“…Records of EEP SST can be divided at the mid‐Pleistocene transition (MPT, ~1.0–0.8 Ma), a period when Pleistocene marine δ 18 O records progressively shifted from being dominated by oscillations at the 41 kyr periodicity to a more asymmetric longer‐term rhythm with colder glacials; this climate shift is likely not the result of a regime change in orbital insolation forcing but rather either the gradual movement over a threshold that changed internal Earth system feedbacks or a more abrupt climate event [e.g., Pisias and Moore , ; Elkibbi and Rial , ; Clark et al ., ; Kitamura , ]. In light of the lack of an obvious insolation‐related mechanism for this MPT shift, possible Earth system explanations include changes in the behavior of ice sheets [ Imbrie et al ., ; Clark and Pollard , ; Gildor and Tziperman , , ; Clark et al ., ; McClymont et al ., ] and/or periodic oceanic carbon sequestration and release [e.g., Schmieder et al ., ; Toggweiler et al ., ; Watson and Naveira Garabato , ; Kemp et al ., ; Sigman et al ., ; Pena and Goldstein , ; Maslin and Brierley , ]. Tropical ocean dynamics could play a role in either of these factors; for instance, cooling tropical Pacific SST prior to 0.9 Ma could be linked to a glacial p CO 2 decline or could have been a precondition for the expansion of ice sheets [ McClymont et al ., ].…”