Rising levels in parts of the Indian Ocean may worsen monsoon flooding in India and Bangladesh.

According to a study led by Weiqing Han, the associate professor in atmospheric and oceanic sciences at the University of Colorado, Boulder, US, this is attributed to warming caused by man-made increase of greenhouse gases.

The parts affected by the rising sea levels are the Bay of Bengal, the Arabian Sea, Sri Lanka, reports Nature Geoscience.

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 manmade increases of greenhouse gases, said Han, according to a Colorado University statement.

Along the coasts of the northern Indian Ocean, seas have risen by an average of about 0.5 inches, or 13 mm, per decade, the study said.

The Indian Ocean is the world’s third largest ocean and makes up about 20 per cent of the water on earth’s surface.