Anthropogenic Forcing of Ocean Warming and Its Effects on the West Antarctic Ice Sheet Theresa Diehl Physical Climatology Fall 2005

Earth’s Energy Imbalance Global net energy surplus of 1 W/m 2 Q. Where does all this energy go? A. ~85% in the last 40 years has gone toward warming the Earth’s oceans

Ocean Warming Barnett et al., 2005

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)

Model Results for Natural Variability Barnett et al., 2005

Model Results for Human Forcing Barnett et al., 2005

Antarctica Oppenheimer, 2005

Schematic Cross-section Oppenheimer, 2005

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 cm of sea level rise possible this century just from WAIS

Jan 31, 2002 – March 7,

What about the other ice shelves?

What’s causing the thinning? Shepherd et al., 2004

Modeling the Observations for PIG Payne et al., 2004

Will this destabilize the ice sheet? Lythe et al., 2004 BEDMAP

Thank you