Beginning in 1938, Guy Stewart Callendar (1898-1964), a noted steam engineer and amateur meteorologist, revived the carbon dioxide theory of climate change by arguing that rising global temperatures and increased coal burning were closely linked. Working from his home in West Sussex, Callendar collected weather data from frontier stations around the world, formulated a coherent theory of infrared absorption by trace gases, and demonstrated that the carbon dioxide content of the atmosphere, like the temperature, was indeed rising. This later became known as the "Callendar effect".

The collection comprises notebooks, correspondence, and other documents of G.S. Callendar. They include family papers and his war-time work on climate. All items have been digitised for reference purposes.

A full description of the collection can be found at the Archives Hub.