Anthropogenic Forcing of Ocean Warming and Its Effects on the West Antarctic Ice Sheet

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Anthropogenic Forcing of Ocean Warming and Its
Effects on the West Antarctic Ice Sheet

• Theresa Diehl
• Physical Climatology
• Fall 2005

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Earths Energy Imbalance

• Global net energy surplus of 1 W/m2
• Q. Where does all this energy go?
• A. 85 in the last 40 years has gone toward
  warming the Earths oceans

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Ocean Warming 1960-2000
Barnett et al., 2005
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Three Possible Causes

1. Natural variability of the air-ocean system
2. External forcing due to solar or volcanic
   variability
3. Anthropogenic forcing from global warming
   (greenhouse gas and aerosol emissions)

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Model Results for Natural Variability
Barnett et al., 2005
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Model Results for Human Forcing
Barnett et al., 2005
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Antarctica
Oppenheimer, 2005
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Schematic Cross-section
Oppenheimer, 2005
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In 1998, Oppenheimer

• Noted that the Larsen and Wordie ice shelves were
  shrinking
• Hypothesized Due to ice shelf basal melting?
• Rejects Fast retreat of grounding lines when ice
  shelf is disrupted
• Predicts Collapse of WAIS realistically within
  next 700 years, as early as 200 years, with
  60-120cm of sea level rise possible this century
  just from WAIS

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Jan 31, 2002 March 7, 2002
http//nsidc.org/iceshelves/larsenb2002/animation.
html
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What about the other ice shelves?
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Whats causing the thinning?
Shepherd et al., 2004
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Modeling the Observations for PIG
Payne et al., 2004
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Will this destabilize the ice sheet?
BEDMAP
Lythe et al., 2004
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Thank you