Human fertility has been dropping for years and is now below replacement levels - the minimum required to prevent depopulation - in scores of countries, including China, Japan, Canada, Brazil, Turkey, and all of Europe. The world's population is still rising, largely because of longer life spans - more people live to old age than in the past. But with far fewer children being born today, there will be far fewer adults bearing children tomorrow. In some countries, the collapse has already begun. Russia, for example, is now losing 700,000 people a year.