Title: Sea-level change: A scientific and social challenge for the 21st century
Venue: Room 412, College of Physical and Environmental Oceanography, Laoshan Campus
Time: 09:30am, 2015.06.18
Speaker: Dr. John A. Church
Affiliation: Centre for Australian Weather and Climate Research, CSIRO Oceans and Atmosphere Flagship, Australia
Abstract:
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 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 (Church et al., 2013) 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. Despite scientific challenges and uncertainties in this multidisciplinary field, urgent mitigation will be essential if the World is to avoid the most severe projections of sea-level rise. Even with significant mitigation, adaptation to future sea-level change will be necessary and involve ongoing challenges for society.
References:
Church, J. A., P. U. Clark, A. Cazenave, J. M. Gregory, S. Jevrejeva, A. Levermann, M. A. Merrifield, G. A. Milne, R. S. Nerem, P. D. Nunn, A. J. Payne, W. T. Pfeffer, D. Stammer and A. S. Unnikrishnan, 2013: Sea Level Change. Pages 1137-1216, in: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T. F., D. Qin, G.-K. Plattner, M. Tignor, S. K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P. M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
Munk, W. (2002). "Twentieth century sea level: An enigma." Proceedings National Academy of Science 99(10): 6550-6555.
Bio:
Dr. John Church is a CSIRO Fellow. He has published across a broad range of topics in oceanography. His area of expertise is the role of the ocean in climate, particularly anthropogenic climate change. He is an expert in estimating and understanding global and regional sea-level rise. He is the author of over 130 refereed publications, over 90 other reports and co-edited three books. He was co-convening lead author for the Chapter on Sea Level in the IPCC Third and Fifth Assessment Reports. He was awarded the 2006 Roger Revelle Medal by the Intergovernmental Oceanographic Commission, was a winner of a CSIRO Medal for Research Achievement in 2006, won the 2007 Eureka Prize for Scientific Research and presented the 2008 AMOS R.H. Clarke Lecture. He is a Fellow of the Australian Academy of Science, the Australian Academy of Technological Sciences and Engineering and the American Meteorological Society.
