A Canadian researcher has found new evidence that — contrary to previous belief — the past 6,000 years have been marked by large-scale climate changes occurring naturally, on a regular basis. He and his research team have documented four abrupt climate shifts over the past 5,500 years in western Canada, occurring on average every 1,220 years. Until now the last 6,000 years has been considered climatically stable, with the main evidence of large-scale shifts being found in the Greenland ice cores and sediments from the Atlantic Ocean. The team’s findings are reported in the current issue of the Proceedings of the National Academy of Sciences.