The climate change is amplifying regional sea rise changes in Bay of Bengal, the Arabian Sea, Sri Lanka, Sumatra and Java.

The rise could threaten lives in Bangladesh and India, causing massive floods in monsoons.

An enormous area of the tropical oceans stretching from the east coast of Africa west to the International Date Line in the Pacific has heated by about 1 degree Fahrenheit, or 0.5 degrees Celsius, in the past 50 years, said CU-Boulder Associate Professor Weiqing Han, lead study author.

The study also indicates that the Seychelles Islands and Zanzibar off Tanzania's coastline show the largest sea level drop.

"Our new results show that human-caused changes of atmospheric and oceanic circulation over the Indian Ocean region are the major cause for the regional variability of sea level change," wrote the authors.

The eastern tropical regions of the Indian Ocean might witness an increase in rainfall while the western equatorial Indian Ocean region, an increase in drought.

"It is important for us to understand the regional changes of the sea level, which will have effects on coastal and island regions," said Hu.

The find is published in Nature Geoscience.