A Winter’s Day

I talk a lot about trend. It’s important. Climate change is, after all, really about the trends — the changes that persist, that portend what we might expect to come.

Weather includes the fluctuations around the trend. They’re always there, things like temperature just won’t stop fluctuating. That’s why, if we want to know how climate is changing we need to attend to the trends. But if you want to deceive yourself, if you’re so determined not to believe nature that trends give you the “willies” and make you cringe, you’re likely to sieze upon the fluctuations and say “Aha!” It was cold!! See — a snowball!!!


Senator Jim Inhofe (R-OK) isn’t the only one who does that. So do Anthony Watts, purveyor of the WUWT blog, and Roy Spencer. Their latest seizures have them pointing out how cold it was — not over the globe this last decade, but over the lower 48 states of the U.S. at 7:00 A.M. yesterday (Dec. 18, 2016). Yes, 2% of the globe for one hour.

Here’s the proof:

dec-18-2016-colder-than-previous-winter-2

Wow! Colder yesterday than all last winter (for 2% of the globe)!! And it’s not even winter yet!!!

Or is it? Perhaps they don’t get the difference between the astronomical definition of “winter” and its climatological definition. If we plot monthly average temperature by month of the year, then winter — the coldest three months of the year — clearly includes December.

bymonth

But, let’s not quibble about that. Instead, let’s think about what Spencer’s/Watts’s graph actually indicates. They really should have thought about that.

Clearly they want to impress people with how amazingly cold it was yesterday. But when you think about it, and look further back than just a single year so you can get some context, that’s not what the graph shows at all. What it really shows is how hot the U.S. was last winter. Here’s the wintertime (done right, Dec-Jan-Feb) average temperature for the lower 48 states of the U.S.:

wintertg

Last winter was the hottest on record. And that is what Spencer’s/Watts’s graph actually shows. Apparently they don’t get that. By and large, neither do their readers.

The reason last winter was so hot in the U.S. is the combination of trend and fluctuation. Fluctuations go up, they go down, and it so happens that last year they went up. That alone would have made last year a hot one in the U.S., but in addition to the upward fluctuation there is also an upward trend. When you put the two together, not only can you get a hot year, you have a pretty good chance of setting a new record. Like last year.

This year, U.S. winter isn’t likely to be as hot. The trend is still there, but the fluctuations probably won’t be as high as last year’s. That means that we’ll have to endure a lot of stupidity, ranging from “not as hot as last year!” to “colder than all last winter!!!”

If only some of those people would put some actual thought into it. Am I just hoping for too much?


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21 responses to “A Winter’s Day

  1. Ah, but they have put some actual thought into it, Tamino. That’s precisely why they use deliberately truncated graphs that support carefully crafted phrases like “not as hot as last year!” and “colder than all last winter!” They use them because they know they work with their intended audience.

  2. Bridge out ahead may not be as accurate as parts of bridge intact ahead. Prepare to stop is the key issue. The trend is over the cliff, off the bridge to nowhere. Our species is not doing what is required to avoid going over the cliff. That is a simple fact that should be communicated loudly and clearly.

    • A nice analogy, simple and to the point.

      • But misleadingly binary. “Cliff” implies that CC mitigation is all or nothing, which is not true. It’s too late to avoid all damage; the possibility of avoiding some damage will remain for quite a while (albeit the value of ‘some’ will be shrinking the whole time.)

      • might be able to add level of complexity this way: it’s like we are on a train and the tracks lead to a rail bridge that is no longer intact. We might not send all of the train cars off the bridge if we prepare to stop, but there is no question at this point that some lead cars are already in trouble. Brake car is at the rear of the train. Do we hit the brakes or trust our experience that bumps are part of life and knowledge that this train has always made it safely across all the bridges in the past? Recent study however indicates that when we talk with conservatives about climate change, they do not hear the problem if we talk about what is ahead, the way to reach conservatives (those that can be reached) is to talk about how things have changed from the past. So, we need to frame this discussion in how this winter is substantially different from past winters, that we have lost something (somewhat stable environment?) that our species had in the past. Conservatives apparently do not respond to concerns about the world they will leave for their grandchildren, you have to talk to them about restoring the world of their grandparents. Bridge out ahead actually does not work. Need to go with: this bridge is so shaky now, beams are rusted and cracking, it’s not the good safe bridge we used to have.

  3. I’ve always liked this presentation of climate/weather data because it manages to get this years weather as well as averages and extremes.
    http://www.weather.gov/hgx/climate_cll

    As you keep pointing out, good graphical presentations enlighten.

  4. It used to be called global warming and climate destabilization.

  5. so based on this… if tomorrow is hotter than today, is this proof of ‘global warming ?

    • No T-rev, that is not how the argument works! But I think you know that and your question is ironic. ;)

      In some peoples minds:
      – any fluctuation down is clear proof against global warming. Any fluctuation up is anything but global warming
      – no low probability event is evidence FOR global warming. But any low probability event in the right direction is clear evidence AGAINST.

      Now look, let’s get this argument right. Global warming is clearly WRONG because it still gets colder EVERY night!!

    • No, that’s just fast-onset el nino.

  6. do you have a data link for the US hourly temperature?
    curious if it goes back a couple of years, judging for the winter averages 2014 could easily have a couple of days colder
    thanks jacob l

  7. Thanks again Tamino for a thorough and well explained analysis. So “the usual suspects” are just reusing a variation of the “no warming since (pick a record high point)” trick.

    As to your final question, the answer that I would suggest is that “wishful thinking” is largely what is involved. Change is often uncomfortable, so some people are prepared to make considerable investments in preserving the status quo. Or persisting with poor choices rather than make a change. Or hoping that the problem will go away if you ignore it. Along those lines, a certain President-elect when campaigning in California is reported to have stated “there is no drought” in California because the state has “plenty of water.” Wishful thinking in abundance I suggest?

    • “Wishful thinking in abundance…”

      You could have fun playing with the preposition in that phrase–“Wishful thinking of abundance? Wishful thinking for abundance?” Perhaps, given Mr. Trump’s economic status, even “Wishful thinking from abundance?”

      • Excellent alternative prepositions Doc.

        I am not hearing much Climate Change denial coming from the poorer parts of the world. The Indian government for instance now has a policy of reducing the proportion of coal generated power. So I think you nailed it at the end, not just for the President-elect but also for “the usual suspects”:

  8. couldn’t find the hourly temps for the usa but i could pull daily data from climate explorer, thanks netherlands. pulling -70 to -120 longitude 50 to 30 latitude I came up with a few candidate days.
    12/07/2013.
    01/23/2014
    01/28/2014
    02/06/2014
    before that its 02/02/2011.
    In the 80’s there where entire weeks colder, so it has been getting warmer.

  9. It continues to amaze me how many people are fooled by these sorts of arguments (if there’s global warming then why is it cold today for instance). Some seem to want to pretend that the longer term upward trend in temperatures means that there won’t be some frigid days. We certainly had that last week, but the lows where I live were still nearly 10F above the record lows sets in 1989 (according to what the Weather Channel was displaying). I also thought “Colder than any day last winter? So What?” It was abnormally warm last winter where I live, and extending the temperature graph back further, as Tamino did, shows just what an outlier it was. It’s like those who talk about “global cooling” because we’ve come off of the El Nino peak. Are some of them out there just looking to be suckered by Watts and others?

    • “Are some of them out there just looking to be suckered by Watts and others?”

      An online acquaintance in denial about climate change recently used the phrase “I would prefer to think…” Can’t remember if it was an actual response or just a thought, but my immediate reaction was “So would I, if only the evidence supported it.”

  10. Timothy (likes zebras)

    I like their graph though. You can use it to show the difference between climate and weather.

    It’s still quite hard to forecast on the winter solstice whether it will be warmer or colder on New Year’s Day. That’s because of the short-term weather fluctuations. But you can predict with a high degree of confidence that it will be warmer on the summer solstice (and vice versa for somewhere in the southern mid-latitudes). That’s climate.