Multiple Proxy Estimates of Atmospheric CO2 From an Early Paleocene Rainforest

  title={Multiple Proxy Estimates of Atmospheric CO2 From an Early Paleocene Rainforest},
  author={Jennifer B. Kowalczyk and Dana L. Royer and Ian M. Miller and Clive W. Anderson and David J. Beerling and Peter J. S. Franks and Michaela Grein and Wilfried Konrad and Anita Roth-Nebelsick and Samuel A. Bowring and Kirk R. Johnson and Jahandar Ramezani},
  journal={Paleoceanography and Paleoclimatology},
  pages={1427 - 1438}
Proxy estimates of atmospheric CO2 are necessary to reconstruct Earth's climate history. Confidence in paleo‐CO2 estimates can be increased by comparing results from multiple proxies at a single site, but so far this strategy has been implemented only for marine‐based techniques. Here we present CO2 estimates for the well‐studied early Paleocene Castle Rock site in Colorado using four paleobotanical proxies. Median estimates range from 470 to 813 ppm, demonstrating fair correspondence. The… 

Moderate to Elevated Atmospheric CO2 During the Early Paleocene Recorded by Platanites Leaves of the San Juan Basin, New Mexico

Throughout the Phanerozoic, estimated CO2 levels from CO2 proxies generally correlate well with independent estimates of temperature. However, some proxy estimates of atmospheric CO2 during the Late

No Evidence for a Large Atmospheric CO2 Spike Across the Cretaceous‐Paleogene Boundary

Currently, there is only one paleo‐CO2 record from plant macrofossils that has sufficient stratigraphic resolution to potentially capture a transient spike related to rapid carbon release at the

The seawater carbon inventory at the Paleocene–Eocene Thermal Maximum

  • L. HaynesB. Hönisch
  • Environmental Science, Geography
    Proceedings of the National Academy of Sciences
  • 2020
The reconstruction invokes volcanic emissions as a driver of PETM warming and suggests that the buffering capacity of the ocean increased, which helped to remove carbon dioxide from the atmosphere, but estimates confirm that modern CO2 release is occurring much faster than PETM carbon release.

Climate and ecology in the Rocky Mountain interior after the early Eocene Climatic Optimum

Abstract. As atmospheric carbon dioxide (CO2) and temperatures increase with modern climate change, ancient hothouse periods become a focal point for understanding ecosystem function under similar

The DeepMIP contribution to PMIP4: methodologies for selection, compilation and analysis of latest Paleocene and early Eocene climate proxy data, incorporating version 0.1 of the DeepMIP database

Abstract. The early Eocene (56 to 48 million years ago) is inferred to have been the most recent time that Earth's atmospheric CO2 concentrations exceeded 1000 ppm. Global mean temperatures were also

Quantitative critique of leaf‐based paleo‐CO2 proxies: Consequences for their reliability and applicability

A variety of proxies have been developed to reconstruct paleo‐CO2 from fossil leaves. These proxies rely on some combination of stomatal morphology, leaf δ13C, and leaf gas exchange. A common

Sensitivity of a leaf gas-exchange model for estimating paleoatmospheric CO2 concentration

Abstract. Leaf gas-exchange models show considerable promise as paleo-CO2 proxies. They are largely mechanistic in nature, provide well-constrained estimates even when CO2 is high, and can be applied

No Consistent Shift in Leaf Dry Mass per Area Across the Cretaceous—Paleogene Boundary

The Chicxulub bolide impact has been linked to a mass extinction of plants at the Cretaceous—Paleogene boundary (KPB; ∼66 Ma), but how this extinction affected plant ecological strategies remains

Plant carbon assimilation rates in atmospheric CO2 reconstructions.

CO2 reconstructions that apply C assimilation rates from modern species based solely on phylogenetic relatedness to fossil species can result in CO2 estimates that are systematically biased by a factor of > 2.



High Arctic forests during the middle Eocene supported by moderate levels of atmospheric CO2

Fossils from Paleogene High Arctic deposits provide some of the clearest evidence for greenhouse climates in the past and offer the potential to improve our understanding of Earth system dynamics in

Geobiological constraints on Earth system sensitivity to CO2 during the Cretaceous and Cenozoic

Earth system climate sensitivity (ESS) is the long‐term (>103 year) response of global surface temperature to doubled CO2 that integrates fast and slow climate feedbacks. ESS has energy policy

Quantitative uncertainty analyses of ancient atmospheric CO2 estimates from fossil leaves

The relationship between atmospheric CO2 and ancient climate is of fundamental importance for gauging the climate sensitivity of the Earth system to a changing CO2 regime. One of the most widely

Fossil bryophytes as recorders of ancient CO2 levels: Experimental evidence and a Cretaceous case study

Biological and geochemical CO2 proxies provide critical constraints on understanding the role of atmospheric CO2 in driving climate change during Earth history. As no single existing CO2 proxy is

Middle Miocene climate instability associated with high‐amplitude CO2 variability

The amplitude of climatic change, as recorded in the benthic oxygen isotope record, has varied throughout geological time. During the late Pleistocene, changes in the atmospheric concentration of

Declining atmospheric CO2 during the late Middle Eocene climate transition

The transition from the extreme greenhouse of the early Paleogene (∼52 Ma) to the present-day icehouse is the most prominent change in Earth’s Cenozoic climate history. During the late Middle Eocene

New constraints on atmospheric CO2 concentration for the Phanerozoic

Earth's atmospheric CO2 concentration (ca) for the Phanerozoic Eon is estimated from proxies and geochemical carbon cycle models. Most estimates come with large, sometimes unbounded uncertainty.

Carbon isotope ratio of Cenozoic CO2: A comparative evaluation of available geochemical proxies

[1] The carbon isotope ratio (δ13C) of plant material is commonly used to reconstruct the relative distribution of C3 and C4 plants in ancient ecosystems. However, such estimates depend on the δ13C