The United Nation's demographic forecast predicts the world's population will be 11 billion by 2100. Bernard Salt takes a look at the numbers.

HE HAS been up close and personal with more dangerous and deadly species than most of us care to imagine.

But according to world-renowned naturalist David Attenborough the deadliest threat facing the Earth today is actually the man-made kind.

The 88-year-old has warned the human race faces dying out unless we tackle the world’s booming populations.

Speaking to UK newspaper The Independent, Sir David said the biggest problem in the natural world was the threat facing our own species.

“We can’t go on increasing at the rate human beings are increasing forever because the Earth is finite and you can’t put infinity into something that is finite,” he said.

“So if we don’t do something about it then the world will do something about it — the natural world that is — we will starve.”

He also said women gaining political control of their bodies and education were vital to ensuring population levels remained stable and viable.

However, Sir David warns even if this does take place, it may not be enough to save us from ourselves.

Sir David, who is a patron of UK charity Population Matters, which advocates for a sustainable future, has previously warned of the dangers humans are causing to the planet.

In a speech in 2011, the popular documentary maker warned overpopulation threatened not only the Earth but also its ecosystems which humans were destroying.

Sir David has been making wildlife shows for the BBC since the 1950s and his groundbreaking work has earned him a slew of awards.

But there’s one species he is yet to find and would be keen to discover — if humans don’t destroy its environment first.

During his long and illustrious career he has travelled across the globe to show viewers the most obscure species on the planet, but there the yeti was one mysterious beast he is keen to find.

The yeti is believed to be a massive apelike creature inhabiting the Himalayan mountains in Nepal.