Program
 
Special Session 5: Ocean-atmosphere interaction, multi-scale climate variability and their implication for biogeochemical processes
 

 
 
1400
Understanding sea level change
Wednesday 11th @ 1400-1425
Room 1
John A Church* , None
Presenter Email: Church.johna@gmail.com
Relatively stable sea levels over the two thousand years prior to the 19th century allowed the development of the World’s coastal zone such that now about 150 million people live and 1 trillion dollars of GDP are generated on land less than 1 m above the current day high tide level. These stable sea levels contrast with changes of over 100 m during the glacial/interglacial cycles of the last million years. An increase in sea level over the last 200 years and the projected sea-level rise during the 21st century and beyond are critically important for our modern coastal society. Understanding past and projecting future regional sea level change is also a significant and multidisciplinary scientific challenge. Understanding of 20th century sea-level rise and our ability to simulate this rise have increased significantly since Munk (2002) outlined the sea-level enigma (the inability to reconcile observations and understanding of 20th century sea-level rise). Future regional sea-level change will result from ocean thermal expansion, loss of mass from glaciers and ice sheets, changes in the storage of water on land, vertical land motion and changes in the Earth’s gravitational field and will be distinguishable from natural variability over most of the global ocean within decades. For continuing business as usual greenhouse-gas emissions, the rate of rise by the end of the 21st century is projected to be similar to that experienced during the last deglaciation of the Earth, with major longer-term commitments. Critically evaluating our understanding of sea level change and reducing uncertainties in projections relies on the highest quality observations of sea level change, as well as the contributions leading to that change.