The world’s population is expected to peak around 9.7 billion in 2064 before falling back by almost a billion by the start of the next century, according to a new study published on Wednesday in the Lancet.
The report’s projected global population of 8.8 billion in 2100 is around two billion lower than some previous estimates, and contrasts with the UN’s consistent projections of continued global growth. It represents a huge challenge to world leaders to re-think policies to cope with changing demographics and their consequences.
Scientists say the key factors in generating widespread, sustained declines in fertility are improvements in access to modern contraception and the education of girls and women. All but seven of 195 countries surveyed are predicted to have falling fertility rates by 2100, according to the Institute for Health Metrics and Evaluation (IHME) at the University of Washington's School of Medicine.
Its report predicts a massive rise in the proportion worldwide of the elderly to those of working age. The over-80s will outnumber under-5s by two to one, say researchers. Immigration will be key to the health of most economies.
It also predicts big shifts in global power, with Africa increasingly important. Nigeria will join the US, China and India as the world’s leading economic powerhouses, the report suggests.
IHME Director Christopher Murray, who led the project, said: "Continued global population growth through the century is no longer the most likely trajectory for the world's population.
"This study provides governments of all countries an opportunity to start rethinking their policies on migration, workforces and economic development to address the challenges presented by demographic change."
Professor Stein Emil Vollset, of IHME, said: "The societal, economic, and geopolitical power implications of our predictions are substantial.
"Our findings suggest that the decline in the numbers of working-age adults alone will reduce GDP growth rates that could result in major shifts in global economic power by the century's end. Responding to population decline is likely to become an overriding policy concern in many nations but must not compromise efforts to enhance women's reproductive health or progress on women's rights.”
The new forecasts highlight the huge challenges to economic growth of a shrinking workforce, the high burden on health and social support systems of an ageing population, and the impact on global power linked to shifts in world population. Free-flowing immigration policies will be essential to prop-up shrinking workforces, researchers say.
Even in Niger, where the fertility rate was the highest in the world in 2017 - with women giving birth to an average of seven children - the rate is projected to decline to around 1.8 by 2100. That compares with the 2.1 figure necessary to sustain population.
More than 20 countries are expected to see their populations shrink by more than 50 per cent. They include Italy, Spain, Japan and Thailand.
China is set to replace the US as the largest economy in 2035, but America is forecast to once again become the largest economy in 2098 - bolstered by immigration, scientists said. Dramatic declines in working age-populations will hamper economic growth even in India and China, though they will be among the major global players.
Richard Horton, editor-in-chief, The Lancet, said: "The 21st Century will see a revolution in the story of our human civilisation. Africa and the Arab World will shape our future, while Europe and Asia will recede in their influence.
"By the end of the century, the world will be multi-polar, with India, Nigeria, China, and the US the dominant powers. This will truly be a new world, one we should be preparing for today."
Fonte: The Telegraph
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