Journal ArticleDOI
The impact of atmospheric and oceanic heat transports on the sea-ice-albedo instability during the Neoproterozoic
TLDR
In this article, a series of simulations with a coupled ocean-atmosphere model of intermediate complexity, CLIMBER-2, using a reduced solar constant of 6% and varied CO2 concentrations was conducted to simulate the climatic conditions of the Neoproterozoic.Abstract:
In order to simulate the climatic conditions of the Neoproterozoic, we have conducted a series of simulations with a coupled ocean–atmosphere model of intermediate complexity, CLIMBER-2, using a reduced solar constant of 6% and varied CO2 concentrations. We have also tested the impact of the breakup of the supercontinent Rodinia that has been hypothesized to play an important role in the initiation of an ice-covered Earth. Our results show that for the critical values of 89 and 149 ppm of atmospheric CO2, a snowball Earth occurs in the supercontinent case and in the dislocated configuration, respectively. The study of the sensitivity of the meridional oceanic energy transport to reductions in CO2 concentration and to the dislocation of the supercontinent demonstrates that dynamics ocean processes can modulate the CO2 threshold value, below which a snowball solution is found, but cannot prevent it. The collapse of the overturning cells and of the oceanic heat transport is mainly due to the reduced zonal temperature gradient once the sea-ice line reaches the 30° latitudinal band but also to the freshening of the tropical ocean by sea-ice melt. In term of feedbacks, the meridional atmospheric heat transport via the Hadley circulation plays the major role, all along the CO2 decrease, by increasing the energy brought in the front of the sea-ice margin but does not appear enough efficient to prevent the onset of the sea-ice-albedo instability in the case of the continental configurations tested in this contribution.read more
Citations
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Journal ArticleDOI
Snowball Earth climate dynamics and Cryogenian geology-geobiology
Paul Hoffman,Paul Hoffman,Dorian S. Abbot,Yosef Ashkenazy,Douglas I. Benn,Jochen J. Brocks,Phoebe Cohen,Grant M. Cox,Grant M. Cox,Jessica R. Creveling,Yannick Donnadieu,Yannick Donnadieu,Douglas H. Erwin,Douglas H. Erwin,Ian J. Fairchild,David Ferreira,Jason C. Goodman,Galen P. Halverson,Malte F. Jansen,Guillaume Le Hir,Gordon D. Love,Francis A. Macdonald,Adam C. Maloof,Camille A. Partin,Gilles Ramstein,Brian E. J. Rose,Catherine V. Rose,Peter M. Sadler,Eli Tziperman,Aiko Voigt,Aiko Voigt,Stephen G. Warren +31 more
TL;DR: Modeling shows that the small thermal inertia of a globally frozen surface reverses the annual mean tropical atmospheric circulation, producing an equatorial desert and net snow and frost accumulation elsewhere, and that the evolutionary legacy of Snowball Earth is perceptible in fossils and living organisms.
Journal ArticleDOI
Climate of the Neoproterozoic
TL;DR: In this paper, a suite of general circulation model simulations designed to facilitate intercomparison between different models is presented, with the most comprehensive model confirmed the possibility of initiating a Snowball event with a plausible reduction of CO2.
Journal ArticleDOI
A ‘snowball Earth’ climate triggered by continental break-up through changes in runoff
TL;DR: Assessment of the palaeogeographic changes preceding the Sturtian glacial period and the long-term evolution of atmospheric carbon dioxide levels using the coupled climate–geochemical model GEOCLIM indicates that tectonic changes could have triggered a progressive transition from a ‘greenhouse’ to an ‘icehouse” climate during the Neoproterozoic era.
Journal ArticleDOI
Millennial and orbital variations of El Niño/Southern Oscillation and high-latitude climate in the last glacial period
Christian Turney,Christian Turney,A. Peter Kershaw,Steven C. Clemens,Nicholas Branch,Patrick Moss,L. Keith Fifield +6 more
TL;DR: A high-resolution record of surface moisture, based on the degree of peat humification and the ratio of sedges to grass, from northern Queensland, Australia, covering the past 45,000 yr is presented, suggesting that climate variations in the tropical Pacific Ocean on millennial as well as orbital timescales, which determined precipitation in northeastern Australia, also exerted an influence on North Atlantic climate through atmospheric and oceanic teleconnections.
Journal ArticleDOI
Sedimentary challenge to Snowball Earth
Philip A. Allen,James L. Etienne +1 more
TL;DR: However, the sedimentary evidence suggests that despite the severity of glaciation, some oceans must have remained ice-free as discussed by the authors, which is contrary to the popular Snowball Earth concept, which predicts a fully frozen Earth for millions of years caused by a runaway ice-albedo feedback.
References
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Book
Physics of Climate
José P. Peixoto,Abraham H. Oort +1 more
TL;DR: A review of the present understanding of the global climate system, consisting of the atmosphere, hydrosphere, cryosphere, lithosphere and biosphere, and their complex interactions and feedbacks is given from the point of view of a physicist as mentioned in this paper.
Journal ArticleDOI
A Neoproterozoic Snowball Earth
TL;DR: Negative carbon isotope anomalies in carbonate rocks bracketing Neoproterozoic glacial deposits in Namibia, combined with estimates of thermal subsidence history, suggest that biological productivity in the surface ocean collapsed for millions of years.
Journal ArticleDOI
Physics of Climate
TL;DR: Physics of Climate as mentioned in this paper is a suitable text for at least part of a general circulation course and the quantity and quality of information in this book are such that anyone involved in the study of the atmosphere or climate will wish to have it handy.
Journal ArticleDOI
Did the breakout of laurentia turn gondwanaland inside-out?
TL;DR: Comparative geology suggests that the continents adjacent to northern, western, southern, and eastern Laurentia in the Late Proterozoic were Siberia, Australia-Antarctica, southern Africa, and Amazonia-Baltica, respectively.
Journal ArticleDOI
The snowball Earth hypothesis: testing the limits of global change
Paul Hoffman,Daniel P. Schrag +1 more
TL;DR: The recent discovery that late Neoproterozoic ice sheets extended to sea level near the equator poses a palaeoenvironmental conundrum as discussed by the authors, which does not account for major features such as abrupt onsets and terminations of discrete glacial events, their close association with large (> 10&) negative d 13 C shifts in seawater proxies, the deposition of strange carbonate layers (cap carbonates) globally during postglacial sea-level rise, and the return of large sedimentary iron formations.