Sediment % coarse fraction (>63 microns), and abundance of fish teeth in coarse fraction. 2016 has been a record breaking year in terms of global temperatures. The high temperatures have resulted from a combination of elevated atmospheric pCO2 coupled with the global impacts of a strong El Nino event. There are many important components of the climate system, and the El Nino phenomenon demonstrates the importance of the low latitude Pacific Ocean. The warm pool of water in the western Pacific Ocean has not always had the same characteristics as it has today, and it has been proposed that its evolution over the past 15 million years has had a major impact on global climate. In order to understand how the warm pool might respond to future climate change, it is important to understand the drivers behind its past evolution. Did it respond simply to the changing shape of ocean basins through time? Or did it respond to other components of the climate system, such as sea level or latitudinal temperature gradients? The changes in warm pool structure may also have impacted the biological ecosystems, and hence the cycling of carbon in this region. The carbon cycle is another key component of the Earth's climate system. Understanding the causes and consequences of these long-term changes in the Pacific warm pool requires a two-pronged approach, using modelling in conjunction with proxy records for different parts of the climate system. This proposal aims to generate some key records of past high latitude temperature and ice volume that can be directly compared with changes in the warm pool through time. These records will be derived from geochemical analyses of microscopic marine fossils collected by the International Ocean Discovery Program (IODP).