The Professor of Gerontology and Director of the Oxford Institute of Population Ageing looks at population trends to highlight the key issues facing us in the coming decades, including the demographic inertia in Europe, demographic dividend in Asia, high fertility and mortality in Africa, the youth bulge in the Middle East, and the balancing act of migration in the Americas. Harper analyses the global challenges we must plan for, such as the impact of climate change and urbanisation, and the difficulty of feeding 10 billion people. She considers ways in which we can prepare for and mitigate against these challenges.