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Sea Leve Rise:  An Overview
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Sea Leve Rise: An Overview

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  • 1. Sea Level Rise & Bay Area Predictions: A Comprehensive Review
    • A Senior Project
    • by Lee Jasperse , SVHS Senior
  • 2. Why should you care?
    • More than 600 million people live in low-lying coastal zones worldwide.
    • 1 meter sea level rise would inundate the San Joaquin Delta, areas of Napa, Palo Alta, Alameda, & San Francisco.
    • Most newly vulnerable areas are developed areas.
  • 3. What will be discussed?
    • Eustatic vs. Local sea level rise
    • Eustatic sea level rise
      • Contributions to global mean sea level rise
      • Global mean sea level rise projections
    • Bay Area sea level rise
      • Contributions to localized flooding
      • Flooding predictions in the Bay Area
      • Implications
    • Next Steps
  • 4. What will be discussed?
    • Eustatic vs. Local sea level rise
    • Eustatic sea level rise
      • Contributions to global mean sea level rise
      • Global mean sea level rise projections
    • Bay Area sea level rise
      • Contributions to localized flooding
      • Flooding predictions in the Bay Area
      • Implications
    • Next Steps
  • 5. What’s the difference?
    • Eustatic SLR: the global mean sea level rise.
      • Caused by temperature changes, melting glaciers, etc.
      • 195 mm from 1870 - 2000
    • Local SLR: Localized, often short term, increases in water levels.
    • Caused by tides, storm conditions, El Nino, floods, etc.
  • 6. Roadmap
    • Eustatic vs. Local sea level rise
    • Eustatic sea level rise
      • Contributions to global mean sea level rise
      • Global mean sea level rise projections
    • Bay Area sea level rise
      • Contributions to localized flooding
      • Flooding predictions in the Bay Area
      • Implications
    • Next Steps
  • 7. Global Sea Level Rise SLR acceleration of .013 ± .0006 mm yr -2
  • 8. Roadmap
    • Eustatic vs. Local sea level rise
    • Eustatic sea level rise
      • Contributions to global mean sea level rise
      • Global mean sea level rise projections
    • Bay Area sea level rise
      • Contributions to localized flooding
      • Flooding predictions in the Bay Area
      • Implications
    • Next Steps
  • 9. Contributing Global Factors
    • Thermal Expansion
    • Ice Loss
    • Glaciers & Ice Caps
    • Greenland
    • Antarctica
  • 10. Contributing Global Factors
    • Thermal Expansion
    • Ice Loss
    • Glaciers & Ice Caps
    • Greenland
    • Antarctica
  • 11. Left: Est. contributions to SLR from 1993-2003 (IPCC). Above: Est. contributions to SLR from 1996-2006 (Meier et al. 2007).
  • 12. Thermal Expansion
    • Water expands as it’s heated.
    • Contributed ~25% of SLR from 1955-1995
    • Contributed ~50% of SLR from 1993-2003
    • Projected to contribute more than 50% to SLR between 2008 and 2100.
    • IPCC TAR estimates 1990-2100 contribution to be 110 - 430 mm.
  • 13. Contributing Global Factors
    • Thermal Expansion
    • Ice Loss
    • Glaciers & Ice Caps
    • Greenland
    • Antarctica
  • 14. Contributions from ice loss Present day contributions From Meier et al. (2007) & Monga Bay
  • 15. Future contributions from ice loss Total contributions from present to 2100 From Meier et al. (2007)
  • 16. Contributing Global Factors
    • Thermal Expansion
    • Ice Loss
    • Glaciers & Ice Caps
    • Greenland
    • Antarctica
  • 17. Glaciers & Ice Caps
    • Historic contribution
    • 1961-2003: 0.5 ± 0.18 mm / year
    • 1993-2003: .77 ± 0.22 mm/year
    • 20% of observed rise by 1998
    • Future Contribution
    • Present - 2100: 240 ± 128 mm
    • Only 35% of volume will be depleted by 2100.
  • 18. Contributing Global Factors
    • Thermal Expansion
    • Ice Loss
    • Glaciers & Ice Caps
    • Greenland
    • Antarctica
  • 19. Contributing Global Factors
    • Thermal Expansion
    • Ice Loss
    • Glaciers & Ice Caps
    • Greenland
    • Antarctica
  • 20. Greenland
    • Potential SLR contribution: 7.2 meters
    • Historic contribution
    • 1993-2003: 0.2 ± 0.1 mm / year
    • Future Contribution
    • Present - 2100: 240 ±128 mm
    • Possibly double or triple current estimates (Csatho 2008, Carlson et al. 2008).
  • 21. Contributing Global Factors
    • Thermal Expansion
    • Ice Loss
    • Glaciers & Ice Caps
    • Greenland
    • Antarctica
  • 22. Antarctica
    • Historic contribution
    • 1993-2003: 0.2 mm / year
    • Future Contribution
    • West Antarctic Ice Sheet: 120 ± 50 mm
    • East Antarctic Ice Sheet: -56 ± 40 mm
  • 23. Roadmap
    • Eustatic vs. Local sea level rise
    • Eustatic sea level rise
      • Contributions to global mean sea level rise
      • Global mean sea level rise projections
    • Bay Area sea level rise
      • Contributions to localized flooding
      • Flooding predictions in the Bay Area
      • Implications
    • Next Steps
  • 24. IPCC Prediction
    • Depending on the greenhouse gas emissions scenario, SLR could range from .18 to .59 meters.
    • Estimates are considered very conservative.
    • Does not include contributions from ice sheet flow.
  • 25. Examining the paleoclimate
    • Models underestimate contributions from the Greenland & Antarctic Ice Sheets.
    • Examine historical sea level rise and deglaciation.
    • Overpeck: 1+ meter of SLR by 2100, and committed to 4-6 meters over the next few hundred years.
    Carlson et al & Overpeck et al
  • 26. A simpler method...
    • Computer modelling has underestimated observed SLR.
    • “Semi-Empirical Approach”: Correlates long term SLR with global temperature.
    • Closely matches observed SLR.
    • Grinsted: .7 - 1.1 meters of SLR for B1 emission scenario. 1.1 - 1.6 meters for the A1F1 scenario.
    Rahmstorf & Grinsted
  • 27. Uncertainty
    • Low Uncertainty:
    • Thermal Expansion
    • High Uncertainty:
    • Greenland & Antarctica
    • Ice sheet flow & ice dynamics
    • Sea levels act as positive feedback, destabalizing ice sheets
    • Increased # of suraglacial lakes
  • 28. Environmental Impacts
    • A collapse of the Western Antarctic Ice Sheet would shift Earth’s rotational axis 500 meters, shifting water globally towards North Americ and the southern Indian Ocean.
    • Arctic animals may go extinct (seals, polar bears).
    • Salt water intrusion in coastal habitats and aquifers.
    • Marshes and wetlands will be inundated.
    • 14,000 sq. miles would be inundated in the US.
  • 29. Social Impacts
    • Coastal and island populations will be displaced.
    • 634 million people live in low-elevation coastal zones.
    • Island nations may be entirely submerged.
      • Kiribati
  • 30. Economic Impacts
    • $1,182 billion (1995 US dollars) will be lost solely from global wetland loss.
    • Global warming may result in a 20% cut in global GDP.
  • 31.  
  • 32. Sea Level Rise in the Bay Area
  • 33.  
  • 34. Oakland Airport
  • 35.  
  • 36.  
  • 37. Roadmap
    • Eustatic vs. Local sea level rise
    • Eustatic sea level rise
      • Contributions to global mean sea level rise
      • Global mean sea level rise projections
    • Bay Area sea level rise
      • Contributions to localized flooding
      • Flooding predictions in the Bay Area
      • Implications
    • Next Steps
  • 38. Contributing Factors
    • Mean SLR (follows global trend)
    • Water level factors
    • Spring tides
    • Storm Surge
    • Barometric effect: -1 atm = +1 inch SLR
    • El Nino
  • 39. Contributing Factors
    • Mean SLR (follows global trend)
    • Water level factors
    • Spring tides
    • Storm Surge
    • Barometric effect: -1 atm = +1 inch SLR
    • El Nino
    • Erosion/Deposition dynamics
  • 40. Tides
    • Vary around mean sea level on a daily time scale.
  • 41. Tides
    • Also vary around a monthly timescale.
  • 42. Tides
    • Tides are highest during spring tides — tides that rise the highest and fall the lowest.
  • 43. Tides
    • Tides are the largest component of sea level change, and are the most predictable.
  • 44. Contributing Factors
    • Mean SLR (follows global trend)
    • Water level factors
    • Spring tides
    • Storm Surge
    • Barometric effect
    • El Nino
    • Erosion/Deposition dynamics
  • 45. Storm Surge & Barometric Effect
    • Combination of persisent winds and low pressure.
    • Strong surface winds causes water levels to increase at the downward shore. Wind whips can cause stronger waves with greater momentum.
    • Low atmospheric pressure increases sea level (-1 atm = +1 inch).
    • In the SF Bay, maximum effect is 1 meter SLR.
    • Impact rarely exceeds .3 m.
    • “ Wave induced surge on a beach... can reach 1.5 m.” (Cayan et al )
  • 46. Contributing Factors
    • Mean SLR (follows global trend)
    • Water level factors
    • Spring tides
    • Storm Surge
    • Barometric effect: -1 atm = +1 inch SLR
    • El Nino
    • Erosion/Deposition dynamics
  • 47. El Nino
    • Sustained sea surface temperature anomalies >5ºC
    • Leads to storm conditions and abnormally high tides.
    • Ex: El Nino caused tides in San Francisco to be ~2 feet higher than normal in the early winter months of 1997 & 1998.
    • Local thermal expansion
  • 48. Contributing Factors
    • Mean SLR (follows global trend)
    • Water level factors
    • Spring tides
    • Storm Surge
    • Barometric effect: -1 atm = +1 inch SLR
    • El Nino
    • Erosion/Deposition dynamics
  • 49. Erosion/Deposition Dynamics
    • Sediment from erosion builds up.
    • Changes spatial component of land.
  • 50. Roadmap
    • Eustatic vs. Local sea level rise
    • Eustatic sea level rise
      • Contributions to global mean sea level rise
      • Global mean sea level rise projections
    • Bay Area sea level rise
      • Contributions to localized flooding
      • Flooding predictions in the Bay Area
      • Implications
    • Next Steps
  • 51. Predictions
    • Likely 1.4 m mean SLR in the Bay Area.
    • Flooding occurs when sea level extremes occur — spring tides, low atmospheric pressure & storm events, and El Nino occur simultaneously.
    • San Francisco Bay appears sensative to sea level changes — the occurrence of extremes has increased 20-fold since 1915.
  • 52. Predictions
    • As mean sea level rises & severe weather conditions potentially become more severe, the risk of large scale flooding increases.
    • Projected monthly SF sea level anomolies from the mean sea level.
    From Cayan et al. (2007)
  • 53. Predictions
    • The amount of land vulnerable to flooding increases significantly.
    • Most newly vulnerable land are the Central and South Bay’s developed areas.
  • 54. Uncertainty
    • Mean global sea level.
    • Sediment erosion, supply, and deposition.
    • Levee failure.
    • Frequency of storm surge / El Nino events.
  • 55. Roadmap
    • Eustatic vs. Local sea level rise
    • Eustatic sea level rise
      • Contributions to global mean sea level rise
      • Global mean sea level rise projections
    • Bay Area sea level rise
      • Contributions to localized flooding
      • Flooding predictions in the Bay Area
      • Implications
    • Next Steps
  • 56. Implications
  • 57. Environmental Impacts
    • Wetlands and grasslands are among those at greatest risk of flooding.
    • Saltwater will flow into the Sacramento-San Joaquin River Delta, from which fresh water is pumped to about 67% of Californians. It will also intrude on aquifers.
    • 22 industrial and municipal wastewater systems are at risk of inundation.
    • Shoreline dumps and military installations threatened by a rising bay could leak biological and chemical contaminents into the bay.
  • 58. Impacts in terms of land cover From Noah Knowles, USGS
  • 59. Image from Noah Knowles, USGS
  • 60. Social Impacts
    • Those who live in parts of Corte Madera, San Rafael, Hayward, Newark, Marin (Sausalito), San Francisco, and the Silicon Valley shoreline would likely be displaced.
    • 480,000 people at risk from SLR along California coast.
      • 9600 people vulnerable in Sonoma County with a 1.4 m mean SLR.
      • Disproportionately high impact on low income families in Sonoma.
  • 61. Economic Impacts
    • High cost due to wetland loss ($6-$30 thousand per acre lost).
    • Substantial damage to infrastructure:
      • 25.9 miles of vulnerable roads and highways in Sonoma County
      • San Francisco and Oakland airports
    • Cost of flooding of buildings & houses along California coast estimated at $100 billion.
      • $.48 billion in Sonoma County.
    • San Francisco and Oakland airports
  • 62. Roadmap
    • Eustatic vs. Local sea level rise
    • Eustatic sea level rise
      • Contributions to global mean sea level rise
      • Global mean sea level rise projections
    • Bay Area sea level rise
      • Contributions to localized flooding
      • Flooding predictions in the Bay Area
      • Implications
    • Next Steps
  • 63. Next Steps
    • Study in greater detail SLR’s spatial impact.
    • Prepare for sea level rise:
      • Revamp levies & walls ($14 billion California-wide investment)
      • Perform a cost/benefit analysis to determine which areas to protect most heavily.
      • Restore buffers.
  • 64. Thank You!