Open AccessTemperature differences between the hemispheres and ice age climate variability
Author(s) -
Toggweiler J. R.,
Lea David W.
Publication year - 2010
Publication title -
paleoceanography
Language(s) - English
Resource type - Journals
eISSN - 1944-9186
pISSN - 0883-8305
DOI - 10.1029/2009pa001758
Subject(s) - younger dryas , climatology , geology , orbital forcing , abrupt climate change , atmosphere (unit) , forcing (mathematics) , little ice age , ice age , paleoclimatology , ice sheet , ice albedo feedback , climate change , atmospheric sciences , global warming , cryosphere , sea ice , oceanography , glacial period , geography , drift ice , meteorology , effects of global warming , paleontology , insolation
The Earth became warmer and cooler during the ice ages along with changes in the Earth's orbit, but the orbital changes themselves are not nearly large enough to explain the magnitude of the warming and cooling. Atmospheric CO 2 also rose and fell, but again, the CO 2 changes are rather small in relation to the warming and cooling. So, how did the Earth manage to warm and cool by so much? Here we argue that, for the big transitions at least, the Earth did not warm and cool as a single entity. Rather, the south warmed instead at the expense of a cooler north through massive redistributions of heat that were set off by the orbital forcing. Oceanic CO 2 was vented up to the atmosphere by the same redistributions. The north then warmed later in response to higher CO 2 and a reduced albedo from smaller ice sheets. This form of north‐south displacement is actually very familiar, as it is readily observed during the Younger Dryas interval 13,000 years ago and in the various millennial‐scale events over the last 90,000 years.