inFact with Brian Dunning inFact with Brian Dunning

 

About That 1970s Global Cooling...

Did climate scientists in the 1970s really think we were headed for a new ice age?

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No, climate scientists in the 1970s did NOT think the planet was cooling and we were headed for another ice age. That's just more climate disinformation.

One of today's most common arguments against the science of global warming is the claim that climatologists of the 1970s were predicting another ice age; and if they were so wrong then, we shouldn't trust what they report now. It's not true, the overwhelming consensus of climate science has always been that manmade warming would be the dominant influence — not just throughout the 1970s but ever since the late 1800s.

To understand why this misinformation exists, you have to open your mind to a concept that's really challenging for a lot of people to accept: the idea that some things on television might not be true.

What's on TV today about the Egyptian pyramids? We're told that aliens built them. Egyptologists don't think that. It's just TV sensationalism.

TV doctors tell us that diet or alternative medicine schemes will cure all diseases. Real medical science has never supported that. It's more TV sensationalism.

And in the 1970s, In Search Of told us that an Ice Age was coming. Climatologists didn't think that — it was just more TV sensationalism.

At the center of this question is sulfate aerosols, the really nasty pollutant responsible for acid rain. It also blocks sunlight from reaching the Earth, acting as a sort of reverse greenhouse gas. When a few climatologists in the 1960s and 70s began publishing that sulfate aerosols could have a temporary cooling effect, the mass media did what it does best: blew it all out of proportion, exaggerated it ridiculously, and trumpeted that scientists think we're headed for another ice age.

What you're seeing here is a collection of mass-media articles on a modern website dedicated to the denial of climate science, misrepresenting these articles as reflecting the scientific consensus of the day. In fact, all these were was mass media fearmongering and sensationalism. But those who reject climate science today still publish these lists.

By 2008, concern about this misinformation grew to the point that a group of researchers did a deep survey of all the climate-related scientific publications between 1965 and 1979. What they found is that of all those articles, 10% found that cooling would temporarily outpace warming over the coming decades; 28% found it too close to call; and 62% remained confident the warming would outpace the cooling. If you want to know the true pulse of what climate scientists believed in the 1970s, this is it.

Well, we know what happened. As acid rain became a serious problem, international efforts to reduce sulfate emissions were undertaken. They were really successful. Sulfate aerosols have a pretty short life, so it cleared up, and soon there were zero published articles predicting cooling might outpace warming. By 1978, even Exxon remained firm in its prediction of large-scale global warming:

A doubling of the CO2 concentration in the atmosphere would produce a mean temperature increase of about 2°C to 3°C over most of the earth... Man has a time window of five to ten years before the need for hard decisions regarding changes in energy strategies might become critical.

So, no. Climate scientists in the 1970s did NOT predict global cooling. Only 10% of them thought for a short time that cooling would temporarily outpace warming, but more data came in and they rejoined the overwhelming consensus.

— Brian Dunning

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References & Further Reading

Banerjee, N., Song, L., Hasemyer, D. "Exxon's Own Research Confirmed Fossil Fuels' Role in Global Warming Decades Ago." Exxon: The Road Not Taken. Inside Climate News, 21 Sep. 2015. Web. 24 Sep. 2015. <http://insideclimatenews.org/content/Exxon-The-Road-Not-Taken>

Black, J. The Greenhouse Effect. Linden: Exxon Research and Engineering Company, 1978. 1-2.

Charlson, R., Wigley, T. "Sulfate Aerosol and Climatic Change." Scientific American. 1 Feb. 1994, Volume 270, Number 2: 48-57.

Mann, M. "Exxon Doubled Down on Climate Denial and Deceit." Insights. EcoWatch, 21 Sep. 2015. Web. 24 Sep. 2015. <http://ecowatch.com/2015/09/21/exxon-climate-denial/>

NAS. Energy and Climate. Washington, DC: National Academy of Sciences, 1977.

Peterson, T., Connolley, W., Fleck, J. "The Myth of the 1970s Global Cooling Scientific Consensus." Bulletin of the American Meteorological Society. 1 Sep. 2008, Volume 89, Issue 9: 1325–1337.

 

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