“In the 1970s, all the scientists were saying an ice age was coming.” This seems to be a popular sentiment echoed in blogs and novels aimed at challenging the consensus views regarding future climate change. It was even a key theme in Michael Crichton’s State of Fear , when a character suggests that scientists only jumped on the global warming bandwagon in a bid to secure funding.
But a new article in the Bulletin of the American Meteorological Society challenges the idea of a ‘global cooling ’ consensus. Thomas Peterson of NOAA teamed with William Connolley of the British Antarctic survey and science reporter John Fleck to create a survey of peer-reviewed climate literature from the 1970s. Looking at every paper that dealt with climate change projections or an aspect of climate forcing from 1965 to 1979, they were able to assess the ‘trends’ in the literature. They found that only 7 of the 71 total papers surveyed predicted global cooling. The vast majority (44) actually predicted that rising atmospheric carbon dioxide could lead to global warming.
The group went even farther, and pulled up some of the most referenced news articles on climate. What they found may be the earliest example of climate whiplash journalism . In 1975, the New York Times published two articles by W Sullivan with the contradictory (partial) titles “major cooling may be ahead” and “warming trend seen in climate.”
Of course, there was a small group of scientists in a new field pointing to the inevitability of the coming ice age – the newly minted palaeoclimatologists. However, as Peterson and colleagues point out, they were speaking on timescales of tens of thousands of years, rather than anything that could occur in a child or grandchild’s lifetime. And in their seminal 1976 paper on the pacemaker of the ice ages, James Hays and colleagues warned that anthropogenic emissions may affect these long term future climate trends more strongly that solar forcing.
Overall, Peterson, Connolley and Fleck have shown that the scientific consensus has actually changed very little since the 1970s. More surprisingly (at least to the sceptics) they show that global warming caused by anthropogenic greenhouse gas emissions has always been a concern, even during the infancy of modern climate science. Anyone care to pass the final nail for the coffin of ‘global cooling’?
Image credit: IStockphotos/Trevor Hunt