About half a century ago, with childbirths increasing, experts warned of a "population bomb" which could lead to catastrophic climate change and widespread food and water shortages.

Today, a growing number of demographers are convinced that, far from continuing to expand, human population on this planet will stabilize and then start to decline.

A U.N. report suggests that the world's population is growing at its slowest pace in 70 years, and will reach a peak before the end of this century.

Low fertility rates combined with better healthcare are accelerating the aging of societies.

So, instead of a population bomb, are we now facing the challenge of a population bust? Should we be worried?

Host Zhao Ying is joined by Prof. Francesco Billari from Bocconi University in Italy, Prof. Lauren Johnston at China Studies Center, University of Sydney, and Chris Rowley, Professor Emeritus at Bayes Business School, City, University of London.