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Global warming has altered a key weather system and that may be whetting cyclones in the Bay of Bengal, decreasing winter rain in north India and altering global rainfall patterns, a study by a team of Indian and U.S. researchers has found. The Madden–Julian Oscillation (MJO), as it’s called, is a moving band of rain clouds that travels around the globe spanning 12,000–20,000 km across the tropical oceans. In its journey, it interacts with surface waters of the Indo-Pacific ocean, the largest pool of warm water in the globe, and due to this the authors say the lifecycle of the MJO gets affected. The MJO clouds on average are spending only 15 days, instead of 19, over the Indian Ocean. Over the west Pacific, it increased by five days (from an average 16 days to 23 days). “It is this change in the residence time of MJO clouds that has altered the weather patterns across the globe,” according to the research paper that appears in the latest edition of the journal Nature.