under a Creative Commons License. Climate of the Past Discussions Interactive comment on “Ice-driven CO2 feedback
Part of Bol’shakov’s criticism is directed at Milankovitch’s orbital insolation theory. His argument for seasonal cancellation of the direct impacts of insolation at the precession cycle and for geographic cancellation at the obliquity cycle echo those voiced in the early-middle 1900’s. Since that t...
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| Language: | English |
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2006
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.498.4729 http://www.cosis.net/copernicus/EGU/cpd/2/S61/cpd-2-S61_p.pdf?PHPSESSID=970f14118aefecc68cd6fd1015681fbe |
| Summary: | Part of Bol’shakov’s criticism is directed at Milankovitch’s orbital insolation theory. His argument for seasonal cancellation of the direct impacts of insolation at the precession cycle and for geographic cancellation at the obliquity cycle echo those voiced in the early-middle 1900’s. Since that time, however, records in marine sediments covering the last 2.75 million years have revealed clear tilt and precession cycles in the ice-sheet responses, and phases that isolate northern summer as the critical forcing (best explained in the introduction section of Imbrie et al., 1989), These findings confirm Milankovitch’s hypothesis that the response to changes in summer insolation outweighs that in winter in determining ice mass balance. A moderate amount of snow falls in winter for a range of temperatures, but warm summers can melt a much larger amount of snow and ice (Figure 9 in my paper). As Bol’shakov states, albedo feedback is an important positive feedback on ice sheets, but the very closely studied last glacial maximum indicates that greenhouse gases are more influential. The direct feedback effects of ice-sheet albedo and greenhouse gases S61 |
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