Among the tropical oceans, the western Indian Ocean hosts one of the largest concentrations of marine phytoplankton blooms in summer. Interestingly, this is also the region with the largest warming trend in sea surface temperatures in the tropics during the past century—although the contribution of such a large warming to productivity changes has remained ambiguous. Earlier studies had described the western Indian Ocean as a region with the largest increase in phytoplankton during the recent decades.

Figures index : From the study "Drying of Indian subcontinent by rapid Indian Ocean warming and a weakening land-sea thermal gradient".

Original Source

This new study led by an Indian scientist Dr Roxy Mathew Koll, from the Indian Institute of Tropical Meteorology (IITM) Pune, points out a significant decreasing trend in the summer monsoon rainfall over the central Indian subcontinent during the past century. It suggests an important role of the rapid warming in the Indian Ocean in weakening of monsoon circulation and rainfall.

Recent studies have pointed out an increased warming over the Indian Ocean warm pool (the central-eastern Indian Ocean characterized by sea surface temperatures greater than 28.08C) during the past half-century, although the reasons behind this monotonous warming are still debated. The results here reveal a larger picture—namely, that the western tropical Indian Ocean has been warming for more than a century, at a rate faster than any other region of the tropical oceans, and turns out to be the largest contributor to the overall trend in the global mean sea surface temperature (SST).