According to the new study, published in the journal The Lancet, the earth's population will be about 8.8 billion people by 2100, which is about one billion more than today.

Contrary to the UN forecast, researchers at the University of Washington in Seattle expect lower birth rates. It is believed that the population will increase in a handful of countries - mainly in sub-Saharan Africa - while birth rates will decrease globally.

Fewer will support more

According to the study, the population may be halved in countries such as Japan, Spain, Italy and Poland. Above all, fertility is affected by the fact that women globally have greater opportunities for education. Women who are educated and working give birth to fewer children.

Livia Oláh, Associate Professor of Demography.

- Fertility is without a doubt the driving force in how many people we will become in the world. Now we have in several countries a fertility development that is at an almost unsustainably low level, says Livia Oláh, associate professor of demography, to SVT News.

At the same time, the population is getting older - which means that fewer able-bodied people have to support more elderly people. It can have major consequences for the economy and several countries are now running active campaigns to get women to give birth to more children and thereby stabilize the age structure. For example, Poland has introduced subsidies to benefit mothers of many children.

- From an economic point of view, it is best to have a population structure where you have more children than older people. This can lead to major political problems, for example, will we be able to afford the welfare state and maintain our standard of living? Maybe we need to raise the retirement age, says Livia Oláh and continues:

- Everyone must go out and work so that we can provide for the elderly population. This does not bode well for the economy in the long run.

Can be positive for the climate

But so it was with the climate.

- In this study, the climate issue is not taken into account, however, it is mentioned that there are better prospects for the climate if we are fewer on earth. So there are positive outcomes of this development.

Livia Oláh has another future investigation that may affect:

- No one can predict how the increasing digitalisation will affect economic development, which may balance out the effect of aging.