Global Warming Science:




[last update: 2010/12/09]



In 2008 the American Meteorological Society published a paper denying the existence of a global cooling consensus in the 1970s


Peterson, Connolley and Fleck, “The Myth of the 1970s Global Cooling Consensus” []


  • the following pervasive myth arose: there was a consensus among climate scientists of the 1970s that either global cooling or a full-fledged ice age was imminent … A review of the climate science literature from 1965 to 1979 shows this myth to be false.


  • The myth’s basis lies in a selective misreading of the texts both by some members of the media at the time and by some observers today. In fact, emphasis on greenhouse warming dominated the scientific literature even then.


In their selective review of the literature they found a total of 5 papers prior to 1975 that predicted future cooling and 13 that predicted future warming, as shown in the following figure from Peterson et al (the original figure continues through 1979, even though the cooling trend ended in the early 1970s).




Consensus is defined as 1: general agreement, and 2: group solidarity in sentiment and belief. []





Cooling Consensus


In the 1970s there were many media reports about the coming ice age – global cooling was occurring and society was encouraged to be fearful and to act to prevent it. For example: Time magazine, 24 June 1974, as shown in the following figure.




Newsweek in 1975 also wrote about global cooling.


New York Times, 1975: “Scientists ask why world climate is changing; major cooling may be ahead”

[]. The article discussed the debate – not a consensus.


Was it a scientific consensus?


James Hansen, NASA’s master alarmist who is very prominent in promoting the current global warming scare, is referenced in a 1971 Washington post article claiming global cooling to be likely: “The world could be as little as 50 or 60 years away from a disastrous new ice age, a leading atmospheric scientist predicts. Dr. S. I. Rasool … a colleague of Mr. Hansen's at the National Aeronautics and Space Administration. The article goes on to say that Mr. Rasool came to his chilling conclusions by resorting in part to a new computer program developed by Mr. Hansen that studied clouds above Venus.” []


It was referring to a 1971 article in Science: Rasool and Schneider: “Atmospheric Carbon Dioxide and Aerosols: Effects of Large Increases on Global Climate” [], which states: “although the addition of carbon dioxide in the atmosphere does increase the surface temperature, the rate of temperature increase diminishes with increasing carbon dioxide in the atmosphere. For aerosols, however, the net effect of increase in density is to reduce the surface temperature of Earth. Because of the exponential dependence of the backscattering, the rate of temperature decrease is augmented with increasing aerosol content. … If sustained over a period of several years, such a temperature decrease over the whole globe is believed to be sufficient to trigger an ice age.” (Coauthor Stephen Schneider is now one of the most prominent global warming alarmists.) This paper is one of the 5 listed by Petrerson et al.


(Climate models overcome the problem of “the rate of temperature increase diminishes with increasing carbon dioxide in the atmosphere”, by using a water vapor feedback to keep the warming happening. See:


John Holdren, Obama’s Science Advisor, referred to the cooling: “Many observers have speculated that the cooling could be the beginning of a long and persistent trend in that direction—that is, an inevitable departure from an abnormally warm period in climatic history” (from Ehrlich, Ehrlich and Holdren, in Ecoscience: Population, Resources and Environment, 1977 []) Holdren and Ehrlich also wrote: “The effects of a new ice age on agriculture and the supportability of large human populations scarcely need elaboration here. … If man survives the comparatively short-term threat of making the planet too cold, there is every indication he is quite capable of making it too warm not long thereafter. For the remaining major means of interference with the global heat balance is the release of energy from fossil and nuclear fuels.” []


So was there a global cooling scientific consensus? The media are in the business of selling fear and promoted the global cooling scare. There may not have been a true scientific consensus about global cooling. There is evidence of widespread belief that global cooling was happening, but many of those believers now deny that there was a consensus. The media played up the fear then like they do with global warming now.


The director of climate research at the University of East Anglia (CRU – the leading proponent of the current global warming scare and provider of data to the IPCC) believed that an ice age was coming: “the rest of this century will grow colder and colder”. The following clip is from the Windsor Star – Sept 9, 1972.





The CIA in 1974 produced a report about global cooling: “The western world’s leading climatologists have confirmed recent reports of detrimental global climate change. … The world is returning to the type of climate which has existed over the last 400 years. That is, the abnormal climate of agricultural-optimum is being replaced by a normal climate of the neo-boreal era.” []



And all these claims of global cooling:


1970 – Colder Winters Held Dawn of New Ice Age – Scientists See Ice Age In the Future (The Washington Post, January 11, 1970)
1970 – Is Mankind Manufacturing a New Ice Age for Itself? (L.A. Times, January 15, 1970)
1970 – Pollution Could Cause Ice Age, Agency Reports (St. Petersburg Times, March 4, 1970)
1970 – Pollution Called Ice Age Threat (St. Petersburg Times, June 26, 1970)
1971 – U.S. Scientist Sees New Ice Age Coming (The Washington Post, July 9, 1971)
1971 – New Ice Age Coming – It’s Already Getting Colder (L.A. Times, October 24, 1971)
1972 – British climate expert predicts new Ice Age (The Christian Science Monitor, September 23, 1972)
1972 – Scientist Sees Chilling Signs of New Ice Age (L.A. Times, September 24, 1972)
1972 – Another Ice Age? (Time Magazine, November 13, 1972)
1973 – Weather-watchers think another ice age may be on the way (The Christian Science Monitor, December 11, 1973)
1974 – Another Ice Age? (Time Magazine, June 24, 1974)
1974 – 2 Scientists Think ‘Little’ Ice Age Near (The Hartford Courant, August 11, 1974)
1974 – Ice Age, worse food crisis seen (The Chicago Tribune, October 30, 1974)
1975 – Climate Changes Called Ominous (PDF) (The New York Times, January 19, 1975)
1975 – Climate Change: Chilling Possibilities (Science News, March 1, 1975)
1975 – B-r-r-r-r: New Ice Age on way soon? (The Chicago Tribune, March 2, 1975)
1975 – The Ice Age cometh: the system that controls our climate (The Chicago Tribune, April 13, 1975)
1975 – The Cooling World (Newsweek, April 28, 1975)
1975 – Scientists Ask Why World Climate Is Changing; Major Cooling May Be Ahead (PDF) (The New York Times, May 21, 1975)
1975 – In the Grip of a New Ice Age? (International Wildlife, July-August, 1975)
1976 – Worrisome CIA Report; Even U.S. Farms May be Hit by Cooling Trend (U.S. News & World Report, May 31, 1976)
1976 – The Cooling: Has the Next Ice Age Already Begun? (Book, 1976)
1977 – The Big Freeze (Time Magazine, January 31, 1977)
1977 – The Weather Conspiracy: The Coming of the New Ice Age (Book, 1977)
1978 – Believe new ice age is coming (The Bryan Times, March 31, 1978)
1978 – The Coming Ice Age (In Search Of – TV Show, Season 2, Episode 23, May 1978)
1979 – New ice age almost upon us? (The Christian Science Monitor, November 14, 1979)


(List from:






Warming Consensus


The media certainly have been playing a large role in the global warming scare. The media stories often report temperature increases over the last century and attribute it to anthropogenic (human caused) CO2 based global warming. The IPCC, however, only attributes warming since the early 1970s to CO2. This is because the climate models can explain the trends prior to that with only natural forcings.

(See also:


The following figure shows the IPCC model simulations (IPCC figure SPM-4 in the 2007 AR4 Summary for Policy Makers) with the Hadley / Met Office global temperature data superimposed. The blue band shows the results of model simulations using only natural forcings. The pink band shows the results of model simulations including anthropogenic CO2. All of the warming in the 1900s prior to 1970 can be modeled with natural causes only – i.e. anthropogenic CO2 only has an effect in the models after 1970.



This fact is also revealed in the CRU emails released in November 2009: An email exchange between: Michael Mann, Edward Cook and Tom Crowley, May 2, 2001, (Subject: “Hockey Stick” []).


Cook to Mann: “I think that most researchers in global change research would agree that
the emergence of a clear greenhouse forcing signal has really only occurred
since after 1970
. I am not debating this point, although I do think that
there still exists a significant uncertainty as to the relative
contributions of natural and greenhouse forcing to warming during the past
20-30 years at least


The media tell us there is a scientific consensus and it is lead by the IPCC. That is partly true – in a Science magazine interview with IPCC Chairman Pachauri, (“Climate Science Leader Rajendra K. Pachauri Confronts the Critics” 2010/01/29 []), he says: “let's face it, that the whole subject of climate change having become so important is largely driven by the work of the IPCC. If the IPCC wasn't there, why would anyone be worried about climate change?” In other words, the U.N. has created the illusion of a consensus.


The IPCC position is at odds with the findings of many other scientists. For example, research at the Harvard-Smithsonian Center for Astrophysics []:A review of more than 200 climate studies led by researchers at the Harvard-Smithsonian Center for Astrophysics has determined that the 20th century is neither the warmest century nor the century with the most extreme weather of the past 1000 years.


The CRU emails released in November 2009 also indicate that certain scientists colluded to prevent the publication of competing viewpoints in order to manufacture a consensus. The former director of the National Hurricane Center, Neil Frank, said: “The [CRU] e-mails document that the attack on the skeptics was twofold. First, the believers gained control of the main climate-profession journals. This allowed them to block publication of papers written by the skeptics and prohibit unfriendly peer review of their own papers. Second, the skeptics were demonized through false labeling and false accusations.” []


The IPCC was supposed to be based on peer reviewed science, but lead authors only allowed sources that matched their beliefs, and they referenced press releases and environmentalist pamphlets (See:


NASA scientist Andrew Lacis was an IPCC AR4 reviewer. He said: “There is no scientific merit to be found in the Executive Summary. The presentation sounds like something put together by Greenpeace activists and their legal department.” []


The IPCC also used unpublished reports – in the following case the final paper changed its conclusion to add ““We find insufficient evidence to claim a statistical relationship between global temperature increase and catastrophe losses.” Despite this change the IPCC did not issue a clarification ahead of the Copenhagen climate summit last month. It has also emerged that at least two scientific reviewers who checked drafts of the IPCC report urged greater caution in proposing a link between climate change and disaster impacts — but were ignored.





Many of the outspoken scientists that disagree are retired. Due to the politicization of climate science, grants and funding are often cut off if scientists do not go along with the political consensus. “Joanne Simpson, the world's first woman to receive a Ph.D. in meteorology, expressed relief upon her retirement last year that she was finally free to speak "frankly" of her nonbelief. Dr. Kiminori Itoh, a Japanese environmental physical chemist who contributed to a U.N. climate report, dubs man-made warming "the worst scientific scandal in history." Norway's Ivar Giaever, Nobel Prize winner for physics, decries it as the "new religion." A group of 54 noted physicists, led by Princeton's Will Happer, is demanding the American Physical Society revise its position that the science is settled.” []


See for a discussion of the political consensus and non-consensus scientists along with problems encountered by dissenting scientists.


See for more than 20 scientists who disagree that anthropogenic CO2 causes problematic warming and describe it in their own words.


See for over 700 scientists who disagree with the IPCC “consensus”.


See: for more than 31,000 scientists who disagree with the IPCC “consensus”, including more than 9,000 PhD scientists (


So is there a global warming scientific consensus? In terms of the definition of consensus, there is “group solidarity in sentiment and belief” among a powerful group of climate scientists, but among the wider spectrum of knowledgeable scientists a “general agreement” does not exist.