Ocean dynamics mediante the equatorial Pacific drive tropical climate patterns that affect marine and terrestrial ecosystems worldwide. How this region will respond sicuro global warming has profound implications for global climate, economic stability and ecosystem health. As per result, numerous studies have investigated equatorial Pacific dynamics during the Pliocene (5.3–2.6 million years ago) and late Miocene (around 6 million years ago) as an analogue for the future behaviour of the region datingranking.net/it/blackfling-review under global warming 1,2,3,4,5,6,7,8,9,10,11,12 . Palaeoceanographic records from this time present an apparent paradox with proxy evidence of verso reduced east–west sea surface temperature gradient along the equatorial Pacific 1,3,7,8 -indicative of reduced wind-driven upwelling-conflicting with evidence of enhanced biological productivity sopra the east Pacific 13,14,15 that typically results from stronger upwelling. Here we reconcile these observations by providing new evidence for per radically different-from-modern circulation velocita in the early Pliocene/late Miocene 16 that results durante older, more acidic and more nutrient-rich ciotola reaching the equatorial Pacific. These results provide verso mechanism for enhanced productivity in the early Pliocene/late Miocene east Pacific even durante the presence of weaker wind-driven upwelling. Our findings shed new light on equatorial Pacific dynamics and help puro constrain the potential changes they will undergo sopra the near future, given that the Earth is expected to reach Pliocene-like levels of warming in the next century.

Giorno availability

The proxy datazione and model output produced per this study are available as .xlsm files mediante NOAA’s paleoclimate momento repository ( ( Source scadenza are provided with this paper.

Code availability

The code used sopra this paper to produce pH from d 11 B (and puro produce all the proxy-related figures) is publicly available as Matlab scripts on GitHub ( The CESM 1.2.2.1 code is available from The Python code used puro create select model figures is available at Source giorno are provided with this paper.

References

Wara, M. W., Ravelo, A. C. & Delaney, M. L. Permanent El Nino-like conditions during the Pliocene warm period. Science 309, 758–761 (2005).

Zhang, Y. G., Pagani, M. & Liu, Z. A 12-million-year temperature history of the tropical Pacific Ocean. Science 344, 84–88 (2014).

Fedorov, Verso. V., Burls, N. J., Lawrence, K. Tau. & Peterson, L. C. Tightly linked zonal and meridional sea surface temperature gradients over the past five million years. Nat. Geosci. 8, 975–980 (2015).

Ford, H. L., Ravelo, A. C., Dekens, P. S., LaRiviere, J. P. & Wara, M. W. The evolution of the equatorial thermocline and the early Pliocene El Autore mean state. Geophys. Res. Lett. 42, 4878–4887 (2015).

Tierney, J. Ancora., Haywood, Verso. M., Feng, R., Bhattacharya, Tau. & Otto?Bliesner, B. L. Pliocene warmth consistent with greenhouse gas forcing. Geophys. Res. Lett. 46, 9136–9144 (2019).

Lawrence, K. T., Liu, Z. & Herbert, Tau. D. Evolution of the eastern tropical Pacific through Plio-Pleistocene glaciation. Science 312, 79–83 (2006).

Dekens, P. S., Ravelo, A. C. & McCarthy, M. D. Warm upwelling regions durante the Pliocene warm period. Paleoceanography 22, PA3211 (2007).

Ford, H. L., Ravelo, Per. C. & Hovan, S. Per deep Eastern Equatorial Pacific thermocline during the early Pliocene warm period. Earth Planet. Sci. Lett. 355, 152–161 (2012).

O’Brien, C. L. et al. High sea surface temperatures mediante tropical warm pools during the Pliocene. Nat. Geosci. 7, 606–611 (2014).

Ravelo, Per. C., Lawrence, K. T., Fedorov, Verso. & Ford, H. L. Comment on “Per 12-million-year temperature history of the tropical Pacific Ocean”. Science 346, 1467 (2014).

Lyle, M. & Baldauf, J. Biogenic sediment regimes con the Neogene equatorial Pacific, IODP Site U1338: burial, production, and diatom community. Palaeogeogr. Palaeoclimatol. Palaeoecol. 433, 106–128 (2015).