Polar bears will slip into extinction before the end of the century as global warming grips, a shock new report has predicted.

Meanwhile, ninety-five per cent of the Great Barrier Reef’s corals could vanish and 75% of the Antarctic’s Adelie penguins be gone by 2050, according to the Climate Change and Species report commissioned by WWF and Earth Hour.

The report examines how some of the globe’s most iconic species will be hit by climate change and rising sea levels — and it makes for grim reading.

It reveals how a host of whale and dolphin species — many of which frequent the waters around Ireland — face starvation as their sea ice habitats and prey species vanish away. Sperm whales and beaked whales could lose their key prey, squid, as increasing levels of carbon dioxide in the atmosphere are absorbed by the ocean, leading to acidification.

Marine turtles are also under threat as temperature extremes cause mortality in eggs and hatchlings. Huge leatherback turtles have been spotted in Northern Ireland’s waters, including the one that was found dead in Strangford Lough last year with a plastic bag in its stomach. The report predicts that sightings of marine turtles in UK waters could become more frequent as changing ocean currents disrupt migration routes.

Species living at the poles are particularly at risk as the rate of warming there is much higher than the global average and there is no colder habitat for the animals to move to, the report revealed.

“At current rates of temperature increase, by the middle of the 21st century, almost half of polar bear summer habitats are predicted to be lost,” the report said. “The thinning and earlier break-up of sea ice in the Arctic is believed to be reducing the body weights of female polar bears and by 2012 the average body weight may be too low for them to reproduce.

“With 2C of warming, thinning sea ice in the Antarctic is predicted to cause the loss of 75% of Emperor penguin colonies and 50% of Adelie penguin colonies.

“Albatross, the most endangered group of birds worldwide, depend on sub-Antarctic islands in the Southern Ocean to breed and nest and are highly susceptible to climate change.”

The report picked out 10 key species and examined how they will be affected — including polar bears, Bengal tigers, reef-building corals, kangaroos, and albatrosses.

Orangutans could be lost from the wild within decades and 400 of the world’s 1,400 wild Bengal tigers live in mangrove swamps in the Sunderbans of India and Bangladesh.

The report has been produced to coincide with Earth Hour at 8.30pm on March 28, when governments, corporations and individuals will switch off the lights for an hour to draw attraction to the need for action on climate change.

In Belfast, the Victoria Square dome, Belfast Wheel, Queen’s University and the City Hall will all be plunged into darkness as part of the biggest ever mass global action on climate change.

WWF aims to inspire one billion people in more than 1,000 cities to sign up and switch off their lights.

To date, nearly 700 cities in more than 75 countries have signed up for Earth Hour, including London, Cardiff, Edinburgh and Belfast in the UK and hundreds of others around the world, from Cape Town, Dubai, Hong Kong and Istanbul to Las Vegas, Los Angeles, Mexico City, Moscow, Singapore, Sydney and Toronto.

Belfast Lord Mayor Tom Hartley said: “Belfast City Council is delighted to support Earth Hour 2009. The Council is committed to creating a greener, cleaner city where good environmental practice is at the core of all policy and practice.

“There are many positive steps that the council, local citizens and businesses can take o reduce the city's carbon footprint and to protect our valuable resources for future generations.” Sign up to WWF Earth Hour on wwf.org.uk/niearthhour or text Earth to 84880.