Most US maximum temperature records set in the 1930s

Global warming is a funny thing. Whenever we experience a heat wave the press proclaims it is the face of global warming, but when we have an unusual cold snap, it is merely natural variation.

The Arizona Daily Star had an interesting article today concerning the number of days in Tucson with maximum temperatures over 100° F. The story says the record was set in 1994 with 99 days over 100° F and speculates upon our chances of breaking that record this year. The “normal” number of days over 100° F is 62 according to the National Weather Service.

Also interesting is the statistic that July 4, 2012, had the coolest maximum temperature on record, 86°F.

Looking at a larger picture and a slightly different statistic, we see that the greatest number of maximum temperature records in the U.S. were set in the 1930s. Below is a graph compiled by Steven Goddard from U.S. Historical Climatology Network (USHCN) records:


Getting back to Tucson, we see from the graphics in the Star article that we have had more years, with more days over 100° F than “normal” within the last 25 years or so. That could be a reflection of the urban heat island effect. Our asphalt and concrete absorbs more heat and reflects it back at night. I discuss that in my post Warmer nights no proof of global warming.

A graphic from that post demonstrates the problem by comparing the temperature trend in urban Tucson with that from rural Tombstone:

Tucson-Tombstone temp

You can see that Tucson temperatures have been rising but there is no trend in the rural Tombstone station. Carbon dioxide works in mysterious ways.

So, the big news from the Arizona Daily Star is: Summers in Tucson are hot.

See also:

Human induced warming in Tucson



  1. Jonathan,

    You’re an extraordinary denier. However, scientific evidence is not on your side. There are multiple lines of evidence that the climate is changing, and it is human-induced.

    Fossil fuel signatures
    Less radiation escaping into space/more heat returning to Earth
    Ocean warming
    Sea ice declining
    Land ice melting
    Sea level rise
    Nights are warming faster than days
    Winter is warming faster
    Upper atmosphere cooling/sun is in a cooling period

    So, deny all you want. This is occurring regardless of what deniers like you have to say. Sadly, by the time you wake up (if ever), it will be to late to make any necessary changes to help avert disaster.

    1. Hello Susan,
      If you were a regular reader you would know that I do not deny climate change. The geologic record shows that climate is always changing. It also shows that what we are experiencing now is not extraordinary. None of the things in your list is evidence for CAGW, but rather natural variation. I challenge you to provide specific physical evidence showing that human carbon dioxide emissions are the major cause of climate change. I doubt any exists. The fact that you resort to name-calling shows that global warming is more of a religion to you rather than an objective opinion based on facts.

      By the way folks, “speakoutforscience” is Susan Callery, a communications specialist for NASA’s JPL. How is she doing?

      1. Considering the combination of her use of the word “denier” and her chosen user name of “speakoutforscience”, I’d say she is undermining her position and credibility. Skeptic scientists, by the way, also ‘speak out for science’, but they speak for the side of the issue that the likes of NASA’s James Hansen and the IPCC’s Michael Mann wants to have suppressed and portrayed as corrupted by fossil fuel industry funding, despite not having an iota of proof to support that accusation.

        Skeptic scientists question all nine of Ms Callery’s ‘evidence’ points, while others such as Donna Laframboise ( ) put the entire IPCC methodology under very hard scrutiny, but how is the public to know this when they don’t hear half the story, as I reported myself in one of my own recent articles, “PBS NewsHour global warming coverage:
        IPCC/NOAA Scientists -18; Skeptic Scientists -€“ 0”

        I have no science expertise to know which side is right, and I don’t ever suggest people like Ms Callery should be silenced. Rather, if she does speak on authority from NASA’s JPL, I’d highly recommend that she appear on the NewsHour to speak about the science, but I also want to see a skeptic of the level of Fred Singer or Richard Lindzen. That way I and all the other viewers could see who makes the most compelling argument or whether we need more debate. Or on a more local level, if Ms Callery is confident her material will stand against Jonathan’s, then she should have no problem engaging in a full debate with him.

        But the tell-tale sign of trouble with those who push the side of man-caused global warming is their propensity to run from debates, hide the data that allows them to make their computer model predictions, and resort to shell-game tactics such as the easily debunked ‘denier’ label or insinuations of ignorance along with assertions of outright disaster that’s too far gone to fix. Such things don’t evoke an appearance of calm rational science discussion, they instead suggest a desperate attempt to bolster a dying political agenda.

  2. Believe what you wish. June broke or tied 3,215 high-temperature records across the U. S. That followed the warmest May on record for the Northern Hemisphere – the 327th consecutive month in which the temperature of the entire globe exceeded the 20th-century average. Those are facts and have nothing to do with “alarmism.

    Confirmation that rising carbon dioxide levels are due to human activity
    comes from analysing the types of carbon found in the air (isotopes). Further confirmation comes by measuring oxygen levels in the atmosphere.

    Satellites measure infrared radiation as it escapes out to space. A number of scientific papers, including a
    comparison between satellite data from 1970 to 1996, found that less
    energy is escaping to space at the wavelengths that greenhouse gases
    absorb energy:
    Also found in Chen 2007, “Spectral signatures of climate change in the Earth’s infrared spectrum between 1970 and 2006.”

    That less heat is escaping out to space is confirmed by surface
    measurements that find more infrared radiation returning to earth.

    Another human fingerprint can be found by looking at temperature trends in the different layers of the atmosphere. What we observe from both satellites and weather balloons is a cooling
    stratosphere and warming troposphere, consistent with carbon dioxide
    warming and solar cooling (Karl et al. 2006).

    Furthermore, if an increased greenhouse effect was causing warming,
    nights would warm faster than days. This is because the greenhouse effect
    operates both day and night. Conversely, if global warming was caused by the
    sun, we would expect the warming trend to be greatest in daytime
    temperatures. What we see is a decrease in cold nights greater than
    the decrease in cold days, and an increase in warm nights greater than
    the increase in warm days (Alexander 2006).

    Finally, there is a large amount of satellite data (coupled with data on the ground) showing massive, rapid sea ice loss as well as land ice loss.

    1. The challenge was to provide physical evidence showing that our emissions were the major cause of recent warming.

      I have seen these arguments before, they are all rather equivocal. For instance,

      Douglass, D.H. et al. 2007, A comparison of tropical temperature trends with model predictions, International Journal of Climatology DOI:10.1002/joc.1651] showed that Karl 2006 which you refer to was wrong. The theoretical “fingerprint” is missing according to actual observational measurement. See my post A Basic Error in climate models.

      Regarding your sentences :”Furthermore, if an increased greenhouse effect was causing warming, nights would warm faster than days. This is because the greenhouse effect operates both day and night. Conversely, if global warming was caused by the sun, we would expect the warming trend to be greatest in daytime temperatures.” Please see “Warmer nights no proof of global warming” in the link above in the post. This shows that the effect you write of is most probably due to the urban heat island effect. There is no observational evidence that it is a greenhouse effect, only theory.

      About the satellite measurements of infrared radiation at various times: The differences measured were very small, well within the range of instrumental error. Additional problems were with cloud interference. The minor differences could have been due to water vapor, the major greenhouse gas, not carbon dioxide. Also some areas showed a negative feedback. These measurement provide no unequivocal evidence.

      You have also not shown that the alleged effects of carbon dioxide are strong enough to overwhelm natural variation, nor did you show that the observed effects could not have been natural variation.

  3. Let me add that the fact that you would include my name and position in a publication shows me what kind of person you really are. It is one thing to learn the information for yourself and another to post it.

    1. To insinuate Mr DuHamel’s action is bad intent is quite a stretch. Are you not proud of your name and position? A Google search of the user name “speakoutforscience” – assuming that is all the same person – does not exactly show results suggesting a tone of non-political discussion of science points. As a private citizen, you are of course entitled to speak as you wish, but in claims that you know more of the science, I’d think it would be in your best interest to not only be confident to have your own name alongside the agency you work for, you’d also be perfectly open to be identified as such.

      Instead, this may instead reveal what kind of person you really are. You do not use your actual name because the political agenda you appear to promote is at odds with the scientific agency you work for?

    2. I think readers should know who is commenting, especially if it is a government employee, (except for whistleblowers). If you want to snipe anonymously, use an anonymous email account.

  4. glow bull worming is nothing but a big hoax and co2 does not cause the planet to warm up but it is necessary for life because the more the better for growing plants.we have not reached the higher tempetures we had before the little ice age and warm is always better than cold.go to junk science and if you can prove glow bull warming you can win a$ 100 large plus.

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