Sunday, December 1, 2019

Global Warming

Robert Barkman, Ph.D :
Who was the first person to sound the alarm, warning of global warming and the impact it might have? Few will recognize the name of Guy Stewart Callendar who published his warning in the Quarterly Journal of the Royal Meteorological Society in 1938, over 80 years ago. His paper, "The Artificial Production of Carbon Dioxide and its Influence on Temperature," was published with little fanfare. It was only in the several decades that followed that the significance of his work could be appreciated.
Up until the 1930s, most thought the earth's temperature scarcely changed. It may have been press reports speculating that the earth was, perhaps, warming, that stimulated an Englishman, Guy Stewart Callendar, to take up climate study as an amateur enthusiast (Applegate, 2013). Callendar painstakingly collected and sorted out data recorded from around the world and found something startling. He announced that the mean global temperature had risen between 1890 and 1935, by close to half a degree Celsius (0.5°C, equal to 0.9°F).
Callendar's temperature data gave him the confidence to push ahead with another, bolder claim. He published a paper in 1938, claiming that carbon dioxide was responsible for the temperature rise. The data he collected comparing carbon dioxide and temperature gave him the confidence to do so (Baff, 1999).
Pre-1900              290
 1910                     303
 1923                    305
 1931                     310      
1935                    320
Callendar pointed out that the rising fuel combustion that was needed to power the industrial revolution generated 150 million tons of carbon dioxide in the first half-century and that three quarters still remained in the atmosphere. He connected the final dots of the pattern by concluding that the agent of change responsible for the temperature-carbon dioxide connection was human. He warned that "man is now changing the composition of the atmosphere at a rate which must be very exceptional on the geological time scale." A model that he constructed from the data he collected predicted that if the carbon dioxide doubled, the world's temperature would increase by two degrees  (Weart, 2012).
When Callendar compared the earth's temperatures to atmospheric carbon dioxide measured at the same time, he connected the trends of earth's rising temperature, carbon dioxide, and human fuel consumption.
In 1938, Guy Callendar saw an increase in global temperatures in previous 50 years and links this to CO2.
Coined the "Callendar Effect" at the time, concerns were expressed in both the popular and scientific press about rising sea levels, loss of habitat, and shifting agriculture zones.  Given the clear pattern that Callendar discovered between carbon dioxide and temperature, why did no one hear the alarm?  
Convincing others about global warming was an uphill battle. Even his scientific colleagues couldn't imagine that human activities had any influence on "phenomena of so vast a scale" as climate. In their eyes, he was just an amateur scientist. The irony of this story of discovery is that Callendar was by no means an environmental alarmist. He wrote of the benefits of the combustion of fossil fuels, including an extension of the cultivated regions (Hickman, 2013) northward, stimulation of plant growth by carbon dioxide, and the probable indefinite delay of the "return of the deadly glaciers."
Today, those concerns about global warming are now real ones. People are personally connected to the severity and frequency of storms and drought, retreat of glaciers, loss of the polar icecaps, and changes in the growing season, changes that we connect to global warming. Almost 50% of Americans now have experienced climate change personally.
"When researchers recently examined the 5-year trends on how Americans view the climate crisis, they learned some fascinating information: From an intellectual perspective, 73 percent believe climate change is happening and 62 percent think it is human-caused. Those numbers reflect an 11 percent and 15 percent increase, respectively, since 2013 (Price-Mitchell, 2019)."

(Robert Barkman, Ph.D., is Professor Emeritus Science and Education at Springfield College in Massachusetts).