James Lovelock, the scientist who created the Gaia hypothesis in the 1970s, died on his 103rd birthday on Tuesday. The independent British scientist was at home and surrounded by his loved ones, his family said. Lovelock’s pioneering climate research led to him becoming one of the most respected researchers in the U.K. His Gaia hypothesis conceives of life on Earth as a self-regulating system of organisms interacting with each other and their inorganic surroundings. His family said in a statement that he was still able to walk along the south coast of England where he lived up until a fall around six months ago. “To the world he was best known as a scientific pioneer, climate prophet and conceiver of the Gaia theory,” his family added. “To us he was a loving husband and wonderful father with a boundless sense of curiosity, a mischievous sense of humor and a passion for nature.”