CBC Digital Archives CBC butterfly logo

CBC Archives has a new look: Please go to cbc.ca/archives to access the new site.

The page you are looking at will not be updated.

1975: Scientist predicts global warming

The Story

"I think every single scientist... we've spoken to for the past year has been forecasting a cooling trend, maybe even an ice age. And you're saying quite the opposite," CBC's Barbara Frum tells W.S. Broecker of Columbia University. He predicts the planet is actually going to warm up soon thanks to all the carbon dioxide in the atmosphere. Frum wonders: is this just an "academic interest" or is it really important? "Possibly, it could be terribly important," answers Broecker in this 1975 clip. 

Medium: Radio
Program: As It Happens
Broadcast Date: April 21, 1975
Guest: W.S. Broecker
Host: Alan Maitland
Interviewer: Barbara Frum
Duration: 4:48

Did You know?

• The Oxford English Dictionary defines the greenhouse effect as "the trapping of the sun's warmth in a planet's lower atmosphere, due to the greater transparency of the atmosphere to visible radiation from the sun than to infrared radiation emitted from the planet's surface." It defines global warming as "the gradual increase in the overall temperature of the Earth's atmosphere due to the greenhouse effect caused by increased levels of carbon dioxide, CFCs, and other pollutants."

Oxford defines greenhouse gas as "a gas, such as carbon dioxide, that contributes to the greenhouse effect by absorbing infrared radiation."

• W.S. Broecker, interviewed in this clip, was a leader among the proponents of global warming theory in the 1970s, according to the 1999 book Greenhouse: The 200-Year Story of Global Warming by Gale E. Christianson.

• The idea that carbon dioxide affects global temperature was not new in the 1970s. Swedish scientist Svante Arrhenius devised a mathematical model in 1896 that demonstrated how cutting the level of carbon dioxide in the air by half could lead to another ice age. Conversely, increasing carbon dioxide would heat things up. But Arrhenius wasn't too concerned about this at the time -- based on the carbon dioxide emissions of the 19th century, he figured it would take 3,000 years before the Earth warmed significantly.

Also on April 21:
• 1926: The future Queen Elizabeth II is born in London. Her parents are the Duke and Duchess of York, who become King George VI and Queen Elizabeth in 1936. The younger Elizabeth assumes the throne when her father dies in 1952.
• 1948: William Lyon Mackenzie King sets a record of service as a Commonwealth prime minister: 20 years, 10 months and 10 days. King, who had been prime minister off and on since 1921, retires the following November.
• 1997: The Ontario legislature passes Bill 103 to amalgamate Toronto's six municipalities and Metro government into one "mega-city".


Turning Up the Heat: Four Decades of Climate Change more