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At a glance - Has the greenhouse effect been falsified?

Posted on 5 December 2023 by John Mason, BaerbelW

On February 14, 2023 we announced our Rebuttal Update Project. This included an ask for feedback about the added "At a glance" section in the updated basic rebuttal versions. This weekly blog post series highlights this new section of one of the updated basic rebuttal versions and serves as a "bump" for our ask. This week features "Has the greenhouse effect been falsified?". More will follow in the upcoming weeks. Please follow the Further Reading link at the bottom to read the full rebuttal and to join the discussion in the comment thread there.


At a glance

Did you know that in the late 1700s, astronomers calculated the Earth-Sun distance to within 3% of the correct average value of 149.6 million kilometres? That was an incredible feat for the time, involving painstaking measurements and some pretty serious number crunching, with no help from computers.

Why is that mentioned here, you might ask. It's because not long afterwards, in the 1820s, French physicist Jean Joseph Baptiste Fourier made another crucial calculation. He worked out that at this distance from the Sun, Earth should have been an uninhabitable iceball.

Fourier suggested there must be some kind of insulating 'blanket' within the atmosphere. By the end of that century, Eunice Foote and John Tyndall had proved him quite correct through their experiments with various gases and Svante Arrhenius quantified matters in 1896, even calculating the effect of doubling the concentration of CO2. They had it largely figured out all that time ago.

If you are still sceptical about the existence of a greenhouse effect on Earth, there's something you can do in order to double-check. Go to the moon.

Well, you don't have to go personally, thanks to remote sensing and lunar landings by both unmanned and manned craft. Such intrepid expeditions mean we have a stack of data regarding lunar properties. The moon is pretty much the same distance from the Sun as Earth, but the lunar atmosphere is so thin it may as well not exist at all. There's virtually nothing to inhibit heat transfer, in or out.

In addition, the Moon turns but slowly on its axis compared to Earth. While a mean Solar day here lasts 24 hours, on the Moon it lasts just under a month. You get the best part of a fortnight of relentless Solar heating followed by a similar period of cooling in the long lunar night. So what's the temperature?

In the vicinity of the Lunar equator, daytime temperatures eventually reach a boiling hot 120oC. During the lunar night, that temperature drops away to -130° C. No atmosphere so no greenhouse effect. All that heat accumulated in the long lunar day just shoots straight back out into space. Nights on Earth may be much shorter, but nevertheless in the absence of a greenhouse effect they would be brutal.

Our approximately Earth-sized near neighbour, Venus, closer to the Sun, is different again. It has a massive dense atmosphere mostly consisting of CO2 with a side-helping of sulphur dioxide. Surface atmospheric pressure on Venus is so great that on Earth you would need to go a kilometre down in the ocean to find similar values. The planet rotates very slowly on its axis so days and nights are even longer than on the Moon. But unlike the Moon, Venus is always a hot place. Its surface temperature is over 450oC, day or night. An extreme greenhouse effect maintains that heat.

Remember: no atmosphere, no greenhouse effect and unimaginably cold lunar nights - but the example of Venus shows you can also have too much of a good thing. Earth really is a Goldilocks planet.

Please use this form to provide feedback about this new "At a glance" section. Read a more technical version below or dig deeper via the tabs above!

Click for Further details

In case you'd like to explore more of our recently updated rebuttals, here are the links to all of them:

Myths with link to rebuttal Short URLs
Ice age predicted in the 1970s
It hasn't warmed since 1998
Antarctica is gaining ice
CRU emails suggest conspiracy
What evidence is there for the hockey stick
CO2 lags temperature
Climate's changed before
It's the sun
Temperature records are unreliable
The greenhouse effect and the 2nd law of thermodynamics
We're heading into an ice age
Positives and negatives of global warming
Global cooling - Is global warming still happening?
How reliable are climate models?
Can animals and plants adapt to global warming?
What's the link between cosmic rays and climate change?
Is Al Gore's An Inconvenient Truth accurate?
Are glaciers growing or retreating?
Ocean acidification: global warming's evil twin
The human fingerprint in global warming
Empirical evidence that humans are causing global warming
How do we know more CO2 is causing warming?
Explaining how the water vapor greenhouse effect works
The tricks employed by the flawed OISM Petition Project to cast doubt on the scientific consensus on climate change
Is extreme weather caused by global warming?
How substances in trace amounts can cause large effects
How much is sea level rising?
Is CO2 a pollutant?
Does cold weather disprove global warming?
Do volcanoes emit more CO2 than humans?
How do human CO2 emissions compare to natural CO2 emissions?
Climate scientists could make more money in other careers
How reliable are CO2 measurements?
Do high levels of CO2 in the past contradict the warming effect of CO2?
What is the net feedback of clouds?
Global warming vs climate change
Is Mars warming?
How the IPCC is more likely to underestimate the climate response
How sensitive is our climate?
Evidence for global warming
Has the greenhouse effect been falsified?


If you think that projects like these rebuttal updates are a good idea, please visit our support page to contribute!

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Comments 1 to 9:

  1. A formatting suggestion if you don't want people to mistake the myth for the debunking - don't use a teeny-tiny white font in a dark orange tab to label the "Climate myth..."

    Those important words are missed "at a glance" by many who don't have eyes that quickly read the smallest line on the eye doctor's exam chart, and including the myth (and its tiny label) INSIDE the frame of a box clearly labeled "What the Science Says" in a large, green font makes being misled even easier.

    Separate and label "MYTH HERE" clearly.


    B Fagan

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  2. re - #1 - thanks for the feedback. Always useful to read people's thoughts about design/accessibility.

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  3. bf @1 :-   A technical question for you:

    Do your eyes rate as "mainstream" on the Ishihara Color Chart ?


    Do the various screens you use get calibrated for color gamut ?

    You are certainly quite right that many people nowadays are using very small screens, though high-resolution (e.g. latest iPhones).

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  4. Eclectic @3 - I've never encountered the Ishihara Color Chart, but never had any known issues with color vision, and never had problems with the old tests where the number in a field of colored dots would be hidden to people with this or that form of colorblindness.

    But the first time I had to pay attention to viewability issues was decades ago when the company I was working at needed to design a standard form for customers to fill out and mail back.  The goal was OCR and the people working that process first suggested a very very light blue drop-out for the form, and I reminded them the senior citizens filling the forms out don't have the same vision as the twenty-somethings putting the thing together.  We went with the highest-contrast, dark red drop-out ink for the form design instead.

    But yesterday I was struck by the fact that I read the "What the science says" and the line in the green box, but my eyes then went immediately to the "The greenhouse effect has been falsified" at the start of the orange box, without noting the much smaller "climate myth" in the tab.  This on a laptop, by the way, and I've got fairly decent vision.

    I've been looking at this site for a long time and this is the first time I realized the readability might need a change to better manage the reader's flow.  Perhaps putting "Climate Myth" at the same size font as the "What the science says...", only have it on white background in the dark orange as font color.  Lots of online text these days in different publications will feature text with different background shades just as decoration, so the shift from green to orange may no longer be enough of a cue.


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  5. Thanks for inserting Eunice Foote as the lead person finding out the role of greenhouse gases, three years before John Tyndall. In fact Tyndall most likely read Foote's article about it before doing his own experiments, and has gotten all of the credit up until recently.  There's an excellent chapter about this in the book All We Can Save edi. by Ayana Elizabeth Johnson and Katharine K. Wilkinson.

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  6. "By the end of that century, Eunice Foote and John Tyndall had proved him quite correct through their experiments with various gases..."

    Exactly so. It might be good to include a brief  statement about how the experiments worked (with canisters of CO2 exposed to a radiant heat source and measurements taken?). I say this because this is really the crucial foundation of things, along with observations of the planets climates and deducations from that. 

    In order to make sense of the whole complicated issue as a non expert, I have always done this. It  seems to we know for a fact from laboratory experiments that CO2 is a greenhouse gas because it (simplifying) absorbs heat while oxygen and nitrogen etc,etc do not. Therefore if you add even very, very small quantities of CO2 to the atmosphere, even one single molecule,  it must absorb heat and thus have at least some  warming effect on the atmosphere, and the issue is entirely about how much CO2 is added to the atmosphere, and what  warming  effect results in total. This is simple logic.

    Arrhenius did some calculations in the 1890s I dont fully understand but they seem robust as they made accurate predictions about warming in the 20th century. While I generally dont like assumptions, it seems safe to assume our current climate calculations are more sophisticated. So I see no need to be scepetical any longer about the greenhouse effect, and the proclamations in the climate myth box that the greenhouse effect contradicts so called physical laws is just ignorance or made up nonsense.

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  7. Eunice Foote certainly deserves to be more notable.  History is often unfair, in its "colloquial" form.


    bf@4 :  Thanks for those thoughts.

    I was intrigued that you had described the color box as dark orange tab ~ rather than the dark red tab  which I had automatically pictured.

    As you say, it is a devilish job to design even a simple black&white "form" for people to fill out correctly (without danger of misinterpretations).

    Then we get to the devilish question of colors themselves ~ and how they are perceived (even at different illumination levels) by the "mainstream" viewers, versus the various so-called "anomalous" genetic subgroups that make up each & every population (and are exhibited differently in males/females).   Fortunately, these different color perceptions are usually not of great importance . . . although camouflage-designers and traffic-light-designers would disagree on that.   [You may have idly wondered why the green "GO" traffic light has a faint tinge of blue.]

    And then there is the psychological component, where humans may mentally perceive the color that they expect to see (in a certain object or context).

    And nowadays we have the problem of designing eye-catching layouts for a target population of people who are busy and/or distractable  ~ and who are viewing on screens (usually without standard color calibration) of widely-differing sizes . . . sizes down to even a few inches, quite commonly.

    But enough of this off-topic verbiage from me.  The small groups of volunteers managing the SkepticalScience website have a wickedly big load on their shoulders, in all sorts of ways.

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  8. @#7 Eclectic,

    Just how important Eunice Foote's work was came to light relatively recently. I've not seen any evidence she corresponded with Tyndall. So far as I am aware the findings occurred independently of one another.

    We revised The History of Climate Science here at SkS, to highlight her contribution, a few years ago after Katharine Hayhoe brought it to my atttention.

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  9. As this is your first post, Skeptical Science respectfully reminds you to please follow our comments policy. Thank You!

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