Global Warming, Climate Change

It seems to me that Roger Pielke Jr. is now persona non grata at Nate Silver’s 538 blog. Silver, whose statistics-based predictions of the last presidential election were stunningly accurate, hoped to capitalize on his celebrity by starting a blog which would present interesting and sometimes important posts which were based on competent analysis of actual data. What a concept! Unfortunately for Silver (in my opinion), he failed miserably when choosing Pielke as his point-man for the global warming/climate change issue. Many of us noted the kerfuffle which followed Pielke’s first foray, with Silver himself admitting publicly that it wasn’t up to the standard he hoped to set.

I wandered over the other day, checked out posts filed under “climate change,” and although I’m gratified to see that Pielke isn’t their point man any more, I wasn’t exactly impressed. The latest is about the use of the phrase “global warming” vs “climate change” by U.S. politicians. First of all, I think it kind of misses the point — which phrase is used is far less important, in my humble opinion, than how often either is uttered, by whom, and in what context.

Second, I didn’t really find much analysis in that post. Yes, there were numbers and yes, they were relevant to the subject — so I suppose I shouldn’t be too critical. Maybe I’m just too immersed in analysis-in-depth to know what the appropriate level is for a “popular” blog. Or, maybe Nate Silver should hire me.

Still, use of the phrases “global warming” and “climate change” is interesting, and happily, Google Trends provided me with data about their use as search terms so I didn’t have to do too much work (after all, Nate Silver isn’t paying me). Let’s look at the use of those phrases as Google search terms over the last 10 years or so, right here in the good old USA.

Here’s the data:


The red line shows the prevalence of searches for “global warming,” the blue line for “climate change,” and the black line is the sum of both. Note that Google Trends doesn’t give actual counts, they scale the data so that the highest value is equal to 100. The highest total is over 100 because I added the separate counts together.

Clearly “global warming” has been a much more prominent search term than “climate change.” But that may soon no longer be true. If we look at the fraction (in percent) of searches for “climate change” we note that it has risen steadily in popularity (compared to “global warming”) since about 2007:


If the present trend continues, “climate change” will soon surpass “global warming” as the search term of choice.

But I’m less interested in the choice of term, more interested in the total searches (the black line). There’s an overall rise up to about 2007, a decline since then, and to my eye it looks like there’s an annual, seasonal cycle present. It also looks like there’s more variation when the level is high than when it’s low, leading to the phenomenon of heteroscedasticity, which can often be removed by log-transforming the data. Here’s the logarithm of the totals (log-10 to be more intuitive rather than log-e which is my intuition):


This makes the presence of a seasonal cycle rather evident. But what is the seasonal pattern? I was expecting more interest during summer, when it’s hot, so I smoothed the data (the red line in the above graph) to remove the secular trend, then “folded” the data with a period of one year to show what that looks like (I’ve plotted two full cycles of the seasons, for clarity):


That’s a surprise. Summer is the season with the fewest searches, and there’s also quite a dip around Christmas, which is obvious if we average the many years’ values:


I have a strong suspicion that what we see here is the seasonal cycle of the school year. When school starts in September, searches go up — when it ends in May/June, they go down — and when students get vacation around the Christmas holiday season, there’s a brief span with very little activity.

Naturally, I subtracted the average seasonal cycle from the log-transformed data, then log-untransformed (i.e. exponentiated) back, to produce what I’ll call anomaly values, which give a much sharper image of the secular trend:


I’ve also plotted a red dot on those values which might suggest an “outburst” of activity.

Wherefore the changes? I can only speculate — but it’s my blog so I’ll speculate freely.

First, let’s consider the rise to 2007 and decline thereafter. I suspect that the rise is due to Al Gore’s film An Incovenient Truth and the publicity which preceded and followed it — including an academy award. This suggests that the person most responsible for making Americans aware of the issue is Al Gore.

As for the decline, I suggest that it does not reflect declining interest in the issue. Rather, I submit, it’s simply due to the fact that people are so much more aware of it today they don’t need to search for “global warming” — they already know what it is (at least roughly). Those who are seeking information these days through google search are probably being more specific in their search terms, looking for things like “sea level rise” and “heat waves” and “hurricane Sandy” rather than “global warming” or “climate change.”

As for the outbursts of search activity, I have hypotheses for at least two of them. The peak in early 2007 coincides with winning the Academy Award for Best Documentary Feature. The outburst in late 2009 coincides with the Copenhagen Summit on climate change, a news event which seems to have spurred public interest in the topic.

I suppose I could dig through news reports to identify what events may have triggered all the other outbursts of activity, and to define more precisely just how statistically significant those outbursts are. But I’ll leave that as an exercise to readers. After all, Nate Silver isn’t paying me for this.

55 responses to “Global Warming, Climate Change

  1. Very interesting!

    But don’t you think that the outburst in late 2009 is probably more associated with the “Climate Gate” emails and subsequent media hype?

    [Response: Ah … you mean the emails which were stolen by a criminal hacker, and which ended up showing no wrong-doing on the part of climate scientists.]

    • Tamino, maybe you should do a post relating the statistics of media attention versus bogosity of scandal. I suspect a lack of correlation.

  2. Interestingly, Google ngrams, which records usage in books, paints quite a different picture–the two terms are used with nearly the same frequency from 1980 through 2008, which, unfortunately, is the end of the data:

  3. What a wonderful discussion this is…. thank you so much.

    Checking with other global warming doom-thusiasts, I note that many have abandoned using either term. I prefer AGW – since it is quicker to type. Others just CC. (Anthropogenic Global Warming and Climate Change) But those are used mostly in emails.

    To many, the argument is moot, since both terms work as they describe slightly different things – one is global, while climate is most always has a regional trait.

    Notice another new term: Anthropocene – (must manually add to dictionary) it just gained wider acceptance in the last few years as the preferred name for our current era. Not sure if we just left the Holocene for the Anthropocene – a time when human marks are all over the Earth. Perhaps search stats will tell?

    And thanks for pointing to Nate Silver’s 538 site. I had overlooked it, and will probably continue to do so.

  4. Tamino,

    My immediate thoughts at the start of this post were about the nature of online news -that there is probably a tendency over time for people to read about climate issues via their preferred news sources, rather than to search via Google. This had me immediately wondering who is likely to search for info on climate via Google nowadays, given so many people who take a position on global warming will know in advance which sources of information they trust.

    Your supposition that the seasonal cycle reflects the school year makes perfect sense to me. School kids may well be the last social group who still look for information without already “knowing” the answer!

  5. If I were to search by either term these days I’d get tens of millions of hits, far too many to contemplate scrolling through to find what I really want. More specific terms really are a necessity. This probably explains the drop off in their usage as search terms since their 2007 peak.

  6. bananastrings

    Yes, you an see the spring break dip in March. Check out the numbers for “Macbeth.” Looks like my dental work.

  7. IMO the UN got it right when they set up the IPCC in 1988. Remember to point it out to the next dernier who tries to tell you that, “They call it climate change now, because there’s been no warming since…”

    • David Lewis

      The Toronto Changing Atmosphere conference of 1988 was said by many at the time as the place where it was decided to create the IPCC. The conference statement is here: It illustrates the terms that were commonly used at the time to describe what scientists were concerned about. “Global warming”, “climate warming” and “climate change” are used in the Toronto statement as if they mean the same thing. “Greenhouse effect” was also commonly used back then in the statements of organizations like the Sierra Club.

  8. Interesting. I see a similar cycle in my Hubpages views–dips around Christmas and during the summer (though the latter isn’t quite so simple as that makes it sound; it’s not homogenous throughout the season by any means.) And that’s despite the fact that there are three major topical areas.

    I’d agree that the school year is part of it; I suspect that holiday ‘busy-ness’ and vacation are part of it, too.

    • Horatio Algeranon

      How about Al Gore? Has he had an effect on your site views?

      I also found the views of my blog went way down (from 10-15 per month to zero) this past Christmas — when I made the blog “view by permission only” (and didn’t grant any permissions.) I find I waste a lot less time since I deep-sixed my blog. Funny that. (though I do still waste time here. :)

      • You’d think he would, wouldn’t you, since the Masters of the Universe (AKA the US House of Representatives) have clearly articulated that when he speaks, there is more Snow.

  9. entropicman

    To some extent the two are synonymous. If a sceptic tries to score points using them I tend to reply thus.

    Anthropogenic carbon release is the cause.

    Global warming is the effect.

    Climate change is the consequences.

  10. Horatio Algeranon

    I actually think Pielke may have benefited more than Silver by parting ways.
    I just read a couple things, but it seems the articles on that site are kind of junky (Sex at the World Cup!) and pretty poorly written.

    Silver is obviously a very smart guy and knows his stats but he seems to have lowered his standards (or thrown them out entirely) with that site.

    [Response: I too find the site disappointing.]

  11. Aaron Lewis

    I believe that the first law of political polling is, “Money buys silence!”, In the days before RCRA, it was often expressed as, “Smells like money to me!”
    (in the context of pig poo or coal tar)

    Now go back and look at the media and count how many ads for cars and gasoline, air travel, and other forms of enhanced fossil fuel consumption there were. Like it or not, interest by the media affects what politicians focus on, and filtering by the medial affects what the public hears from politicians. And, the media gets most of their money from industries related to fossil fuel consumption. To the media, fossil fuel consumption smells like money.

    A politician that makes an extended speech; and, the 30 second sound bite from that speech on the evening news will be selected by a media organization that makes most of its money selling ads related to fossil fuel consumption. That is, the public allows fossil fuel interests to fund our data collection (news). PBS allowed NMA,Chevron and the Kock Brothers to fund news and science programming, and thanked them every day. And, in those days, anybody that brought up global warming in an interview on the NewsHour knew that the NewsHour would present “balanced” coverage by presenting an opposing view. The BBC did the same thing. . . .

    For the politician, “climate change” and “global warming” were not the magic words that will get them more favorable treatment on the evening news.

    By cherry picking start and end dates it is easy to prove that politicians’ use of the phases are the inverse of Kock Brothers spending on the topic –including their money funneled through organizations such as the Tea Party. However, that is the tip of the iceberg, and icebergs roll frequently.

  12. Carl Campbell

    I have a problem with both of these terms because of how they are misused. “Climate change” has a traditional meaning that is applied regionally to any of several measures of climate, not just temperature. That need not have changed. “Global warming” is more modern jargon, referring specifically to a rise in mean air temperatures on a global scale, due to the greenhouse effect. It would better have been defined early on as a warming of the entire surface of the globe, for the same reason, but with a strong focus on ocean waters. That is where 93% of the heat goes, and will remain for ages, dragging the atmosphere along behind, but in an irregular way that confuses people.

    • arch stanton

      Many others agree with you. Got a catchy 2 word sound bite that summarizes “infrared energy flux modifier that will in general warm the planet’s surface, but will also cause regionally nonuniform changes in rainfall and wind”?

  13. Gilbert Plass published “The Carbon Dioxide Theory of Climate Change” in 1956. The Springer journal “Climatic Change” started publication in 1977 and is still going, and, as noted above, the “CC” in IPCC (1988) stands for climate change.

    The terms have indeed been in use for a while.

  14. When I see these two terms, global warming and climate change, being discussed, I feel I have to link to this video on the terms from Peter Sinclair:

  15. Whilst I agree the term used shouldn’t really matter, in my experience the the term “climate change” has become a very useful straight line that reliably elicits a “climate has always been changing” response from the deniers. The response itself is denial with deniability for those who find outright denial is less effective than obfuscation in the service of climate action obstruction – e.g. Australia’s Prime Minister – who refuses to be pinned down and assiduously avoids admissions of outright rejection of climate science – uses the “climate is always changing” line; current climate change having nothing or little to do with emissions is clearly implied but, if cornered on the issue (“do you reject the science?” – not that Australia’s media ever really press him to be forthcoming!) he can easily dodge.

    The term “global warming” leaves less wriggle room in my opinion, and, with heat content of land, ice, atmosphere and most of all, oceans, rising, it expresses clearly the fundamental nature of the change currently underway.

    • Martin Vermeer

      Eh, when you add ‘anthropogenic’ this cop-out no longer works — for either term.

      BTW when I hear this old saw ‘the climate has always been changing’, somehow I cannot help adding ‘except lower tropospheric temperatures, according to one analysis, for the last 17 years’. Platitudes and picked cherries happily co-existing ;-/

      • arch stanton

        ‘except lower tropospheric temperatures, according to one analysis, for the last 17 years’.


  16. I would use the term anthropogenic climate change if the topic is specifically focused on humanity’s impact on climate. If the topic is more general, for example a discussion about the ice ages, the climate change seems proper.

    I’m fairly picky with terminology, but that’s caused by my background. I spent a lot of time editing reports, and theses written by others, and I found there was an emerging tendency to ignore fundamentals, such as the proper use of units, definition of acronyms (or avoiding their use), overstating significant figures, and other basics. I know this may sound a bit silly, bit fuzzy writing does kill people and can cause mars landers to crash.

  17. Horatio Algeranon

    “The Silver Bullet”
    — Another 5 minutes wasted by Horatio Algeranon

    Beware wolfs in sheep’s clothing
    They’ll fool you every time
    Especially with self-loathing
    ‘Bout global warming crime

  18. Wendy Crowell

    Of course he should hire you. You should offer your services to him. You bring to climate data the same types of data analysis and interpretation he brings to political polling data.

  19. cosmicomics

    I prefer anthropogenic climate change or ACC. It’s more analytical, more precise, and can’t be misused the way climate change can. But I’ve read that the term global warming is more emotionally persuasive.

  20. I tend to use Global Warming on a purely ‘reclaim the language’ basis, because of the use of the argument ‘It was changed from global warming to climate change..’ on a regular basis.

    As an aside, whenever people use the ‘CAGW’ term – i.e. Catastrophic Anthropogenic Global Warming – always be sure to ask them to define what they mean by catastrophic. You’d be surprised how many times you have to ask to get a straight answer.

    • David B. Benson

      I have yet to be successful. Sometimes they will ask me. I respond by suggesting they read “Six Degrees” by Mark Lynas.

      • In something of the same spirit, here’s my “Laughing Fool Blues”:

        The planet she is cooling– Ice Age is coming soon. (2x)
        Dropped ten whole degrees now, just since I checked at noon.

        The planet isn’t warming, but Mars is warming just the same. (2x)
        Well, it’s anything but carbon–that’s the name of the game.

        The planet might be warming, but we really cannot tell. (2x)
        That’s what they say in Alabama–New York can go to–well…

        Bridge 1 (Polka feel)
        Alarmist con men tell you that we’re gonna drown in floods,
        We’ll be choking in a dust bowl, or else trying to swim in mud;
        That we’re gonna be a-runnin’ from some crazy cyclone storm,
        But how bad can it really be to get a little warm?

        Oh, the planet might be warming but it’s natural as can be. (2x)
        Just an oceanic cycle, or Ice Age recovery.

        Oh, the planet has stopped warming, so dry your foolish tears. (2x)
        Stopped in ’09 and 2000, hasn’t warmed in sixteen years.

        An Ice Age is coming, a grand Solar minimum. (2x)
        We can’t predict the Earthly weather, but we sure do know our Sun.

        Bridge 2
        We love our scary stories of famine and of flood,
        Of drowning infrastructure, of climate war and blood,
        Of sickness and starvation, some crazy “clathrate gun,”
        But why should the alarmists get to have all the fun?

        So I’m gonna tell a story if you’ve followed me this far. (2x)
        The UN will tax your breathing and confiscate your car.

        Those scientists hate freedom; they won’t give cash a chance. (2x)
        They’ll kill democracy just to pad their grants.

        They’re gonna take your money, gonna take your freedom, too. (2x)
        Gonna waste it on some ice cap or conservation zoo.

        Bridge 3
        Some people say I’m crazy, they say I’m “in denial,”
        They say my thoughts are reckless, I’ve “unscientific style.”
        They seem to find me foolish; they do not think I see
        Just because I cannot spell “Bibliography.”

        But I see right through them, all these snooty elites. (2x)
        They call me senseless, but I just know they’re cheats.

        They’ve got these graphs and data of ice and air and sea; (2x)
        They prophesy disaster–they just won’t let me be.

        They prophesy disaster, make me feel like a clown. (2x)
        I’ve got me a solution: Just turn their graph upside down.

        Which can be heard, for the time being, at:

    • “because of the use of the argument ‘It was changed from global warming to climate change..’ ”

      The argument is historically baseless. The term climate change preceded the term global warming, which first appeared in a 1975 paper by Wallace Broecker. The Republican strategist Frank Luntz later found that climate change was less intimidating, and suggested that it be used to minimize the threat. Polls have shown that people are more concerned about global warming, which is understandable because it’s less diffuse than climate change.

  21. “Maybe I’m just too immersed in analysis-in-depth to know what the appropriate level is for a “popular” blog. Or, maybe Nate Silver should hire me.”

    Honestly, that’d be pretty awesome.

    Has anyone considered the fact that global warming leads to climate change and that they’re not just two completely synonymous terms? The global mean temperature going up by 1C doesn’t directly affect us. It’s the climate change that’s going to screw with our stuff. Another thing: We’ve established anthropogenic global warming—I think the key issue now is whether there’s anthropogenic climate change as a result of that. Of course we’re already seeing signs, but unfortunately there’s a lot more to come, and people won’t be convinced until after it happens. So it’s the climate change that’s the point of contention.

    • “We’ve established anthropogenic global warming—I think the key issue now is whether there’s anthropogenic climate change as a result of that.”

      For the septics the fundamental contention has been that there hasn’t been a warming trend, which is why we hear of fudged temperature data and “no warming since…” This is why the hockey stick graphs are so inconvenient and why Michael Mann must be vilified. As climate change is the result of global warming, that too is denied.

      For the overwhelming majority of climate scientists anthropogenic climate change is not an issue. There can be disagreements about certain details, such as whether warming causes hurricanes, but there seems to be wide agreement regarding other phenomena such as the frequency and intensity of heatwaves, and changing precipitation patterns.

      “Has anyone considered the fact that global warming leads to climate change and that they’re not just two completely synonymous terms?”

      I think the term you choose should be based on context. In everyday communication they’re used synonymously. If the aim is to convey the breadth of the changes caused by continuing emissions, then I think (anthropogenic) climate change is preferable.

  22. Hopefully not too far OT, but today’s news making the rounds is begging for the Tamino touch.

    • tamino did already cover that ca. 1992 step change in the data here:

      But the recent paper may be more conclusive.

      • It’s the same paper. That journal publishes things online for a discussion period, then in final version. Tamino’s April post was referring to the initial (discussion) version of the paper, this Phys.Org article is presumably about the final version.

        Someone who is motivated could look to see whether and how Tamino’s comments were incorporated in the final version. It’s a bit surprising if they’re still billing this as “the Antarctic increase might not be real” since there obviously is an Antarctic increase during the past two decades that has nothing to do with any 1991 step change.

  23. I’ve taken to playing the opposition with CAGW= Conventional Anthropogenic Global Warming. I figure fight fire with fire.

  24. Back to Nate Silver – I have to wonder why he would ever have thought Pielke was an appropriate “expert”, him being most notable for his disagreement that GHG’s have been the dominant forcing in recent climate change, yet failing to convince the broader climate science community of that via peer reviewed publication. It’s one thing – for the sake of our descendants – to heartily wish that the mainstream concensus be wrong, another to imagine that Pielke would convincingly, and presumably with superior use of statistics, show that to be the case. ie, Silver jumped in thinking the climate science ‘controversy’ was genuine and deep.

    It could be the case that, like so many others who we would like to think would do so as a matter of course, Silver hasn’t really found cause to make himself well informed. Not so much because of Silver specifically, but as a broader phenomena, that failure to seek to be well informed is a bit scary.

    • David Lewis

      Michael Mann says Silver visited him when he researched the climate chapter for his book – The Signal and the Noise. Mann is sure Silver also visited other climate scientists during that period as well.

      It doesn’t seem to be the case that Silver didn’t seek to become well informed. He’s obviously intelligent as well.

      What we’re faced with is our civilization is crumbling because so many of our best minds can seek to become well informed and blow it so badly.

      Silver demonstrated in his climate chapter that he doesn’t have a clue about climate science. He spent pages discussing what any climate scientist would see as the noise in the average global surface temperature chart, i.e. any few years of it, but Silver duly wrote about it as if a few years of it was the signal.

      People shouldn’t have been surprised he latched on to Pielke for a while.

      The fact is Silver has been good at predicting US elections. When he went to the UK and studied what he took to be the “signal” in an election campaign there, he made an incredibly bad prediction of what would happen, because he couldn’t figure out what the signal was there either.

  25. horatio Algeranon

    I don’t blame you if you don’t post this, but after looking some more at the “538 Blog”, here’s my take

    538’s the number
    Of nutty worthless posts
    On a blog that’s unencumbered
    By editing by hosts

    I agree that you could really raise the bar with your expertise, but then again, that may be more than a little like raising the Titanic

  26. My impression about 538 and Nate Silver is that he is trying to do a bit of the “freakenomics” thing. So Pielke Jr. would fit right in. Someone who sounds reasonable but can spin a story opposite to what the experts are saying.

  27. offtopic, mostly, but a statistical question of interest
    quoting from::

    “… NASA’s online article about the science of this solar storm is well-worth the read.  Perhaps the scariest finding reported in the article is this:  There is a 12 percent chance of a Carrington-type event on Earth in the next 10 years according to Pete Riley of Predictive Science Inc.
    “Initially, I was quite surprised that the odds were so high, but the statistics appear to be correct,” Riley tells NASA.  “It is a sobering figure.””

  28. Hank,
    The media has really overhyped this. I read the original article in Nature. For one thing, the story is nearly 6 months old! For another, this would not have been a civilization-destroying event. Very destructive, but not an end.

    What is more, in reality, this probably was not quite on a par with the Carrington event. True, particle fluxes were very high, but that was in part due to the earlier flares that cleared out the space plasma along the CME’s path and allowed it to propagate unimpeded. Total particle fluences were likely below the Carrington event.

    Another example of lazy, sensationalistic journalism.

  29. > Very destructive, but not an end
    I agree, and that’s how I read it; civilization-destroying I leave to those more alarmed than I. I’m interested in major inconvenience events.

    I saw the original paper when it came out, and I recall it being about the same as what’s now being repeated — I figured that the statistical analysis by “Predictive Science” — whoever that is — might be worth a look by Tamino now that it’s attracting attention.

    1 in 8 of major inconvenience and expense per decade — enough to merit attention. 1 in, I dunno, at what point not to worry.

  30. I’ve pointed out before, inspired by an original suggestion on Climate Progress (I think), that using Google Trends to look at worldwide searches for “global warming” and “climate change” shows that the Philipines and, lately, India are usually at the very top. It was suggested that some organisation might be flooding the comment sections of major media articles about climate matters with denialist memes by employing teams of sock puppets to respond quickly so that innocent onlookers got a biased view of the numbers of the “public” who supported one side or the other. Such a method of opinion management would be really cheap to do. People have said the Trend results are more likely to be because of, respectively, drought and typhoons in India and the Philippines but the steady situation on Google Trends over years doesn’t really fit very well with this…