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GLOBAL CLIMATE CHANGE AND SEA LEVEL CHANGE by Bob Dean University of Florida

GLOBAL CLIMATE CHANGE AND SEA LEVEL CHANGE by Bob Dean University of Florida. Questions to Address. (1)Is Global Sea Level Rising? If so, What is the Rate? (2) Is Global Sea Level Accelerating? If so, What is the Rate? (3) Prognosis for Future Sea Level Rise Rates. .

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GLOBAL CLIMATE CHANGE AND SEA LEVEL CHANGE by Bob Dean University of Florida

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  1. GLOBAL CLIMATE CHANGE AND SEA LEVEL CHANGE by Bob Dean University of Florida

  2. Questions to Address (1)Is Global Sea Level Rising? If so, What is the Rate?(2) Is Global Sea Level Accelerating? If so, What is the Rate?(3) Prognosis for Future Sea Level Rise Rates.

  3. Questions to Address(The Engineering Response) (1) Incorporate Effect in Design(2) Retrofit

  4. Long-Term Sea Level Changes

  5. Relative Sea Level Rise: Definitions Relative Sea Level Rise (RSLR) = Global Sea Level Rise + Local EffectsGlobal = EustaticLocal = Tectonic + Compaction + Post Glacial Rebound = Subsidence

  6. Subsidence • Subsidence can be substantial exceeding the eustatic component significantlyLong Beach, CA: > 20 feet due to hydrocarbon extractionTokyo: 14 feet due to water extractionOsaka: > 8 feet due to water extractionCoastal Louisiana: Up to 3 feet per century due to natural and anthropogenic causes

  7. Components of Eustatic SLR (1)Thermal expansion of water(2) Alpine glaciers(3) Greenland, and(4) Antartica

  8. World Wide Distribution of Long- Term Tide Gages

  9. Relative Sea Level Change Based on Tide Gage Data

  10. RSLR: San Francisco, CA

  11. RSLR: Atlantic City, NJ

  12. RSLR: Juneau, AK

  13. Eustatic Sea Level Rise Rates

  14. Is Global Sea Level Rising? Yes. Over the Past Century, the Rate Has Been Between 1 and 2 mm/year (I Like 1.2 mm/year).A Caveat: Most Tide Gages Are Located Near Areas of Ground Water Extraction. Effect on Gage Readings?

  15. Is Sea Level Rise Accelerating? Rate of CO2 Increase

  16. Is Sea Level Rise Accelerating? Consider:and evaluate a and b from the data on the following slide. b is an acceleration term.

  17. Eustatic Sea Level Rise Rates

  18. Is Sea Level Rise Accelerating? This leads to: Where Is the average of the time period over which is determined. Solving for a and b from the data yields very unrealistic results signifying that the data are not well conditioned for this purpose.

  19. Plot of Level Rise Rate vs Average Date of Analysis

  20. Is Sea Level Accelerating?

  21. Is Sea Level Accelerating? (1) There are Indications of Sea Level Acceleration Although They Are Weak and do not Appear to be Increasing(2) Probably Won’t Know About Anthropogenic Effects Definitively for 30 Years

  22. Some Predictions and Considerations of Future Sea Level Rise, 1987

  23. Example of Acceleration Concerns of Sea Level Rates (1983)

  24. Sea Level Rise Projections (IPCC) Long-term Eustatic Rate

  25. Will Sea Level Rise Accelerate in the Future? Probably, However, the Timing and Rates are Extremely UncertainAs Support, the Predicted Rates of Acceleration Have Decreased Since 1983 When Predictions Started

  26. Engineering ResponseNRC Report, 1987

  27. Committee Composition

  28. Engineering Response NRC Report (1984)“The Prognosis for Sea Level Rise Should Not be a Cause for Alarm or Complacency”

  29. Engineering Responses Highways: Increase Elevation as Need Becomes ApparentBridges and Other Infrastructure Less Suited for Retrofitting: Allow for RSLR in Original Design

  30. Questions/Discussion

  31. Report to be Reviewed (in Part)

  32. Measurement of Sea Level Change

  33. Outline (1) Definitions(2) Discuss Magnitudes of Relative Sea Level Rise(3) Is the rate of sea level rise increasing(4) Engineering responses to sea level rise (NRC Report)

  34. Sea Level Rise Projections

  35. Sea Level Rise Projections

  36. Bruun Rule for Shoreline Response to Sea Level Rise

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