The beginning of the mid-Brunhes event ca. 430 ka coincided with the largest-amplitude change in delta (super 18) O in the global ocean over the past 6 m.y. This large delta (super 18) O change recorded a major ice-sheet expansion that cannot be explained by small changes in orbital forcing. Our recent studies at Ocean Drilling Program Site 1143 from the South China Sea show that this large delta (super 18) O change was preceded by a significant negative delta (super 13) C shift. A global survey of long deep-sea records has revealed periodic delta (super 13) C (sub max) episodes (i.e., maximum positive values of delta (super 13) C), and both major ice-sheet expansion events in the Pleistocene (the mid-Brunhes event and the middle Pleistocene revolution) were preceded by delta (super 13) C (sub max) episodes followed by negative delta (super 13) C shifts. This new finding suggests that disturbance in carbon reservoirs leads to major growth of ice-sheet size and challenges the prevalent concept of Arctic control of glacial cycles. Because Earth is now passing again through a delta (super 13) C (sub max) episode, it is crucial to understand the causal relationship between the successive delta (super 13) C changes and ice-sheet growth events.