Climate scientists say as glaciers and polar ice melt, plant and animal species go extinct at a rapid rate, and sea levels rise. With information like that, it’s likely the public isn’t asking, “Are we at the dawn of a new ice age?”
However, if that question was asked just 40 years ago, a large number of people — including some climatologists — would have answered yes.
On April 28, 1975, Newsweek published an article called, “The Cooling World,” in which writer and science editor, Peter Gwynne, described a significant chilling of the world’s climate, with evidence “accumulating so massively that meteorologists are hard-pressed to keep up with it.”
He raised the possibility of shorter growing seasons and poor crop yields, famine, and shipping lanes blocked by ice, perhaps to begin as soon as the mid-1980s. Meteorologists, he wrote, were “almost unanimous” in the opinion that our planet was getting colder. During the years that followed, Gwynne’s article became one of the most-cited stories in Newsweek’s history.
The scientific study of the climate is not very old. Collection of global temperature data started in the 1870s. It wasn’t until 1963 did J. Murray Mitchell bring together information from hundreds of weather stations around the world to build a modern representation of Earth’s temperature. His work suggested a steady increase in global temperatures from around 1880, followed by a cooling of the planet from about 1940. In addition, satellites of the early 1970s spotted more snow and ice across the Northern Hemisphere, and people were well aware of unusually harsh winters in North America during 1972-73.
Some years before, scientist Charles David Keeling took atmospheric measurements from posts atop Mauna Loa and in Antarctica. Keeling launched an investigation of the changes in the levels of carbon dioxide. By 1965 he had found that CO2 was rapidly increasing. A presidential scientific advisory committee that same year advised that a rise in temperatures worldwide, from CO2-related emissions, could result.
How wide-spread were worries about global warming, then? An examination of peer-reviewed scientific literature conducted by a group of researchers in 2008, covering the mid-1960s through the 1970s, revealed that papers warning of global warming outnumbered those projecting cooling by a factor of six. We can then infer that climate change in the form of global warming was a widespread topic of concern during this era, and there was no consensus that the Earth would cool in the immediate future.
In this light, the Newsweek article of 1975 is a fascinating artifact of a scientific era of the past. For journalists, it can often be humbling to revisit old work, especially stories more than 40 years old. But in recent years, Peter Gwynne mustered the courage to look again at “The Cooling World.” Writing in Inside Science Minds, an independent editorial publication of the American Institute of Physics in 2014, he explained how he produced the 1975 article.
“While the hypotheses described in that original story seemed right at the time, climate scientists now know that they were seriously incomplete. Our climate is warming, not cooling, as the original story suggested,” Gwynne explained. “Put simply, climate science evolved and advanced, resulting in new knowledge,” Gwynne said.