View of NY harbor from the JOIDES Resolution!in an ice-free world (73 m rise)!

100 Million Years of Sea-level Change:!Should I Sell My Shore House?!

Onshore Bass River, NJ! JOIDES Resolution!

Kenneth G. Miller (and friends), Earth & Planetary Sciences Rutgers, The State University of New Jersey

DOSECC Distinguished Lecturer geology.rutgers.edu/miller.shtml!

Sea-level measurements !

• Satellite altimetry!• Tide gauges!• Coastal sediments!

!< 20,000 yr!• Reef terraces!

!< 130,000 yr!• Oxygen isotopes a proxy record!

!increasing uncertainty 125,000-7,000,000+ yr!

• Sequence stratigraphy!!< 1,000,000,000+ yr!

instruments / modern!

rock record / ancient!Second part: !deep time!

First 10-15 min.!

Flooding of NYC: An Inconvenient Truth!“If Greenland broke up and melted…this is what would happen to Manhattan. They can measure this precisely, just as the scientists could predict precisely how much water would breach the levee in New Orleans… the WTC memorial … would be underwater.” !Al Gore!

Screenshot from the movie!

NYC after 5 m (15 ft) sea-level

rise!

How long to achieve Goreʼs 5 m rise?!

= sea level 125,000 y ago: !IPCC 2001: 300-700 years; !

IPCC 2007: 700-1000 yr !New: Greenland surging, much sooner, but >>100 yr !

125,000 y ago last interglacial!

Otto-Bleisner et al. (2006) simulation !

The future: IPCC (2007)!

2007 2300 2700 3100 3800 AD!

2266!

2364!

Sea-level forecast: IPCC 2001 & 2007!

40 cm (1.25 ft) rise by 2100, 1 m (3.3 ft) by 2200 IPCC 2001 error estimate: 20-80 cm !

IPPC 2007 error: 20-60 cm (does not include ice sheet melting)!

http://www.realclimate.org/images/sealevel_1.jpg!

2007!2001!

20th Century ~1.8 mm/yr tide gauges Church & White (2006) !0.6 ft every 100 yr!

Global sea level is rising !

Satellite data!3.2±0.4 ʻ93-10 http://sealevel.colorado.edu/!12 inches every 100 yr!

Why Is global sea level is rising today?!

Thermal Expansion: ocean has gained heat!

Warmer water less dense global 20th century warming ~0.6°C !1.6 mm/yr sea-level rise!

Melting Glaciers & Ice Caps:!Melting land ice adds to ocean

volume, but not sea ice!

IPCC2001!

Alpine!

Why Is global sea level Is rising today?!

.!

Melting mountain glaciers/ice caps (“alpine” and! continental ice sheets (Greenland & Antarctica):!

Alpine glaciers 0.6 mm/yr !Greenland IPCC2001: near 0!

Cazenave & Nerem (2004): >0.15 mm/yr !0.6 mm/yr 2005 (Sterns & Hamilton 2007)!

We are tracking high end predictions!Not a Gorian 5 m, but not IPCC2007 40±20 cm!

Best estimate >80 cm global; Rahmsdorf et al. (2007)!max. 1 m? 2m?? MWP1a maximium 20-40 mm/yr!

Tide Gauges

Rahmstorf, Cazenave, Church, Hansen, Keeling, Parker and Somerville (Science 2007)

-­‐100  

-­‐200  

-­‐300  

1993   1997   2001   2005   2009  0  

Gt/year  

Annual ice mass loss - Greenland!

Mean trend (1993-2009) ~0.4 mm/yr sea level rise

GRACE

Altimetry InSAR

Slide provided by A. Casenave!

New record of melting: Rignot et al. (2011)!Two independent techniques: 1) mass budget estimates; 2) GRACE!

Left: Greenland!

Right: Greenland & Antarctica!

Left: Antarctica!

Right: projection using Rignotʼs rates and IPCC steric + “alpine” contribution (Miller, unpublished)!Estimate ~1 m!

cm a

bove

pre

sent!

Barbados lowstand!A. palmata (fossil sunshine) 120 m below present day at

18 ka (Fairbanks, 1989)!120 m ± 5 m lowstand Last

Glacial Maximum

Rate up 20-40 m/1000 yr!(2-4 cm/yr @ 14 ka MWP1a)!

New Barbados data: >40 mm/yr!Testing by Tahiti IODP Exp. 310!

47 mm/yr!!!!

Last 20 kyr (last glacial-now) Barbados Curve!

New Jersey, Delaware, So. New England = 1.8 mm/y; subsidence 1 mm/yr? !Natural global sea-level rise <0.75±0.25 mm/yr!

Sea-level rise past 5000 years !

North Carollna!

Is sea-level rise today part of natural cycle? !

Prior to 1850: !!0-0.75 mm/yr!

20th Century: 1.8 mm/yr!Today: 3.3 mm/yr!

Therefore, the natural background rise only 15-25% of modern, rest due to human influence!

Background vs. human effects !

North Carolina Kemp et al. (2011)!

NY/NJ/DE region !higher sea-level rise!

Processes:!•  Global (eustatic) rise !

1.8 mm/yr!

•  Regional subsidence !Glacial Isostatic Adjustment!!1 mm/yr!

•  Local subsidence!!due to water withdrawal ! !& compaction!! 1 mm/yr!

Modified after Psuty and Collins (1986)!

Global, regional, and local effects!

Un-Vailing eustasy: An ad-Haq hypothesis?!1977! 1987!

Jersey outcrop sequence boundary!

Campanian/Maastrichtian unconformity!Matawan, NJ

Sequence: stratigraphic unit of relatively conformable, genetically related strata bounded by unconformities and correlative surfaces associated with baselevel lowering (tectonic & eustatic)!

NJ/MAT sea-level transect !3 seismic grids, onshore & offshore coreholes!

3 seismic grids x-shelf (Ew9009), OCS/slope (Oc270), nearshore (CH0698)!

Top: Cape May, NJ; bottom: JOIDES Resolution!Top: Island Beach, NJ; bottom: Atlantic City!

Sequence boundaries witha sea-level falls!

Sequence boundaries subdivide onshore record!14 Miocene, 8 Oligocene, 12 Eocene, 7 Paleocene 15-17 Late K!

Offshore prograding Miocene sequences!

Identifying marine sequence boundaries in cores!

Physical evidence •  Sharp unconformable contacts •  Lag gravels, phosphorites •  Shell beds/hash •  Rip-up clasts •  Extensive burrowing and bioturbation •  Geophysical log characteristics •  Overstepping of lithofacies successions •  Facies succession (model dependent) •  Dramatic paleodepth changes

Must show geographic distribution (not local surface)

Temporal Hiatuses •  Sr-isotopic stratigraphy •  Biostratigraphy (e.g., planktonic

foraminiferal zones)

Oligocene!(~ 26.6 Ma)!

Mid-!Miocene!(M4)!18.0-18.4 Ma)!

Onshore: Predictable facies!

Characteristic!• erosional boundaries!• shoaling upwards,

paleodepth from litho- and biofacies!

• each ends near shore!• ages Sr-isotopic dating &

biostrat. ±0.3-0.5 Ma !• ~1.5 Ma duration!

Example lo. Miocene onshore sequences, !

Cape May,NJ!

Onshore !sequences!

9030

1

2

3

Ew9009 Line 1005

K/T o1

m5m3

m2m1

p6

p4

35 kmIsland BeachTwo-way

travel time (s)

0 20 km

Shelf sequence boundaries dated on the slope!

Onshore Hiatuses = Offshore seismic sequence boundaries!= baselevel lowerings!

Glacioeustasy controls icehouse sequence boundaries!

Sequence boundaries = global δ18O increases!

Ice-volume (glacioeustasy) controls Icehouse (33-0 Ma) sequence boundaries!

Miller et al. Science! (1996)!

Backstripping provides eustatic estimate!

Backstripping onshore NJ!1-D backstripping accounts for!

•  compaction !•  loading (Airy)!•  thermal subsidence fit !McKenzie stretching !exponential curve!

2-D (Oligocene) accounts for !flexural loading !!(Kominz & Pekar)!

Residual R2 eustatic estimate!

ρa - ρw

T.S. = Φ ρa ρs*ρ

a ρw

-ΔSL

ρwρa - ρw

+ WD - ΔSLS* - -

BACKSTRIPPING EQUATIONS

Φ = the basement response function to loadingS* = the decompacted sediment thicknessρ = densitya = asthenospherew = water∆SL = change in eustatic (global) sea-levelWD = paleo-water depth of the sediments

T.S. = tectonic subsidence, or the subsidence of the basin floor in water without any sediment load.

R1 = T.S. ρa ρs*ρ

a ρw

-ΔSL

ρρa - ρw

S* -+ a = + WD

R2 = R1 - T.S. ΔSLρa

=

Backstripping provides eustatic estimate!

Van Sickel et al. (2004) and Miller et al. (2005): !6 onshore sites (only 2 Cretaceous)!

New Sites!

Leg 174AX onshore!

5 Cretaceous sites !

10 Cenozoic sites !

Kominz et al. (2008)!Browning et al. (2008) !

2008 New sites!

Continental flooding & backstripped estimates !Late Cretaceous estimates!

NJ: 50-70 m (now 100 m)!Exxon: 250 m!Müller (2008): 175 m!Kominz Ridge: 45-365 m (230 m)!Scotian backstrip: 120 m !Continental flooding:!!Harrison (1990): 150 m!

Bond (1979): ~140 (80-200) m !QED: 150±50 !Consistent with small changes!!in spreading rates!

Müller !

Miller et al. (2011) Oceanography, 24, 40-53, doi:10.5670/oceanog.2011.26., 2011.!

Posted at http://geology.rutgers.edu/miller.shtml!

•  3 recent studies NJ sat high in Cretaceous due to subducting Farallon plate (Müller et al., Science, 2008; Moucha et al., EPSL, 2008; Spasojevic et a., GRL, 2008)

•  estimate of 150±50 m for Late Cretaceous peak

No such thing as a stable continent!

•  Late Cretaceous-Eocene: Ephemeral Antarctic ice 15-30 m sea-level changes!

•  Oligocene-early Pliocene: large, variable Antarctic ice !

30-60 m sea-level changes!

•  late Pliocene-Recent: Antarctic and large, variable Northern Hemisphere ice 30-120 m sea-level!

δ18O and sea level 105-106 yr scale!

Large (>25 m), rapid (<1 myr) sea-level changes only explained by glacioeustasy, yet high latitudes were warm!

Cretaceous-Eocene: An ice-free greenhouse? !

An Ice-Free World: !eastern U.S.!

Shoreline assuming 64 m higher sea level!

~15 Ma = modern!

Greenhouse ice sheets restricted to Antarctic interior !

Antarctic Ice Sheet!

~70 Ma, largest Cretaceous, 40 m!

~33 Ma, e. Oligocene, 55-80 m!

~92 & 96 Ma, big Cretaceous, 25 m!

~93 Ma, typical Cretaceous, 15 m!

Maps from models Deconto & Pollard (2002) Sea-level from Kominz et al. (2008) update!

Heartbeat of the Greenhouse-Icehouse transition!

Animation courtesy of D. Pollard after DeConto and Pollard (2002)!

Beginning illustrates Greenhouse ice growth and decay (~3x CO2)!

End illustrates Oligocene Icehouse (<2.8 CO2 )!

Timing falls ± correct!

long-term 100 vs. 250 m!

myr scale amplitudes 30-80 m, not 100+ m!

Sahagian Russian platform backstripping overlaps & extends ours to E. Jurassic!

“It has been said that ours is the worst form of sea-level curves except all the others that have been tried. “ Churchill, 1947

Comparison with EPR estimates!

Test Eustatic Estimates !Pose Thorny Problem!

ODP Leg 194 drilled !NE Australian margin estimated

eustatic lowering 85±30 m!ca. 11 Ma late middle Miocene!

i.e., double NJ but 1/2 of Haq!

Then reduced to 33±12 m!story of flexural vs. Airy !

John et al. !55±15 m!

NJ 40±15 m (but we miss Miocene lowstands onshore)!

Future work!

Scale δ18O to sea-level!Late Miocene ice volume

similar to today, δ18O 0.5‰ lower due to 2° C cooling!

0.1 ‰/10 m calibration!Miller et al. (2011) update using

Lisiecki and Raymo stack and 67:33 ice:temperature attribution !

δ18O and sea level 105-106 yr scale!

Site 1308 N. Atlantic!

Integration atoll, margin, deep-sea records!Pliocene ca. 3 Ma peak sea level 20 m CO2 ~400 ppm, !

global T = 1-2°C warmer (Miller et al., Geology, in review)!

Eyreville, VA!

Enewetak Atoll!

Wanganui Basin!New Zealand!

“likely” (68%) peak sea-levels 17-27 m higher than modern “extremely likely” (95%)” was 12-32 m higher !

IODP Ex. 313: NJ/Mid-Atlantic Transect!

Focus on lower Miocene sequences!

Integrated Ocean Drilling Program!

Conclusions!

•  Long-term sea level 150±50 m 100-60 Ma!

•  Fell ~100 m from 50 to 0 Ma!

•  Consistent with small changes spreading rate!

107 yr scale!No such thing as a stable continent, but…!

•  Late Cretaceous-Eocene (100-33 Ma): Ephemeral Antarctic ice sheets ~30 m sea-level changes!

•  Oligocene-early Pliocene (33-2.7 Ma): Large, variable Antarctic ice sheets 30-60 m sea-level changes!

•  Late Pliocene-Recent (2.5-0 Ma): Antarctic and large, variable Northern Hemisphere ice sheets 30-120 m sea-level changes!

Conclusions!

105-106 yr scale!

104 yr scale!•  Natural sea level globally rising since 5 ka, 0.75±0.25 mm/yr!•  20th century, 1.8 mm/yr!•  Today, 3.2 mm/yr, anthropogenic!

Should I sell my shore house?!

Donʼt sell: insure!!global >80 cm (2.4 ft) by 2100!NJ >-100 cm (>3 ft)!Global 1.2±0.6 m by 2100!

View of NY harbor in an ice-free world (73 m rise)!

More beach erosion, rollback!More cost to replenish!Loss of marshland!Increased storm intensity?!What about those coming behind?!

Vanuatu!

Carteret Is.!

Tuvalu !