The long-term ice record (from 1964 to 2008) of an Arctic lake in northern Europe (Lake Kilpisjärvi) reveals the response of lake ice to climate change at local and regional scales. Average freeze-up and ice breakup occurred on 9 November and 19 June, respectively. The freeze-up has been significantly delayed at a rate of 2.3 d per decade from 1964 onward (P