Per the linked reference, the Indo-Pacific warm pool is growing (32% in the past 60-years) and warming due to anthropogenic causes:
Evan Weller, Seung-Ki Min, Wenju Cai, Francis W. Zwiers, Yeon-Hee Kim and Donghyun Lee (01 Jul 2016), "Human-caused Indo-Pacific warm pool expansion", Science Advances, Vol. 2, no. 7, e1501719, DOI: 10.1126/sciadv.1501719
http://advances.sciencemag.org/content/2/7/e1501719Abstract: "The Indo-Pacific warm pool (IPWP) has warmed and grown substantially during the past century. The IPWP is Earth’s largest region of warm sea surface temperatures (SSTs), has the highest rainfall, and is fundamental to global atmospheric circulation and hydrological cycle. The region has also experienced the world’s highest rates of sea-level rise in recent decades, indicating large increases in ocean heat content and leading to substantial impacts on small island states in the region. Previous studies have considered mechanisms for the basin-scale ocean warming, but not the causes of the observed IPWP expansion, where expansion in the Indian Ocean has far exceeded that in the Pacific Ocean. We identify human and natural contributions to the observed IPWP changes since the 1950s by comparing observations with climate model simulations using an optimal fingerprinting technique. Greenhouse gas forcing is found to be the dominant cause of the observed increases in IPWP intensity and size, whereas natural fluctuations associated with the Pacific Decadal Oscillation have played a smaller yet significant role. Further, we show that the shape and impact of human-induced IPWP growth could be asymmetric between the Indian and Pacific basins, the causes of which remain uncertain. Human-induced changes in the IPWP have important implications for understanding and projecting related changes in monsoonal rainfall, and frequency or intensity of tropical storms, which have profound socioeconomic consequences."
See also:
https://www.washingtonpost.com/news/energy-environment/wp/2016/07/01/the-biggest-body-of-warm-water-on-earth-is-getting-even-bigger/Extract: "And the warm pool is growing.
“It is about four or five times larger than Australia,” said Seung-Ki Min, a researcher at Pohang University of Science and Technology in South Korea and an author of a new study in Science Advances on the warm pool’s expansion. “It has been increasing about 32 percent over the last 60 years in size.”"
