We don’t know too much about Guy Stewart Callendar as a person. Except that he was a steam engineer, minor inventor, and amateur climatologist / weather watcher. Interestingly, his father Hugh was a professor at Imperial College London who invented a rolling chart thermometer that measured climatic data over long periods. So it seems Guy pulled these threads together to put a callendar line on global warming.
A Short History of the Guy Callendar Line on Climate Change
In the public eye, Guy Callendar was an unassuming man conducting steam and pressure research on behalf of the British Electrical and Allied Industries Research Association. He also researched batteries as we shall investigate for another post.

In his spare time, he loved to walk across the hills and dales of England watching clouds of water vapor form and dissipate in the sky. He began to collect historic global temperature measurements be believed related to carbon dioxide emissions. However, like Svante Arrhenius he thought this was a good thing, because it would prevent ‘deadly glaciers’ forming and enable richer harvests.
He published a callendar line of his findings in 1938. This showed ‘temperature variations of the zones and of the earth from 1901 to 1930’. While creating the graph may seem a simple matter now, there were no computers – or even pocket calculators in 1938. His numbers proved remarkably accurate.

Organized science treated his work as scribblings by a naive amateur and generally ignored them. As recently as April, 2013, Prof. Jones, of the UEA’s Climatic Research Unit and Dr. Hawkins, from Reading’s National Centre for Atmospheric Science commented, “He is still relatively unknown as a scientist, but his contribution was fundamental to climate science today.”
Scientists Could Not Believe the Human Impact
Guy Stewart Callendar, the first person to prove the mechanics of global warming died almost unnoticed aged 67 in 1964. “Scientists at the time also couldn’t really believe that humans could impact such a large system as the climate,” Dr. Hawkins told BBC News ruefully. “A problem that climate science still encounters from some people today, despite the compelling evidence to the contrary.”
How Carbon Dioxide Is Earth’s Thermostat
Climate Change Part 5: Greenhouse Understood
Preview Image: Guy Callendar
Link to Guy Callendar’s Original Report