Guest Post by Willis Eschenbach
A while back in the US there was an ad for a hamburger chain. It featured an old lady who bought a competitor’s hamburger with a great big hamburger bun. But when she opened it up she asked …
I got to thinking about this in the context of whether there is any real danger in a degree or two of average temperature rise, or whether it’s a big bun with no beef. In my previous post, “Lies, Damned Lies, Statistics … and Graphs”, I closed by saying:
My conclusion? Move along, folks, nothing to see here …
A commenter took exception to this, saying
When talking about global average temperatures, tenths of a degree really do matter.
Now, if tenths of a degree changes over a century “matter” for the globe, they certainly must matter for parts of the globe.
So here’s your pop quiz for the day: Which US State warmed the most, which cooled the most, and by how much?
To answer this, I used the USHCN State Temperature Database. Here are my findings:
Figure 1. Temperature trends by state, USHCN data. Seven states cooled, and forty-one warmed.
The state that warmed the most was North Dakota (top center), which warmed 1.4°C per century. The state that cooled the most was Alabama (middle of three dark blue states, lower right). It cooled by 0.3°C/century.
To compare with my previous post, here’s a similar graph, of the decadal changes in North Dakota by month.
Figure 2. North Dakota decadal average temperatures by month, 1900-2009. Red line is the average for the decade 2000-2009. Photo is an old North Dakota farmhouse.
As with the US, for much of the year there is little change, and the warming is in November to February. Note that unlike the US, during that four months, the temperature of North Dakota is below freezing (32°F) …
Now, if tenths of a degree “matter”, if they are as important as the commenter claimed, we should have seen some problems in North Dakota. After all, it has warmed by 1.6°C since 1895. That’s almost three times the global average warming.
But somehow, I must have missed all of the headlines about the temperature calamities that have befallen the poor residents of the benighted state of North Dakota. I haven’t seen stories about them being “climate refugees”. I didn’t catch the newspaper articles about how it has been so hard on the farmers and the frogs. I am unaware of folks moving in droves to Alabama, which has cooled by -0.4° since 1895, and thus should be the natural refuge of those fleeing the thermal holocaust striking North Dakota.
In fact, I don’t remember seeing anything that would support the commenter’s claims that tenths of a degree are so important. North Dakota has warmed near the low end of the range forecast by the IPCC for the coming century, and there have been no problems at all that I can find. So I have to say, as I said before,
My conclusion? Move along, folks, nothing to see here … where’s the beef?
APPENDIX: R Code for the US Map
(I think this is turnkey. Sometimes WordPress puts in extra line breaks. If so, it is also available as a Word document here.)
The code requires that you download the USHCN Temperature Data cited above and save it as a “Comma Separated Values” (CSV) file. I downloaded it, opened it in Excel. I split it using “Text to Columns …” into the following columns, as detailed in the USHCN ReadMe file:
FILE FORMAT:
STATE-CODE 1-3 STATE-CODE as indicated in State Code Table above. Range of values is 001-110.
DIVISION-NUMBER 4 DIVISION NUMBER. Value is 0 which indicates an area-averaged element.
ELEMENT-CODE 5-6
02 = Temperature (adjusted for time of observation bias)
YEAR 7-10 This is the year of record. Range is 1895 to current
year processed.
JAN-VALUE 11-17 Monthly Temperature format: Range of values -50.00 to 140.00 degrees Fahrenheit. Decimals retain a position in the 7-character field. Missing values in the latest year are indicated by -99.90.
FEB-VALUE 18-24
MAR-VALUE 25-31
APR-VALUE 32-38
MAY-VALUE 39-45
JUNE-VALUE 46-52
JULY-VALUE 53-59
AUG-VALUE 60-66
SEPT-VALUE 67-73
OCT-VALUE 74-80
NOV-VALUE 81-87
DEC-VALUE 88-94
If that is too complex, the CSV file is here.
Here’s the R code:
# The code requires that you download
# the USHCN Temperature Data
# and save it as a "Comma Separated Values" (CSV) file.
# I downloaded it, opened it in Excel, and used
# "Save As ..." to save
# it as "USHCN temp.csv"
#Libraries needed
library("mapdata")
library("mapproj")
library("maps")
# Functions
regm =function(x) {lm(x~c(1:length(x)))[[1]][[2]]}
#Read in data
tempmat=read.csv('USHCN temp.csv')
# Replace no data code -99.9 with NA
tempmat[tempmat==-99.9]=NA
# split off actual temps
temps=tempmat[,5:16]
# calculate row averages
tempavg=apply(temps,1,FUN=mean)
# calculate trends in °C by state
temptrends=round(tapply(tempavg,as.factor(tempmat[,1]),regm)*100*5/9,2)
# split off states from regional and national
statetrends=temptrends[1:48]
#calculate ranges for colors
statemax=max(statetrends)
statemin=min(statetrends)
statefract=(statetrends-statemin)/staterange
#set color ramp
myramp=colorRamp(c("blue","white","yellow","orange","darkorange","red"))
# assign state colors
mycol=myramp(statefract)
# names of the states (north michigan is missing for ease of programming)
myregions=c("alabama", "arizona", "arkansas", "california", "colorado", "connecticut", "delaware",
"florida", "georgia", "idaho", "illinois", "indiana", "iowa", "kansas", "kentucky", "louisiana", "maine",
"maryland", "massachusetts:main", "michigan:south", "minnesota", "mississippi", "missouri", "montana", "nebraska",
"nevada", "new hampshire", "new jersey", "new mexico", "new york:main", "north carolina:main", "north dakota",
"ohio", "oklahoma", "oregon", "pennsylvania", "rhode island", "south carolina", "south dakota", "tennessee", "texas",
"utah", "vermont", "virginia:main", "washington:main", "west virginia", "wisconsin", "wyoming")
# draw map
par(mar=c(6.01,2.01,4.01,2.01))
return=map('state',regions=myregions, exact=T,projection='mercator',fill=T,
mar=c(5.01,8.01,4.01,2.01),col=rgb(mycol,maxColorValue=255),ylim=c(10,60))
# set up legend boxes
xlref=-.48
yb=.37
ht=.05
wd=.08
textoff=.025
# assign legend labels
mylabels=round(seq(from=statemin,by=staterange/12,length.out=13),2)
#draw legend
myindex=0
for (i in seq(from=xlref,by=wd,length.out=12)){
xl=i
xr=xl+wd
yt=yb+ht
rectcolor=myramp(myindex/11)
rect(xl,yb,xr,yt,col=rgb(rectcolor,maxColorValue=255))
text(xl,yb-textoff,mylabels[myindex+1],cex=.65)
myindex=myindex+1
}
text(xl+wd,yb-textoff,mylabels[myindex+1],cex=.65)
# add annotations
text(0,1.08,"US Temperature Trends (°C/century)")
text(0,1.03,"USHCN Dataset, 1895-2009",cex=.8)
Johnny D (04:26:18)
Johnny, the flooding is hardly new. The Red River Valley could have been designed specifically to flood, and has been doing so since forever. There’s a large (4.7Mb) but very good historical overview of the flooding from the USGS. Has lots of photos, some from the 1800’s.
w.
C3 Editor (05:14:44)
Good stuff, C3. A small point, my data is from USHCN.
For most of my work I use Excel. The computer language “R” is much better than Excel for big datasets and specialty work, it’s what I used to make the US map, using the “R” code posted at the end of the article. So Fig. 1 is done in “R”, and Fig. 2 is done in Excel.
w.
meklly,
The key word is complex. Complex molecules, consisting of many atoms (chlorophyll b, for example, has 136) absorb visible light and emit IR. Certain simple molecules, such as CO2 and H2O absorb and emit IR, because they have molecular bonds with the ability to vibrate.
O2 and N2, which make up 99% of the atmosphere, are unusual in that they do not have any ability to vibrate or absorb or re-emit in the low IR range (they can do so in the upper IR range, due to rotational energy, however the energy level there is so low, and the physics are such, that it is inconsequential).
This is because O2 and N2 consist of two equal atoms bound together by a single, very strong, very stable covalent molecular bond. There is no room for vibration in that bond, unlike H2O, which has a “V” shape in the bonds between the two hydrogen atoms and the central oxygen atom, or like CO2, which normally has a perfectly linear shape but is induced to bend and vibrate.
Again, I would encourage you to follow this link to read about the vibration of gases, and this link in general to read about the physics behind the absorption and emission of infrared radiation by molecules. It’s not that complicated.
VicV,
I’m not sure what your point is. I explicitly said “but I’m not touching that here and now at all.” What part of that sentence is unclear, or untrue?
Merrick (05:50:14)
As you note, if you look at my code, it says
R calls the two halve “michigan:north” and “michigan:south”. I have 48 sets of data, corresponding to the 48 lower states. But in the R mapping software, they divide north and south Michigan. It was late (2 AM) and I didn’t feel like munging the code to make it use the same set of data twice, so I just left out the upper Peninsula … no slight intended.
The USHCN only has data for the “Lower 48”, as they say in Alaska.
sphaerica (09:37:52) :
Thanks for the explanation.
Allan M (13:14:02)
Anything that threatens the University of Southern North Dakota at Hoople, Professor Peter Schickele or the works of P.D.Q. Bach would certainly run into a great deal of resistance.
In fact, almost as much resistance as any attempt to perform any of those works usually generates?
The 48 States as a group represent only about 1.5 % of the earth’s surface, so obviously aren’t a big part of global warming. But do State trends tell us anything about local trends? Perhaps they do for people who live in small States like Rhode Island. But for other States, particularly the large ones like Texas and California, the trends don’t tell residents much about where they live.
sphaerica (08:34:02) :
If you add up a bunch of temperatures measured in different places which have an error of +/- 1 deg C and divide by the number of readings the average still has an error of +/-1 deg C.
This is a different situation from measuring a physical variable with a noisy sensor where you can reduce the error by averaging over time and taking lots of readings.
“”” Vincent (04:24:31) :
urederra,
“Here is my line of thought. If CO2 were the main culprit of warming, I would expect to see it acting mainly during summer in the north hemisphere. when there is more light and therefore more uv-visible-ir .”
Most people say the opposite. The problem with your theory is that the forcing due to GHG is constant, at about 1.5 W/M^2. During the summer, insolation is very high, maybe 500 W/M^2 so the proportion added to by CO2 is very small. In winter however, insolation may be only 100 W/M^2 and the addition made by CO2 is proportionally greater. Even more, during winter, absolute humidity is lower, so the proportion of CO2/H2O is greater than during summer. “””
Well there is also a problem with your theory. The 500 W/m^2 solar insolation is 6000 K black body spectrum radiation, which travels deep into the oceanic waters. The 1.5 W/m^2 +/- 50 %CO2 “forcing” is LWIR radiation which is stopped in the top ten microns of any water body, and leads promptly to evaporation.
so you cannot compare the two on a W/m^2 “forcing” basis because the physical response to each is entirely different.
Adn that seems to be what classical climate scientists do not seem to understand; they are comparing Strawberries and coconuts.
Hypothermia is defined as the body’s temperature dropping below that required for normal metabolism and body functions: 95.0 °F
Normal body temperature is in a range of 98–100 °F
Now, I got to thinking: if 3 or 5 °F “matter” for the entire body, they certainly must matter for parts of the body.
Trying for the slam dunk, we got Timmy to prove that even with his hand at an average temperature of 50 °F (cooled in ice), this didn’t really “matter”:
http://www.upaa.org/winners_mic/2005_09/news3.jpg
Timmy quit the study.
Next, we asked Makiko to keep her hand in 60 °F water for 2 hours.
Later, using an infrared scanner, her hand measured an average of 91 °F in temperature. Now, if 4 °F “matter”, clearly we should have seen some problems with 8 °F, double the magic “cooling”. Somehow, Makiko managed to avoid shivering, mental confusion and hepatic dysfunction, proving that hypothermia is not a problem.
My conclusion? Move along, folks, nothing to see here with this hypothermia alarmism …
Gary (06:23:11), thanks for the thoughts. I love climate science, there’s so much to learn.
Climate has always changed. Always. At any given instant, it is either getting warmer, or it is getting cooler.
The shift in the Pacific Decadal Oscillation from warm to cool spelled the end of the sardine fishery in Monterrey Bay, California, the site of Steinbeck’s “Cannery Row”.
So yes, I agree with you, when the climate changes (which is always), species adapt. My point is that a slight winter warming is a very minor change, not one to spend trillions of dollars trying to avoid.
Next, in truth we don’t really know if Narragansett Bay has warmed or how much. From The Warming of Narragansett Bay, I find:
So there are records at one site from 1878 to 1942, and another site from 1954 to the mid ’90s. Not good.
Despite not having data for Narragansett Bay for the period, they make the (in my opinion unfounded) claim that Narragansett Bay is warming … why? Because Woods Hole Oceanographic Institute, in a small bay on the open ocean, thirty-five miles from the mouth of Narragansett Bay, is warming.
They go on to look at the Woods Hole data, and as is depressingly common, say that recent changes are “due to the emission of anthropogenic (human-induced) greenhouse gases.”
Fortunately, they link to the Woods Hole data. They have good data from 1970 to 2009. Here is the decadal change in that record:
Figure 3. Sea temperatures taken at the dock of the Woods Hole Oceanographic Institute. Photo is of the Woods Hole dock.
Now, the Woods Hole dock is a busy dock in a busy bay. It is likely that a variety of warm water is discharged into the bay from industry, fish processing, septic systems, warm water discharges from ships’ engine and refrigeration cooling systems, and the like. Of course, in the summer this makes little difference. But in the winter …
In any case, we see that the big changes in the Woods Hole sea temperatures take place in January and February, with the rest of the year showing little change. Same pattern as in North Dakota, and the US as a whole. Will this affect the fish and other sea creatures? If the changes are real rather than a warm fresh water artifact, sure, and the PDO affected the sardines, wiped out a huge commercial fishery … but that’s the nature of climate.
Smokey: “Mercury thermometers are relatively easy to calibrate. They are accurate to well within 1°C if done properly.”
My Chemistry professor back in 1953 didn’t agree with your statement. What you got from calibrating a mercury thermometer was that you knew, for an individual thermometer, was where the top of the mercury column was at the boiling point and the freezing point of water. He said that midrange readings were uncertain due to variances in among other things, the cross sectional area of the mercury tube itself, which was known to not be constant for any thermometer. The actual volume of mercury in the bulbs of thermometers varied, also making midrange readings uncertain as to accuracy.
Errors can also be introduced if the reader’s eye is not at a right angle to the thermometer at the top of the mercury column due to parallax.
If there was bit of a “pinch” (smaller cross section area) in the tube below the top of the mercury column, the temperature reading would be higher than the actual temperature, and there was a bit of a “wow” (larger cross section area), the temperature indicated would be lower than the actual temperature. Mercury thermometers aren’t perfect, nor are they the same.
We students were also cautioned not to assume that the “pinches” and “wows” would “average out”.
Even the $10 thermometers back then, however well calibrated, had these inaccuracies regarding mid-range readings.
Also, as to what the real margin of error was, there was no possible way to determine that one, as there was no standard of temperature by which it could have been determined for midrange temperatures.
And the above is with laboratory conditions. In the world outside of the laboratory, in the actual measurement of temperatures, lie a good many problems.
Another thing I was taught was that the result of averaging set of numbers could be no more precise than the least precise of the datum in the numbers set. That is, if the most precise was say 50.5, then the result could not be more precise than one figure after the decimal point. Averaging a set of numbers with one figure after the decimal point and then producing an average with 2 figures after the decimal; is most improper, and is implying a level of accuracy that simply isn’t there.
To average a set of numbers with the most precise having one significant number after the decimal point, with a margin of error of +/- 1 and showing a result with 2 figures after the decimal point is sheer folly, and most improper.
HR (06:23:41)
My point is exactly that. When the change is so tiny that it is hidden in the thickness of the lines on a graph of the monthly temperatures, I don’t see much to get excited about.
First, lots and lots and lots and lots of people have made the claim that a couple of degrees rise in land temperatures would cause all kinds of calamities. According to them, it is not just sea levels that matters.
Second, the claim has been made over and over that with AGW, we would see an acceleration in the rate of sea level rise. Nothing even remotely resembling an acceleration in the rate of rise has occurred, despite a century of warming. See Fig. 2 and Fig. 3 in my reply to Dr. Meier for what’s actually happening with the sea levels.
Alan D McIntire (07:31:18)
Alan, you may have read it, but there’s a great study of the effects of irrigation in the Central Valley of California by John Christy of UAH here.
Paul Daniel Ash (07:38:48)
Well, the premise seemed so obviously true I didn’t bother to support it. So lets try it this way.
Suppose the whole globe warmed up by 2°C, evenly around the planet. In that case all of say Africa would warm up by 2°C. And whatever effects that would have on Africa would occur.
Now suppose that all of Africa warmed up by 2°C, and the rest of the world didn’t. Since the warming of Africa (2°C) is exactly the same in both cases, the effects of the 2°C warming on Africa would be the same in both cases.
Thus, if 2°C matters for the globe, then 2°C matters for Africa. Sure, it takes more energy to heat the globe than to heat Africa … so? That has nothing to do with whether the warming matters for Africa.
I didn’t link the comment because I didn’t think it fair to the commenter to single him/her out. However, if you can’t find it with Google …
Boris (09:44:36)
No, you missed the record floods of earlier years. See my post and citation above.
VicV (11:36:05)
Yeah, I have. Over the surface of the planet it’s trivial, from memory some tenths of a W/m2. In densely populated developed areas like say Holland, on the other hand, I have read that it gets up to a watt or two … I should look at that … in my spare time …
VicV (11:36:05)
Well, things like this are like a very bad itch … I have to scratch it.
From the BP Energy Excel Spreadsheet, I find that in 2008 Netherlands used the following energy in megatonnes of oil equivalent (MTOE).
Oil, 46.5
Coal, 9.2
Gas, 42.4
Total, 98.1
One TOE contains 42 gigajoules of energy. 98.1 MTOE when burned releases 4.12E+18 joules annually. Divide through by the number of seconds in a year (365.25*24*60*60) gives us 1.3E+11 watts instantaneous.
Surface area of the Netherlands is 41,526 sq km, or 4.15E+10 sq metres.
Divide watts by square metres gives us … 3.1 W/m2, slightly less than the doubling of CO2.
Hmm.
Check my numbers, I’ve been wrong before …
The heat release from nuclear power generators also has to go somewhere into the environment. In NZ we have no nuclear power, and mostly use hydro power with a bit of geothermal and wind power. Also a bit of coal since we have enough coal to last thousands of years.
Phil M (12:31:24)
Heck, Phil, all that means is that sometimes you agree with me (in which case my arguments are “compelling and well thought out”), and sometimes you don’t. Did you expect otherwise? Do you find that meaningful?
Well, when someone says a tenth of a degree rise in average temperature is important, I say “OK, let’s go find some big area with that kind of rise and see how important it is.” Perhaps you think that a state that is bigger than many countries of the world, a state filled with farms and hills and cities and rivers, is too small … why? If a tenth of a degree is important, and North Dakota has warmed sixteen times that since 1895, surely we should see some kind of deleterious effects?
Same objection. If North Dakota’s air can’t hold as much moisture and that causes “serious consequences”, why do we see no evidence of that?
I think what you mean is “for decades now scientists have been pointing out that even “modest” changes in global temperatures might possibly have serious consquences for the atmospheric capacity to hold moisture”. However, the wide range of temperatures seen on the planet makes that doubtful. If the atmosphere were that sensitive to temperature, we’d all be dead.
And what “serious consequences” are they saying might happen? And why haven’t we seen these “serious consequences” already, since the world has been warming for three centuries?
The ability of scientists to conjure up doomsday scenarios, with lots of “might” and “maybe” and “possibly” and “could happen”, might impress you. If so, you should read Paul Ehrlich’s work. Near as I can tell, he’s never once made a correct prediction … but the climate scientists continue to fete him and laud him and give him awards. Then you tell me I should pay attention to dire warnings of imaginary heat death from those same scientists who think Paul Erlich deserves awards?
Again, we have seen no evidence of any increase in sea level rise. Sure, water expands when heated. When you heat it a little, it expands a little. So? What ever happened to evidence? I show the evidence, you tell horror stories designed to frighten children … I know which one I follow, I follow the facts. The fact is, despite the horror stories, there has been no acceleration in sea level rise, it’s still doing what it has done for decades. Come back to scare us when you have facts on your side.
Of course it is. Now, look at the water temperature in Woods Hole I show above. Over the year, it ranges from about 30°F to 70°F, or about -1 to 21C.
The corresponding dissolved oxygen content ranges from 14.6 mg/l to 8.9 mg/l, whatever lives there can handle a huge temperature swing, and a nearly two to one change in the DOC … and you want me to worry about tenths of a degree? Climate changes. Get used to it, because the plants and animals are.
Not true. While (as you point out) some kinds of life can only exist in a very, very narrow range of environmental conditions, the fact that we have winters and summers and wet and dry times on the planet restricts them to a very, very narrow subset of locations. Most animals and plants can handle a wide range of conditions, or they would have died out long ago. Like say anything living in North Dakota has to be able to handle huge temperature swings. You don’t give nature enough credit, life is generally tough.
“Out of sight, out of mind”??? I’ve never said that. I’ve said that small factors have small effects, and large factors have large effects. Your point of view seems to be that of homeopathy, where the more diluted the factor is, the more effect it is claimed to have. This is homeopathic climatology, the idea that an animal that can handle fifty degree temperature swings on a regular basis is going to be irreparably damaged by a change in the average temperatures of tenths of a degree.
Right, before evil humans came along and screwed with the temperature, there were never insect outbreaks …
The relationship between insects and plants is quite complex, and often cyclical. When enough plants grow, they get dense and get stressed. Suppression of fire can create extremely dense stands of a single species. So can increased warmth in the proper seasons.
In such dense stands, insects that feed on them can have a huge population boom. For some kinds of plants, they kill masses of them. Then, of course, there’s no food for the insects … so they die way back. Freed of the insects, the plants recover, and the cycle starts again. You seem to think this is new, or is significant. It is part of the natural cycle of forests.
Often climate is a factor in this, with a host of important variables which may or may not play a part – summer temperature, winter temperature, timing of frosts, humidity, soil moisture, rainfall amount, rainfall timing, the list is long. You seem to think “heat –> insects killing plants”. It is far, far from that simple.
Not sure which “observe then act” paradigm I’m promoting, I’ve never used that term, so your meaning isn’t clear. Are you proposing “don’t observe, just act” would be better? Or “just observe, then don’t act”? Or “don’t observe, then don’t act”? Those seem to be all the possible combinations , and of the four, I’d take the first …
Finally, what is my “myopic view of resource management”? I can’t recall discussing resource management. I’ve been talking about whether tenths of a degree of warming will bring us terrible outcomes. To observe that, I looked at North Dakota, where we’ve seen sixteen tenths of a degree of warming since 1895, with very little to show for it.
Yes, you’ll find changes, climate is like that … but are they of a scale worth spending trillions of dollars and impeding the development of the poorest countries to avoid? And do you think this is the first time in history that pine bark beetles have killed scads of trees?
The pine bark beetles will be back down to low levels in a while, and the forests will regrow, as they have done for millennia, they go up, they go down. For example …
ND warmed the most ??….
”Cold comfort” if I would have known; in mid-winter 2009 when it got down to -42.7 degrees BELOW zero F. one morning.
Of course have to admit it wasn’t as cold this winter here in northern ND:
Low temp for 2010 was ”only” -33 degrees below zero F. on New Years Day; not worth mentioning; just another routine winter day. Still:
It would be fine by me if it would only get down to, say, -25 or so degrees below zero F. for the lowest winter temp. I could accept that much ”global warming” during the ND winter; NO problem.
LarryOldtimer (16:42:41),
You are exactly right in your analysis. I especially agree with your comments regarding the averaging of data points.
I worked in a metrology lab for thirty years, and one of my jobs was calibrating mercury thermometers.
There are two levels of calibration traceable to N.I.S.T. [formerly the National Bureau of Standards]. The most accurate calibrations are those using a physical standard as a reference, such as the triple point of water.
Secondary calibration is done by calibrating an instrument to another instrument, which in turn was calibrated to a primary physical standard, and remains within its calibration interval.
Normally the instrument used as a secondary standard for calibration is required to have a 4:1 ratio of accuracy over the instrument being calibrated. Secondary calibrations are much less expensive and time consuming, and are the industry norm. Primary calibrations are done only when the best possible accuracy is required.
Calibration labs are aware of the concerns you identified regarding the linearity issue, which applies to all calibrations, not just mercury thermometers. Glass slump over time is also an issue [but a relatively minor one]. There is much more to calibration than first meets the eye.
We found that even old mercury thermometers from the 1930s and 1940s retained their accuracy for the temperatures they were designed to measure. In fact, a good mercury thermometer retains its calibration much longer than modern electronic thermometers. We would often do a quick ‘n’ dirty check verifying an electronic thermometer using a known accurate mercury thermometer.
I would have to research the question, but I think by the 1890s the construction of precision mercury thermometers was very good. Methods of measuring column diameter were quite advanced by the 1890s, due to the requirement of accurate, linear bore diameters in rifles to within thousandths of an inch.
Even the old mercury thermometers we calibrated retained the required accuracy for their particular use. Unlike numerous electronic thermometers, I can’t recall a mercury thermometer ever failing routine secondary calibration.
That is why I gave an example of a tolerance of ±1°C, which is quite generous. Most merc thermometers have tighter tolerances. I still have an old mercury thermometer with a magnifying lens and double reticle that allows you to line up at an exact right angle and view the temperature in 0.1°F increments. Before I retired I calibrated it, and it was right on throughout its range [-8° to +89°F].
Aside from the question of accuracy, if the same thermometer is used correctly for X number of years, it will show if there is a trend even if it’s an alcohol thermometer and not very accurate. That can’t be said for electronic thermometers, which rely on PRTs, thermistors, or thermocouples that have an output in microvolts, and which drift over time due to thermocouple degradation, hysteresis, and/or changes in the voltmeter-based temperature readout if it is not regularly calibrated. It doesn’t take much to alter the output of a thermocouple by a few tens of microvolts, or drift in the voltmeter, which can translate into an out of tolerance temperature reading, or an erroneous in tolerance reading.
For long term reliability in measurements like Surface Stations, I would prefer a good mercury thermometer.
jaymam (18:33:06) : edit
True, but globally (and in most countries) nuclear is a small fraction of total energy use. Belgium/Luxembourg and Japan lead the pack, nuclear contributes about 0.2 W/m2 of heating to each country.
Peter Pond (03:08:11) :
Where I live (in SE Australia) there were two occasions this recent summer where there was a 20C difference in the max temps on succeeding days.
Heck that’s nothing, in Calgary we can have a change of 20°C in the winter, and in either direction!