Large inert carbon pool in the terrestrial biosphere during the Last Glacial Maximum

Abstract. The terrestrial biosphere is thought to be a key component in the climatic variability seen in the palaeo-record. 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 atmosphere–ocean–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 CO2 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.

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Continental/Cordilleran ice interactions: a dominant cause of westward super-elevation of the last glacial maximum continental ice limit in southwestern Alberta, Canada

CrossRef Listing of Deleted DOIs ◽

10.1080/030094801300062284 ◽

2001 ◽

Vol 30 (1) ◽

pp. 43-52 ◽

Cited By ~ 4

Author(s):

Edward C. Little ◽

Lionel E. Jackson ◽

Thomas S. James ◽

Stephen R. Hicock ◽

Elizabeth R. Leboe

Keyword(s):

Last Glacial Maximum ◽

Glacial Maximum ◽

Last Glacial ◽

The Last Glacial Maximum ◽

The Last Glacial

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Mollusk record of millennial climate variability in the Loess Plateau during the Last Glacial Maximum

Boreas ◽

10.1080/03009480210648 ◽

2002 ◽

Vol 31 (1) ◽

pp. 20-27 ◽

Cited By ~ 31

Author(s):

Naiqin Wu ◽

Tungsheng Liu ◽

Xiuping Liu ◽

Zhaoyan Gu

Keyword(s):

Climate Variability ◽

Last Glacial Maximum ◽

Loess Plateau ◽

Glacial Maximum ◽

The Loess Plateau ◽

Last Glacial ◽

The Last Glacial Maximum ◽

The Last Glacial

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Reconstructions of the past distribution of Testudo graeca mitochondrial lineages in the Middle East and Transcaucasia support multiple refugia since the Last Glacial Maximum

Herpetological Journal ◽

10.33256/31.1.1017 ◽

2021 ◽

pp. 10-17

Author(s):

Oguz Turkozan

Keyword(s):

Middle East ◽

Last Glacial Maximum ◽

Glacial Maximum ◽

Testudo Graeca ◽

Last Glacial ◽

The Past ◽

Precipitation Seasonality ◽

Multiple Refugia ◽

The Last Glacial Maximum ◽

The Last Glacial

A cycle of glacial and interglacial periods in the Quaternary caused species’ ranges to expand and contract in response to climatic and environmental changes. During interglacial periods, many species expanded their distribution ranges from refugia into higher elevations and latitudes. In the present work, we projected the responses of the five lineages of Testudo graeca in the Middle East and Transcaucasia as the climate shifted from the Last Glacial Maximum (LGM, Mid – Holocene), to the present. Under the past LGM and Mid-Holocene bioclimatic conditions, models predicted relatively more suitable habitats for some of the lineages. The most significant bioclimatic variables in predicting the present and past potential distribution of clades are the precipitation of the warmest quarter for T. g. armeniaca (95.8 %), precipitation seasonality for T. g. buxtoni (85.0 %), minimum temperature of the coldest month for T. g. ibera (75.4 %), precipitation of the coldest quarter for T. g. terrestris (34.1 %), and the mean temperature of the driest quarter for T. g. zarudyni (88.8 %). Since the LGM, we hypothesise that the ranges of lineages have either expanded (T. g. ibera), contracted (T. g. zarudnyi) or remained stable (T. g. terrestris), and for other two taxa (T. g. armeniaca and T. g. buxtoni) the pattern remains unclear. Our analysis predicts multiple refugia for Testudo during the LGM and supports previous hypotheses about high lineage richness in Anatolia resulting from secondary contact.

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