The role of orbital forcing, carbon dioxide and regolith in 100 kyr glacial cycles
The origin of the 100 kyr cyclicity, which dominates ice volume variations and other climate records over the past million years, remains debatable. Here, using a comprehensive Earth system model of intermediate complexity, we demonstrate that both strong 100 kyr periodicity in the ice volume variat...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2011-12-01
|
| Series: | Climate of the Past |
| Online Access: | http://www.clim-past.net/7/1415/2011/cp-7-1415-2011.pdf |
| Summary: | The origin of the 100 kyr cyclicity, which dominates ice volume variations and other climate records over the past million years, remains debatable. Here, using a comprehensive Earth system model of intermediate complexity, we demonstrate that both strong 100 kyr periodicity in the ice volume variations and the timing of glacial terminations during past 800 kyr can be successfully simulated as direct, strongly nonlinear responses of the climate-cryosphere system to orbital forcing alone, if the atmospheric CO<sub>2</sub> concentration stays below its typical interglacial value. The existence of long glacial cycles is primarily attributed to the North American ice sheet and requires the presence of a large continental area with exposed rocks. We show that the sharp, 100 kyr peak in the power spectrum of ice volume results from the long glacial cycles being synchronized with the Earth's orbital eccentricity. Although 100 kyr cyclicity can be simulated with a constant CO<sub>2</sub> concentration, temporal variability in the CO<sub>2</sub> concentration plays an important role in the amplification of the 100 kyr cycles. |
|---|---|
| ISSN: | 1814-9324 1814-9332 |