Global Change In Sea Level
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Transcript of Global Change In Sea Level
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Global Change In Sea Level
Seds Lab 9
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Currently Rising
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May lead to
• Loss of property and coastal habitats
• Flood risk and potential loss of life
• Loss of renewable/subsistence resources
• Loss of Tourism, Recreation and Transportation Functions
• Loss of non-monetary cultural resources
• Loss in agriculture/aquaculture
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History
• Evidence from Fossil and Sedimentary Record
• Correlation in time in significant part of sedimentary record
• Oxygen isotope evidence from plankton or ice cores
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Mass Extinctions
• Strong relationship between Eustatic sea level and Mass Extinctions
• 5 of 6 show evident correlation
Ordovician Permian Triassic Cretaceous Late Devonian
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Methods of Sea-Level Change
Isostacy• Regional continental uplift
Glaciation• Global (glacieustatic)
Greenhouse Effect• Expansion of water at higher T
Tectonic activity• Displacement due to mid-oceanic ridges, or Continental Flood
Basalts (tectonoeustatic)• Increased sedimentation due to continental uplift• Breakup of super continents, creation of less dense Oceanic crust
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Modern Sea Level Rise
Various Projections• 18-60cm by 2050, 24-108cm by 2080 (Gornitz)• 100yr storm flood could be reduced to 19-68yr by 2050, 4-60yr by 2080• Rates of Beach Erosion will increase 3-6 times by 2050, 4-8 times by 2080• 9-88cm by 2100, 12m in the next 1000 years (Nichols)
Once lost, a return to present atmospheric conditions will NOT be adequate to regenerate modern ice sheets
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Consequences
• Loss of property and coastal habitats
• Flood risk and potential loss of life
• Loss of renewable/subsistence resources
• Loss of Tourism, Recreation and Transportation Functions
• Loss of non-monetary cultural resources
• Loss in agriculture/aquaculture
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Canada Susceptibility
Map based on 7 attributes• Geology• Modern rate of sea level rise• Coastal type• Relief• Tidal range• Wave energy• Modern rates of erosion
Eg. A highly sensitive area has low relief, a high rising sea level already, a high tidal range, high tidal energy, high rates of erosion today, and is composed of beaches or marshes
• High Risk: Atlantic Canada, the Beaufort Sea and the Frazer Delta
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What can we do?
• A mitigated sea level rise is likely to be less devastating
• Correlation with paleo-sea level and atmospheric CO2 is observed but direct consequence of burning of hydrocarbons uncertain
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Bibliography• Couch S, Gornitz V, 2002. Impacts of Sea Level Rise in the New
York City Metropolitan Area. Global and Planetary Change. 32: 61-88
• Hallam A, Wignall P, 1999. Mass Extinctions and Sea Level Changes. Earths-Science Reviews. 48:217-250
• Herrmann A, Huapt B, Patzkowsky M, Seidov D, Slingerland R, 2004. Response of late Ordovician Paleoceanography to changes in sea level, continental drif, and atmospheric pCO2: otential cases for longterm cooling and glaciation. Paleo 210:385-401
• Hitz S, Smith J, 2004. Estimating Global Impacts from climate change. Global and Environmental Change. 14:201-218
• Leeder M, 2003. Sedimentology and Sedimentary Basins: From Turbulence to Tectonics. Blackwell, pp 258-266
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• Monroe J, Wicander R, 2004. Historical Geology. Edited by Dodson K. Thomson Brooks/Cole, pp192, 213, 335
• Nicholls R, Lowe J, 2004. Benefits of Mitigation of climate change for coastal areas. Global and Environmental Change.
14:229-244• UNEP-www.grida.no/climate/vital/33.htm
Thanks to John Shaw of the GSC for the swift and concise response to my email