Claude Lorius, a leading glaciologist whose expeditions helped prove that humans were responsible for global warming, has died at the age of 91. He led 22 expeditions to Greenland and Antarctica during his lifetime. It was during one trip to Antarctica in 1965 where ice cubes in his drink one evening led him to prove humankind"s role in the heating of the Earth"s surface. Lorius died on Tuesday morning in the French region of Burgundy. It was his love of adventure which set him on the path to identifying and predicting an impending catastrophe for the planet. In 1956, just out of university, he joined an expedition to Antarctica. Temperatures there were as low as -40C (-40F). Despite this, Lorius and two other people lived there for two years, surviving with limited supplies and a faulty radio. The more polar expeditions he led to the continent, the more he became fascinated with Antarctica"s mysteries. In 1965, Lorius had a revelation by gathering ice samples and dropping them in alcohol. He spoke about it half a century later. "Seeing the bubbles of air sparkling in our glasses, I came to the idea that they were samples of the atmosphere trapped in the ice." Realizing the scientific potential of analyzing trapped air, he then decided to study ice cores - samples drilled out of the ice which act as frozen time capsules. By drilling into the ice, Lorius drilled into the past, penetrating, in his words, the "ice of the first Ice Age". His research into air bubbles trapped in the ice was published in 1987. It showed that while carbon dioxide had varied slightly, after the Industrial Revolution concentrations of the greenhouse gas had rocketed as temperatures rose. Lorius"s research brought him international renown and allowed scientists to look back over 160,000 years" worth of glacial records. The French National Center for Scientific Research (CNRS) said it left "no room for doubt" that global warming was due to man made pollution. From then on he became a campaigner and in 1988 he was the inaugural expert of the United Nations Intergovernmental Panel on Climate Change. In 2002, he was awarded the CNRS gold medal along with his colleague Jean Jouzel. Lorius was also the first Frenchmen to receive the prestigious Blue Planet Prize. — BBC