Global climate rapidly shifted from a relatively ice-free world to one with massive ice sheets on Antarctica about 34 million years ago. What happened? What changed? A team of scientists led by Yale geologists offers a new perspective on the nature of changing climatic conditions across this greenhouse-to-icehouse transition — one that refutes earlier theories and has important implications for predicting future climate changes. Detailed in the February 27 issue of Science, their data disproves a long-held idea that massive ice growth in the Antarctic was accompanied by little to no global temperature change. This report shows that before the Southern Hemisphere ice expansion, high-latitude temperatures were at least 10°C (about 18˚F) warmer than previously estimated and that there was a 5˚C - 10˚C drop in surface-water temperature during the climate transition.
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