The Effect of Obliquity-Driven Changes on Paleoclimate Sensitivity During the Late Pleistocene
We reanalyze existing paleodata of global mean surface temperature ΔT g and radiative forcing ΔR of CO 2 and land ice albedo for the last 800,000 years to show that a state-dependency in paleoclimate sensitivity S, as previously suggested, is only found if ΔT g is based on reconstructions, and not w...
Published in: | Geophysical Research Letters |
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Main Authors: | , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2018
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Subjects: | |
Online Access: | https://research.vu.nl/en/publications/c447ee5e-2d15-4e4f-9cbd-d6f5e376c185 https://doi.org/10.1029/2018GL077717 https://hdl.handle.net/1871.1/c447ee5e-2d15-4e4f-9cbd-d6f5e376c185 http://www.scopus.com/inward/record.url?scp=85050552064&partnerID=8YFLogxK http://www.scopus.com/inward/citedby.url?scp=85050552064&partnerID=8YFLogxK |
Summary: | We reanalyze existing paleodata of global mean surface temperature ΔT g and radiative forcing ΔR of CO 2 and land ice albedo for the last 800,000 years to show that a state-dependency in paleoclimate sensitivity S, as previously suggested, is only found if ΔT g is based on reconstructions, and not when ΔT g is based on model simulations. Furthermore, during times of decreasing obliquity (periods of land ice sheet growth and sea level fall) the multimillennial component of reconstructed ΔT g diverges from CO 2 , while in simulations both variables vary more synchronously, suggesting that the differences during these times are due to relatively low rates of simulated land ice growth and associated cooling. To produce a reconstruction-based extrapolation of S for the future, we exclude intervals with strong ΔT g -CO 2 divergence and find that S is less state-dependent, or even constant state-independent), yielding a mean equilibrium warming of 2–4 K for a doubling of CO 2 . |
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