Humans currently number about 7 billion. This number is projected to exceed 9 billion by mid-century.
As our population grows, humans consume ever greater amounts of the Earth’s limited resources. Human overpopulation relates to every sustainability concern—from food supply and health to climate change and an Earth-centered economy.
The Industrial Revolution accelerated human population growth. For thousands of years, human population on Earth remained relatively steady. About 200 years ago, humans learned how to harness the energy of fossil fuels. This led to dramatically greater agricultural productivity, and human population began to grow exponentially.
The trajectory of population growth is unsustainable. It took all of human history until 1830 for world population to reach one billion. The second billion was achieved in 100 years, the third billion in 30 years, the fourth billion in 15 years, and the fifth billion in only 12 years.
For a helpful overview of the population crisis, see the summary at Worldometers.
The good news: our best strategies to curb population growth also achieve other sustainability goals. Actively improving the lives of people worldwide is our best insurance against the woes of overpopulation:
• Educate women and girls.
• Make health care available, including family planning.
• Alleviate poverty.
In taking these actions, we also achieve other important universal goals.
We Have Just Passed the 7 Billion Mark