Paleoceanographic Dynamics of Cenozoic Climate Systems

The Cenozoic era witnessed a profound transformation of Earth’s climate from a greenhouse world to the present icehouse state. Throughout this interval, evolving plate tectonics, seaway reorganisations and mountain uplift reconfigured ocean circulation, driving shifts in heat transport, carbon storage and biogeochemical feedbacks. Deep-sea proxies such as benthic foraminiferal δ18O and carbonate sedimentation records chronicle a long-term cooling trend punctuated by transient thermal maxima and abrupt glaciations. Milankovitch-scale orbital forcing imposed rhythmic variability on ice volume, monsoon dynamics and carbonate compensation depth, while episodes of ocean acidification and carbonate burial influenced atmospheric CO2 on million-year timescales. Key events include the middle Miocene climatic optimum, the middle to late Miocene carbonate crash and the Pliocene onset of Northern Hemisphere glaciation. Underlying these large-scale transitions, interactions among thermohaline circulation, marine biota and rock weathering drove climate–carbon cycle feedbacks that determined the system’s sensitivity to external and internal forcings. Modern observational and modelling studies of Cenozoic archives offer critical analogues for understanding the state dependence of extreme events under anthropogenic warming, illuminating the potential for renewed thermal extremes and altered biogenic calcification around the globe.

Research from Nature Portfolio

Recent studies have quantified the nature and distribution of thermal extremes throughout the Cenozoic, demonstrating that warmer background climates foster more frequent and intense heat anomalies in the ocean system. Analyses of global foraminiferal δ18O compilations reveal that extreme temperature fluctuations follow a generalised extreme value distribution whose shape parameter varies with baseline climate state, suggesting a heightened risk of large‐scale thermal anomalies under sustained warming. Complementary work has integrated deep‐ocean δ13C and δ18O megasplices to assess the phasing of carbon cycle and temperature on eccentricity timescales. This approach has uncovered a switch in phase relationship around 6 Ma, attributed to Arctic biome reorganisation, indicating that system-level feedbacks between rock weathering, high-latitude carbon reservoirs and ice dynamics fundamentally alter climate–carbon interactions through time.

Paleoceanographic Dynamics of Cenozoic Climate Systems publication trend

The graph below shows the total number of articles in paleoceanographic dynamics of cenozoic climate systems across all publications each year (not limited to Nature Index journals).

Technical terms

Cenozoic: The geologic era from 66 Ma to present, encompassing major climate evolution from greenhouse to icehouse.

δ18O: The ratio of heavy to light oxygen isotopes in foraminifera, used as a proxy for past temperature and ice volume.

Carbonate compensation depth (CCD): The ocean depth below which carbonate dissolves faster than it accumulates, indicative of acidification and dissolution.

Thermohaline circulation: Global ocean circulation driven by density differences from temperature and salinity variations, crucial for heat distribution.

Biogenic calcification: Production of calcium carbonate by marine organisms, a key process for carbon export and sediment formation.

Milankovitch cycles: Variations in Earth’s orbital parameters (eccentricity, obliquity, precession) that drive periodic climate changes.

References

1. State-dependence of Cenozoic thermal extremes. Communications Earth & Environment (2023).
2. Increased Biogenic Calcification and Burial Under Elevated pCO2 During the Miocene: A Model‐Data Comparison. Global Biogeochemical Cycles (2023).
3. Seismically-derived porosity of deep-sea sediments over the last 74 Ma in the equatorial Atlantic Ocean: Implications for paleo-climate. Earth and Planetary Science Letters (2023).
4. Nature and origin of variations in pelagic carbonate production in the tropical ocean since the mid-Miocene (ODP Site 927). Biogeosciences (2023).
5. High-latitude biomes and rock weathering mediate climate–carbon cycle feedbacks on eccentricity timescales. Nature Communications (2020).