What the hell is this global cooling I hear sceptics harping on about?

Question

I'm 26 years old have studied climatology and climate change in college and know little about it. Is it just a myth conconted by deniers or was it a genuine fear? More importantly did the theory achieve the backing of the overwhelming majority of the (qualified) scientific community?
I'm familiar with the concept of a nuclear winter but global cooling...I'm ignorant.
Constructive answers please. No politics.

Niv; I studied them both through modules in physical geography at the National University of Ireland, UCD, Dublin.
If the inverted commas around sceptical indicate that you think I misspelt the word you'd be incorrect. That's just how we spell it here on this side of the pond.
You're answer wasn't very constructive. Dunno why you wasted your time.

Roadkill; Read the question. I never said that I've never heard of an Ice Age. The phrases "patience" and "wearing thin" come to mind.

Answer 1

Ok--I'm a historian with work in hstory of science and technology (one of my areas). Here's the deal--

In the 1970s climate study in the modern sense wass just getting started. Scientists were none too sure about what long-term trends might be operating--so there was some speculation that Earth might be in a cooling, rather than a warming trend. And, with the growing awareness of the complexity ofearth's history of climate shifts, there was also a realization tha tat some point, we might (and probably would) have another ice age--though not for millenia, most likely.

A number of popular magazines (Time, Newsweek,etc.) picked up this and ran speculative pop-sci articles, usually with lurid titles such as "The Coming Ice Age." That's all there was to the whole thing.

Fast forward to now. the deniers, ignorant of scince themselves, don't know the difference between a pop-sci article and a scientific journal--or the difference between the hypothesizing phases of science and a scientific cnsensus. So they fixate on these articles in a attempt to convince people that scientists once believed earth was cooling, then jsut changed thir minds--and go on to ridicule scientists as not really knowing anything. Yada, yada, yada. . . .

Now--an interesting point. There has recently emerged a concept called "global dimming." This is not junk science--though there is, at present, no scientific consensus. The basic idea is that there is some (not conclusive, as far as I know) evidence that some forms of pollution--particularly high-altitude emissions in the form of jet exausts--may be having a cooling effect by blocking some of the sun's radiation.

The thinking now is that, if this proves to be the case, this "global dimming" effect may be masking part of the effects of global warming--up to a third, if I'm reading their figures correctly.

Which--of course--doesn't call global warming into question. It might indicate that the basic processes of global warming aare stronger than previously thought, but partly offset by this factor. Which is, ultimately, also supportive of the global warming model: in such case, the global warming trend must be seen as deeper and firmly established enough to overcome a fairly significant counter-factor. Which may support gglobal warming modells, but is hardly comforting news.

Let me emphasize, however, that this is NOT, at this point, a topic of inquiry developed enough to warrent any definitive conclusions.

Answer 2

For starters, there were only 1 or 2 scientific papers which made claims anything like this. The media made a big deal out of it, but most scientists knew better than to make long-term predictions based on the very crude climate models that existed in the 1970s. Further details here:

http://gristmill.grist.org/story/2006/11/23/18534/222

And a collection of scientific papers and articles at the time to prove my point here:

http://www.wmconnolley.org.uk/sci/iceage/

However, the 1 or 2 papers that made this conclusion were not necessarily wrong.

Predictions of an impending ice age were made based on rapidly accelerating sulphur emissions. Human sulphur dioxide (SO2) emissions were skyrocketing up until the early 1970s. SO2 blocks sunlight and causes global dimming and thus global cooling. It was the main reason for the minor global cooling from 1940-1970.

So some scientists studied this and said "hey, if we keep emitting more and more SO2, it will block more and more sunlight, and eventually (I think they predicted something like 50 years in the future) it will send us into an ice age.

Know what happened next? The USA and many other countries passed Clean Air Acts. Not only did SO2 emissions stop skyrocketing, but they have actually decreased since 1980, as you can see in pages 12-14 here:

http://www.pnl.gov/main/publications/external/technical_reports/PNNL-14537.pdf

So the reason their prediction didn't come true was that the scenario they based it on didn't happen. It's very similar to global warming - if we decrease our CO2 emissions we can avoid the scenario where global warming causes catastrophic climate change.

So to sum up, only a few scientists made these predictions, the media blew it out of proportion, but the scenario on which the predictions were based was avoided. We can only hope that global warming has the same result.

Answer 3

People have be studying the sun for centuries and have found a strong correlation between the sun's activity and temperature. The Maunder Minimum is the name given to the period roughly from 1645 to 1715 where the sun's activity dropped and so did temperatures on earth.
People who study the sun today agree that sun has been unusually active for the last 100 years and believe that is somehow connected to the recent warming even if they don't know why. These people also believe that the sun will become less active in the next 20 years which should cause global temperatures to drop as they did in the late 1600s. That is why some people claim that global cooling could be coming soon.
No one knows for sure whether the sun's will actually decrease and no one knows for sure that it will cause the world to cool. However, it is a reasonable hypothesis based on sound science. GW advocates that try to dismiss it simply demonstrate that they know nothing about science.

Answer 4

There is no global cooling. If there was, glaciers would not be retreating worldwide and arctic sea ice and tundra would not be melting at an alarming rate and if you have studied climatology you must surely be aware of this. The media publicity given to cooling in the 70s was just that, sparked largely by the nuclear winter scare but since global cooling wasn't happening it did not have the 'backing' of the scientific commumity as there was nothing to back.

Answer 5

The possibility exists that the climate can cool abruptly within just a couple of decades as it has many times in the past. To think that we have sufficient knowledge to forecast climate even 50 years into the future would be a mistake. There are so many unknowns about the effects of solar. Just the fact that the asymmetrical aspects of Earth's orbit causes summer in the northern hemisphere to receive 1321 W/m^2 and summer in the Southern Hemisphere to receive 1412 W/m^2 is not even considered in climatological models. I could go on but it might start to bore you.

Answer 6

I know how you feel. I have a PHD in a science and people treat me like an idiot if I don't follow the herd. I guess if I was 18 again I would have all the answers and there would be no doubt about the truth.

Yes, I grew up during the global cooling era and look how that turned out. Global warming may be real but I don't blame it ALL on us wasteful humans. Sometimes the earth just decides to throw us a curve ball and there's nothing we can do about it.

Answer 7

Uh, 26 years old and never heard of an "ice age". Ice ages are the result of global cooling. During the last ice age it has been estimated that the average temperature was 18 degrees cooler than it is right now. Ice sheets covered large area's of the northern hemisphere. All of Canada, and the Northern tier of states in the U.S.

There is geological evidence that ice ages have occurred many times and generally last around 100,000 years, followed by relatively short periods of warming lasting on average 10,000 years plus or minus 2,000 years. Its been almost 12,000 years since the last ice age so we are due.

The conflict in the 1970's has more to do with how fast an ice age can start. No one was claiming anywhere near the speed shown in the hollywood version of global cooliing. But there was plenty of evidence that an ice age could occur fairly suddenly, in less than one decade. It simply snows one winter and doesn't melt the next summer.

The consequences of an ice age are far more serious than global warming. World wide crop failures, famine and sub zero temperatures.

I think its clear we have more to fear from global cooling than global warming and it is a more imediate threat.

Answer 8

A Priori - above - has the history right.

There's a lot more about the state of play in the 60s & 70s here. Follow the links after that on the right and at bottom.
http://www.aip.org/history/climate/Winter.htm

http://www.aip.org/history/climate/aerosol.htm#L_0334

http://www.aip.org/history/climate/cycles.htm

Spencer Weart's website (and book) is probably the best resource on the History of Global Warming from Fourier onwards.
http://www.aip.org/history/climate/index.html

This website, by a scientist with the British Antarctic Survey is also good on the fallout from a now infamous 1976 Newsweek article on Global Cooling.
http://www.wmconnolley.org.uk/sci/iceage/

The Newsweek article was written by staff writer - Peter Gwynne - based on an application by the National Academy of Science (NAS) for funds to ‘Establish a national climatic research program’.
Peter Gwynne is not a climatologist, just a journalist.
Nor was its conclusion – Global Cooling - based on any scientific paper published in a scientific journal.
My guess it was a case of staff writer trying to fill a couple of pages in a quiet week for news and trying to make a dull paper requesting funding for climate research interesting. Possibly he thought he was doing the scientists a favour and helping ‘nudge’ the politicians towards supporting them. Who knows? He doesn't even have a direct quote from one of the meteorologists and scientists he refers to in general terms.
Newsweek article here:
http://www.wmconnolley.org.uk/sci/iceage/newsweek-coolingworld.pdf

Newsweek have apologised in the past couple of years for this article.

The new York times also ran an article on the same funding application and came to the opposite conclusion, The NYT notes concern over CO2 levels and fears that production of energy 'heat waste' will generate so much heat as to have a major climate impact.
http://www.digg.com/environment/The_NY_Times1975_Same_story_as_Newsweek_s_COOLING_NYT_says_HEATING
Click on the blue heading to go to the NYT article.

At the time the media was full of articles about ice ages. The major breakthrough were isotopes from sea-bed sediment cores showing that Milankovitch's calculations about astronomical cycles were correct and explained the occurrence of ice ages. The first mammoths were dug out of Siberian permafrost at this time and so on.
In the media there was debate as to when the next ice age was due? (In about 20,000 yrs according to John Imbrie's 1979 book - Ice Ages: Solving the Mystery. Imbrie also devoted a chapter to the effects of rising CO2 concentrations. Imbrie was one of the researchers into isotopes and astronomical cycles.)

Atmospheric aerosols were also a new discovery together with the realisation they could cause cooling, an idea still with us now known as global dimming.

There was also a book by a Reader's Digest staff writer, Lowell Ponte, called 'The Cooling' that took all the above, mixed it together and did forecast an imminent ice age. Ponte is now an American Libertarian radio talk show host and climate skeptic. (Irony) The book's been out of print for decades. It didn't make a much of an impact but is still cited today as evidence that scientists forecast an ice age back in the '70s.

Answer 9

I'm sorry. You sound like a nice young person. But you can't ask your question and want to disregard politics. The simple reason for this is because Republicans have came up with this as a political counter to the true global warming situation which has been made publicly knowledgeable in most recent times by Democrats. Me, I am neutral. Expand your mind and you perhaps can make a change that can effect all the world. Best wishes to you and Happy Holidays.

Answer 10

in the 70's a couple of scientists suggested the world would undergo global cooling. the majority of scientists, the consensus, rejected their theory, and they were right. still, skeptics keep using this an example of how science was wrong, when, in fact, the majority was right. today the majority is saying AGW is real, and the minority is saying it's not.