The global population has passed eight billion, the United Nations (UN) announced on Tuesday.
“This unprecedented growth is due to the gradual increase in human lifespan owing to improvements in public health, nutrition, personal hygiene, and medicine. It is also the result of high and persistent levels of fertility in some countries,” the UN says.
The organization estimates it will take approximately 15 years—until 2037— to reach 9 billion. According to the UN, it is a sign that the overall growth rate of the global population is slowing, as it took 12 years to grow from 7 to 8 billion.
Global population growth has over time become increasingly concentrated among the world’s poorest countries, most of which are in sub-Saharan Africa.
“In these countries, sustained rapid population growth can thwart the achievement of the Sustainable Development Goals (SDGs), which remain the world’s best pathway toward a happy and healthy future,” the organization says.