根据最新数据，当今世界一半多的人口、相当于39亿人居住在城镇地区；到2050年，城镇人口将再增加25亿，而且绝大部分增加的城镇人口将集中在 ...

BBC Bitesize has spoken to a selection of experts from different industries about some of the inventions we’re on ... The United Nations estimate that, by 2050, 10 million people per year ...