introduction to the Old World from the Americas, to estimate the impact of potatoes on Old World population and urbanization. Our … urbanization observed during the 18th and 19th centuries …

live in cities, about 55 per cent of the world's population. While population growth rates are declining and the world …'s population is likely to level off from the middle of the 21st century, probably ending up around 10 billion, further urbanization … the world will be sheltered from sweeping demographic changes due to population ageing and increasing migration. Such …

variety of historical and contemporary sources, it shows that there exists marked variation in the age structure of the world …