Sea Level Rise & Implication for Harbors and Marinas Ronald M. Noble

Looking Into a Warmer Future… MSLR by 2100 Assuming ΔT < 4° C (Nicholls, et al Phil. Trans. Roy. Soc.) Greenland (+21 ft) and Antarctica (+200 ft) melting will become largest contributor to global MSL rise

Global ≠ Regional MSLR Fast Rise No Rise Global MSLR not evenly distributed dynamical effects! Global MSLR 3.3 mm/yr or 33 cm/cy Is MSL rise acceleration imminent on west coast? “Regime Shift” Reversal? Bromirski, Miller, Flick, Auad, Dynamical suppression of sea level rise along the Pacific coast of North America: Indications for imminent acceleration, Jour. Geophys. Res. 116(C07005) Bromirski, Miller, Flick, 2012, North Pacific Sea Level Trends, Eos Trans. AGU, 93(27),

Historical Mean Sea Level Trend: San Francisco Source: NOAA Website

Historical Mean Sea Level Trend: Los Angeles Source: NOAA Website

“Prediction is very difficult, especially if it's about the future.” - Niels ‘Yogi Berra’ Bohr

Global Sea Level Change Prediction (by 2100) Source: USACE EC

USACE SLR Guidance: EC (2011) Three SLR scenarios:  “Low” SLR rate: using the historical rate of SLR  “Intermediate” SLR rate: using modified NRC Curve I  “High” SLR rate: using modified NRC Curve III

CO-CAT includes state entities: − Business, Transportation and Housing Agency − Coastal Commission − Dept of Fish and Game − Dept of Parks and Recreation − Dept of Public Health − Dept of Toxic Substances Control − Dept of Transportation − Dept of Water Resources − Environmental Protection Agency − Governor’s Office of Planning and Research − Natural Resources Agency − Ocean Protection Council − Ocean Science Trust − San Francisco BCDC − State Coastal Conservancy − State Lands Commission − State Water Resources Control Board California Sea-Level Rise Guidance Document California Climate Action Team (CO-CAT) developed a SLR Guidance based upon NRC 2012 report SLR.

NRC (2012) SLR Report

California Sea-Level Rise Guidance Document CO-CAT reached agreement on the following policy recommendations for SLR Time Period North of Cape Mendocino South of Cape Mendocino to 23 cm (-0.13 to 0.75 ft) 4 to 30 cm (0.13 to 0.98 ft) 2000 – to 48 cm (-0.1 to 1.57 ft) 12 to 61 cm (0.39 to 2.0 ft) 2000 – to 143 cm (0.3 to 4.69 ft) 42 to 167 cm (1.38 to 5.48 ft)

CCC (2013) Draft Sea-Level Rise Policy Guidance

SLR Projects between USACE and CA State

Cardiff State Beach, 1998 Stinson Beach, 1998 MSL is 20 feet lower! wave ^ Wave-Driven Runup & Overtopping = Damage Both private and public infrastructure is and will be at risk!

Waves, Storm Surge & High Tides Flooding & Erosion December 1982 January 1983 Mission Beach 2010 Hs 4 m Hs 3 m

Beaches and infrastructure are “tuned” to current extremes of ~3m (10 ft) MSL (Bill O’Reilly cartoon) Extra m! “ Tuned” MSLR

SF Bay Area Potentially Exposed to SLR

Over 1 in 6 chance sea level rise + storm surge + tide will overtop + 6 ft by 2100 Implication of SLR: Marina del Rey, California Src:

Over 1 in 6 chance sea level rise + storm surge + tide will overtop +7 ft by 2100 Implication of SLR: San Francisco, California Src:

Impact of SLR on Yosemite Slough Wetlands Restoration

MSL is 20 feet lower! Return-Period ‘Creep’ 100-yr Maximum Water Level (+5.2 ft MSL) in 2000 becomes 10-yr event in 2017, 1-yr event in 2048, and monthly in 2083 Projections based on MSL rise “central” value +3 ft ( ) NRC (2012)

Waves, Storm Surge & High Tides Flooding & Erosion December 1982 January 1983 Mission Beach 2010 Hs 4 m Hs 3 m

Cardiff State Beach, 1998 Stinson Beach, 1998 MSL is 20 feet lower! wave ^ Wave-Driven Runup & Overtopping = Damage Both private and public infrastructure is and will be at risk!

Wet Dry Mild -but- Variable Climate Decades drought Decades wet Extremes 111⁰ - 26 Sep ” rain - 5 Apr ” rain ” rain CA Four “Seasons” Quake Drought Fire Flood Dry?

Sea Level Rise Rates Vary Regional MSLR rates depend on large-scale atmospheric conditions over North Pacific Ocean El Niño -5.4 cm/cy 18 cm/cy -0.7 cm/cy