The northern ice sheets arrive
Continental glaciers spread across North America and Eurasia, and the ice ages begin.
- When
- —
- Duration
- 170 thousand years
- Known to
- ± 100 thousand years
- Era
- Pliocene, Cenozoic
Around 2.7 million years ago, ice-rafted debris and oxygen isotope records register the onset of large-scale Northern Hemisphere glaciation: ice sheets growing over Canada, Scandinavia and northern Eurasia, not just Greenland. The causes are layered — declining carbon dioxide as the fundamental control, with the closure of Panama, the uplift of Tibet, and favourable orbital geometry contributing. This is the transition into the current ice age, which has been running ever since and which we are currently inside, in an interglacial.