BBC Future answers five key questions about China's recent population decline and what it might mean for global demographic trends.

With up to three billion people expected to be displaced by climate change by 2100, does there need to be a shift in the way we think about national borders, asks Gaia Vince?

This year, the human population on Earth is expected to reach eight billion. To mark the occasion, BBC Future takes a look at one of the most controversial issues of our time.

China's population is set to get smaller for the first time since the great famine struck 60 years ago. Why? And how will this affect the rest of the world?

One of the most important economic hubs in Latin America, rich in history, arts, culture and gastronomy, this metropolis has become 'the one' to visit