Which British engineer linked fossil-fuel CO2 to warming in a 1938 paper?

Guy Stewart Callendar was the British engineer who linked fossil-fuel carbon dioxide to warming in a 1938 paper. His paper, “The Artificial Production of Carbon Dioxide and Its Influence on Temperature,” connected rising CO₂ with rising land temperatures.

Callendar was an engineer and inventor rather than a university climate specialist. He studied steam, high-temperature thermodynamics, batteries and fuel cells, but pursued climate questions as an independent researcher. In 1938 he assembled historical temperature records and atmospheric CO₂ measurements, concluding that global land temperatures had increased during the previous half-century.

His work built on the earlier greenhouse-effect calculations of Svante Arrhenius and other scientists. Callendar estimated climate sensitivity at about 2°C for a doubling of carbon dioxide, a value that was low compared with many modern estimates but strikingly influential for its time.

The paper initially met scepticism, yet Callendar continued publishing on warming, infrared radiation and anthropogenic CO₂. Charles Keeling’s precise Mauna Loa measurements, begun in 1958, later supplied the famous long-term record that strengthened the case for human-caused warming. The “Callendar effect” commemorates his contribution.