The role of CO2 decline for the onset of Northern Hemisphere glaciation

Willeit, Matteo; Ganopolski, Andrey; Calov, Reinhard; Robinson, Alexander; Maslin, Mark

doi:10.1016/j.quascirev.2015.04.015

Cited by 59 publications

(60 citation statements)

References 139 publications

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“…For example, neither Quaternary nor future glacial-interglacial cycles can be simulated using the current version of the emulator. Furthermore, even during the Pliocene, it is likely that the extent of ice sheets in the Northern Hemisphere varied beyond the range simulated in this study (Willeit et al, 2015), and the emulator in its current form cannot represent this.…”

Section: Limitationsmentioning

confidence: 81%

Emulation of long-term changes in global climate: application to the late Pliocene and future

et al. 2017

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Abstract. Multi-millennial transient simulations of climate changes have a range of important applications, such as for investigating key geologic events and transitions for which high-resolution palaeoenvironmental proxy data are available, or for projecting the long-term impacts of future climate evolution on the performance of geological repositories for the disposal of radioactive wastes. However, due to the high computational requirements of current fully coupled general circulation models (GCMs), long-term simulations can generally only be performed with less complex models and/or at lower spatial resolution. In this study, we present novel longterm "continuous" projections of climate evolution based on the output from GCMs, via the use of a statistical emulator. The emulator is calibrated using ensembles of GCM simulations, which have varying orbital configurations and atmospheric CO 2 concentrations and enables a variety of investigations of long-term climate change to be conducted, which would not be possible with other modelling techniques on the same temporal and spatial scales. To illustrate the potential applications, we apply the emulator to the late Pliocene (by modelling surface air temperature -SAT), comparing its results with palaeo-proxy data for a number of global sites, and to the next 200 kyr (thousand years) (by modelling SAT and precipitation). A range of CO 2 scenarios are prescribed for each period. During the late Pliocene, we find that emulated SAT varies on an approximately precessional timescale, with evidence of increased obliquity response at times. A comparison of atmospheric CO 2 concentration for this period, estimated using the proxy sea surface temperature (SST) data from different sites and emulator results, finds that relatively similar CO 2 concentrations are estimated based on sites at lower latitudes, whereas higher-latitude sites show larger discrepancies. In our second illustrative application, spanning the next 200 kyr into the future, we find that SAT oscillations appear to be primarily influenced by obliquity for the first ∼ 120 kyr, whilst eccentricity is relatively low, after which precession plays a more dominant role. Conversely, variations in precipitation over the entire period demonstrate a strong precessional signal. Overall, we find that the emulator provides a useful and powerful tool for rapidly simulating the long-term evolution of climate, both past and future, due to its relatively high spatial resolution and relatively low computational cost. However, there are uncertainties associated with the approach used, including the inability of the emulaPublished by Copernicus Publications on behalf of the European Geosciences Union. 1540 N. S. Lord et al.: Emulation of long-term changes in global climate tor to capture deviations from a quasi-stationary response to the forcing, such as transient adjustments of the deep-ocean temperature and circulation, in addition to its limited range of fixed ice sheet configurations and its requirement for prescribed atmos...

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Section: Limitationsmentioning

confidence: 81%

Emulation of long-term changes in global climate: application to the late Pliocene and future

et al. 2017

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“…However, the changes in the North Pacific could significantly increase the carbon stored and drive a geological rapid fall in atmospheric carbon dioxide concentrations. This change provides a plausible mechanism for Antarctica to drive the changes in the ocean at the Plio-Pleistocene transition and intensification of the Northern Hemisphere glaciation through reduced atmospheric CO 2 concentrations, which has already been shown to be the key factor in ice advance282930. However, the overall impact of changes in Pacific Ocean circulation on the carbon cycle and especially atmospheric carbon dioxide levels needs to be quantified and modelling of these effects is beyond the scope of this modelling study and the capabilities of this modelling framework.…”

Section: Discussionmentioning

confidence: 94%

Modelled ocean changes at the Plio-Pleistocene transition driven by Antarctic ice advance

2017

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The Earth underwent a major transition from the warm climates of the Pliocene to the Pleistocene ice ages between 3.2 and 2.6 million years ago. The intensification of Northern Hemisphere Glaciation is the most obvious result of the Plio-Pleistocene transition. However, recent data show that the ocean also underwent a significant change, with the convergence of deep water mass properties in the North Pacific and North Atlantic Ocean. Here we show that the lack of coastal ice in the Pacific sector of Antarctica leads to major reductions in Pacific Ocean overturning and the loss of the modern North Pacific Deep Water (NPDW) mass in climate models of the warmest periods of the Pliocene. These results potentially explain the convergence of global deep water mass properties at the Plio-Pleistocene transition, as Circumpolar Deep Water (CDW) became the common source.

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“…This implies long-term global cooling following the late Paleocene-early Eocene (~60-50 Ma) climate warming (e.g., Zachos et al, 2001). Antarctica was ice free until about~30 Ma (e.g., Barrett et al, 1987;DeConto & Pollard, 2003;Pagani et al, 2011), and glaciation of the Northern Hemisphere only started during the Plio-Quaternary (last 5 Myr; e.g., Raymo, 1994;Willeit et al, 2015). Thus, early Cenozoic δ 18 O trends are driven primarily by temperature changes.…”

Section: Solid Earth Control On Cenozoic Climate Coolingmentioning

confidence: 99%

Magmatic Forcing of Cenozoic Climate?

et al. 2020

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Established theories ascribe much of the observed long-term Cenozoic climate cooling to atmospheric carbon consumption by erosion and weathering of tectonically uplifted terrains, but climatic effects due to changes in magmatism and carbon degassing are also involved. At timescales comparable to those of Milankovitch cycles, late Cenozoic building/melting of continental ice sheets, erosion, and sea level changes can affect magmatism, which provides an opportunity to explore possible feedbacks between climate and volcanic changes. Existing data show that extinction of Neo-Tethyan volcanic arcs is largely synchronous with phases of atmospheric carbon reduction, suggesting waning degassing as a possible contribution to climate cooling throughout the early to middle Cenozoic. In addition, the increase in atmospheric CO 2 concentrations during the last deglaciation may be ascribed to enhanced volcanism and carbon emissions due to unloading of active magmatic provinces on continents. The deglacial rise in atmospheric CO 2 points to a mutual feedback between climate and volcanism mediated by the redistribution of surface masses and carbon emissions. This may explain the progression to higher amplitude and increasingly asymmetric cycles of late Cenozoic climate oscillations. Unifying theories relating tectonic, erosional, climatic, and magmatic changes across timescales via the carbon cycle offer an opportunity for future research into the coupling between surface and deep Earth processes. Plain Language Summary Among the most fascinating contemporary developments in theEarth Sciences is the idea that plate tectonics and climate changes are coupled through complex cycles. More than four decades of study have revealed tantalizing examples of relationships between processes near the Earth's surface and deeper within. Accounting for such a surface-deep Earth process coupling has improved our understanding of major climate and tectonic events for virtually all timescales. So far, however, the role of magmatism was overlooked. Magmatism exerts a strong influence on the amount of greenhouse gasses in the atmosphere because of volcanic outgassing. In turn, tectonic and climatic changes control the transfer of rocks, water, and ice masses at the Earth surface and within the Earth's interior, thereby affecting the production, transfer, and eruption of magmas. Unravelling the interactions between surface and deep Earth processes accounting for magmatism will help managing natural resources and mitigating natural hazards. Even more importantly, understanding how climate is naturally related to plate tectonics and magmatism will allow scientists to assess the anthropogenic perturbations to the Earth system and anticipate ongoing and future climate changes.

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The role of CO2 decline for the onset of Northern Hemisphere glaciation

Cited by 59 publications

References 139 publications

Emulation of long-term changes in global climate: application to the late Pliocene and future

Emulation of long-term changes in global climate: application to the late Pliocene and future

Modelled ocean changes at the Plio-Pleistocene transition driven by Antarctic ice advance

Magmatic Forcing of Cenozoic Climate?

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