Simulating changes in the terrestrial biosphere during the last glacial/interglacial transition

Köhler, Peter; Fischer, Hubertus

doi:10.1016/j.gloplacha.2004.02.005

Cited by 59 publications

(99 citation statements)

References 116 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…According to our model, various factors such as reduced iron fertilization, ocean circulation and stratifi cation, as well as sea ice coverage of the Southern Ocean, contributed to the overall G/ IG change at different times. (Köhler et al, 2004, Smith et al 1999. Thus, initial processes during deglaciation in the Southern Ocean, followed by the 1500 year delayed kick-in of the thermohaline circulation (THC) in the North Atlantic (as revealed in the DEKLIM project CliTrans, Knorr and Lohmann, 2003) are consistent with atmospheric carbon records.…”

Section: Acknowledgementssupporting

confidence: 63%

See 1 more Smart Citation

The Global Carbon Cycle During the Last Glacial/Interglacial Transition

Fischer¹,

Köhler²,

Schmitt³

et al. 2004

PAGES news

View full text Add to dashboard Cite

Section: Acknowledgementssupporting

confidence: 63%

“…Further insight into changes in the carbon cycle can be expected from temporally better resolved and (Köhler and Fischer, 2004) (Smith et al, 1999, Monnin et al, 2001 …”

Section: Acknowledgementsmentioning

confidence: 99%

The Global Carbon Cycle During the Last Glacial/Interglacial Transition

Fischer¹,

Köhler²,

Schmitt³

et al. 2004

PAGES news

View full text Add to dashboard Cite

“…Ultimately, the model could also be coupled to a carbon cycle model, e.g. BICY-CLE (Köhler and Fischer, 2004), in order to simulate climate using only insolation data as input.…”

Section: Discussionmentioning

confidence: 99%

The influence of ice sheets on temperature during the past 38 million years inferred from a one-dimensional ice sheet–climate model

et al. 2017

View full text Add to dashboard Cite

Abstract. Since the inception of the Antarctic ice sheet at the Eocene-Oligocene transition ( ∼ 34 Myr ago), land ice has played a crucial role in Earth's climate. Through feedbacks in the climate system, land ice variability modifies atmospheric temperature changes induced by orbital, topographical, and greenhouse gas variations. Quantification of these feedbacks on long timescales has hitherto scarcely been undertaken. In this study, we use a zonally averaged energy balance climate model bidirectionally coupled to a one-dimensional ice sheet model, capturing the ice-albedo and surface-height-temperature feedbacks. Potentially important transient changes in topographic boundary conditions by tectonics and erosion are not taken into account but are briefly discussed. The relative simplicity of the coupled model allows us to perform integrations over the past 38 Myr in a fully transient fashion using a benthic oxygen isotope record as forcing to inversely simulate CO 2 . Firstly, we find that the results of the simulations over the past 5 Myr are dependent on whether the model run is started at 5 or 38 Myr ago. This is because the relation between CO 2 and temperature is subject to hysteresis. When the climate cools from very high CO 2 levels, as in the longer transient 38 Myr run, temperatures in the lower CO 2 range of the past 5 Myr are higher than when the climate is initialised at low temperatures. Consequently, the modelled CO 2 concentrations depend on the initial state. Taking the realistic warm initialisation into account, we come to a best estimate of CO 2 , temperature, ice-volume-equivalent sea level, and benthic δ 18 O over the past 38 Myr. Secondly, we study the influence of ice sheets on the evolution of global temperature and polar amplification by comparing runs with ice sheet-climate interaction switched on and off. By passing only albedo or surface height changes to the climate model, we can distinguish the separate effects of the ice-albedo and surfaceheight-temperature feedbacks. We find that ice volume variability has a strong enhancing effect on atmospheric temperature changes, particularly in the regions where the ice sheets are located. As a result, polar amplification in the Northern Hemisphere decreases towards warmer climates as there is little land ice left to melt. Conversely, decay of the Antarctic ice sheet increases polar amplification in the Southern Hemisphere in the high-CO 2 regime. Our results also show that in cooler climates than the pre-industrial, the ice-albedo feedback predominates the surface-heighttemperature feedback, while in warmer climates they are more equal in strength.

show abstract

“…Zimov et al (2006Zimov et al ( , 2009 have argued that permafrost storage could be a major source of carbon through the deglaciation, and Ciais et al (2012) argue that there was a large extra pool of inert carbon at the LGM. Similarly, Köhler et al (2014) have argued that large amounts of carbon were locked into permafrost which were then released rapidly at the Bølling-Allerød.…”

Section: Discussionmentioning

confidence: 99%

Quantifying the influence of the terrestrial biosphere on glacial–interglacial climate dynamics

et al. 2017

View full text Add to dashboard Cite

Abstract. The terrestrial biosphere is thought to be a key component in the climatic variability seen in the palaeorecord. It has a direct impact on surface temperature through changes in surface albedo and evapotranspiration (so-called biogeophysical effects) and, in addition, has an important indirect effect through changes in vegetation and soil carbon storage (biogeochemical effects) and hence modulates the concentrations of greenhouse gases in the atmosphere. The biogeochemical and biogeophysical effects generally have opposite signs, meaning that the terrestrial biosphere could potentially have played only a very minor role in the dynamics of the glacial-interglacial cycles of the late Quaternary. Here we use a fully coupled dynamic atmosphereocean-vegetation general circulation model (GCM) to generate a set of 62 equilibrium simulations spanning the last 120 kyr. The analysis of these simulations elucidates the relative importance of the biogeophysical versus biogeochemical terrestrial biosphere interactions with climate. We find that the biogeophysical effects of vegetation account for up to an additional −0.91 • C global mean cooling, with regional cooling as large as −5 • C, but with considerable variability across the glacial-interglacial cycle. By comparison, while opposite in sign, our model estimates of the biogeochemical impacts are substantially smaller in magnitude. Offline simulations show a maximum of +0.33 • C warming due to an increase of 25 ppm above our (pre-industrial) baseline atmospheric CO 2 mixing ratio. In contrast to shorter (century) timescale projections of future terrestrial biosphere response where direct and indirect responses may at times cancel out, we find that the biogeophysical effects consistently and strongly dominate the biogeochemical effect over the inter-glacial cycle. On average across the period, the terrestrial biosphere has a −0.26 • C effect on temperature, with −0.58 • C at the Last Glacial Maximum. Depending on assumptions made about the destination of terrestrial carbon under ice sheets and where sea level has changed, the average terrestrial biosphere contribution over the last 120 kyr could be as much as −50 • C and −0.83 • C at the Last Glacial Maximum.

show abstract

Simulating changes in the terrestrial biosphere during the last glacial/interglacial transition

Cited by 59 publications

References 116 publications

The Global Carbon Cycle During the Last Glacial/Interglacial Transition

The Global Carbon Cycle During the Last Glacial/Interglacial Transition

The influence of ice sheets on temperature during the past 38 million years inferred from a one-dimensional ice sheet–climate model

Quantifying the influence of the terrestrial biosphere on glacial–interglacial climate dynamics

Contact Info

Product

Resources

About