there is a so-called ‘sub-Milankovitch’ variability corresponding to the Dansgaard-Oeschger and Heinrich events. It
is likely that cyclicities of this type have also existed at other
times in Earth’s history. For example, the 470 m thick Triassic strata, observed in Latemar in the Italian Dolomites,
have a well-marked periodic structure showing about 600
cycles. There is controversy between those who support the
hypotheses of astronomical cycles, who see precession
cycles and therefore a total recording time of around 10
million years, and the proponents of much quicker environmental variations, using radiometric dating to estimate a
total duration of around a million years only, hence an order
of magnitude faster. Although the debate is not yet settled, it
highlights that it is not enough to identify the cycles in
geological records to systematically find an astronomical
signature. The dynamics of the Earth system are indeed
likely to reveal many more surprises.
Conclusions
The dynamics of the glacial-interglacial cycles of the Quaternary are far from fully understood and this is even more
true for the pre-Quaternary astronomical cycles. Moreover,
the climate during glacial periods can sometimes change
very abruptly during the Dansgaard-Oeschger or Heinrich
events, for reasons unrelated to astronomical forcing or to
atmospheric CO 2 variations. It is noteworthy that the last
deglaciation was punctuated by such rapid events. It is
therefore quite possible that they also play a decisive role in
the dynamics of large cycles, and even more so if one
considers that they are based on tipping points that allow a
shift from a glacial state to an interglacial state.
The conceptual models presented here are far from sufficient to account for the physical and biogeochemical interactions involved in these climate changes. The most
sophisticated climate models that are used to simulate the
twenty-first century, or ‘general circulation models’, are
unfortunately unable to simulate these changes because the
time scales involved are far too long. In addition, the ice cap
changes and the dynamics of the main biogeochemical cycles
must also be taken into account, which these models are not
yet able to do correctly. For all these reasons, simpler models
of the ‘Earth system’ (or models of intermediate complexity)
are used to address this type of question. Recent advances,
both in terms of paleoclimate reconstructions but also in
terms of modeling (Bouttes et al. 2011), provide hope that a
new theory of the glacial-interglacial cycles of the Quaternary that takes into account the various aspects of terrestrial
environmental changes (ice caps, carbon, vegetation, climate)
can be developed in the years to come. An overview of this
type would provide a much better understanding of the great
climate changes experienced so far by homo sapiens.
References
Adkins, J., McIntyre, K., & Schrag, D. (2002). The salinity, temperature and d
18
O of the glacial deep Ocean. Science, 298, 1769–1773.
Arrhenius, S. (1896). On the influence of carbonic acid in the air upon
the temperature of the ground. Philosophical Magazine and Journal
of Science, 41, 237–276.
Bard, E. (2004). Greenhouse effect and ice ages: Historical perspective.
C. R. Geoscience, 336, 603–638.
Bard, E., Hamelin, B., Arnold, M., Montaggioni, L., Cabioch, G., Faure,
G., et al. (1996). Deglacial sea-level record from tahiti corals and the
timing of global meltwater discharge. Nature, 382, 241–244.
Berger, A. (1978). Long-term variations of daily insolation and
quaternary climatic change. Journal of the Atmospheric Sciences,
35, 2362–2367.
Bouttes, N., Paillard, D., Roche, D. M., Brovkin, V., & Bopp, L.
(2011). Last glacial maximum CO 2 and d
13
C successfully reconciled. Geophysical Reseach Letters, 38, 1–5.
Broecker, W., & van Donk, J. (1970). insolation changes, ice volumes
and the O
18 record in deep-sea cores. Reviews of Geophysics and
Space Physics, 8, 169–197.
Calder, N. (1974). Arithmetic of ice ages. Nature, 252, 216–218.
Gale, A. S., Young, J. R., Shackleton, N. J., Crowhurst, S. J., & Wray,
D. S. (1999). Orbital tuning of cenomanian marly chalk successions:
Towards a milankovitch time-scale for the late cretaceous. Philosophical Transactions of the Royal Society A, 357, 1815–1829.
Hays, J., Imbrie, J., & Shackleton, N. J. (1976). Variations in the earth’s
orbit: Pacemakers of the ice ages. Science, 194, 1121–1132.
Hofmann, A., Dirks, P. H. G. M., & Jelsma, H. A. (2004).
Shallowing-upward carbonate cycles in the belingwe greenstone
belt, zimbabwe: A record of archean sea-level oscillations. Journal
of Sedimentary Research, 74, 64–81.
Huybers, P. (2006). Early pleistocene glacial cycles and the integrated
summer insolation forcing. Science, 313, 508–511.
Huybers, P., & Wunsch, C. (2005). Obliquity pacing of the late
pleistocene glacial terminations. Nature, 434, 491–494.
Imbrie, J., Hays, J., Martinson, D., McIntyre, A., Mix, A., Morley, J. J.,
Pisias, N., Prell, W., Shackleton, N., Berger, A., Kukla, G., &
Saltzman, B. (1984). The orbital theory of pleistocene climate:
Support from a revised chronology of the marine d
18
O record. In A.
dans Berger (Ed.), Milankovitch and climate (pp. 269–305),
Dordrecht: Kluwer Academic Publishers (Nato ASI Ser. C).
Joussaume, S., Braconnot, P. (1997). Sensitivity of paleoclimate
simulation results to season definitions. Journal of Geophysical
Research D, 102, 1943–1956.
Kuiper, K., Deino, A., Hilgen, F. J., Krijgsman, W., Renne, P. R., &
Wijbrans, J. R. (2008). Synchronizing rock clocks of earth history.
Science, 320, 500–504.
Laskar, J., Robutel, P., Joutel, F., Gastineau, M., Correia, A. C. M., &
Levrard, B. (2004). A long-term numerical solution for the
insolation quantities of the earth. Astronomy & Astrophysics, 428,
261–285.
Lisiecki, L. E., & Raymo, M. E. (2005). A pliocene-pleistocene stack of
57 globally distributed benthic d
18
O records. Paleoceanography,
20, PA1003. https://doi.org/10.1029/2004pa001071.
Milankovitch, M. (1941). Kanon der Erdbestrahlung und seine
Andwendung auf das Eiszeiten-problem. (p. 633).
Monnin, E., Indermühle, A., Dällenbach, A., Flückiger, J., Stauffer, B.,
Stocker, T., et al. (2001). Atmospheric CO 2 concentrations over the
last glacial termination. Science, 291, 112–114.
Ohshima, et al. (2013). Antarctic bottom water production by intense
sea-ice formation in the Cape Darnley polynya. Nature Geoscience,
6, 235–240.
28 Climate and Astronomical Cycles
403
is likely that cyclicities of this type have also existed at other
times in Earth’s history. For example, the 470 m thick Triassic strata, observed in Latemar in the Italian Dolomites,
have a well-marked periodic structure showing about 600
cycles. There is controversy between those who support the
hypotheses of astronomical cycles, who see precession
cycles and therefore a total recording time of around 10
million years, and the proponents of much quicker environmental variations, using radiometric dating to estimate a
total duration of around a million years only, hence an order
of magnitude faster. Although the debate is not yet settled, it
highlights that it is not enough to identify the cycles in
geological records to systematically find an astronomical
signature. The dynamics of the Earth system are indeed
likely to reveal many more surprises.
Conclusions
The dynamics of the glacial-interglacial cycles of the Quaternary are far from fully understood and this is even more
true for the pre-Quaternary astronomical cycles. Moreover,
the climate during glacial periods can sometimes change
very abruptly during the Dansgaard-Oeschger or Heinrich
events, for reasons unrelated to astronomical forcing or to
atmospheric CO 2 variations. It is noteworthy that the last
deglaciation was punctuated by such rapid events. It is
therefore quite possible that they also play a decisive role in
the dynamics of large cycles, and even more so if one
considers that they are based on tipping points that allow a
shift from a glacial state to an interglacial state.
The conceptual models presented here are far from sufficient to account for the physical and biogeochemical interactions involved in these climate changes. The most
sophisticated climate models that are used to simulate the
twenty-first century, or ‘general circulation models’, are
unfortunately unable to simulate these changes because the
time scales involved are far too long. In addition, the ice cap
changes and the dynamics of the main biogeochemical cycles
must also be taken into account, which these models are not
yet able to do correctly. For all these reasons, simpler models
of the ‘Earth system’ (or models of intermediate complexity)
are used to address this type of question. Recent advances,
both in terms of paleoclimate reconstructions but also in
terms of modeling (Bouttes et al. 2011), provide hope that a
new theory of the glacial-interglacial cycles of the Quaternary that takes into account the various aspects of terrestrial
environmental changes (ice caps, carbon, vegetation, climate)
can be developed in the years to come. An overview of this
type would provide a much better understanding of the great
climate changes experienced so far by homo sapiens.
References
Adkins, J., McIntyre, K., & Schrag, D. (2002). The salinity, temperature and d
18
O of the glacial deep Ocean. Science, 298, 1769–1773.
Arrhenius, S. (1896). On the influence of carbonic acid in the air upon
the temperature of the ground. Philosophical Magazine and Journal
of Science, 41, 237–276.
Bard, E. (2004). Greenhouse effect and ice ages: Historical perspective.
C. R. Geoscience, 336, 603–638.
Bard, E., Hamelin, B., Arnold, M., Montaggioni, L., Cabioch, G., Faure,
G., et al. (1996). Deglacial sea-level record from tahiti corals and the
timing of global meltwater discharge. Nature, 382, 241–244.
Berger, A. (1978). Long-term variations of daily insolation and
quaternary climatic change. Journal of the Atmospheric Sciences,
35, 2362–2367.
Bouttes, N., Paillard, D., Roche, D. M., Brovkin, V., & Bopp, L.
(2011). Last glacial maximum CO 2 and d
13
C successfully reconciled. Geophysical Reseach Letters, 38, 1–5.
Broecker, W., & van Donk, J. (1970). insolation changes, ice volumes
and the O
18 record in deep-sea cores. Reviews of Geophysics and
Space Physics, 8, 169–197.
Calder, N. (1974). Arithmetic of ice ages. Nature, 252, 216–218.
Gale, A. S., Young, J. R., Shackleton, N. J., Crowhurst, S. J., & Wray,
D. S. (1999). Orbital tuning of cenomanian marly chalk successions:
Towards a milankovitch time-scale for the late cretaceous. Philosophical Transactions of the Royal Society A, 357, 1815–1829.
Hays, J., Imbrie, J., & Shackleton, N. J. (1976). Variations in the earth’s
orbit: Pacemakers of the ice ages. Science, 194, 1121–1132.
Hofmann, A., Dirks, P. H. G. M., & Jelsma, H. A. (2004).
Shallowing-upward carbonate cycles in the belingwe greenstone
belt, zimbabwe: A record of archean sea-level oscillations. Journal
of Sedimentary Research, 74, 64–81.
Huybers, P. (2006). Early pleistocene glacial cycles and the integrated
summer insolation forcing. Science, 313, 508–511.
Huybers, P., & Wunsch, C. (2005). Obliquity pacing of the late
pleistocene glacial terminations. Nature, 434, 491–494.
Imbrie, J., Hays, J., Martinson, D., McIntyre, A., Mix, A., Morley, J. J.,
Pisias, N., Prell, W., Shackleton, N., Berger, A., Kukla, G., &
Saltzman, B. (1984). The orbital theory of pleistocene climate:
Support from a revised chronology of the marine d
18
O record. In A.
dans Berger (Ed.), Milankovitch and climate (pp. 269–305),
Dordrecht: Kluwer Academic Publishers (Nato ASI Ser. C).
Joussaume, S., Braconnot, P. (1997). Sensitivity of paleoclimate
simulation results to season definitions. Journal of Geophysical
Research D, 102, 1943–1956.
Kuiper, K., Deino, A., Hilgen, F. J., Krijgsman, W., Renne, P. R., &
Wijbrans, J. R. (2008). Synchronizing rock clocks of earth history.
Science, 320, 500–504.
Laskar, J., Robutel, P., Joutel, F., Gastineau, M., Correia, A. C. M., &
Levrard, B. (2004). A long-term numerical solution for the
insolation quantities of the earth. Astronomy & Astrophysics, 428,
261–285.
Lisiecki, L. E., & Raymo, M. E. (2005). A pliocene-pleistocene stack of
57 globally distributed benthic d
18
O records. Paleoceanography,
20, PA1003. https://doi.org/10.1029/2004pa001071.
Milankovitch, M. (1941). Kanon der Erdbestrahlung und seine
Andwendung auf das Eiszeiten-problem. (p. 633).
Monnin, E., Indermühle, A., Dällenbach, A., Flückiger, J., Stauffer, B.,
Stocker, T., et al. (2001). Atmospheric CO 2 concentrations over the
last glacial termination. Science, 291, 112–114.
Ohshima, et al. (2013). Antarctic bottom water production by intense
sea-ice formation in the Cape Darnley polynya. Nature Geoscience,
6, 235–240.
28 Climate and Astronomical Cycles
403