World renowned Brazilian photographer Sebastiao Salgado has crisscrossed the globe to document the extremes of globalisation, migration and unchartered territories, but is most troubled by mankind's reckless plundering of the planet, which he says is lethally short-sighted.

On a visit to Hong Kong to promote "Genesis", an exhibition of images which is a result of an epic eight-year worldwide expedition, the 70-year-old said humankind's drive to tame nature was taking the world to the brink of extinction.

"If we don't come back to our planet... we won't be here for too long," Salgado told AFP in an interview. "We are not part of our planet anymore, we have become aliens."

The documentary photographer has travelled to more than 100 countries, including Rwanda, Guatemala and Bangladesh, documenting some of the most gruesome horrors of the modern world: starvation, war, poverty and displacement.

His dramatic portraits of remote, decimated landscapes and vulnerable or exploited communities -- including ship breakers in Bangladesh and gold mineworkers in Brazil -- profoundly shaped the medium of black and white photography and inspired generations of photographers.

Raised in a rural part of central Brazil, Salgado was trained as an economist before turning to photography. He first picked up a camera loaned to him by his wife in his mid-twenties, and though he came to the profession later in life than most, he knew then his calling had come.

"For the first time I saw through a viewfinder and from this moment on, my life changed," Salgado said.

- 'Humans are profound predators' -

He turned professional in the early 1970s, and has since won an avalanche of prestigious awards, with his photographs hanging on the walls of the Barbican Gallery, London and the International Center of Photography in New York.

In the late 1990s, he was forced to take a hiatus after covering the Rwandan genocide, where he documented countless deaths, an experience that took a heavy psychological toll.

Salgado recalls the overwhelming stench of human decay as he watched piles of bodies being dumped in the ground by bulldozers, a sight that seared itself into his memory.

"I started to die, my body started to be sick," he said.

To recuperate, he decided to return to the farmland in Brazil where he spent his boyhood.

"I grew up in the hilly area... I remember my father walked with me in the big farms, we would walk to the highest part of the farm and sit there for hours seeing these incredible clouds, the lights crossing in between, it was enormous," he said.

But to his horror, the lakes had dried up and much of the rainforest had been lost to deforestation.

As his body and mind began to heal, he decided with his wife, Lelia to replant the rainforest that was there.

"Today we plant more than 2.5 million trees, it's all rainforest again. (We) saved the jaguars, we have more than 170 different species of birds," he said.

The husband-and-wife team run Amazonas Images, which handles the research, production and publishing of Salgado's photographs.

Salgado's stunning wildlife images -- penguins skidding across icebergs, a lone baboon crossing sand dunes, water dripping from the tail of a whale -- are matched by his robust criticism of humans, who he describes as "profound predators".

His stunning array of images is widely perceived as a call to arms for humans to preserve what they have.

"We start to destroy everything, we start to domesticate the cattle and put cattle in prison, we create them by the tens of thousands and millions so we can eat them," he said.