Surface and subsurface single foraminifera analyses from the Western Pacific Warm Pool over the Plio-Pleistocene

Because the tropics are not sensitive to ice‐albedo feedbacks, the WEP's response to radiative forcing can be used to constrain a minimum estimate of Earth system sensitivity. Climate modeling of pCO2‐radiative warming projections shows little change in WEP variability; here we use temperature distributions of individual surface and subsurface dwelling fossil foraminifera to evaluate past variability and possible radiative and dynamic climate forcing over the Plio‐Pleistocene.

We investigate WEP warm pool variability within paired glacial‐interglacial (G‐IG) intervals for four times: the Holocene‐Last Glacial Maximum, ~2 Ma, ~3 Ma, and ~ 4 Ma. Our results show that these surface and subsurface temperature distributions are similar for all G‐IG pairs, indicating no change in variability, even as pCO2‐radiative forcing and other boundary conditions changed on G‐IG timescales. Plio‐Pleistocene SST distributions are similar to those from the Holocene, indicating WEP SSTs respond to pCO2‐radiative forcing and associated feedbacks.