Marked Decline in Atmospheric Carbon Dioxide Concentrations During the Paleogene

  title={Marked Decline in Atmospheric Carbon Dioxide Concentrations During the Paleogene},
  author={Mark Pagani and James C. Zachos and Katherine H. Freeman and Brett James Tipple and Steven M. Bohaty},
  pages={600 - 603}
The relation between the partial pressure of atmospheric carbon dioxide (pCO2) and Paleogene climate is poorly resolved. We used stable carbon isotopic values of di-unsaturated alkenones extracted from deep sea cores to reconstruct pCO2 fromthe middle Eocene to the late Oligocene (∼45 to 25 million years ago). Our results demonstrate that pCO2 ranged between 1000 to 1500 parts per million by volume in the middle to late Eocene, then decreased in several steps during the Oligocene, and reached… 
CO2-Forced Climate and Vegetation Instability During Late Paleozoic Deglaciation
Major restructuring of paleotropical flora in western Euramerica occurred in step with climate and pCO2 shifts, illustrating the biotic impact associated with past CO2-forced turnover to a permanent ice-free world.
New Caledonian carbon sinks at the onset of Antarctic glaciation
  • D. Reusch
  • Environmental Science, Geography
  • 2011
During the latest Eocene, as Earth9s climate transitioned from a greenhouse to an icehouse state, likely forced by declining atmospheric carbon dioxide pressure ( p CO 2 ), a large tract of basic and
The impact of Miocene atmospheric carbon dioxide fluctuations on climate and the evolution of terrestrial ecosystems
The authors' data point to a long-term coupling between atmospheric CO2 and climate, which can be linked to major changes in Miocene terrestrial ecosystems, such as the expansion of grasslands and radiations among terrestrial herbivores such as horses.
CO2 drawdown following the middle Miocene expansion of the Antarctic Ice Sheet
The development of a permanent, stable ice sheet in East Antarctica happened during the middle Miocene, about 14 Myr (million years) ago. The middle Miocene therefore represents one of the distinct
Missing organic carbon in Eocene marine sediments: Is metabolism the biological feedback that maintains end-member climates?
[1] Ocean chemistry is affected by pCO2 in the atmosphere by increasing the dissolution of solid calcium carbonate and elevating the dissolved inorganic carbon concentrations in seawater. Positive
Atmospheric carbon dioxide through the Eocene–Oligocene climate transition
The results confirm the central role of declining in the development of the Antarctic ice sheet (in broad agreement with carbon cycle modelling) and help to constrain mechanisms and feedbacks associated with the Earth’s biggest climate switch of the past 65 Myr.


Atmospheric carbon dioxide concentrations over the past 60 million years
The boron-isotope ratios of ancient planktonic foraminifer shells are used to estimate the pH of surface-layer sea water throughout the past 60 million years, which can be used to reconstruct atmospheric CO2 concentrations.
Miocene evolution of atmospheric carbon dioxide
Changes in pCO2 or ocean circulation are generally invoked to explain warm early Miocene climates and a rapid East Antarctic ice sheet (EAIS) expansion in the middle Miocene. This study reconstructs
Global vegetation change through the Miocene/Pliocene boundary
Between 8 and 6 million years ago, there was a global increase in the biomass of plants using C4 photosynthesis as indicated by changes in the carbon isotope ratios of fossil tooth enamel in Asia,
Tertiary history of C4 biomass in the Great Plains, USA
We use the carbon isotope composition of paleosols to reconstruct the history of C4 biomass on the Great Plains from ca. 23 to 1 Ma. The proportion of C4 biomass was uniform and moderate (12%‐34%)
Rapid stepwise onset of Antarctic glaciation and deeper calcite compensation in the Pacific Ocean
The changes in oxygen-isotope composition across the Eocene/Oligocene boundary are too large to be explained by Antarctic ice-sheet growth alone and must therefore also indicate contemporaneous global cooling and/or Northern Hemisphere glaciation.
Late miocene atmospheric CO(2) concentrations and the expansion of C(4) grasses
The estimates presented here provide no evidence for major changes in pCO(2) during the late Miocene, and C(4) plant expansion was likely driven by additional factors, possibly a tectonically related episode of enhanced low-latitude aridity or changes in seasonal precipitation patterns on a global scale.
Evolution of Early Cenozoic marine temperatures
The equator to high southern latitude sea surface and vertical temperature gradients are reconstructed from oxygen isotope values of planktonic and benthic foraminifers for the following five time
Warm tropical sea surface temperatures in the Late Cretaceous and Eocene epochs
New data from exceptionally well preserved foraminifer shells extracted from impermeable clay-rich sediments indicate that for the intervals studied, tropical sea surface temperatures were at least 28–32 °C, more in line with the understanding of the geographical distributions of temperature-sensitive fossil organisms and the results of climate models with increased CO2 levels.