The distinguished climate scientists Thomas Anderson, Ed Hawkins and Phil Jones addressed this issue raised by some climate sceptics who thought that the climate system was too complex for meaningful analysis by ESMs. In a deeply researched paper Anderson, Hawkins and Jones totally repudiated such a view.

They concluded that ESMs were essentially trustworthy and had made a compelling case that global climate would continue to undergo significant warming in response to ongoing emissions of greenhouse gases to the atmosphere. This was even in the best scenario of reducing emissions.

Endeavour, July 2016 (online)

There us a widespread impression that the fact of global warming was only discovered recently. This is wrong.

The idea has been around for more than a century but it was only really put on the scientific map through the tremendous research of the British meteorologist and steam engineer Guy Callendar. He published a ground-breaking paper in 1938. A year later he reported a 7% increase in anthropogenic CO2 since 1900, the result of industrial emissions, the burning of fossil fuel:

“As man is now changing the composition of the atmosphere at a rate which must be very exceptional on the geological time scale, it is natural to seek for the probable effects of such a change. From the best laboratory observations it appears that the principal result of increasing CO2… would be a gradual increase in the mean temperature of the colder regions of the earth” (too little data was available for the southern hemisphere at that time).

Quarterly Journal Royal Meteorological Society (1939).

Scholars from ancient Greece to Fourier in the 18C, John Tyndall and Svante Arrhenius in the C19,, and since 1900, had debated the nature and causes of climate change they had observed (unsystematically). But it took a “weather nut”, Guy Callendar(1899-1964), first to identify that global warming had taken place by at least 0.5 degrees Celsius in the first three decades of the C20; and scientifically to identify expanding CO2 in the atmosphere from industrialisation as the likeliest culprit.

He estimated there had been a 10% increase in the concentration of CO2 between 1900 and 1938, the year he wrote a truly pioneering paper on the subject.

Callendar, who was a distinguished English steam and combustion engineer, a specialist in high steam temperatures and pressures, applied this knowledge to atmospheric heating. Always obsessive about collecting data (on railway engines for example), he painstakingly compiled weather statistics from around Britain and then the rest of the world, over many years. He not only showed global warming but effects such as the melting of glaciers. His theory was met with consternation and scepticism, but would be revived and expanded in a few decades time. Climate change is now recognised for the global crisis it it

For more details see James Rodgers Fleming, The Callendar Effect: The Life and Work of Guy Stewart Callendar …The Scientist Who Established the Carbon Dioxide Theory of Climate Change (2007).