Scientists predicted global cooling in the 1970s
There was media coverage of cooling concerns in the early 1970s, but peer-reviewed science of the period was dominated by warming projections. A 2008 systematic review found 44 warming papers versus only 7 cooling papers from 1965 to 1979.
What we know
The claim of a 1970s scientific consensus on global cooling persists largely through selective memory of popular magazine articles and a few widely cited papers rather than the peer-reviewed record. A comprehensive review by Peterson, Connolley, and Fleck (2008), published in the Bulletin of the American Meteorological Society, examined 71 peer-reviewed climate papers from 1965 to 1979. They found 44 papers predicting warming, 20 neutral papers, and only 7 predicting cooling. Greenhouse warming concerns dominated the scientific literature throughout the entire period.
There was genuine scientific uncertainty in the early 1970s about the balance between aerosol cooling (particulate pollution was high) and greenhouse warming. Some scientists, noting the observed cooling trend from the 1940s to 1970s, raised the possibility that aerosols might dominate. This concern was real but marginal and was largely resolved by the late 1970s as researchers recognized that aerosol effects were regional and temporary while CO2 effects were global and cumulative.
The myth persists partly because the aerosol cooling concern was a legitimate scientific topic and partly because a few influential popular articles (including a famous 1975 Newsweek piece titled The Cooling World) were written in alarmist language. These articles were not representative of scientific opinion. By 1979 the Charney Report, commissioned by the U.S. National Academy of Sciences, concluded with confidence that doubling CO2 would produce 1.5 to 4.5 degrees of warming, a range almost identical to modern IPCC estimates.
Common claims
- Scientists in the 1970s predicted an ice ageMostly false - a few papers raised concerns; warming dominated peer-reviewed literature
- Since scientists were wrong about cooling, we shouldn't trust warming predictionsFalse premise - there was no consensus for cooling; warming has been consistently projected
- Media in the 1970s reported on a cooling scareTrue - but media coverage misrepresented the scientific literature