Revisiting the Myth of Global Cooling in the 1970s
Dr. Thomas C. Peterson
NOAA National Environmental Satellite, Data, and Information Service
National Climatic Data Center
 Dr. Thomas C. Peterson Photo credit: NOAA. |
Thirty years ago, media headlines warned of a looming ice age. Back then, the first satellite records showed a growing snow and ice cover across the Northern Hemisphere. Then, there was a string of brutal winters in Asia and parts of North America in the early 1970s, coupled with the famous Newsweek story about the “cooling world” in 1975.
The ingredients for a new ice age all seemed to be falling into place, if you relied on the news reports.
A new research paper co-authored by Dr. Thomas C. Peterson, of NOAA’s National Climatic Data Center, looks at reasons why some scientists drew this conclusion. The paper notes that even in the 1970s, scientists’ concerns about greenhouse warming far exceeded concerns about possible global cooling.
Dr. Peterson recently spoke with NOAA World about the paper and the impact global cooling may have on today’s study of climate change.
1) What prompted you to revisit the "global cooling myth" and the way climate science was studied in 1960s and 1970s?
While writing the Historical Overview of Climate Change Science introductory chapter of IPCC in 2006, we were describing how science was “self-correcting.” But when I tried to use the 1970s global cooling consensus as an example, I found nothing to reference. It was a myth. Yet, there was also no paper to reference that said it is a myth. So, that’s what led us to do the research and write the paper.
2) How could scientists have been so off the mark with their global cooling conclusion? Or was it just a perception that they were?
Scientists really weren’t off the mark at all about global cooling conclusions because they never concluded that the Earth was going to cool. A survey of 24 eminent climatologists in the 1970s indicated that they anticipated slight global warming and the peer-reviewed literature of the time focused far more on potential warming influences.
3) In researching the paper, did you determine why the global cooling school of thought seemed to capture the headlines?
One cause is “the tyranny of the news peg.” That is, reporters need a “peg” on which to hang a story. The cold winters of the1970s served as a handy peg on which to hang stories about climate change science.
4) As you researched this paper, what was most surprising thing that jumped out at you?
Two aspects: The first was how strongly global warming dominated the peer-reviewed climate literature of the 1970s with six times more articles discussing potential warming influences than cooling influences. The second was how insightful some of the climatologists were at the time in piecing together disparate pieces of the puzzle into a comprehensive view of global climate change.
5) Because of the global cooling myth, is it possible that the study of climate change is better off today?
No. The myth is actively used to make a case that climate change scientists don’t know what they are doing. But scientists were not wrong about global cooling because they never predicted global cooling on decadal to century scales.
6) Can today's climate scientists -- and even those of the future -- learn anything from the mistakes made during this time?
No. The science at the time was quite robust. Indeed, of the 71 scientific articles we surveyed during this period, only two would be considered wrong according to our modern understanding, and both were immediately challenged in the peer-review literature.