Emperor penguins could face extinction if temperatures continue to rise as melting sea ice will have a ripple effect on the birds’ food chain, new research has warned.

At nearly four feet tall, Antarctica’s largest sea bird has gained worldwide affection thanks to films like March Of The Penguins and Happy Feet, but if temperatures were to rise their numbers could fall by a third by the end of the century.

Researchers behind the first comprehensive study into the future of the species say their findings suggest that emperor penguins should be protected by the Endangered Species Act.

The study was published in the journal Nature Climate Change and is based on computer models simulating melting sea ice if temperatures in the region rise.

Too little affects food availability as it reduces the amount of marine prey available to the penguins, whereas too much forces adults to travel further to forage for food to bring back to their chicks.

Disappearing ice affects the fish, squid and krill the penguins eat, which in turn feed on zooplankton and phytoplankton that grow on the ice. If the ice goes, so will the plankton - causing a ripple effect through the food web that could starve the various species penguins rely on for food.

Dr Stephanie Jenouvrier, of Woods Hole Oceanographic Institution, Massachusetts, and colleagues analysed population trends for the 45 known emperor penguin colonies, taking account of the various sea ice conditions forecast.