Pro ISSI Talk: “A Warming Indian Ocean on Planet Earth: Changes in Ocean Circulation, Sea Level and Heat Content” with Weiqing Han (the University of Colorado, USA)

The Indian Ocean rim is home to one third of the world’s population, mostly living in developing countries with low-lying coastal areas that are vulnerable to climate change. Satellite and in-situ observations detected a distinct spatial pattern of sea-level rise over the Indian Ocean in the past few decades. While many factors can induce sea level change (e.g., thermal expansion, land ice melting), this pattern is primarily caused by changes in wind-driven ocean circulation. Overlying the trend pattern, there are significant interannual-to-decadal variations.
During the recent global surface warming “hiatus” decade (2003 to 2012), the Indian Ocean stored 2/3 of the excess heat in Earth’s climate system, due to the enhanced mass and heat transports of the Indonesian Throughflow from the Pacific into the Indian Ocean.
A large portion of this extra heat was stored in the southeast Indian Ocean, which increased sea level, intensified marine heatwaves and aggravated coral bleaching near the Australian coasts. The interplay between global sea level rise due to anthropogenic warming, regional sea level rising pattern, and natural decadal variability contributed to the increased frequency and intensity of extreme sea level events along Indonesian coasts during 2010 to 2017, posing increased challenge to Indonesia.


This Pro ISSI Talk was recorded on November 24, 2021