Thread by @newscientist

The global population has hit 8 billion

Yet while our overall numbers are still growing fast, fertility rates are plummeting and in much of the world are now below replacement level🧵
#8billion
newscientist.com/article/234615…

In these countries, populations are either falling already - as in Japan - or will do within decades

Where there is a high proportion of young people, there can be a lag between fertility falling below replacement and the population starting to fall
newscientist.com/article/mg2483…

Take the three largest countries

The population of China will begin to fall soon and could halve by 2100. India's could peak around 2050. And the US population would fall from the 2030s if not for immigration
newscientist.com/article/216911…

In 2019, the UN forecast that the population would keep rising to 11 billion by 2100, but its latest forecast this year is that it will peak in the 2080s at 10.4 billion

Two other forecasts predict the peak will come even earlier, by around 2070 and under 10 billion

It's the number of rich people that matters when it comes to climate change and biodiversity - the rich have vastly larger environmental footprints

Nevertheless, an early peak in population will make it easier to limit the damage
newscientist.com/article/223201…

But declining populations with a growing proportion of older people will bring big challenges too, putting huge pressure on care and pension systems
newscientist.com/article/mg2563…