New research suggests reducing the world's population will not reverse the global sustainability problem.
The researchers said the "virtually locked-in" population growth means policy makers must enact policies that focus on reducing consumption and encouraging recycling rather than reducing the number of people on the planet, the University of Adelaide reported.
"Global population has risen so fast over the past century that roughly 14% of all the human beings that have ever existed are still alive today - that's a sobering statistic," said Professor Bradshaw, Director of Ecological Modelling in the Environment Institute and School of Earth and Environmental Sciences. "This is considered unsustainable for a range of reasons, not least being able to feed everyone as well as the impact on the climate and environment."
To make their finding the researchers looked at different population change scenarios up to the year 2100 by adjusting fertility and mortality rates. They went through nine different population scenarios including "business as usual," fertility reductions, and large-scale catastrophes that cause loss of life.
"Even a world-wide one-child policy like China's, implemented over the coming century, or catastrophic mortality events like global conflict or a disease pandemic, would still likely result in [five to] 10 billion people by 2100," Bradshaw said.
Even a scenario in which as many people died as in the First and Second World Wars combined, there was little change in the population trajectory for the century.
"Our work reveals that effective family planning and reproduction education worldwide have great potential to constrain the size of the human population and alleviate pressure on resource availability over the longer term. Our great-great-great-great grandchildren might ultimately benefit from such planning, but people alive today will not," he explained.
The findings were published Oct. 27 in the journal Proceedings of the National Academy of Sciences.
