The world's population reached 8 billion today, which the UN described as a "milestone in human development" before it projects that birth rates will start to slow.

Having more people on the planet puts more pressure on our natural resources as people compete with wildlife for water, food and space. Experts have said that the rapid population growth, when combined with the effects of climate change, will cause mass migration and conflict in the years to come.

Middle-income countries, mostly in Asia, accounted for most of the growth over the past 10 years, adding around 700 million people since 2011. India added around 180 million and will overtake China as the most populated country next year.

The fossil fuels consumed by the population is not equal across all parts of the world. Carbon emissions of the richest 1% (around 63 million people) were more than double the emissions of the poorest half of the population according to analysis by the Stockholm Environment Institute and Oxfam International.

UN Secretary General António Guterres said: “Unless we bridge the yawning chasm between the global haves and have-nots, we are setting ourselves up for an 8-billion-strong world filled with tensions and mistrust, crisis and conflict."

Li Junhua, UN Under-Secretary-General for Economic and Social Affairs, said: "We need a rapid decoupling of economic activity from the current over-reliance on fossil-fuel energy, as well as greater efficiency in the use of those resources, and we need to make this a just and inclusive transition that supports those left furthest behind.”