The Tropical Warm Pool (TWP) or Indo-Pacific Warm Pool is a mass of ocean water located in the western Pacific Ocean and eastern Indian Ocean which consistently exhibits the highest water temperatures over the largest expanse of the Earth's surface. This is due to seasonal changes in precipitation along the path of the Great Ocean Conveyor Belt, from the western Pacific Ocean across the Indonesian Archipelago into the eastern Indian Ocean. Its intensity and extent appear to oscillate over a time period measured in decades.
The Indo-Pacific warm pool has been warming rapidly and expanding during the recent decades, largely from climate change in response to increased carbon emissions from fossil fuel burning. The warm pool nearly doubled in size, from an area of 22 million km<sup>2</sup> during 1900âÂÂ1980, to an area of 40 million km<sup>2</sup> during 1981âÂÂ2018; however, latest research suggests that this expansion rate may be overestimated. This expansion of the warm pool has allowed more cyclones as well as altered global rainfall patterns and variations by changing the life cycle of the Madden Julian Oscillation (MJO), which is the most dominant mode of weather fluctuation originating in the tropics. This oscillation is showcased by eastward movement of suppressed tropical rainfall, specifically over the Pacific and Indian Oceans.