Transcript Sealevel - Department of Earth and Planetary Sciences

Global Change In Sea Level
Seds Lab 9
Currently Rising
May lead to
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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
History
• Evidence from Fossil and Sedimentary
Record
• Correlation in time in significant part of
sedimentary record
• Oxygen isotope evidence from plankton or
ice cores
Mass Extinctions
• Strong relationship between Eustatic sea
level and Mass Extinctions
• 5 of 6 show evident correlation
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Ordovician
Permian
Triassic
Cretaceous
Late Devonian
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
Modern Sea Level Rise
Various Projections
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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
Consequences
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•
•
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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
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
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
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
• 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. 14:229244
• UNEP-www.grida.no/climate/vital/33.htm
Thanks to John Shaw of the GSC for the swift and concise response to
my email