When Will the Population Reach 9 Billion? The more people who need food, water, shelter, health care, education, and employment, the more our agricultural systems, human institutions, and public infrastructure will need to grow and the more the environment and other species feel the strain. Consumption levels vary by individual and by world region, but everyone has infrastructure needs and contributes to environmental degradation to some degree. The steep ascent over the past two centuries has created growing pains for families, communities, countries, and the planet.

The growth of the human population over time can be depicted by what is known as the population j-curve, which shows how sharply our population has risen in the last 200+ years. In fact, 96% of global population growth since the 7 billion milestone has occurred in less developed countries.

Most of the growth around the world occurs in less developed countries-places already struggling to provide for their citizens, especially in the midst of the climate crisis (which has been disproportionately caused by people in high-income countries). The UN projects that it will take 15 years to reach the 9 billion mark and 21 more years to reach 10 billion. The last several billion milestones (4, 5, 6, 7, and 8 billion) were reached in 14, 13, 11, 12, and 12 years, respectively. It took 123 years to reach 2 billion, and only 33 years to reach 3 billion. When Did the World Population Reach Other Milestones? With more people surviving to adulthood and then having kids of their own, the human population started growing exponentially. The drop in mortality while fertility remained unchanged caused the beginning of what is now known as the J-curve (see below). Modern medicine and sanitation played heavily in reducing mortality rates-especially among infants and children-but there wasn’t yet a reliable way to reduce fertility (the first modern contraceptive, the birth control pill, wasn’t introduced until 1960). In fact, it took all of human history, until around 1804, to reach 1 billion people. Until the Industrial Revolution began, birth rates and death rates were both very high, which kept the global human population relatively stable. When Did the World Population Reach 1 Billion? After passing the 7 billion milestone in 2010, it has only taken 12 years to add the latest billion. We will become a world of 8 billion in 2022.

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