On the effect of orbital forcing on mid-Pliocene climate, vegetation and ice sheets

Abstract. We present results from modelling of the mid-Pliocene warm period (3.3–3 million years ago) using the Earth system model of intermediate complexity CLIMBER-2 analysing the effect of changes in boundary conditions as well as of orbital forcing on climate. First we performed equilibrium experiments following the PlioMIP (Pliocene Model Intercomparison Project) protocol with a CO2 concentration of 405 ppm, reconstructed mid-Pliocene orography and vegetation and a present-day orbital configuration. Simulated global Pliocene warming is about 2.5 °C, fully consistent with results of atmosphere–ocean general circulation model simulations performed for the same modelling setup. A factor separation analysis attributes 1.5 °C warming to CO2, 0.3 °C to orography, 0.2 °C to ice sheets and 0.4 °C to vegetation. Transient simulations for the entire mid-Pliocene warm period with time-dependent orbital forcing as well as interactive ice sheets and vegetation give a global warming varying within the range 1.9–2.8 °C. Ice sheet and vegetation feedbacks in synergy act as amplifiers of the orbital forcing, transforming seasonal insolation variations into an annual mean temperature signal. The effect of orbital forcing is more significant at high latitudes, especially during boreal summer, when the warming over land varies in the wide range from 0 to 10 °C. The modelled ice-sheet extent and vegetation distribution also show significant temporal variations. Modelled and reconstructed data for Northern Hemisphere sea-surface temperatures and vegetation distribution show the best agreement if the reconstructions are assumed to be representative for the warmest periods during the orbital cycles. This suggests that low-resolution Pliocene palaeoclimate reconstructions can reflect not only the impact of increased CO2 concentrations and topography changes but also the effect of orbital forcing. Therefore, the climate (Earth system) sensitivity estimates from Pliocene reconstructions which do not account for the effect of orbital forcing can be biased toward high values.

• Publication year

  2013

• Venue

  Climate of The Past

• Publication date

  2013-08-01

• Fields of study

  Geology, Environmental Science

• Identifiers
  DOI 10.5194/CP-9-1749-2013
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar

• Ignoring orbital forcing in Pliocene-based climate-sensitivity estimates can bias those estimates toward high values.

  Confidence 0.90

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review
• Ice-sheet and vegetation feedbacks amplify orbital forcing, and the best match to Northern Hemisphere sea-surface temperature and vegetation reconstructions occurs when those reconstructions are treated as representing the warmest parts of the orbital cycles.

  Confidence 0.94

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review
• Transient simulations with time-dependent orbital forcing plus interactive ice sheets and vegetation produce global warming that varies between 1.9 °C and 2.8 °C.

  Confidence 0.96

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review
• Factor separation assigns most of the simulated warming to CO2, with smaller contributions from orography, ice sheets, and vegetation.

  Confidence 0.96

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review
• Equilibrium CLIMBER-2 experiments set up with the PlioMIP boundary conditions simulate about 2.5 °C of global mid-Pliocene warming, in line with atmosphere-ocean general circulation model results for the same setup.

  Confidence 0.97

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review

• climate sensitivity estimates

  estimate, metric

  Estimates of how strongly climate responds to forcing, discussed here in the context of Pliocene reconstructions.

  Aliases: Earth system sensitivity estimates

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review
• climber-2

  model

  An Earth system model of intermediate complexity used for the Pliocene climate simulations.

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review
• co2 concentration

  forcing, boundary condition

  The atmospheric carbon dioxide level prescribed in the experiments, set to 405 ppm in the equilibrium setup.

  Aliases: CO2, carbon dioxide concentration

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review
• factor separation analysis

  method

  A decomposition method used to partition simulated warming among different boundary-condition changes.

  Aliases: factor separation

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review
• ice sheets

  cryosphere component, boundary condition

  Large continental ice masses whose extent is allowed to vary interactively in the simulations.

  Aliases: ice-sheet extent

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review
• mid-pliocene warm period

  geologic period

  The warm climate interval about 3.3 to 3 million years ago analyzed in the simulations.

  Aliases: mid-Pliocene, Pliocene warm period

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review
• northern hemisphere sea-surface temperatures

  proxy reconstruction, observation

  Reconstructed ocean-surface temperature evidence from the Northern Hemisphere used for comparison with model output.

  Aliases: NH sea-surface temperatures, Northern Hemisphere SSTs

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review
• orbital forcing

  forcing, boundary condition

  Time-dependent changes in Earth's orbital configuration that alter incoming solar radiation.

  Aliases: orbital configuration, insolation forcing

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review
• pliomip

  protocol, project

  The Pliocene Model Intercomparison Project protocol that specifies the boundary conditions used in the equilibrium experiments.

  Aliases: Pliocene Model Intercomparison Project

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review
• vegetation

  biosphere, boundary condition

  The spatial distribution of plant cover used as a boundary condition and interactive feedback in the model.

  Aliases: vegetation distribution

  박진우 (dztg5apj7m) extraction뀨 (7c402c1b98) reviewq (76h6bfydm6) reviewJake Seo (Twitter) (bmuzj8twwb) review

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  2013influential reference
• Relationship between sea level and climate forcing by CO2 on geological timescales

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• Historical and idealized climate model experiments: an intercomparison of Earth system models of intermediate complexity

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• Sensitivity of Pliocene Ice Sheets to Orbital Forcing

  2011influential reference
• Glacial CO2 cycle as a succession of key physical and biogeochemical processes

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  2004influential reference
• Modelling Pliocene Warmth: Contribution of Atmosphere, Oceans and Cryosphere Revisited

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• CLIMBER-2: a climate system model of intermediate complexity. Part II: model sensitivity

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• Glacial cycles: Toward a new paradigm

  2001influential reference
• Global scale palaeoclimate reconstruction of the middle Pliocene climate using the UKMO GCM: initial results

  2000influential reference
• CLIMBER-2: a climate system model of intermediate complexity. Part I: model description and performance for present climate

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• The influence of vegetation-atmosphere-ocean interaction on climate during the mid-holocene

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• Application of a polythermal three-dimensional ice sheet model to the Greenland Ice Sheet : Response to steady-state and transient climate scenarios

  1997cited by this paper
• A continuous climate-vegetation classification for use in climate-biosphere studies

  1997cited by this paper
• Mid-Pliocene warmth: stronger greenhouse and stronger conveyor

  1996cited by this paper
• Modeling of middle Pliocene climate with the NCAR GENESIS general circulation model

  1996influential reference
• Middle Pliocene vegetation: reconstructions, paleoclimatic inferences, and boundary conditions for climate modeling

  1996cited by this paper
• Joint investigations of the middle Pliocene climate II: GISS GCM Northern Hemisphere results

  1994cited by this paper
• Astronomical Solutions for Paleoclimate Studies Over the Last 3 Million Years

  1992cited by this paper

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  2020cites this paper
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  2018cites this paper
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  2016cites this paper
• Stratigraphic and paleogeographic significance of lacustrine mollusks from the Pliocene Viviparus beds in central Croatia

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