"The rapid surface warming of the Antarctic Peninsula and the enhanced global warming signal over the whole continent shows the complexity of climate change," said lead author John Turner of the British Antarctic Survey, which published the study in the Friday edition of Science magazine.

"Greenhouse gases could be having a bigger impact in Antarctica than across the rest of the world and we don't understand why."

Weather-balloon instrument readings high in the Antarctic atmosphere showed the continent warming at a rate of 0.5 to 0.7 degrees C (0.9 to 1.26 degrees F) per decade during the 30-year study. The average rise worldwide has been 0.2 degrees C (0.36 degree F) per decade, the study said.

"The largest warming of almost 0.75 degree C (1.35 degrees F) per decade was found close to five kilometres (13,000 feet) above the surface," the study said.

"That is over three times the rate of warming observed for the world as a whole."

The study used radiosonde wintertime measurements between 1971 and 2003.

Scientists added that although the warming atmosphere at earth's surface receives the most attention, the upper atmosphere is warming more rapidly, some 4,000 to 5,000 meters (13,000 to 16,000 feet).