Sir David Attenborough has said coral reefs could be dead within 80 years time due to environmental pollution and human “maltreatment of the oceans”.

The naturalist, who made the stark warning on Blue Planet II’s final episode on Sunday, said carbon dioxide emissions were making the oceans more acidic.

The growing acidity of the ocean could signal catastrophe for the fragile eco-system of reefs because coral and seashells are dissipating more speedily than sea creatures are able to reconstruct them.

The veteran broadcaster said the world’s oceans were "under threat now as never before” and the reef would be dead by 2100. Sir David said the combination of climate change, plastic pollution and over-fishing was all contributing to the death of coral reefs.

"Coral reefs could be gone by the end of this century," Chris Langdon, professor of Marine Biology and Ecology at the University of Miami's Rosenstiel School of Marine and Atmospheric Science, told Sir David on the show.

The 91-year-old replied: "The cause of this? Carbon dioxide. The more carbon dioxide in the atmosphere, the more acidic the ocean becomes”.

"Evidence points to the burning of fossil fuels as the primary cause for these increasing levels of carbon dioxide. And this is man-made beyond question?" Sir David asked Langdon.

David Attenborough: Life in pictures Show all 35 1 /35 David Attenborough: Life in pictures David Attenborough: Life in pictures 1957 David Attenborough with his three-year-old daughter Susan, as they cover their ears while sulphur-crested cockatoo Georgie lets out a piercing shriek David Attenborough: Life in pictures 1950 David Attenborough with his wife Jane Oriel and older brother and film actor Richard Attenborough at St. Anne's Church, Kew Green David Attenborough: Life in pictures 1955 David Attenborough, holding his son Robert, whilst looking at an animal called a coatimundi, brought home from the combined London Zoo David Attenborough: Life in pictures 1955 David Attenborough and Jack Lester, curator of London Zoo's reptile house, plan their next expedition to British Guiana with the help of Gregory the parrot David Attenborough: Life in pictures 1956 David Attenborough with six-year-old Michael Webb of Kingsbury pets a Capybara after Sir David had lectured to children on the 'Zoological Expedition to British Guiana' at the Royal Geographical Society in Kensington David Attenborough: Life in pictures 1957 David Attenborough, with wildlife photographer Charles Lagus, preparing to depart for New Guinea to make 'Zoo Quest' at London Airport Getty Images David Attenborough: Life in pictures 1958 Prince Charles with his sister Princess Anne meeting Sir David Attenborough and Cocky, the cockatoo brought back from his last Zoo Quest expedition, at the BBC Television Studios in Lime Grove, London David Attenborough: Life in pictures 1961 David Attenborough with two ring-tailed lemurs during a Christmas lecture at London zoo David Attenborough: Life in pictures 1963 David Attenborough with an armadillo from 'Attenborough's Animals' David Attenborough: Life in pictures 1965 David Attenborough after he was appointed the new head of BBC 2 David Attenborough: Life in pictures 1965 David Attenborough and Michael Peacock, Contoller of the BBC, with soft toy versions of Hullabaloo and Custard, the kangaroo mascots which were used as logos for the launch of BBC 2 David Attenborough: Life in pictures 1980 David Attenborough shows Charlie the Llama to schoolboy Patrick Flynn, the millionth child to attend London Zoo's educational lectures and tours David Attenborough: Life in pictures 1982 David Attenborough feeds orangutan David Attenborough: Life in pictures 1985 David Attenborough after being knighted by the Queen at an investiture at Buckingham Palace, London, with his wife Jane (right) and daughter Susan David Attenborough: Life in pictures 1985 David Attenborough signs his book 'the Living Planet' in a Sydney Bookstore in Australia 2004 Getty Images David Attenborough: Life in pictures 1986 David Attenborough with Queen Elizabeth II filming the Christmas Message in the Royal Mews at Buckingham Palace David Attenborough: Life in pictures 1990 David Attenborough poses for a photograph David Attenborough: Life in pictures 1995 David Attenborough watches nature during the filming of Natural Curiosities David Attenborough: Life in pictures 2000 David Attenborough and his wife at the Tate Modern Art Gallery opening party David Attenborough: Life in pictures 2002 David Attenborough with meerkat on his shoulder being filmed for BBC series Life of Mammals David Attenborough: Life in pictures 2003 A python greets Sir David Attenborough during a photo opportunity at Taronga Park Zoo in Sydney, Australia Getty Images David Attenborough: Life in pictures 2003 Sir David Attenborough holds a baby salt water crocodile during a photo opportunity at Taronga Park Zoo in Sydney, Australia Getty Images David Attenborough: Life in pictures 2005 David Attenborough poses with The Swan Hellenic Oldie of the Year Award at the 'Oldie Of The Year Awards' honouring veteran notables together with Britain's oldest celebrity superstars, at Simpsons in the Strand in London. Sir David Attenborough was announced as the Swan Hellenic Oldie of the Year at the 13th annual awards Getty Images David Attenborough: Life in pictures 2005 David Attenborough plants a Wollemei Pine at Kew Gardens in London Getty Images David Attenborough: Life in pictures 2005 David Attenborough signs copies of his latest publication Life In The Undergrowth, published in relation to the BBC One series, at the Natural History Museum in London Getty Images David Attenborough: Life in pictures 2006 Sir David Attenborough and Lord Richard Attenborough robe up, before they are awarded the title of Distinguished Honorary Fellowships from the University of Leicester at De Montfort Hall in Leicester Getty Images David Attenborough: Life in pictures 2007 Sir David Attenborough launches National Moth Recording Scheme at London Zoo in London Getty Images David Attenborough: Life in pictures 2008 Sir David Attenborough sits in The Queen's Gallery, Buckingham Palace in the Amazing Rare Things exhibition in London Getty Images David Attenborough: Life in pictures 2009 Prince William, Dr Michael Dixon and Sir David Attenborough host the opening of the The New Darwin Centre at The Natural History Museum in London Getty Images David Attenborough: Life in pictures 2011 Britain's Queen Elizabeth II speaks with naturalist David Attenborough during a special exhibition of artefacts from the Royal Collection and Royal Archives at Buckingham Palace in London Getty Images David Attenborough: Life in pictures 2011 Sir David Attenborough with the Specialist Factual award at the Philips British Academy Television Awards at the Grosvenor House in London David Attenborough: Life in pictures 2012 Sir David Attenborough poses with a floral sculpture of himself outside the Royal Botanical Gardens at Kew Gardens in London Getty Images David Attenborough: Life in pictures 2012 Sir David Attenborough at the UKTV Showcase held at the Saatchi Gallery in west London David Attenborough: Life in pictures 2013 David Attenborough during the filming of "Micro Monsters with David Attenborough," a series about insects David Attenborough: Life in pictures 2016 Sir David Attenborough attends the launch of the London Wildlife Trust's new Flagship nature reserve Woodberry Wetlands in London Getty Images

He replied "beyond question” but said the demise of the reefs could be prevented by moving from fossil fuels to renewable energy sources such as solar and wind.

“For years we thought the oceans were so vast and the inhabitants so infinitely numerous that nothing we could do could have an effect upon them. But now we know that was wrong,” Sir David said.

“It is now clear our actions are having a significant impact on the world’s oceans. [They] are under threat now as never before in human history. Many people believe the oceans have reached a crisis point.

“Surely we have a responsibility to care for our blue planet. The future of humanity, and indeed all life on Earth, now depends on us.”

Blue Planet II, which was Britain’s most-watched show of 2017 and saw 14 million tune in for the first episode, released an article explaining what can be done to help preserve the sea. The first piece of advice was simple and was just to pick up litter at the beach.

The Great Barrier Reef, which is the world’s largest coral reef system and made up of almost 3,000 individual reefs and 900 islands, was of course included in Sir David’s warning.

Climate change and consequential sea temperature rises are believed to have led to widespread coral “bleaching” of the reef which is located off the Queensland Coast – with the reef also under threat from pollution.

While bleaching is not always fatal for coral last year a study found the “largest die-off of corals ever recorded” with about 67 per cent of shallow water coral found dead in a survey of a 700km stretch.

Unesco has fought against calls to return the reef to its “endangered” list but it has voiced “serious concerns” and called for the Australian government to improve water quality.