Did Earth drive itself to a snowball?

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2018,（16）
• 页码范围: 1032-1033
• 页数: 2页
• 语种: 英文

摘要

The icehouse model,in terms of low CO2 effect,elegantly accounted for the global cooling events on Earth's surface,which has occurred at least several times in the history of Earth evolution.However,it does not appear to explain the great cooling events such as the Late Ordovician glaciation with an unusually high CO2 level of 4,000 ppmv [1],more than ten times higher than the CO2 level of today.Previous published records shows a CO2 increase during some glaciations [2],conflicting with the mainstream theory.Although Pagani et al.[3] later suggested that the evidences available support a drop in CO2 as a critical condition for global cooling,whether CO2 played a dominant role alone to cause the greenhouse-icehouse transition or whether a threshold level of CO2 ultimately induced global cooling cannot be determined from their results.