Global warming will drive billions of people out of the "climatic niche" in which humanity has thrived for millennia, a study estimates, exposing them to unprecedented temperatures and extreme weather. The world is on track for 2.7°C of warming with current action plans, which would mean that by 2030, 2 billion people will have average annual temperatures above 29°C, a level at which very few communities have lived in the past. Scientists said up to 1 billion people could choose to migrate to cooler places, although those areas that remain in the climate niche will continue to experience heat and drought. However, urgent action to reduce carbon emissions and keep global temperature increases to 1.5°C would reduce the number of people pushed out of the climate gap by 80 % to 400 million. The analysis is the first of its kind and manages to treat every citizen equally, unlike previous economic assessments of the damage caused by the climate crisis, which have been biased towards the rich. (Damian Carrington)