.

Thursday, March 17, 2016

Denier weirdness: How not to look at temperature changes in USA, with Leland Park at WUWT

Sou | 1:06 AM Go to the first of 6 comments. Add a comment
There's a very weird bit of denier weirdness at WUWT today. It's from some bloke called Leland Park. He's put together some charts and is, I think, protesting the warming of the USA (archived here). I'm not sure about that because his article is very odd. I've read it twice and then read it again and I still can't figure out what point he is trying to make.

I'll go through what he did and see if anyone here can help me out. Leland started off with an equation that he's obviously quite proud of. He wrote it like this:
the relationship between the heat content of a substance and changes in its temperature is given by:
Q = m * c * ΔT
where m is the mass and c is the heat capacity of the substance being measured
His Q is usually written as ΔQ but I won't quibble over that. What I don't understand is why he wrote the equation. He does use it elsewhere in his article, but how he uses it doesn't make sense. What's the mass? What's the specific heat capacity of the surface?



So let's move on. The next thing that Leland does is plot some charts of the annual change in surface temperature. He does this separately for the average monthly maxima and average monthly minima of "each USHCN station". Or at least that's what he said he did. I don't know how much work that took him. There are a lot of USHCN stations. In any case,
  • averaging USHCN stations won't tell you as much about the temperature changes over the contiguous USA as proper gridding and homogenisation will, and
  • plotting the annual difference doesn't tell you much of anything at all. All you're doing is getting rid of any trend in the data.
I'll illustrate the second point. I won't bother with separating into maxima and minima. I'll just plot a chart showing the change from one year to the next for consecutive years from 1895 to 2015. That is, 1896 minus 1895 all the way through to 2015 minus 2014:

Figure 1 | Annual temperature difference from one year to the next for the contiguous USA. Data source: NOAA ClimDiv.
As you can see the plot has a zero trend line - you have to go to four decimal places just to get a trend line of 0.0001 C/year and R2 is also all but zero. So the chart is trendless. This is what you should have expected. Temperature fluctuates from year to year. There is more above the line than below. If you add up all the positives and all the negatives, you'll find that the positives outweigh the negatives by 2.26 C. That's a lot, but you won't see it by eyeballing the chart or adding a linear trend line.

Here's another chart showing how the temperature of the contiguous USA has changed over the same period. Just so you can compare, I've added a red line on the left that measure 2.25 C (roughly):

Figure 2 | Annual surface temperature contiguous USA from 1895 to 2015. Data source: NOAA ClimDiv
I included a linear trend line for the whole period, but it's pretty useless because you can see that the USA didn't warm continuously in a linear fashion for the entire period. If you look across the above chart (and the LOESS curve), you can see that the annual temperature starts to rise around the late 1970s. So here's a chart of US temperatures starting in 1971:

Figure 3 | Annual surface temperature contiguous USA from 1971 to 2015. Data source: NOAA ClimDiv
The trend since the early 1970s is around 0.26 C/decade. That's rather a lot of warming.

To round things off, below is a chart of decadal changes, which are more appropriate when considering climate change:

Figure 4 | Decadal surface temperature contiguous USA from 1895 to 2015. Data source: NOAA ClimDiv
There was a big shift to warming between the decade ending in 1985 and that ending in 1995. There's a difference of more than 0.8 C between the decade ending 1985 and that ending in 2015.

The above charts don't really have much to do with Leland's article. What they do illustrate is that you aren't going to learn much about surface temperature changes by looking at annual differences in temperature for consecutive years. You'll learn a lot more just by plotting the actual annual or decadal temperature.


Winter is cooler than summer - who knew?


If you're hoping that I'll have by now figured out what were the main messages Leland Park wanted to convey, you're out of luck. About the only other thing he did was point out that winter is colder than summer in the mid-latitudes. I'm guessing you knew that already. Leland thought it was a notion so stupendous that climate scientists must have overlooked it. He posted a chart that he called "seasonal variation" and wrote:
Figure 6 displays the pattern of seasonal warming over time based on the difference in temperature between January and July, the peak temperature points. For the US, the seasonal warming is around 45°F while the range is from about 40 to 55°F. That is a massive amount of warming and a large amount of variation. It is much larger than the presumed trigger level for global warming, yet is unremarkable to climate scientists.

The mystery of Climate Science is that massive, regular seasonal warming cycles are unremarkable, but small changes in annual temperatures signal catastrophic climate change. Go figure.
Just think. This is the calibre of article at the climate conspiracy blog WUWT.

I'm guessing that Leland missed the class on averaging in primary (grade) school. If he'd been there he'd have surely figured out that an increase in global mean surface temperature of 2 degrees or more will have huge ramifications for drought, flood, wildfire, heat waves, sea level rise, ice melt and more. It will mean that farmers and others in agriculture will have to adapt if they can. It will mean that fishers will need to adjust to different catches, if there are any commercial fish around, or follow the fish as they shift poleward. It will mean port authorities will need to spend vast amounts to adapt port infrastructure to maintain sea transport around the world. It will mean millions of people will need to find somewhere else to live as the coastal towns and cities are inundated from storm surges and rising seas. And the rest...


From the WUWT comments


There aren't a lot of comments, only 14 in two hours. I guess Leland stumped even the usual WUWT crowd.

Greg seems to be puzzled by the article, and wrote several comments starting with this one:
March 16, 2016 at 3:12 am
While eyeballing the data is a good start to get an overview , it hardly ‘proves’ anything without some numbers.
Are we supposed to be able to tell by eye if either graph has a mean of exactly zero ? Since this is essentially a rate of change plot a small offset from zero could be masked by the fairly large swings. Differentiation does exaggerate the high frequency content.
Also you Tmax histogram clearly has a deficit in -1 values, How much of a warming does that represent? Is it significant?

fredb thinks what Leland did is silly, and pointed out what I illustrated above:
March 16, 2016 at 4:02 am
This is silly. By taking year to year differences you are removing the trend. Not surprising you get the results you do. 

emsnews decides that Leland's article holds no interest for him or her, but takes the opportunity to type out a rather silly "thought":
March 16, 2016 at 5:02 am
Many of these debates about weather data seem increasingly similar to earlier debates about how many angels can dance on the head of a pin. We already know for certain that the planet has had not one but many ‘Ice Ages’ and the warm cycles are very much shorter and come with some regularity and that humans changed the flora and fauna of the earth massively due to our hunting and farming methods.
If the humanoid apes didn’t figure out how to attach chipped up rocks to pieces of trees, we would still have most of the Ice Age animals here today such as mastodons, for example.
We don’t have them anymore, alas. We definitely changed the planet’s life evolutionary cycles. Now the question is for us humans, what happens next? Some say we will burn in h*ll and others, freeze to death.
I think our planet will roll onwards relentlessly continuing the sudden warm/long cold cycles. 

6 comments:

  1. Don't forget that the trend line in figure 1 starts at 0.013031, which by itself corresponds to an increase of 1.3 C/century. And the upward slope means that it actually goes faster later. At 2015, it would be at 0.024336, which corresponds to an increase of over 2.4 C/century.

    I assume that x=0 at 1896.

    ReplyDelete
    Replies
    1. Of course, this is hard to see by simply eye-balling your graph - and even harder to see in Park's original graphs, which do not include any trend lines at all.

      Delete
  2. Creative PR, that works.
    Uses Bob 'Smirkin' Carter's 'idea' of pretending average is meaningless: "Tavg is not a measurement parameter, conflates Tmax and Tmin behaviors, so it is not used in the analysis."

    ReplyDelete
  3. The mystery of Climate Science is that massive, regular seasonal warming cycles are unremarkable, but small changes in annual temperatures signal catastrophic climate change. Go figure.

    I presume that the gentleman also views the past ice ages as no big deal. The decrease in the global mean temperature was much less than the annual cycle after all.

    ReplyDelete
  4. Plotting annual difference, and monthly difference, is the same trend-disappearing canard that idiot Tisdale uses in his latest Gish Gallop on GAT / ENSO.

    I guess he cribbed it from Leland. Great how they have the courage to share mediocre ideas. Who knew that interannual and monthly variation was normal ?

    ReplyDelete
  5. The mystery of Climate Science is that massive, regular seasonal warming cycles are unremarkable, but small changes in annual temperatures signal catastrophic climate change. Go figure.


    So he's saying that scientists in multiple disciplines in multiple countries over a couple of generations (at least) have all overlooked this bit of information (incompetence), or have deliberately ignored it (conspiracy)?

    It reminds me of the canard that melting ice won't raise sea levels because melting ice in your drink doesn't make it overflow--that means scientists have overlooked something most people already know. If scientists were involved in a conspiracy theory you'd think they'd have chosen a line of evidence that grade school kids could not disprove.

    ReplyDelete

Instead of commenting as "Anonymous", please comment using "Name/URL" and your name, initials or pseudonym or whatever. You can leave the "URL" box blank. This isn't mandatory. You can also sign in using your Google ID, Wordpress ID etc as indicated. NOTE: Some Wordpress users are having trouble signing in. If that's you, try signing in using Name/URL or OpenID. Details here.

Click here to read the HotWhopper comment policy.