June 2009 Update on Global Temperature – UAH

The UAH anomaly this month was 0.043. The link to the data can be found on the right of the page, under the Temperature Resources section.

The May data point
If you think that an anomaly near zero sounds about average, you’re right. In fact, it’s also around median (slightly below, actually). Go figure… The current anomaly ranks 16th of 31 May anomalies (48th percentile) and 202nd out of 366 overall anomalies (44th percentile).

The anomaly is stated in terms of degrees Celsius, but I will use the convention of 0.01 degrees Celsius, which translates to an anomaly of 4.3. When I say “units” I mean “0.01 degrees Celsius.” Units is more convenient.

The May anomaly was 4.7 units less than the April anomaly. However, due to a sharp negative reading last year, we were up 22.6 units this May over last May.

Averages

The current 12-month average is 14.0. Despite the lower anomaly this month, the annual average actually increased due to the fact that a cold anomaly dropped off from a year ago in the 12-month average calculation. The current average is the highest since the period ending April 2008. I’ve shown the plotted running 12-month average below. Note the easily seen single-step upward that looks to occur around 1997-98. I’ve noted that in the past.

12-month running average anomaly - UAH

For giggles, I looked at a couple other running averages, as well. The 36-month average is 18.85 ending May 2009. Interestingly, this average had trended downward every month since September 2007 until this month. It blipped up a bit this time around from the last month’s average of 18.70. (For those who like to accuse me of cherry-picking data, note that all the averages from 18-month average to 30-month average declined, and then every average from 42-months through 108-months declined from last month). Obviously, if you’ve thought about the math on this, it means that a low anomaly from three years ago dropped off. Going forward, it is probable that this average will continue to decline, barring some major warming.

36-month running average anomaly - UAH

Finally, I pulled the 120-month running average anomaly, which was 20.26. This is the fifth consecutive increase in the 120-month average. It is likely that we will see this average continue to increase over the next year+, unless we start seeing consistent single-digit or negative anomalies.

Comparison of UAH versus RSS – Lucia’s Blackboard

I’ve started looking at some of the other blogs I’ve noted over the last few months. I’ve added Jennifer Marohasy’s and Lucia’s Blackboard to the blogroll. More are sure to come, but since I don’t have all the time in the world to give them a good look, I’ll add as I come across sources that look to have value. Value is defined here as “any blog that I feel inclined to visit every now and then.”

It just so happens that as I checked out Lucia’s Blackboard, she had a post up that was very similar to one that I was contemplating once I had updated the UAH trends (to come soon…). There’s no point in me duplicating work, so I’m linking to her post here:

————–

UAH temperature anomalies were officially posted yesterday. I thought you all might like to see a graph of temperature anomalies with uncertainty intervals. I included a trend of 2C/century for references:

UAH vs. RSS

Click here for the rest of her post.

12 Years Of No Warming, Part 2 – Update on UAH, May 2009

UAH is basically tracking with RSS in the end conclusion of no warming for the last 12 years. It doesn’t go back quite as far as RSS – the UAH is truly at 12 years, going back to May 1997. RSS went back to March 1997. Since these are both satellite readings, they provide a nice check against the other. They are not necessarily in concert at all times. But the overall results are in line.

I won’t belabor the same old points as made in the RSS post. So, I’ll pretty much just get to things here:

Data source: UAH Data – link can be found on the right side of the page.

Data Point:
The April anomaly was 0.091 (in degrees Celsius. Heretofore, I’ll state as 9.1 – in hundredths of a degree Celsius). This is higher than last year by 7.6, and lower than last month by 11.5.

Rank:
The April anomaly ranks 15th of 31 Aprils (51st percentile) and 167th of 365 total anomaly readings (54th percentile).

Average:
The annual average is 12.1. This is the highest average since the year ending May 2008, and has increased each month since its low value of 3.9 in October 2008.

Streaks:
This is the sixth consecutive month of anomalies that are above the same month of the previous year. Unless there is a significant drop in May’s anomaly, this will likely be extended, since May of 2008 was -18.3 and June 2008 was -11.4.

Trends:
I have discussed the limitations of looking at a 30 year trend in the past. This is because it is apparent that cycles affecting temperature range over 60-100 years or more. I have also discussed the limitations of applying linear trends to the temperature charts. Primarily, in the UAH chart, a step is apparent around 1998. Applying separate trend lines to pre-1998 and post-1998 show two fairly flat lines with a step up at that point. This limitation is why I normally provide the charts of how the linear trend line slope changes. It provides a perfect example of why the linear trend cannot be used to extrapolate forward – it is constantly changing and cycling.

Other than the 60-month slopes, I didn’t provide that this time. So just take the linear trends presented below for what they are: a current snapshot of best-fit trend line. I understand the limitations, and so should the reader and user of such data.

The overall UAH picture:

Overall UAH trend line.

12-Year Flat Trend Line:
We can extend a trend line back to May 1997 and show a best-fit trend line with no warming. Yes, it’s true that 1998 had a super El Nino. While that certainly acts to help explain one reason for the line, one could also argue that if you eliminate that event, subsequent temperatures may well have been cooler. You can’t simply remove that one event without making subsequent adjustments to the points that follow. Our atmosphere simply doesn’t react like that. But, in any case, the data is the data. If things are truly warming as people say, eventually they will lose credibility on the 1998 El Nino point, because even despite that we should see temperatures eventually exceed that level.

Current Flat UAH trend line.

60-month trend lines:
The 60-month trend line is -0.20434. This is the rate of change in 0.01 C per month. This corresponds to a rate of cooling of 2.45 degrees per Century. I won’t continue to make this point, but it bears repeating once more that this represents a current rate based on 5 years of data, and that this rate changes. I certainly wouldn’t extrapolate the 5-year trend rate to a Century. But then, I wouldn’t extrapolate the 10, 15, 20, 25, or 30 year rate like that either. But, it’s the way we measure these things, so I’ll play along.

This is lower (more negative) than last month, after an increase in the previous few months. If the next four anomalies come in at the current annual average of 12.1, this slope will decrease briskly, reaching -0.42. This would be its steepest decline in quite some time, even below the levels of last year. Even at an anomaly of 20 over the next four months, it will exceed last year’s steepness (-0.369). That is because the anomalies at this point in 2004 were single digits or negative in May – Aug. So, unless things really heat up, we’re likely going to see a sharp downturn in the trend line over the next few months before moderating once again.

April 2009 Update on Global Temperature – UAH

OK, I’ve spilled my guts on where I’ve been and what I’ve been doing. So, let’s get back to some temperature analysis…

No major changes are afoot in the overall trends. The UAH overall data is presented here.

I had presented a chart taking a closer look at the UAH data, basically showing that the chart consists of a flat line from 1979 to 1998, and then another flat (or slightly cooling) line from 1998 to current. Just observing the raw anomalies, one can easily see this characteristic in the data. We had some cooler anomalies in 2008 that show up under the zero line of the chart, that are similar to some other lows in 1997 and 2000, but we have not seen low levels similar to those that occurred in the mid-1980s or early 1990s. Basically, I have posited that the key to this is the 1998 spike. I think it makes sense that we saw some elevation that we never completely recovered from, not as part of a gradual warming trend, but as more of an isolated event. However, this is related to the cycles I have also discussed regarding the PDO and AMO. The 1998 deviation, in respect to the point of the cycle where it is located, was not something that is outside of predictablility. It seems high on a chart where the basis is a linear measure, but if you incorporate the sine waves of the cycles, it rides that wave nicely. So, I think we saw a combination of cycle peaks and a fairly significant upward deviation. Then, after that, due to the natural greenhouse effect and continued elevated temperatures related to cycle peaks, we have not seen it subside greatly.

The AMO has peaked, and the PDO is entering its cold phase. The future is interesting.

The second part of that chart is flat to cooling, starting nearly 12 years ago. I may be able to declare a full 12-year non-warming trend next month.

Starting in May 1997, we have not cooled, based on the best fit trend line. This is simple observation. You will find other individuals on the internet with claims of fancy statistical backgrounds who will actually dispute this simple fact. But they are arguing a different thing. All I’m doing is showing the actual trend line. The fact is, that the trend line demonstrates that there has been no warming. If that lasts one more month, it will have gone on 12 years. Of course, we’ll be told that such a short time frame is insufficient. As we will be told when it’s 13, 14, and 15 years….

Now, you may wonder what there can be to dispute about a trend line? It’s a good question. You see, these people make the mistake of finding situations where a flat trend line of this length can exist within an overall warming trend, and then use this fact to imply that the trend line itself does not tell us what it tells us. This is like saying that parts of the earth are not actually flat because we all know that the earth is round. So, let’s be clear: (1) there is an actual, fitted, statistically viable trend line that is fitted that tells us that no warming has occurred in nearly 12 years; (2) the conclusion that can be drawn from this is exactly “there has been no warming in the last (nearly) 12 years.” (3) Using the last 12 years alone to argue that overall warming has stopped is a flawed application of the observation. (4) Using ARMA analysis or any other kind of analysis to suggest that the 12 year non-warming trend doesn’t actually exist is not just flawed, but simply incorrect on its face. (5) Using the fact that a 12-year non-warming trend can occur during a warming trend is not confirmation that it properly reflects the current situation.

Now, both sides can present other analysis to show why they believe the current trend is consistent with the longer-term view. But you can’t just dismiss the current trend as if it doesn’t exist. And the longer it goes on, the less appropriate it is to fail to give it attention.

Speaking of short-term trends....

Now, I will wholeheartedly agree with some of the criticisms of looking at short periods and drawing broad conclusions. The 60-month trend has been negative since I’ve started looking at it on this blog. It is presented more from an interest standpoint. It fluctuates quite a bit over time, and we certainly can’t extrapolate it as an indication of anything except, perhaps, the very near term. Nonetheless, it does tell us what has happened to global temps in the last 5 years, and it is just another piece of the overall puzzle when questioning whether or not the global warming fears are warranted. It obviously has taken a breather lately if it exists at all.

We can get a feel for the fluctuation of the 60-month trends here.

We can see how the 60-month trends have cycled over the last 30 years. Given this chart, it’s not much of a surprise that we’d be seeing an increasing trend. We’ll see if anything shifts gears over the next few years.

While the 180-month trend is positive, we still continue toi see a very steady decline in the slope value. So, even if one argues that warming exists, any claims of acceleration are clearly false. While I only present the 180-month slope changes here, we see a similar story in all the longer periods.

It’s been a clear and steady decline in slope values for the 180-month trend over the last couple years. It will be interesting to see if the latest blip over the trend line is a reversal of this, or just a little “retracement.”

Here are some of the relevant stats:

Current (March) anomaly: 20.80 (stated in hundredths of a degree Celsius)

Ranking: 11th of 30 March anomalies; 89th of 364 overall anomalies in the data set

Deviations from previous: This is an increase of 11.90 increase over March 2008; it is a 13.90 reduction from the February 2009 anomaly

Averages: 12-month average of 11.50 is highest since the period ending May 2008. However, the 24-month average is the lowest since January 2002.

Consecutive Run:This is the fifth consecutive month where the anomaly is higher over the previous year.

Slopes:
60-month: The current slope of -.1802 (2.16 degrees cooling per century) is actually higher (less negative) than at any point since May 2008. So, while negative, we’ve seen a few straight months of moderation in the slope.

120-month: Current slope = 0.107107 (1.29 degrees warming/Century) is right around the level it’s been at for the last few months. This had trended down continuously until recently, when it flattened. We now wait to see if this is the start of a reversal, or if the reduced slopes will continue. I had predicted this based on the front-end temperatures. Within a few months, we should see the slopes continue to decline, barring some significant warm temperature anomalies.

180-month: Current slope = 0.096950 (1.16 degrees warming/century). This has now fallen to its lowest level since the period ending December 2001.

240-month: Current slope = 0.142172 (1.71 degrees Celsius/Century). This is at its lowest level since the period ending December 2006.

300-month: Current slope = 0.144783 (1.74 degrees Celsius/Century). This is at its lowest level since the period ending February 2006.

360-month: Current slope = 0.105704 (1.27 degrees Celsius/Century). There are only 5 observations of this slope measure, due to the limited data. This is in the ballpark of previous slope levels.

I’m going to try and get a couple more posts up this next week. Just a head’s up that after that the family and I are going on a two-week vacation. Of all places, we’re heading to Delaware… But I will not be posting during that time (April 25 through the first week of May).

December 2008 Update on Global Temperature – UAH

Congratulations, UAH, on a full 30 years of temperature anomaly data!  We all knew you could do it!

OK, admittedly, it’s pretty hokey to be congratulating a data set, and really, to be getting excited about celebrating an anniversary of sorts for temperature anomaly data.  But sometimes you just have to be hokey.  Life’s too short.

With that, let us proceed to the wrap-up for the month, and a few charts…

Data

• The UAH data set can be found here.
• The November 2008 anomaly was 0.254 (in degrees Celsius)
• November 2008 was 0.045 degrees warmer than November 2007, and had an anomaly of 0.088 degrees higher than October 2008.

Rank

• The November 2008 anomaly was the 65th highest anomaly of the 360 months in the data
• It was the 7th highest November of the 30 years in the data

Slopes

The overall slope for the 30 years is 0.1064 (the lowest of all the temperature data sets).  That corresponds to 1.28 degrees warming per Century.  The chart is below:

We can extend a trend line back as far as May 1997 to see a non-warming trend. This represents an 11 and a half year period of stagnation:

November 2008 Update on Global Temperature – UAH

UAH has released the October anomaly, which I have finally gotten around to taking a look at.

DATA
The information is found here.

The September anomaly is 16.7 (in terms of 0.01 degree Celsius – the data in the link is in terms of degrees Celsius.).

HISTORICAL COMPARISON OF THE SINGLE DATA POINT
*It is 0.064 degrees cooler than October 2007
*It is 0.006 degrees warmer than September 2008

RANK
*It is the 10th warmest October anomaly (21st coolest) of all Septembers in the data set
*It is the 106th warmest (254th coolest) anomaly in the total of 359 observations
*It is the highest anomaly since November 2007

AVERAGES
*The latest 12-month average is now 3.9, which continues this measure’s continued decline.
*The last time a 12-month average reached current levels was the period ending December 2000.

STREAK
*This is the 14th consecutive year over year decrease in the anomaly reading
*The last such consecutive cooling streak was the period ending February 2000 (which ended a 16-month cooling stretch).
*There is only one other streak of 14 or more months in the data aside from the current streak and the streak ending February 2000: October 1991 – April 1993 (19 consecutive months).

SLOPES AND CHANGES IN SLOPE
*Overall trend line since inception is presented below. This represents warming of 1.28 degrees per Century. Of course, the history of this data only goes back to December 1978, which is a steeper warming trend than the longer-term surface data presents.

*Current running negative slope extends back to May 1997, or 137 months (graph below)
*The current cooling trend line added one data point with the new month, but did not extend the initial starting point back any further

*Current 60-month slope is -0.3604, about the same as a month ago.

The trend of slopes:

*Current running 120-month slope is 0.0963
*This slope value has increased for 11 consecutive months. While there is a longer-term decline since March 2002, this is the chart where the 1998 El Nino shows its major impact. The spike in anomalies has been dropping off the front end, which lowers the point of origin of the line, increasing overall slope. We can expect to see this continue for a few more months (check out the chart to get the visual).
*The slope value is the highest since March 2007

*180-month slope is 0.1107, continuing to decrease as time goes on.
*Lowest value since the period ending January 2002

*240-month slope is currently at 0.1511
*This has bounced around in a generally flat pattern for a few months

*300-month trend is at 0.1483
*The same observed pattern in the last few anomalies is seen here as in the 240-month slopes

There certainly does seem to be somewhat of an upward tick from earlier in the year, but current temperatures are still tracking below year-ago levels. The current upward trend probably is related to a neutral ENSO value. Unless an El Nino is on the way, or there is more unwinding in average temperature affects from the diminishing La Nina, it appears that this is probably about the level we’re settling into, absent other effects. It will be interesting to see what future months hold if the ENSO effects stay neutral.