This article was published in Nature and summarized the presentations of a six-day symposium held 3-8 July 1995 on Climate Variability and Forcing over the past mellennium. Our present climate is unusually warm, and the pattern of warming over the past century strongly suggests an anthropogenic influence from greenhouse gas and sulphate aerosols. That was the message emerging from a week-long symposium examining climate variability over the past 1,000 years, which brought together results from a growing array of observational techniques, analyses of natural records and model results.