

Antarctica (0.25 mm/yr)

Thermal expansion

Glaciers

Sum (components)

Observed

Jevrejeva et al, 2012 Gaps in the 20th century sea level budget

AR5 IPCC (2013) Possible resolutions of the 20th century “ sea level enigma”

Sea Level Expansion Glaciers Greenland Antarctica Land Water Possible resolutions of the “ sea level enigma”:

(1) Improvement of global sea level rise estimates from tide gauge

Data archaeology

Making data available

Vertical land movement (past and present day information)

GIA corrections Distribution of tide gauge data (PSMSL) Survivors

Credits to PSMSL Data archaeology

Bradshaw et al, (2016) Local vertical land movement

King et al, 2012

Bucx et al., 2015

Serpelloni et al., 2013 GIA: Individual locations (ICE 5G-ICE 4G, mm/yr)

Jevrejeva et al, 2014 Maps of differences between GIA corrections from ICE 6G and ICE 4G (top) and ICE 6G and ICE 5G (bottom) at individual locations of tide gauges. Color bar in mm yr-1 and circle size in mm.

Jevrejeva et al., 2017 Gaps in the 20th century sea level budget

AR5 IPCC (2013) Possible resolutions of the “ sea level enigma”:

(2) Improvement of contribution from component

Bjork et al, 2012

Kjeldsen et al. 2015 Future Sea level budget

1993-2010, 11%

By year 3000, 60%

Greenland

Goelzer et al, 2012 (2) Improvement of contribution from component

< 1% Sea Level budget - Short conclusion

1. Huge progress has been made in our understanding of changes in sea level rise and its components over the 20th century

2. Substantial gap in our knowledge about contribution from the main components in the first half of the 20th century

3. Knowledge from modern observations could contribute greatly to the improvement of the process based models for sea level components

4. Multi-disciplinary research and international co-operation References (only 20th century budget)

• Bindoff, N. L., and Coauthors, 2007, Observations: Oceanic climate change and sea level. Climate Change 2007: The Physical Science Basis, S. Solomon et al., Eds., Cambridge University Press, 385–432. • Domingues, C. M., J. A. Church, N. J. White, P. J. Gleckler, S. E. Wijffels, P. l. M. Barker, and J. R. Dunn, 2008, Improved estimates of upper-ocean warming and multi-decadal sea-level rise. Nature, 453, 1090-1093 • Gregory, J. M., et al., 2013, Twentieth-century global-mean sea level rise: is the whole greater than the sum of the parts? Journal of Climate, doi:0.1175/JCLI-D-12-00319.1 • Jevrejeva, S., J.C. Moore and A. Grinsted. 2008. Relative importance of mass and volume changes to global sea level rise, Journal of Geophysical Research 113, D08105, doi:10.1029/2007JD009208. • Jevrejeva, S., J. C. Moore, and A. Grinsted, 2012, Potential for bias in 21st century semiempirical sea level projections, J. Geophys. Res., 117, D20116, doi:10.1029/2012JD017704 • Jevrejeva, S., A. Matthews and A. Slangen, 2017, The Twentieth-Century sea level budget: recent progress and challenges, Surveys in Geophysics, Volume 38, Issue 1, pp 295–307 • Moore, J. C., S. Jevrejeva, and A. Grinsted, 2011, The historical global sea level budget. Annals of Glaciology, 52, 8- 14. • Munk, W., 2002, Twentieth century sea level: An enigma. Proc. Natl. Acad. Sci. USA, 99, 6550– 6555. Challenges: Sea level observations

Observations, space missions and networks

• Insure continuity of long term tide gauge observations with global coverage • Data archaeology • Data processing and data distribution via portals • New tide gauge (including high frequency data) • Satellite altimetry (sea level+ice sheets) • Space gravity missions (land water, ice sheets/glaciers mass balance) • Argo (including deep ocean) • Monitoring of changes in cryosphere (geodetic, field measurements) • GPS in tide gauge locations Challenges: Interpretation of sea level observations

Understanding of sea level rise using observations • Reconstructions (spatial variability in the past) • Corrections- use of advanced models • Systematic comparisons between observations and climate model hindcasts • Extreme sea levels (past, future) • Understanding of the past sea level rise (budget)

• NEW ideas!!!!! The 85th anniversary of the Permanent Service for Mean Sea Level (PSMSL)

Invited Speakers

• Anny Cazenave, International Space Science Institute (ISSI) • Jérôme Benveniste, European Space Agency (ESA-ESRIN), Italy • Richard Greatbatch, GEOMAR, Germany • Paolo Cipollini, NOC, UK • Mark Merrifield, University of Hawaii, US • Begoña Pérez, Spanish Port Authority, Spain • Benoit Meyssignac, (LEGOS), France, • Sönke Dangendorf, University of Siegen, Germany http://conference.noc.ac.uk/sea-level-futures-2018 Vertical land movement calculated using GPS measurements

Serpelloni et al., 2013