 The world's population is expected to grow by more than 2 billion people in the next decades and peak in the 2080s at around 10.3 billion. That is a major shift from a decade ago, according to a new report by the United Nations. Thursday's report, released on World Population Day, said the global population is then expected to decline to around 10.2 billion by the end of the century. John Wilmot, the head of the UN Population Division, which prepared the report, said the probability that the world's population will peak within the current century is quite high.