Warming Rate in the US Slowed during the Recent Warming Period

The Contiguous U.S. Surface Air Temperature Data Through 2012 – Is the Recent Warming Trend Unusual?

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There’s going to be a press conference today with James Hansen of GISS and Tom Karl of NOAA. According to the press release, at 10AM EST on Tuesday January 15th, they’re going to tell us all about nasty weather around the globe in 2012.

Right up there near the tops of their lists has to be surface air temperatures in the United States, Figure 1, which were thankfully warm in the 2012. (I’m old. I prefer warm weather.) We’ve been hearing for months about how warm it was. I’m sure they’ll be happy to tell us about it at least one more time.

Figure 1

Figure 1

As many of you know, I normally don’t pay any attention to land surface air temperatures. I study sea surface temperature data. So, with all of the nonsense we’ve been hearing this year, I was surprised to see there was nothing unusual about the rate of warming over the past couple of decades in the contiguous U.S., even with the thankfully warm weather in 2012.

It’s very obvious that land surface air temperatures in the U.S. warmed rapidly from 1917 to 1934. Then there was a cooling period for a number of decades, which was followed by the recent warming period. What’s unusual about that? It could be argued that the recent warming started in 1979 or 1993. So let’s compare the trend of the early warming period to the trends of the recent warming period with the start years of 1979 and 1993.

The linear trend of the early warming period (1917 to 1934) was 0.997 Deg F/ Decade. The linear trend for the recent warming period with the start year of 1979 is far below it, at 0.537 Deg F/Decade. See Figure 2. If we start the recent warming period in 1993 (Figure 3), the rate of warming is a little higher at 0.674 Deg F/Decade, but that’s still far less than the warming rate of the early warming period.

Figure 2

Figure 2


Figure 3

Figure 3

Now a question for Hansen and Karl: what’s all the hubbub, bubs? If anything, U.S. temperatures are warming at a slower rate in recent decades compared to the early warming period, even with all of that lovely warm weather last year.


It’s doubtful that Hansen and Karl will mention the fact that the ocean heat content records since 1955 and the satellite-era sea surface temperatures show no evidence of a manmade global warming signal. That is, while they’ve warmed, it’s blatantly obvious that Mother Nature was responsible for the warming. Since they won’t raise that topic, I will.

I’ve recently published my e-book (pdf) about the phenomena called El Niño and La Niña. It’s titled Who Turned on the Heat? with the subtitle The Unsuspected Global Warming Culprit, El Niño Southern Oscillation. It is intended for persons (with or without technical backgrounds) interested in learning about El Niño and La Niña events and in understanding the natural causes of the warming of our global oceans for the past 31 years. Because land surface air temperatures simply exaggerate the natural warming of the global oceans over annual and multidecadal time periods, the vast majority of the warming taking place on land is natural as well. The book is the product of years of research of the satellite-era sea surface temperature data that’s available to the public via the internet. It presents how the data accounts for its warming—and there are no indications the warming was caused by manmade greenhouse gases. None at all.

Who Turned on the Heat? was introduced in the blog post Everything You Every Wanted to Know about El Niño and La Niña… …Well Just about Everything. The Free Preview includes the Table of Contents; the Introduction; the beginning of Section 1, with the cartoon-like illustrations; the discussion About the Cover; and the Closing.

Please buy a copy. (Paypal or Credit/Debit Card). It’s only US$8.00.

You’re probably asking yourself why you should spend $8.00 for a book written by an independent climate researcher. There aren’t many independent researchers investigating El Niño-Southern Oscillation or its long-term impacts on global surface temperatures. In fact, if you were to perform a Google image search of NINO3.4 sea surface temperature anomalies, the vast majority of the graphs and images are from my blog posts. Try it. Cut and paste NINO3.4 sea surface temperature anomalies into Google. Click over to images and start counting the number of times you see Bob Tisdale.

By independent I mean I am not employed in a research or academic position; I’m not obligated to publish results that encourage future funding for my research—that is, my research is not agenda-driven. I’m a retiree, a pensioner. The only funding I receive is from book sales and donations at my blog. Also, I’m independent inasmuch as I’m not tied to consensus opinions so that my findings will pass through the gauntlet of peer-review gatekeepers. Truth be told, it’s unlikely the results of my research would pass through that gauntlet because the satellite-era sea surface temperature data contradicts the tenets of the consensus.


Contiguous U.S. land surface air data is available in Table form through the NOAA/NCDC webpage here.

49 thoughts on “Warming Rate in the US Slowed during the Recent Warming Period

  1. I’m quiet agree with you and want to add that we have found the evidence that in general observed in the past century warming was not continuous but step function. There were two climate shifts in 1925/1926 and 1987/1988 years. During each shift mean temperatures in tropics/north middle altitudes increased by about 0.28/0.36 °C. Other temperature anomalies are explained by natural variability. And the existence of these shifts also masked by natural variability. This hypothesis allows to develop very simple linear regression models which explain main features of observed in the past century temperature anomalies. Now we are working on publication them in peer-review journal and are interested in opinions and replies.
    There are two remarkable moments. The first one is that linear regression coefficients can be fitted by the small part of data (from 1900 till 1940 for example) and quite well reproduce the whole period from 1900 till now. The second one is that good quality of reproduction is achieved by using only three factors (ENSO/PDO, volcanoes and shifts for tropics/northern middle altitudes).
    A draft of manuscript can be downloaded by link
    If you are interested I can send all the data and calculations.
    if you have any ideas we can unite our effort

  2. I don’t like all those straight lines through time series data, bit dependent upon where you shoose to start and finish drawing them.

  3. One reason temps in the eastern US have risen in the past decade is the mandated reduction of sulfate. In dry conditions, sulfate forms a whitish haze, reflecting light back to space and thus reducing warming. In humid conditions, sulfate ions form cloud condensation nuclei, creating clouds, and also make clouds whiter. These processes also reduce rates of warming, because low to mid troposphere clouds on balance provide cooling, and whiter clouds are more reflective.
    So reducing sulfate increases warming.
    This isn’t an argument that we should flood the atmosphere with sulfate. Rather, it raises the question of where the balance of reduction should be. One reason we are reducing sulfate is because of fears of acid rain. The National Academy of Sciences in 1981 predicted that by 1990, half of eastern lakes would be acidified. In fact, by 1990, there was almost no change in acidified lakes. It was found that many of the lakes in places like the Adirondacks had become adidified since the 1920s is that denuded forests were allowed to grow back, and the leaf litter decay is acidic. In other words, some lakes are acidified naturally. So the problem was overhyped, although it was a problem.
    Where is the right balance, then, if you believe that climate change is a major ecological disaster waiting to happen?
    The issue is more complicated (and I’d be glad to say more), but it is important to recognize that we can’t see pollutants in a vacuum, we have to have a mechanism to look at them in a way that encompasses all their effects.

  4. David Shaw says: “I don’t like all those straight lines through time series data, bit dependent upon where you shoose to start and finish drawing them.”
    The start and end dates of the warming and cooling periods are pretty obvious with the annual data. But the start date of the late warming period was debatable, so I presented the linear trends for both.

  5. 2012 in the US should be seen as a good test of CAGW.. How well did the US cope with a jump of 1°F?
    Were there thousands of climate refugees fleeing to Canada?
    How many coastal cities lost property?
    Somewhat tongue in cheek, but it might be instructive to go through a number of metrics and see how the US was affected by 1°F change.

  6. Perhaps at the top of the Modern Warm Period we should expect the rate of warming to moderate. I’m concerned about what’s coming next. If we see warming resume after our current temperature plateau, we can breath a sigh of relief; if we have a downward trend, we may be in trouble.

  7. Time to remind those Newspapers in California that the extreme cold snap is caused by Global warming! LOL

  8. Bob Berwyn says: “You got the time of the press conference wrong.”
    Thanks. I can’t claim that one was a typo. That I’ll blame on lack of caffeine.
    I’ll fix the cross post at my blog. Thanks again.

  9. I unfortunately see a declining trend in temps look at the No nino in the Pacific as we speak.
    in fact some are saying Nino’s been [kicked] out of the crib by an oncoming Nina..
    what do you say Bob?

  10. When I look at the Contiguous US Land Surface air Temperature graph that Bob provided , one of the common variables that strikes me is that warm Atlantic SST as measured by AMO was present during most of the major drought and warm spells ,namely 1931-1939,1953-1956,and again 1995-2012 . The paper KEY ROLE OF THE ATLANTIC MULTIDECADAL OSCILLATION IN THE 20TH CENTURY DROUGHT AND WET PERIODS OVER THE GREAT PLAINS by Sumaant Nigam et al.2011 speaks to this in more detail. The impact is the greatest in the midwest, southwest and Rocky mountains /Great basin areas. The presence of more colder water along the Pacific East coast than in the western and central Pacific coast which happened also during the positive AMO periods also seems to be a contributor. Mc Cabe et al wrote about this same topic in their paper PACIFIC AND ATLANTIC OCEAN INFLUENCES ON MULTIDECADAL DROUGHT FREQUENCY IN THE UNITED STATES .[2004] Blaming the 2o12 US warm year entirely on global warming is wrong . This may be a regional short term event that cannot be lifted onto the global stage and blamed on man generated greenhouse gases because globally the temperatures have been actually flat and most recently decliningg over the last 10 years . We just cannot blame every regional climate event on global warming. Just look at the spike in 1921 or those in the 1930’s in the US . These were local short term events that I am sure have happened before in this part of the world and will happen again.

  11. lgl says: “and there are no indications the 0.7 C warming since 1880 was caused by ENSO,
    Not sure what you’re trying to show with the graph, but I only deal with satellite-era sea surface temperatures. That’s the time period the IPCC says that only greenhouse gases can explain the warming.
    Also, in looking at your graph, what’s HadSST1? There’s no sea surface temperature dataset by that name.

  12. Out of curiosity where did data for figures 2 & 3 come from. The temps for the time period 2000 – present don’t look right.
    I thought GISS was called out once already for manipulating the data to show the last 10 years were warmer than the 1930’s.
    It is my understanding that the 1930’s are warmer than the most recent warm spell, right?

  13. tgmccoy says: “I unfortunately see a declining trend in temps look at the No nino in the Pacific as we speak. infact some are saying Nino’s been icke out of the crib by an oncoming Nina.. what do you say Bob?”
    I was asked a similar question a couple of days ago on another thread. I hope you don’t mind if I cut and paste that reply and update it. (In fact, I think I’m going to turn it into a post at my blog. Thanks for reminding me.)
    It appears the sea surface temperatures in the eastern equatorial Pacific might continue to cool below the present NINO3.4 values of -0.52 deg C:
    There’s lots of cool subsurface water from the last upwelling Kelvin wave. See here:
    and the Hovmoller on page 16 here:
    How long will La Niña conditions last if they reach that level? Dunno.
    There’s an off-equatorial pool of warm water that shows up in the NODC ocean heat content data…
    ..and in the AVISO sea level anomalies for Dec 2012…
    …and the JPL sea level anomalies, but not as pronounced. See the JPL map here:
    I appears to be the leftovers from the El Niño conditions earlier in 2012. Run back in time a few maps here:
    If that pool heads north or works its way into the Indian Ocean, then it won’t be involved in the next downwelling Kelvin wave, but if it migrates south, it could help to strengthen the next one and bring us back to El Niño conditions again in 2013.
    We’ll have to wait and watch.

  14. Here are some concluding remarks from the authors of the first paper noted above [Sumant Nigam et al]
    “We find Atlantic SSTs, tropical and extratropical, to be particularly
    influential; often, more than the Pacific ones, and more than
    in previous analyses, especially from the SST‐forced atmospheric models: AMO is the dominant contributor (∼50% of
    the signal) in the Dust Bowl spring drought and in the 1980s
    fall wetness (i.e., in 2 of the 4 episodes) while the Atlantic
    Nino is in another (Dust Bowl summer).
    Atlantic is more influential than the Pacific in 3 of the
    4 reconstructed episodes
    The AMO’s influence on continental hydroclimate is
    provided circulation context from analysis of low‐level flow
    and the column stationary moisture flux, both obtained from
    NOAA’s 20th Century Reanalysis; the modulation of
    moisture transport was consequential. A hypothesis for how
    the AMO atmospheric circulation anomalies are generated
    from AMO SSTs is proposed.
    The Atlantic SSTs evidently exert a profound influence
    on Great Plains hydroclimate on decadal timescales, especially in the transition seasons; an influence not represented
    in the SST‐forced dynamical models of the atmosphere. For
    instance, Schubert et al. [2009] find a cold‐Pacific and neutral
    Atlantic to be significantly more influential for US droughts
    than a neutral‐Pacific and warm‐Atlantic (PcAnPnAw in
    their drought modeling experiment nomenclature).
    Our analysis suggests that the La Nina–US drought
    paradigm, operative on interannual time scales, has been
    conferred excessive relevance on decadal time scales in the
    recent literature, in part, because dynamical models of the
    atmosphere are unable to represent the influence of Atlantic
    SSTs on Great Plains hydroclimate. Regardless, the present
    analysis is encouraging for the investigation of SST‐based
    decadal drought/wetness predictability.”

  15. higley7 says:
    So, is this the data after value has been added? It is hard to believe that 2012 was at all warmer than 1938.

    I thought it was ’36–but what confuses me is that we read continously (at WUWT) that 1936 (US) and 34 (global) {or is it the reverse?} was the hottest ever and that they “cooked” the books to make the past cooler and the present hotter–but then we keep using graphs and charts to make points which give credence to teh claims that today is hotter? What gives?
    Are they (book cookers) right and 1998, 2005, and 2012 are hotter then the thirties? Why do we allow that to stand? Should I be conceeding that today’s records beat the thirties both in the US and globally?
    THANKS Box of Rocks!!!!!! My point exactly.
    I thought GISS was called out once already for manipulating the data to show the last 10 years were warmer than the 1930′s.It is my understanding that the 1930′s are warmer than the most recent warm spell, right?

  16. vukcevic says:
    “At the moment UK has been hit by cold spell. The weather-man suspect the Sudden Stratospheric Warming.”
    It’s called winter.

  17. Your trends start at 1895. I assume that’s because a standard was established and/or there were enough records to say that they represent the contiguous US.
    I wonder how many records there are that are older even if they don’t give a complete record?
    Here’s the link to the info I’ve pasted here. (Notice that 5 of the top ten warmest years for Cincinnati Ohio were before 1895.)
    1136 AM EST TUE JAN 1 2013
    1. 58.1 / 1881 1. 56.6 / 2012* 1. 56.2 / 1921
    2. 57.3 / 1882 2. 56.4 / 1998 2. 56.0 / 1931
    3. 57.2 / 1913 3. 55.5 / 1931 3. 55.5 / 1946
    57.2 / 1874 4. 55.4 / 1991 4. 55.3 / 2012*
    5. 57.1 / 2012* 55.4 / 1921 5. 55.2 / 1998
    57.1 / 1921 6. 55.3 / 1938 6. 55.1 / 1938
    57.1 / 1878 7. 55.0 / 2007 7. 54.7 / 1944
    8. 57.0 / 1880 55.0 / 1946 54.7 / 1939
    9. 56.9 / 1931 9. 54.9 / 1999 9. 54.6 / 1896
    10. 56.8 / 1911 54.9 / 1939 10. 54.5 / 1922
    NORMAL: 54.1 NORMAL: 53.0 NORMAL: 52.1

  18. higley7 says:
    January 15, 2013 at 7:02 am
    So, is this the data after value has been added? It is hard to believe that 2012 was at all warmer than 1938
    I’m with higley7. Certainly the Texas panhandle area of 2012 can’t be compared to 1936-38.
    The temperature records as used create artefacts of apparent warming when they show nighttime warming equal to daytime warming. Numerically the same, practically different. As we all understand.
    There is a lot of mathematical correctness being used to mislead us. Tornado numbers, adding GIA into sea-level rise. Others.
    I arrived in Calgary in Feb. 1979, thought I was in the Promised Land: a chinook got rid of a cold spell and the warmth continued into summer. Feb 28th and I’m in shorts and a T-shirt. Hardly any rain, none to ruin our outdoor fun. Then I found we were in a drought, ended in the late 80s. But I wonder what that weather would be “blamed on” today.
    There is a chinook today. Last week it was -15C, today is +3C. I’ll be listening for the “weird” weather that CO2 has caused.

  19. Bob Tisdale says:
    “Not sure what you’re trying to show with the graph, but I only deal with satellite-era sea surface temperatures. That’s the time period the IPCC says that only greenhouse gases can explain the warming.”
    Dear Bob, you can easily extend your analysis to 1900. For example, adequate reconstruction of HadSST2 temperatures of tropics (30S-30N) by linear regression could be achieved by consideration only 3 factors – ENSO (Nino34 index from HadSST2), volcanoes (global Optical Thickness at 550 nm, from NASA/GISS) and climate regime shifts in 1925/1926 and 1987.
    Calculations are in this simple Excel file:
    Correlation coefficient for monthly mean time series – 0.86! Another remarkable moment is that coefficients of linear regression can be fitted by small amount of data – for example, from 1910 till 1940, for adequate reconstruction of the whole period.
    Reality of climate regime shifts in 1925/1926 and 1987 is proved by many independent studies that are summarized in our preprint: http://vixra.org/abs/1212.0172

  20. If you look at 20 year periods starting in any year, the linear rate of warming for those 20 year periods is pretty variable, but the highest rate of warming is for periods ending in the mid 1930s.
    However, once you look at periods of 35+ years, then the greatest warming is for the period ending now.
    So you could say that there were more rapid short warmings in the past, but todays warming is more sustained.

  21. Arbitrarily choosing the start and end dates of the analyses along with comparing time periods of different length invalidates the conclusions of this post. There are far more statistically robust methods that could have been used. One wonders why they weren’t.

  22. After correcting for UHI (92% inflated trends 1979-2008), 2012 would be around 53.2 deg, well below the 1934 record. And the UHI increase from 1934-1979 is not yet included.

  23. Surely this is a joke?
    Your trend for the early period is computed from either 18 or 16 years (the text and figures disagree), but you compute trends for the late period for a longer year.
    If you’d listened to any of the arguments about recent changes in global temperature you would know that noise int he temperature record can have a big effect on short period trends, so it’s not surprising that you can find a short period early in the record that has a higher trend than a long period late in the record.
    That is just what you’d expect from a basic understanding of statistics. It’s why sample sizes are important.
    Why don’t you do some proper trend analysis and then see what that says?

  24. vukcevik,
    I looked at your link and the stratosphere warming that you attribute to a huge flow of warm air from the pacific, if this is true it is a huge dump of heat into space. With the sun slumbering and La Nina kicking back in this could mean some serious global cooling? What is your take on this.?

  25. I’m sorry Bob you draw a couple of simplistic lines through arbitrary choose points and come to a conclusion, is that joke??? Is that what passes for “analysis” these days, if I were you I’d ask to remove this post as it really undermines your credibility.

  26. Hi Wayne
    I am not in any way en expert on the SSW effect on the cooling. About two years ago I noticed that SSW (which occurs only in the winters) appears to coincide with the Kamchatka volcanic eruptions. Interesting fact is that the SSW events are very rare in the South Hemisphere, only one in the last 30 years. Heat from the ocean escaping into stratosphere may be of some interest but density of the stratosphere is very, very low.
    Maybe someone else more knowledgeable would like to comment. Here is the link again:

  27. If you were being hyper-critical, you could argue that the early 20th century warming was ‘only’ for 17 years, so a better comparison might be a 19th century warming period, which would be equally as long as the modern one.
    Any data on 19th century warming rates available?

  28. misfratz says:January 15, 2013 at 11:22 pm
    Surely this is a joke?

    The joke is the reduced rate of warming in the second sample that is Thermageddonally® charged with CO2.
    MorningGuy, look up linear regression.

  29. Bob
    What base years did you use for the HADISST-based NINO3.4 sea surface temperature anomalies and what’s the scaling factor?
    My Nino3.4 running sum is also detrended. Some dataset(s) show weak negative trend, others weak positive so it doesn’t matter. For this purpose (running sum) we must assume a no-trend. Otherwise you end up claiming global warming is caused by Nino3.4 warming which would probably be caused by global warming, i.e global warming is caused by global warming. (and I’m talking 60 yrs+ )
    Scaling also does not matter. The shape is the important, so I used ‘scale-to-fit’ factor.

  30. lgl: Thanks for the update. Now back to your original comment, which was, “and there are no indications the 0.7 C warming since 1880 was caused by ENSO,
    Are you falling into the trap of assuming the ENSO index represents the process of ENSO? It doesn’t.
    NINO3.4 sea surface temperature anomalies only represent the impacts of ENSO on the temperature of the NINO3.4 region. They do not account the warm water remaining (the leftovers) from the ENSO events:

  31. Bob,
    No I’m not. I agree it seems likely there is an integrating effect creating the ~60 yrs cycle, but if there is no trend in ENSO since 1880 I see no reason to believe ENSO would drive temp higher and higher ‘forever’.
    I suspect the normal situation is warming in steps, like you say, and slow cooling. GHGs don’t change the warming much but they slow down the cooling. If so then the flat trends between major Ninos do not mean “no man made warming”. They could mean “man made reduced cooling”. Just a thought, no evidence 🙂

  32. [snip. Calm down, don’t label others “deniers”, follow the site Policy, and you will get your comment approved. — mod.]

  33. OK, Bob, this retired pension-dependant finally coughed up the $8. Because you deserve it.
    Long may the Warming, if any, continue! Max CO2 output would be appreciated, too. Thanks, BRIC!

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