Will Global Cooling Continue in 2014? (Now Includes January Data)

WoodForTrees.org – Paul Clark – Click the pic to view at source

Image Credit: WoodForTrees.org

Guest Post By Werner Brozek, Edited By Just The Facts

You may have seen the following recent articles (1, 2 and 3) by Walter Dnes on his January Leading Indicator. The same idea can also be shown in a different way. Namely, we can compare this decade to the last decade and see how things are turning out. We have all read that the 2001 to 2010 decade was the hottest in recorded history. But what has happened since then? How does 2001 compare with 2011, and 2002 with 2012, and 2003 with 2013? And what will happen in 2014?

See the above graph that shows January 2001 to January 2004 and then from January 2011 to January 2014 for RSS. Compare the left red point with the left green point. Note that the left red point is higher than the left green point indicating that January 2001 was warmer than January 2011. As it turns out, 2001 was warmer than 2011. Now compare the right red point with the right green point. Note that the right red point is higher than the right green point indicating that January 2004 was warmer than January 2014. What logical predictions can be made here?

I am now going to provide 8 pairs of numbers, however the final number in the last pair will be missing until next January. The format of the numbers is as follows:

(Jan 2001, Jan 2011); (2001 anomaly, 2011 anomaly);

(Jan 2002, Jan 2012); (2002 anomaly, 2012 anomaly);

(Jan 2003, Jan 2013); (2003 anomaly, 2013 anomaly);

(Jan 2004, Jan 2014); (2004 anomaly, 2014 anomaly?).

For the RSS data, note that in every case, the second number is lower than the first. What do you predict for *?

(0.101, 0.080), (0.246, 0.143);

(0.359, -0.064), (0.315, 0.187);

(0.440, 0.439), (0.320, 0.218);

(0.311, 0.262), (0.202, *).

Information on the prior Januaries for the other 5 data sets can be found in Section 3 below.

Are there physical reasons to explain Walter Dnes January Leading Indicator? I can think of several. Perhaps you can add to this list.

1. By the laws of averages, half of all Januaries should be above the yearly average and half should be below. So with a number of high Januaries, the final anomalies would be higher than for a number of low Januaries.

2. Related to the above, if the January anomaly went from 0.4 to 0.3, and if we assume the previous year also had an average anomaly of 0.4, and with the chances being 50% for an anomaly of less than 0.3 for the new year, the odds are greater than 50% for an anomaly of less than 0.4.

3. The number in January may be so much higher or lower that it takes 11 months of normal values to partially negate the effect of the high or low January value. To use a sports analogy, two teams may be very equal, but one team has the jitters for the first 5 minutes and is down by 3 goals in this time. It is quite possible that the rest of the game is not long enough for this deficit to be overcome. Walter’s method is analogous to being allowed to predict the outcome of a game after watching the first 5 minutes.

4. According to Bob Tisdale, effects of El Nino or La Nina often show themselves in January so in those cases, it would be obvious why the rest of the year follows.

5. Any other cycle such as a sun that getting quieter every year would automatically be reflected in the anomalies for January and the rest of the year as well.

6. Can you think of others?

In the sections below, we will present you with the latest facts. The information will be presented in three sections and an appendix.

The first section will show for how long there has been no warming on several data sets.

The second section will show for how long there has been no statistically significant warming on several data sets.

The third section will show how January of 2014 compares with 2013 and the warmest years and months on record so far. In addition to what I have presented previously, I will compare the anomalies for January 2013 with those of 2014 as well as January 2004 with those of 2014

The appendix will illustrate sections 1 and 2 in a different way. Graphs and a table will be used to illustrate the data.

Section 1

This analysis uses the latest month for which data is available on WoodForTrees.com (WFT). All of the data on WFT is also available at the specific sources as outlined below. We start with the present date and go to the furthest month in the past where the slope is a least slightly negative. So if the slope from September is 4 x 10^-4 but it is – 4 x 10^-4 from October, we give the time from October so no one can accuse us of being less than honest if we say the slope is flat from a certain month.

On all data sets below, the different times for a slope that is at least very slightly negative ranges from 9 years and 1 month to 17 years and 5 months.

1. For GISS, the slope is flat since November 2001 or 12 years, 3 months. (goes to January)

2. For Hadcrut3, the slope is flat since August 1997 or 16 years, 6 months. (goes to January)

3. For a combination of GISS, Hadcrut3, UAH and RSS, the slope is flat since January 2001 or 13 years, 1 month. (goes to January)

4. For Hadcrut4, the slope is flat since January 2001 or 13 years, 1 month. (goes to January)

5. For Hadsst3, the slope is flat since December 2000 or 13 years, 2 months. (goes to January)

6. For UAH, the slope is flat since January 2005 or 9 years, 1 month. (goes to January using version 5.5)

7. For RSS, the slope is flat since September 1996 or 17 years, 5 months (goes to January). So RSS has passed Ben Santer’s 17 years.

(P.S. The anomaly for February for RSS has come in and the time is now 17 years and 6 months going from September 1996 to February 2014.)

The next graph shows just the lines to illustrate the above. Think of it as a sideways bar graph where the lengths of the lines indicate the relative times where the slope is 0. In addition, the sloped wiggly line shows how CO2 has increased over this period.

WoodForTrees.org – Paul Clark – Click the pic to view at source

When two things are plotted as I have done, the left only shows a temperature anomaly.

The actual numbers are meaningless since all slopes are essentially zero and the position of each line is merely a reflection of the base period from which anomalies are taken for each set. No numbers are given for CO2. Some have asked that the log of the concentration of CO2 be plotted. However WFT does not give this option. The upward sloping CO2 line only shows that while CO2 has been going up over the last 17 years, the temperatures have been flat for varying periods on various data sets.

The next graph shows the above, but this time, the actual plotted points are shown along with the slope lines and the CO2 is omitted.

WoodForTrees.org – Paul Clark – Click the pic to view at source

Section 2

For this analysis, data was retrieved from Nick Stokes’ Trendviewer page. This analysis indicates for how long there has not been statistically significant warming according to Nick’s criteria. Data go to their latest update for each set. In every case, note that the lower error bar is negative so a slope of 0 cannot be ruled out from the month indicated.

On several different data sets, there has been no statistically significant warming for between 16 and 21 years.

The details for several sets are below.

For UAH: Since February 1996: CI from -0.042 to 2.415

For RSS: Since November 1992: CI from -0.022 to 1.900

For Hadcrut4: Since October 1996: CI from -0.027 to 1.234

For Hadsst3: Since January 1993: CI from -0.016 to 1.812

For GISS: Since September 1997: CI from -0.014 to 1.299

Section 3

This section shows data about January 2014 and other information in the form of a table. The table shows the six data sources along the top and other places so they should be visible at all times. The sources are UAH, RSS, Hadcrut4, Hadcrut3, Hadsst3, GISS. Down the column, are the following:

1. 13ra: This is the final ranking for 2013 on each data set.

2. 13a: Here I give the average anomaly for 2013.

3. year: This indicates the warmest year on record so far for that particular data set. Note that two of the data sets have 2010 as the warmest year and four have 1998 as the warmest year.

4. ano: This is the average of the monthly anomalies of the warmest year just above.

5. mon: This is the month where that particular data set showed the highest anomaly. The months are identified by the first three letters of the month and the last two numbers of the year.

6. ano: This is the anomaly of the month just above.

7. y/m: This is the longest period of time where the slope is not positive given in years/months. So 16/2 means that for 16 years and 2 months the slope is essentially 0.

8. sig: This the first month for which warming is not statistically significant according to Nick’s criteria. The first three letters of the month is followed by the last two numbers of the year.

9. Jan14: This is the January 2014 anomaly for that particular data set.

10.Jan13: This is the January 2013 anomaly for that particular data set.

11.diff: Here I simply indicate if the difference between the January 2014 number is negative or positive with respect to the January 2013 number. A negative difference indicates 2014 will be forecast to be cooler than 2013 and vice versa. See Row 1 for the 2013 rank.

12.Jan14: This is a repeat of the January 2014 anomaly for that particular data set. I am repeating row 9 for clarity as row 12 will now be compared to row 13.

13.Jan04: This is the January 2004 anomaly for that particular data set.

14.diff: Here I simply indicate if the difference between the January 2014 number is negative or positive with respect to the 2004 number. A negative difference indicates 2014 will be forecast to be cooler than 2004 and vice versa.

15.04rk: Here I give the rank in 2004 for each particular data set.

16.rnk: This is the rank that each particular data set would have if the anomaly for January 2014 were to remain that way for the rest of the year. Of course it will not, but think of it as an update 5 minutes into a game. Due to different base periods, the rank is more meaningful than the average anomaly.

Source UAH RSS Had4 Had3 Sst3 GISS
1. 13ra 7th 10th 8th 6th 6th 6th
2. 13a 0.197 0.218 0.486 0.459 0.376 0.60
3. year 1998 1998 2010 1998 1998 2010
4. ano 0.419 0.55 0.547 0.548 0.416 0.66
5. mon Apr98 Apr98 Jan07 Feb98 Jul98 Jan07
6. ano 0.662 0.857 0.829 0.756 0.526 0.93
7. y/m 9/1 17/5 13/1 16/6 13/2 12/3
8. sig Feb96 Nov92 Oct96 Jan93 Sep97
Source UAH RSS Had4 Had3 Sst3 GISS
9.Jan14 0.235 0.262 0.506 0.472 0.341 0.70
10.Jan13 0.504 0.439 0.450 0.392 0.292 0.63
11.diff neg neg pos pos pos pos
12.Jan14 0.235 0.262 0.506 0.472 0.341 0.70
13.Jan04 0.184 0.311 0.516 0.504 0.359 0.56
14.diff pos neg neg neg neg pos
15.04rk 12th 11th 11th 7th 9th 13th
Source UAH RSS Had4 Had3 Sst3 GISS
16.rnk 4th 6th 4th 5th 11th 1st

(P.S. The RSS anomaly for February is in and it has a value of 0.162. When averaged with the January anomaly of 0.262, it comes to 0.212 and this would make 2014 rank 11th if it stayed this way.)

What can we conclude from the two sets of differences above? Below, I will assume that Walter Dnes’ qualitative prediction holds true and give the results.

For UAH, the final rank would be colder than 7th but warmer than 12th.

For RSS, the final rank would be colder than 11th.

For Hadcrut4, the final rank would be colder than 11th but warmer than 8th.*

For Hadcrut3, the final rank would be colder than 7th but warmer than 6th.*

For Hadsst3, the final rank would be colder than 9th but warmer than 6th.*

For GISS, the final rank would be warmer than 6th.

*Obviously we cannot have any contradictions. As Walter explained, there is a lot of noise in these numbers. To find the true prediction, we need to find the place that January 2014 fits on the best fit line. The January 2004 numbers were closer to the line on Walter’s graphs, so they would give the most reliable estimate in my opinion. Note that my numbers are for version 5.5 for UAH and I have numbers for Hadsst3 that Walter does not have, so I cannot comment on those. However it seems as if the odds favour cooling according to Walter.

See the following graph:

WoodForTrees.org – Paul Clark – Click the pic to view at source

All graphs have been offset so they start at 0.4 for January 2004. So to see if 2014 is expected to be colder or warmer than 2004, see if the final point, namely January 2014, is above or below 0.4. But keep in mind this is only a qualitative estimate.

If you wish to verify all of the latest anomalies, go to the following:

For UAH, version 5.5 was used since that is what WFT used.

http://vortex.nsstc.uah.edu/public/msu/t2lt/tltglhmam_5.5.txt

For RSS, see: ftp://ftp.ssmi.com/msu/monthly_time_series/rss_monthly_msu_amsu_channel_tlt_anomalies_land_and_ocean_v03_3.txt

For HadCRUT4, see: http://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/time_series/HadCRUT.4.2.0.0.monthly_ns_avg.txt

For HadCRUT3, see: http://www.cru.uea.ac.uk/cru/data/temperature/HadCRUT3-gl.dat

For HadSST3, see: http://www.cru.uea.ac.uk/cru/data/temperature/HadSST3-gl.dat

For GISS, see: http://data.giss.nasa.gov/gistemp/tabledata_v3/GLB.Ts+dSST.txt

To see all points since January 2013 in the form of a graph, see the WFT graph below:

WoodForTrees.org – Paul Clark – Click the pic to view at source

As you can see, all lines have been offset so they all start at the same place in January. This makes it easy to compare last January 2013 with January 2014.

Appendix

In this part, we are summarizing data for each set separately.

RSS

The slope is flat since September 1996 or 17 years, 5 months. (goes to January) So RSS has passed Ben Santer’s 17 years.

For RSS: There is no statistically significant warming since November 1992: CI from -0.022 to 1.900.

The RSS anomaly for January is 0.262. This would rank it in 6th place if it stayed this way. 1998 was the warmest at 0.55. The highest ever monthly anomaly was in April of 1998 when it reached 0.857. The anomaly in 2013 was 0.218 and it is ranked 10th.

(P.S. The anomaly for February for RSS has come in and the time is now 17 years and 6 months going from September 1996 to February 2014. Also, when the February anomaly of 0.162 is averaged with the January anomaly of 0.262, it comes to 0.212 and this would make 2014 rank 11th if it stayed this way.)

UAH

The slope is flat since January 2005 or 9 years, 1 month. (goes to January using version 5.5)

For UAH: There is no statistically significant warming since February 1996: CI from -0.048 to 2.415.

The UAH anomaly for January is 0.235. This would rank it in 4th place if it stayed this way. 1998 was the warmest at 0.419. The highest ever monthly anomaly was in April of 1998 when it reached 0.662. The anomaly in 2013 was 0.197 and it is ranked 7th.

Hadcrut4

The slope is flat since January 2001 or 13 years and 1 month. (goes to January)

For Hadcrut4: There is no statistically significant warming since October 1996: CI from -0.027 to 1.234.

The Hadcrut4 anomaly for January is 0.506. This would rank it in 4th place if it stayed this way. 2010 was the warmest at 0.547. The highest ever monthly anomaly was in January of 2007 when it reached 0.829. The anomaly in 2013 was 0.486 and it is ranked 8th.

Hadcrut3

The slope is flat since August 1997 or 16 years, 6 months. (goes to January)

The Hadcrut3 anomaly for January is 0.472. This would rank it in 5th place if it stayed this way. 1998 was the warmest at 0.548. The highest ever monthly anomaly was in February of 1998 when it reached 0.756. One has to go back to the 1940s to find the previous time that a Hadcrut3 record was not beaten in 10 years or less. The anomaly in 2013 was 0.459 and it is ranked 6th.

Hadsst3

For Hadsst3, the slope is flat since December 2000 or 13 years and 2 months. (goes to January).

For Hadsst3: There is no statistically significant warming since January 1993: CI from -0.016 to 1.812.

The Hadsst3 anomaly for January is 0.341. This would rank it in 11th place if it stayed this way. 1998 was the warmest at 0.416. The highest ever monthly anomaly was in July of 1998 when it reached 0.526. The anomaly in 2013 was 0.376 and it is ranked 6th.

GISS

The slope is flat since November 2001 or 12 years, 3 months. (goes to January)

For GISS: There is no statistically significant warming since September 1997: CI from -0.014 to 1.299.

The GISS anomaly for January is 0.70. This would rank it as 1st place if it stayed this way. 2010 was the warmest at 0.66. The highest ever monthly anomaly was in January of 2007 when it reached 0.93. The anomaly in 2013 was 0.60 and it is ranked 6th.

Conclusion

According to Walter’s criteria, the message seems to be rather mixed as to whether we will have cooling or warming this year. At times, the qualitative indication is opposite to the quantitative indication. This shows that there is quite a bit of noise in the data. Overall, there seems to be a greater indication of cooling. My inclination is to trust the quantitative number in these cases to give the best indication as to where we are headed.

I would say that unless a very strong El Nino develops fairly quickly, there will be little change this year and the length of the period of no warming will continue to increase. As well, the period of no statistically significant warming will also increase this year unless we have an El Nino. Do you agree?

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NZ Willy
March 9, 2014 12:08 pm

Your pedantic insistence on starting decades on the “1” year is a fatal distraction to the whole article. When people say “nineties” or “noughties”, they mean the decade starting on the “0” year. Stick to popular convention or lose the attention of your audience from the very outset.

March 9, 2014 12:20 pm

NZ Willy says:
March 9, 2014 at 12:08 pm
Your pedantic insistence on starting decades on the “1″ year is a fatal distraction to the whole article.
You raise a good point, but see:
http://wattsupwiththat.com/2014/03/07/jli-final-forecasts-for-2014/#comment-1585645
A few quotes:
“Can anyone explain why the Met Office refers its prediction on a long term (1961-1990) average? Why not (1951-1980) or (1971-1990) or the most recent (1981-2010)? Is it because the anomaly may look higher when using 1961-1990 as the base?”
Climate science seems to follow its own rules with regards to the start and end of decades.

March 9, 2014 12:20 pm

NZ Willy: though I certainly agree with you in general, and I celebrated the new millennium at the start of 2000 not 2001, unfortunately meteorological organizations all use xxx1 to yyy0, silly though it may be.
Rich.

Otter (ClimateOtter on Twitter)
March 9, 2014 12:21 pm

I’ve been hearing a distant grinding sound for some time now. Guessing that would be nicky’s teeth….

David in Cal
March 9, 2014 12:25 pm

The word “decade” is ambiguous. It can refer to a ten year period ending with a zero, or a 10 year period ending with a 9, or any ten year period. For the purposes of science, the latter definition is what we should look at IMHO. Nature doesn’t care what sort of number our calendar assigns to a given year.
If we take “decade” to mean any 10 year period, then the most recent decade is 2004 – 2013. And, this decade is not the warmest decade on record.

R. Shearer
March 9, 2014 12:28 pm

So far, interannual temperature variation is on par with the variability over a period of ~150 years. If the interannual variability represents noise and this is compared to the signal of the long-term trend, the signal to noise is insignificant.

Alan Millar
March 9, 2014 12:30 pm

NZ Willy says:
March 9, 2014 at 12:08 pm
“Your pedantic insistence on starting decades on the “1″ year is a fatal distraction to the whole article. When people say “nineties” or “noughties”, they mean the decade starting on the “0″ year. Stick to popular convention or lose the attention of your audience from the very outset.”
Pedantic!
Are you one of those people who count to ten starting at zero and ending at nine?
In year terms all centuries and decades start at one. The first decade AD was not 0 to 9 AD , it was 1 to 10 AD. No such year as 0 AD mate. All other decades have followed on from this one.
Alan

RichardLH
March 9, 2014 12:32 pm

One reason for having such a long flat period (and having it increase in width backwards as time goes by) would be if we are over some local peak and headed downwards for a time into the near future.

March 9, 2014 12:39 pm

David in Cal says:
March 9, 2014 at 12:25 pm
If we take “decade” to mean any 10 year period, then the most recent decade is 2004 – 2013. And, this decade is not the warmest decade on record.
True, but one needs to be careful how this is interpreted. 2004 to 2013 is warmer than 1994 to 2003.
However check out the following. The green line for the 2001 to 2011 decade is certainly higher than the blue line which is the line for the most recent 120 months.
http://www.woodfortrees.org/plot/rss/from:2001/to/plot/rss/from:2001/to:2011/trend/plot/rss/last:120/trend

John F. Hultquist
March 9, 2014 12:39 pm

NZ Willy says:
March 9, 2014 at 12:08 pm
“nineties” or “noughties”

Say what? You just made those up. Don’t make stuff up.
The post is about Januaries. Start with link #1 above. There you can see the original idea:
“. . . the rule goes like so…
If this year’s January anomaly is warmer than last year’s January anomaly, then this year’s annual anomaly will likely be warmer than last year’s annual anomaly.
If this year’s January anomaly is colder than last year’s January anomaly, then this year’s annual anomaly will likely be colder than last year’s annual anomaly.”

March 9, 2014 12:51 pm

Even if there is a strong el-Nino, unless it is stronger than 1998-99 we should not expect a significant change in the long term slope. What goes up, comes down and usually more rapidly.

March 9, 2014 12:51 pm

Farmer wise, any change in more than an average of four degrees in annual, monthly and weekly can be a disaster to farming. Now that we are in a sunspot minimum and new data is pouring in we really don’t know where the bottom is.
Now let’s take Joseph D’Aleo’s work..the minimum will last until 2030. One s identity points out there is a climate lag for 5 years. So an equal Medieval Global Warming period will not resume until 2036.
All the data here is greatly appreciated an should be stored for later analysis. We don’t have much in the way of solar minimum data other than historical items reflecting cold and drought in the early 1700s and 1800s.
I greatly appreciate this document, Dr. Watts.
Paul

March 9, 2014 12:57 pm

January 2000 had an anomaly of -0.055 and the average for 2000 was 0.092. January 2010 had an anomaly of 0.593 and the average for 2010 was 0.472.
So the relationship certainly applied then.
As well, RSS shows cooling from January 2000, but not as steep as from 2001. See:
http://www.woodfortrees.org/plot/rss/from:2000/to:2014.05/plot/rss/from:2000/to:2014.05/trend

March 9, 2014 1:09 pm

Most misleading of all to most folks is the phrase “in recorded history.” Most folks probably
assume that is the period in which written human records exist, not since weather data has
been systematically recorded. Big difference.

March 9, 2014 1:12 pm

fhhaynie says:
March 9, 2014 at 12:51 pm
Even if there is a strong el-Nino, unless it is stronger than 1998-99 we should not expect a significant change in the long term slope.
That is a good point. In the following, check out the area below the green line from September 1996 to December 1997. Then check out the area above the green line from December 1997 to December 1998.
http://www.woodfortrees.org/plot/rss/from:1996.65/plot/rss/from:1996.65/trend
The positive area is larger than the negative area so a 1998 El Nino would push the flat slope start time into the 2000s. However if there is a delay before a strong El Nino manifests itself, then it may be possible that the start of the flat slope line will not go past December 1997.

AndyL
March 9, 2014 1:12 pm

So which ten year period was the warmest, according to official figures?
How high up the list of ten year periods was the most recent such period (2004-2013?

Visiting Physicist (who is actually Doug Cotton - Anthony)
March 9, 2014 1:13 pm

You’re getting a mention on several climate blogs …
http://www.climate-resistance.org/2014/03/the-gwpf-crok-lewis-and-positioning-sceptics.html#comment-301039
For the public record, the blogs on which the above linked comments (or similar) have been deleted are ..
Skeptical Science
Watts Up With That
Stoat-Connelly
Science of Doom
Lucia’s Blackboard
The Air Vent
Australian Climate Madness
[Request “you” (the Visiting Physicist) identify who the “you” is in the first sentence above. Mod]
REPLY: The reason for your multiple comment removal is simple, Doug Cotton: you’re a spamming idiotic troll that won’t take “go away” for an answer. Look forward to a post here all about your antics. – Anthony

March 9, 2014 1:14 pm

“1. By the laws of averages, half of all Januaries should be above the yearly average and half should be below.”
Really? What’s the average of 1,1,1 and 3? By the “laws of averages” half should be above and half should be below if and only if half are above and half below. It’s risky to generalize about the distribution given only the mean — the half above and half below conclusion assumes facts not in evidence.

March 9, 2014 1:26 pm

AndyL says:
March 9, 2014 at 1:12 pm
So which ten year period was the warmest, according to official figures?
It would depend on your data set. See the following where I plotted RSS from the beginning and then took the mean of 120 months or 10 years. The peak is at October 2002. So the highest 10 year period would be 5 years before this to 5 years after this. In other words from October 1997 to September 2007.
http://www.woodfortrees.org/plot/rss/from:1979/mean:120

Kristian
March 9, 2014 1:28 pm

According to that other global satellite dataset, UAH, there is no ongoing cooling trend. There is an ongoing warming trend:
http://woodfortrees.org/plot/uah/from:2001/to:2004.08/plot/uah/from:2011/plot/uah/from:2001/trend

Kev-in-Uk
March 9, 2014 1:28 pm

Col Mosby says:
March 9, 2014 at 1:09 pm
absolutely! – and a pet peeve of mine that most layfolk don’t or cannot be bothered to know the difference. However, it is even worse for geologists (like myself) – who would generally consider the whole existence of human life (and all and any records thereof – including cave drawings, etc) to be but a drop in the proverbial ocean in terms of the [geological] ‘record’ !

Hoser
March 9, 2014 1:31 pm

After the first third, OMG, what a mess. Makes me pine for Willis.

March 9, 2014 1:38 pm

Kate Forney says:
March 9, 2014 at 1:14 pm
“1. By the laws of averages, half of all Januaries should be above the yearly average and half should be below.”
Really? What’s the average of 1,1,1 and 3?

I was not thinking of only 4 numbers when I made that statement. If you have a 160 year record for Hadcrut4 for example, you can say that half of all Januaries and half of all Februaries, etc would be above the annual average and half would be below. Naturally, if you have 34 years, then you would expect 17 to be above and 17 below. In real life, for a short period, you would likely have a range such as 14 to 20 being above or below.
It is something like flipping a coin. Wide differences can happen with 10 flips, but with 500 flips, you would get very close to 250 heads and 250 tails.

Mike McMillan
March 9, 2014 1:44 pm

“1. By the laws of averages, half of all Januaries should be above the yearly average and half should be below.”
I think you mean “median,” not “average.”

March 9, 2014 1:50 pm

Kristian says:
March 9, 2014 at 1:28 pm
According to that other global satellite dataset, UAH, there is no ongoing cooling trend. There is an ongoing warming trend:
True enough. On the other hand, if we use the WTI which combines Hadcrut3, GISS, RSS and UAHversion5.5, then the slope is very slightly negative but it is certainly not statistically significant.
http://www.woodfortrees.org/plot/wti/from:2001/plot/wti/from:2001/trend

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