大象传媒

Physicist Helen Czerski discovers evidence for the climatic cycles that produce ice ages. She finds that tiny changes in Earth鈥檚 orbit are enough to create ice ages that could be catastrophic to much of life on Earth. Another one is due in about 60,000 years. She uses an interesting, counterintuitive clue. Ice ages result in much lower sea levels. So, by diving into an extraordinary cave system, the Blue Hole, off Belize, Helen finds evidence that the underwater caves used to be on dry land. That is because they contain stalactites, which cannot have formed underwater. Helen also goes to Scotland to show that if Summers are slightly cooler ice can begin to stay all year. This can then build up to form a glacier.