Abrupt climate change has occurred on earth many times over the past millions of years. Climate scientists hypothesize that these sharp transitions may be caused when the earth system reaches a tipping point, or a critical value, resulting in a change of several degrees. These abrupt transitions have caused, for example, the formation and melting of glaciers throughout the earth, North Africa’s change from savannah to desert 5,000 years ago, and various other changes.  Read More

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