Projections of Relative Sea-level Change in the Canadian ... - ArcticNet

Earth Sciences Sector

Projections of Relative Sea-level Change in the Canadian Arctic

Arviat, Nunavut

Thomas James1,2, Karen Simon2,1, Donald Forbes1,3, Arthur Dyke1, Stephane Mazzotti1,2, Dave Mate1,4, James Stephaniuk2,1 1Geological

Survey of Canada, 2University of Victoria, BC, Canada 3Memorial University of Newfoundland, 4Canada Nunavut Geoscience Office

Earth Sciences Sector

Outline  Sea-level projections – why are they needed?  Components (ingredients) of a sea-level projection  Global projections of sea-level change  Local vertical crustal motion  “sea-level fingerprinting”

 Assembling the ingredients  Results – big differences from location to location in northern Canada  Summary and a look forward

Earth Sciences Sector

Outline  Sea-level projections – why are they needed?  Components (ingredients) of a sea-level projection  Global projections of sea-level change  Local vertical crustal motion  “sea-level fingerprinting”

 Assembling the ingredients  Results – big differences from location to location in northern Canada  Summary and a look forward

Earth Sciences Sector

Past, Present and Future Global Sea Level IPCC AR4 = Fourth Assessment Report of the Intergovernmental Panel on Climate Change

© IPCC AR4 2007

Earth Sciences Sector

Sea-level Change in the North

Northern communities are supplied by sea-lift – sea-level change has implications for port and wharf facilities -coastline erosion issues -coastline and oceans support traditional lifestyle

Earth Sciences Sector

Outline  Sea-level projections – why are they needed?  Components (ingredients) of a sea-level projection  Global projections of sea-level change  Local vertical crustal motion  “sea-level fingerprinting”

 Assembling the ingredients  Results – big differences from location to location in northern Canada  Summary and a look forward

Earth Sciences Sector

Outline  Sea-level projections – why are they needed?  Components (ingredients) of a sea-level projection  Global projections of sea-level change  Local vertical crustal motion  “sea-level fingerprinting”

 Assembling the ingredients  Results – big differences from location to location in northern Canada  Summary and a look forward

Earth Sciences Sector

Semi-Empirical Sea-level Projections  Correlate past sea-level change to temperature change  Use IPCC projections of future temperature change  Apply the correlation to project future sea-level change

Result: Sea-level projections are much larger than IPCC AR4 projections

Vermeer and Rahmstorf, PNAS, 2009

Earth Sciences Sector

Global Sea-level Projections After IPCC AR4 Upper bound

The IPCC AR4 projected 15 to 50 cm of sea-level rise from 2010 to 2100 (90 years). Later publications project larger amounts of sea-level rise.

Earth Sciences Sector

Outline  Sea-level projections – why are they needed?  Components (ingredients) of a sea-level projection  Global projections of sea-level change  Local vertical crustal motion  “sea-level fingerprinting”

 Assembling the ingredients  Results – big differences from location to location in northern Canada  Summary and a look forward

Earth Sciences Sector

Sea-level Change in the North Raised beaches on shore of Hudson Bay

Earth Sciences Sector

Paleo-sea-level and GPS  Over 11,000 observations of paleo-sea-level.  Contoured at 500 year intervals  GPS – relatively sparse, recently infilled  Presently processing the network shown here.

Vertical land motion from past sea-level change

Earth Sciences Sector

Contours are amount of sea-level fall in last 500 years Slope at t=0  empirical current uplift rate

Dyke, 1996, and updates

Earth Sciences Sector

Outline  Sea-level projections – why are they needed?  Components (ingredients) of a sea-level projection  Global projections of sea-level change  Local vertical crustal motion  “Sea-level fingerprinting”

 Assembling the ingredients  Results – big differences from location to location in northern Canada  Summary and a look forward

Earth Sciences Sector

Sea-level Fingerprinting Antarctica Melt water from ice sheets and glaciers is NOT distributed uniformly. Greenland

Mountain glaciers and ice caps

Antarctica

A contribution from Greenland of 1 mm/yr global sea-level rise will cause sea level to DROP by 1.2 mm/yr at Iqaluit.

Earth Sciences Sector

Outline  Sea-level projections – why are they needed?  Components (ingredients) of a sea-level projection  Global projections of sea-level change  Local vertical crustal motion  “sea-level fingerprinting”

 Assembling the ingredients  Results – big differences from location to location in northern Canada

 Summary and a look forward

Earth Sciences Sector

Assembling the Ingredients: Fingerprinting

Sea-level fingerprinting reduces global sea-level rise substantially in northern Canada.

Earth Sciences Sector

Assembling the Ingredients: Vertical Crustal Motion

~0 uplift Slower uplift Rapid uplift

Earth Sciences Sector

Outline  Sea-level projections – why are they needed?  Components (ingredients) of a sea-level projection  Global projections of sea-level change  Local vertical crustal motion  “sea-level fingerprinting”

 Assembling the ingredients  Results – big differences from location to location in northern Canada

 Summary and a look forward

Earth Sciences Sector

Sea-level Projections for Five Northern Communities

Earth Sciences Sector

Summary  Projections of sea-level in northern Canada differ substantially from one location to another  Vertical crustal motion  Sea-level fingerprinting

 Most locations will experience sea-level rise at amounts less than the average global sea-level rise  Some locations are likely to experience sea-level fall

Earth Sciences Sector

Looking Forward Sea-level Projections for Northern Canada

Earth Sciences Sector