New evidence from ancient Antarctic ice cores suggests that at certain transition points, ocean temperatures may have had greater influence over Earth's climate than greenhouse gases. The research was conducted by two research teams from the Allan Hills, a blue ice region of Antarctica, where samples date back to 6 million years ago. The cores contain samples of some of the world's oldest ice and can provide a climate snapshot that can tell us a lot about what was happening at the time of freezing. They also trap tiny bubbles of the air, revealing the historic gas composition of the atmosphere across millions of years. The data also suggests that average ocean temperatures remained relatively stable across the Mid-Pleistocene Transition, another shift in glacial cycles that occurred between 1.2 and 0.8 million years. However, there are limitations to interpret these records.