Study: Glaciers Survived Global Hothouse

Glaciers persisted when the Earth was far hotter than today, scientists have found.

Earth was thought to be ice-free during the so-called Turonian period, a "supergreenhouse world" between 93.5 million and 89.3 million years ago. But studies of tiny plankton and other marine organisms in tropical waters show that large ice-sheets existed about 91 million years ago, during one of the warmest periods in the past 500 million years, the international team reports in the journal Science.

The scientists from Britain, Germany, America, and the Netherlands found evidence of an approximately 200,000-year period of widespread glaciation, with ice sheets about 60% the size of the modern Antarctic ice cap.