Open AccessImplications of the glacial CO 2 “iron hypothesis” for Quaternary climate change
Author(s) -
Ridgwell Andy J.
Publication year - 2003
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2003gc000563
Subject(s) - glacial period , interglacial , climate state , climate change , geology , quaternary , climatology , climate oscillation , climate system , environmental science , physical geography , oceanography , global warming , effects of global warming , paleontology , geography
The “iron hypothesis” posits a role for increased supply of mineral aerosol to the ocean surface during glacial periods in driving atmospheric CO 2 lower; that changes in CO 2 and climate strongly affect dust supply raises the possibility of feedback. Here I take a systems view in analyzing the properties and implications of such a feedback and consider three primary state variables that can be related empirically to each other: dust supply, atmospheric CO 2 , and “climate” (surface air temperature). The results of this analysis suggest that the dust‐CO 2 ‐climate feedback is primarily an intra glacial phenomenon, when it can account for about a third of the temperature variability recorded in Antarctic ice cores. Since glacial‐interglacial cyclicity prior to ca. 800 kyr BP is characterized by the absence of a “full” glacial state (such as the Last Glacial Maximum), it is possible that destabilization of climate by the marine iron cycle is fundamental to the differences between “41 kyr” and “100 kyr” climatic regimes. The critical role played by the state of the land surface in this feedback also has implications for the longer‐term evolution of the Earth system during the Cenozoic.