The West Pacific Warm Pool (WPWP) exerts a dominant role in global climate by releasing huge amounts of water vapor and latent heat to the atmosphere and modulating upper ocean heat content. However, how WPWP changed before the instrumental period (~1850 AD) remain poorly understood. Considering the sea surface temperature is often used to infer the area and intensity of WPWP, here, we present coral-based monthly sea surface temperature reconstructions in the WPWP regions since 1840. The WPWP has been expanding and strengthening on average by 4.30 × 10¹⁰ m² per year and 5.38 ℃ per year during 1840-1997 and at an accelerated average rate of 2.01 × 10¹¹ m² per year and 24.76 ℃ per year during 1960-1997, which was dominated by greenhouse gas forcing. Tropical Pacific decadal variability plays a fundamental role in modulating the decadal changes of the WPWP. Our results imply that the WPWP could be further expanded and intensified under future global warming.
 

coral, δ18O, SST, the West Pacific Warm Pool