In the disturbing segment, walruses could be seen perched precariously on the edge of the rocky cliffs.
The show is now being accused of over-dramatising the wildlife footage by unnecessarily linking it to climate change.
Susan Crockford, a leading zoologist and professor at the University of Victoria in British Columbia, Canada, says the animals were likely to have been driven over the cliffs by polar bears chasing them
She accuses the documentary film-makers of "tragedy porn" and "emotional manipulation" for the sake of audience numbers.
Crockford described the segment as "contrived nonsense" in an interview with the Telegraph.
"This powerful story is fiction and emotional manipulation at its worst," she said.
"The walruses shown in this Netflix film were almost certainly driven over the cliff by polar bears during a well-publicised incident in 2017, not because they were confused by a combination of shrinking ice cover and their own poor eyesight.
"Even if the footage shown by Attenborough was not the 2017 incident in Ryrkaypiy, we know that walruses reach the top of cliffs in some locations and might fall if startled by polar bears, people or aircraft overhead, not because they are confused by shrinking sea ice cover.
"The bears were then able to feed off the many carcasses after the survivors took to the water."
This is not the first time a David Attenborough show faces this type of accusations.
In 2011, Frozen Planet was forced to admit that film-makers used footage of cubs taken at a zoo using fake snow in the Netherlands and spliced it with polar bear clips from the wild.
In 2017, BBC's Blue Planet 2 admtted using studio shots taken in laboratories, featuring images of coral bleaching that could only be filmed with lights and specialised cameras.
