摘要
Ticino in southern Switzerland played host this summer to a most extraordinary meeting of minds. About eighty scientists from all over the world came together in the exquisite setting of Monte Verita to discuss possibly the coldest spell in our planet＇s long history： the Cryogenian Period. ‘Snowball Earth 2006＇ was organized by a research group at the ETH in Zurich under the leadership of Professor Philip Allen, now at Imperial College, London, and was the first conference to focus solely on this topic. The Cryogenian global freeze of about 7204535 million years ago closely preceded--some would say ominously so--the first fossil evidence for animal life on Earth, and as such has attracted the attention of natural scientists worldwide. Such a resurgence of interest in deep Earth history has not been witnessed since the great K/T boundary debate of the early 1980s. On the first day of the conference, on a hot and sultry evening during the hottest July on record, it was ice of a different kind that was being broken high above Lago Maggiore. The first hesitant introductions over chilled white wine made it clear that a tluly multidisciplinary throng had been invited for what promised to be a vigorous debate on the causes and effects of Neoproterozoic climate change. Gathered for the ＇snowball fight＇ were geologists, palaeobiologists, geochemists, geophysicists and climate modellers, all of whom would, one-by-one over the coming five days, borrow centre stage to offer their unique perspective on this most polarizing of topics.
