RT Journal Article
SR Electronic
T1 Early Pleistocene Glacial Cycles and the Integrated Summer Insolation Forcing
JF Science
JO Science
FD American Association for the Advancement of Science
SP 508
OP 511
DO 10.1126/science.1125249
VO 313
IS 5786
A1 Huybers, Peter
YR 2006
UL http://science.sciencemag.org/content/313/5786/508.abstract
AB Long-term variations in Northern Hemisphere summer insolation are generally thought to control glaciation. But the intensity of summer insolation is primarily controlled by 20,000-year cycles in the precession of the equinoxes, whereas early Pleistocene glacial cycles occur at 40,000-year intervals, matching the period of changes in Earth's obliquity. The resolution of this 40,000-year problem is that glaciers are sensitive to insolation integrated over the duration of the summer. The integrated summer insolation is primarily controlled by obliquity and not precession because, by Kepler's second law, the duration of the summer is inversely proportional to Earth's distance from the Sun.