Every child in the world is at risk from ecological degradation, climate change, migration and "predatory" marketing practices that push heavily processed food, warns a joint report by the UN, the World Health Organization and the Lancet medical journal.

Ranking 180 countries, child and adolescent health experts from around the world said that children in Norway, South Korea, and the Netherlands had the best chances to "survive and thrive".

Children in the Central African Republic, Chad, Somalia, Niger and Mali had the worst chances, it found.

"While some of the poorest countries have among the lowest carbon dioxide emissions, many are exposed to the harshest impacts of a rapidly changing climate," said Minister Awa Coll-Seck from Senegal, Co-Chair of the Commission.

The report also found that childhood obesity had increased 11-fold over four decades. Adverts for alcohol and e-cigarettes, as well as fast food and sugary drinks, are increasingly reaching children, it adds.

"The big message is that no single country is protecting children's health today and for their future," Anthony Costello, professor of International Child Health and Director of the Institute for Global Health at University College London, told AFP.