Researchers at the University of Washington’s Institute for Health Metrics and Evaluation have warned that the planet is not prepared for an ongoing global population crash, and that the impact will be “jaw dropping”.

The BBC reports that the research, published in the Lancet highlights that the global fertility rate almost halved to 2.4 in 2017, and projections indicate that it will fall below 1.7 by 2100. For further context, In 1950, an average of 4.7 children were being born for every woman. The research suggests that almost every country on the planet could have shrinking populations by the end of this century, with 23 nations projected to see their populations halve by 2100.

The research indicates that the total global population will peak at 9.7 billion in 2064, and then naturally shrink back to 8.8 billion come the end of the century. Fewer births and longer life expectancy will also mean a drastically older population. “That’s a pretty big thing; most of the world is transitioning into natural population decline,” Professor Christopher Murray noted. “I think it’s incredibly hard to think this through and recognize how big a thing this is; it’s extraordinary, we’ll have to reorganise societies,” Murray further warned.

The research highlights that Japan’s population likely peaked at 128 million in 2017 yet will fall below 53 million by 2100. In addition, Italy’s population is expected to crash from 61 million to 28 million in the same time period. “It will create enormous social change,” Professor Murray urged, adding “Who pays tax in a massively aged world? Who pays for healthcare for the elderly? Who looks after the elderly? Will people still be able to retire from work?” “We need a soft landing,” Murray warned.

When asked whether the trend could threaten the human race, Murray said “I find people laugh it off; they can’t imagine it could be true, they think women will just decide to have more kids.”

“If you can’t [find a solution] then eventually the species disappears, but that’s a few centuries away.” Murray added.