Symposium

01. Predicting Sea Level Rise, Bounding Uncertainties

 01: Predicting Sea Level Rise, Bounding Uncertainties

Coordinator:  William Lipscomb, Scientist 3, Group T-3 (Fluid Dynamics and Solid Mechanics), Los Alamos National Laboratory

Speakers:

1. R. Steven Nerem, Professor, Colorado Center for Astrodynamics Research, University of Colorado at Boulder
   
2. John Moore, Chief Scientist, College of Global Change and Earth System Science, Beijing Normal University
   
3. Ana Unruh Cohen, Former Deputy Staff Director, U.S. House of Representatives, House Select Committee on Energy Independence and Global Warming
   
4. Courtney St. John, Climate Change Affairs Officer, U.S. Navy Task Force Climate Change
   

Summary: 

Global average sea level is expected to rise significantly during the 21st century as a result of ocean thermal expansion and the melting of land ice. Satellite observations show that the land-ice contribution is growing, thanks to increased surface melting and the acceleration of large outlet glaciers in Greenland and Antarctica.  It is not yet possible to give a best estimate or upper bound for 21st century sea level rise, mainly because ice sheet dynamical feedbacks are not well understood.  Semi-empirical models, however, suggest that sea level could rise by a meter or more during this century.   Rapid sea-level rise would affect coastal populations, infrastructure, and ecosystems through increased flooding, storm surges, saltwater intrusion, and coastal erosion.  Improved sea-level predictions are critical for designing effective mitigation and adaptation strategies.
This session will assess prospects for providing policymakers and planners with useful scientific predictions of 21st century sea-level rise. The panel will include speakers with expertise in:

• Ice-sheet and sea-level observations
• Sea-level prediction using semi-empirical methods and Earth-system models
  
• Coastal planning and adaptation
  
• Government policy on sea-level rise
  

The following are among the questions to be addressed:

• What do tide gauges, satellite records, and other observations tell us about historical levels of sea-level rise and the recent contributions from different sources (e.g., ocean thermal expansion, glaciers and ice caps, and large ice sheets)?
• How much confidence can be placed in semi-empirical sea-level predictions?
  
• What innovations are needed to obtain plausible sea-level predictions from climate and Earth-system models?  When will these predictions be available, and what are the major uncertainties?
  
• What sea-level information (e.g., appropriate temporal and spatial scales and acceptable levels of uncertainty) is needed by coastal planners to assess risks and carry out cost-effective adaptations?
  
• How important is sea-level rise to policymakers, relative to other expected climate change impacts?  What information from observations and models is most likely to be influential or useful?
  
• What are the best mechanisms for governments and others to provide formal sea-level assessments for planners and policymakers?
  

Following a brief introduction by the moderator, each speaker will be invited to give a short (10-15 minute) presentation.  The remainder of the 90-minute session will consist of a moderated panel discussion, including questions from the audience.