Proving climate change: the 'Keeling Curve'

A young American scientist began the work that would show how our climate is changing in 1958. His name was Charles Keeling and he started meticulously recording levels of CO2 in the atmosphere. He would carry on taking measurements for decades. His wife Louise and son Ralph spoke to Louise Hidalgo about him and his work. (Photo: Thick black smoke blowing out of an industrial chimney. Credit: John Giles/PA)