Sub-Saharan extends from West Africa to Kenya and Ethiopia. About a billion people live there at the moment. Most live off what they grow themselves. If the total climate measure there increases by just two degrees, the productivity of working people drops by almost 50 percent! This is the case with everyone, no matter how long they have lived under these conditions. Contrary to what many believe, people do not adapt. This means that people can only work half the day and have less to eat. So they will migrate, to regions that are not so hot. There is the metaphor, the earth has fever - we are the pathogen because we underestimated which Stress means eight billion people for this planet. In the history of the development of the earth. I also studied geology and paleontology - there are periods during which the earth became very warm for a short time. The high temperatures meant that mainly small organisms survived.