Sea Leve Rise: An Overview

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  • Sea Leve Rise: An Overview

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

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