Newly detected rising sea levels in parts of the Indian Ocean, including the coastlines of the Bay of Bengal, the Arabian Sea, Sri Lanka, Sumatra and Java, appear to be at least partly a result of human-induced increases of atmospheric greenhouse gases, says a study led by the University of Colorado at Boulder. Along the coasts of northern Indian Ocean, seas have risen by an average of 0.5 inches, or 13 millimeters, per decade.
The study, which combined sea surface measurements going back to the 1960s and satellite observations, indicates anthropogenic climate warming likely is amplifying regional sea rise changes in parts of the Indian Ocean, threatening inhabitants of some coastal areas and islands, The sea level rise -- which may aggravate monsoon flooding in Bangladesh and India -- could have far-reaching impacts on both future regional and global climate.
The key player in the process is the Indo-Pacific warm pool, an enormous, bathtub-shaped area of the tropical oceans stretching from the east coast of Africa west to the International Date Line in the Pacific. The warm pool has heated by about 1 degree Fahrenheit, or 0.5 degrees Celsius, in the past 50 years, primarily caused by human-generated increases of greenhouse gases.
These new results show that human-caused changes of atmospheric and oceanic circulation over the Indian Ocean region -- which have not been studied previously -- are the major cause for the regional variability of sea level change.
This study appeared in this week's issue of Nature Geoscience. Prof. Weiqing Han from ATOC led the study and Prof. Balaji Rajagopalan from CEAE was one of the Co-authors - the other Co-authors include, Xiao-Wei Quan, Jih-wang Wang and Laurie Trenary of CU-Boulder, Gerald Meehl, John Fasullo, Aixue Hu, William Large and Stephen Yeager of the National Center for Atmospheric Research in Boulder, Jialin Lin of Ohio State University, and Alan Walcraft and Toshiaki Shinoda of the Naval Research Laboratory in Mississippi.