The Indian monsoon has well-known features, such as the onset, the withdrawal, the active and break periods, and low-pressure systems (or monsoon depressions). Every aspect of the monsoon has been affected by global warming. The monsoon onset has been delayed of late as well as being affected by cyclones. Its withdrawal has been affected by Arctic warming.
The total seasonal rainfall has also trended downwards for more than seven decades, due to the differential heating of the land versus the ocean due to global warming. However, this trend has been distributed unevenly through the monsoon season – as manifest in the longer duration but lower intensity of dry spells and the greater intensity of wet spells.
Some researchers have argued that the intense wet spells have become larger in scale, over Central India in particular. The influence of the Arabian Sea and the Bay of Bengal combine to produce dynamic conditions for generating large-scale extreme rainfall events.
