Global warming is pushing the tropical regions of the planet towards the limits of human livability, according to a new study by researchers from the Princeton University.
If global heating is not curbed to 1.5C above the pre-industrial era, tropical areas could change into whole 'new environments that would hit the limit of human adaptation'.
Currently, 40% of the world's population live in the tropics and this population will only increase by 2050.
The study concludes that in the coming decades, 3 billion people could be pushed beyond the historical range of temperature that humans have survived.