PANJIM: Monsoons in the country may be in for bad news as scientists predict a significant decreasing trend in the monsoon rainfall over central India. Dr Roxy Mathew Koll, scientist at the Indian Institute of Tropical Meteorology in a recent paper published in the Nature Communications journal said that rapid warming in the Indian Ocean played an important role in weakening the monsoon circulation and rainfall. In Goa too, the weakening monsoon has made its presence felt with the rainfall deficit till Thursday at 21 percent. Since June this year, the State has received 2295.9 mm of rain. In his report, Dr Koll said that one of the major monsoon drivers is the difference in the land-sea temperature. “Previous studies suggested that the land in the northern hemisphere is warming faster than the oceans, which implies that the monsoon drivers (land-sea temperature) should be getting stronger. Increased land-sea temperature contrast and moisture availability should ideally increase the monsoon rainfall. However, that is not the case for the Indian monsoon,” he said. The warming Indian Ocean plays a significant role in the weakening of the monsoon circulation. Increased warming in the ocean enhances the upward motion of warm moist air over the ocean. This upward motion is compensated by subsidence of dry air over the country, inhibiting rainfall over the landmass. This explains the reason there has been surplus rain over the ocean than over land, therefore drying the land. Based on a climate model the scientist and his team worked on, the Indian Ocean will continue to warm under increasing greenhouse gases but the question still remained as to whether it will continue to decrease. “The critical role of the warm Indian Ocean deserves special attention for its decisive effect on the food security of a large fraction of the world’s population, and its role in inducing a drought over the Indian subcontinent,” he said.