Climate a factor in Rome's rise and fall - study

OSLO (Reuters) - Climate change seems a factor in the rise and fall of the Roman empire, according to a study of ancient tree growth that urges greater awareness of the risks of global warming in the 21st century.

Good growth by oak and pine trees in central Europe in the past 2,500 years signalled warm and wet summers and coincided with periods of wealth among farming societies, for instance around the height of the Roman empire or in medieval times.