Testing Hypotheses About Glacial Cycles Against the Observational Record

TY - JOUR

T1 - Testing Hypotheses About Glacial Cycles Against the Observational Record

AU - Kaufmann, Robert

AU - Juselius, Katarina

PY - 2013/3/1

Y1 - 2013/3/1

N2 - We estimate an identified cointegrated vector autoregression model of the climate system to test hypotheses about the physical mechanisms that may drive glacial cycles during the late Pleistocene. Results indicate that a permanent doubling of CO2 generates a 11.1°C rise in Antarctic temperature. Large variations in atmospheric CO2 over glacial cycles are driven by changes in sea ice and sea surface temperature in southern oceans and marine biological activity. The latter can be represented by a two-step process in which iron dust increases biological activity and the increase in biological activity reduces CO2 concentrations. Glacial variations in ice volume, as proxied by δ18O are driven by changes in CO 2 concentrations, global and high latitude solar insolation, latitudinal gradients in solar insolation, and the atmospheric concentration of CO2. The model is able to quantify the effects of ice volume and temperature on sea level, such that in the long-run, sea level rises 14 m per 0.11‰ δ18O and about 17 m/°C of sea surface temperature in southern oceans. Beyond these specific results, the multivariate model suggests omitted variables may bias bivariate analyses of these mechanisms.

AB - We estimate an identified cointegrated vector autoregression model of the climate system to test hypotheses about the physical mechanisms that may drive glacial cycles during the late Pleistocene. Results indicate that a permanent doubling of CO2 generates a 11.1°C rise in Antarctic temperature. Large variations in atmospheric CO2 over glacial cycles are driven by changes in sea ice and sea surface temperature in southern oceans and marine biological activity. The latter can be represented by a two-step process in which iron dust increases biological activity and the increase in biological activity reduces CO2 concentrations. Glacial variations in ice volume, as proxied by δ18O are driven by changes in CO 2 concentrations, global and high latitude solar insolation, latitudinal gradients in solar insolation, and the atmospheric concentration of CO2. The model is able to quantify the effects of ice volume and temperature on sea level, such that in the long-run, sea level rises 14 m per 0.11‰ δ18O and about 17 m/°C of sea surface temperature in southern oceans. Beyond these specific results, the multivariate model suggests omitted variables may bias bivariate analyses of these mechanisms.

KW - Faculty of Social Sciences

KW - glacial cycles

KW - climate model

U2 - 10.1002/palo.20021

DO - 10.1002/palo.20021

M3 - Journal article

SN - 0883-8305

VL - 28

SP - 175

EP - 184

JO - Paleoceanography

JF - Paleoceanography

IS - 1

ER -