What do periods of weak low-latitude rainfall have to do with the
meltdown of great ice sheets? Cheng et al. show that this counterintuitive association contains a hot clue about
the much-debated causes of the ice age cycles that end every 100,000
years or so in a collapse of the great Northern Hemisphere ice sheets
(a glacial termination).

The bipolar see-saw hypothesis provides an explanation for why temperature shifts in the two hemispheres were out of phase at certain times. The hypothesis has now passed a test of one of its predictions.