Digital Diatribes

A presentation of data on climate and other stuff

July 2008 Update on Global Temperature – NCDC

Posted by The Diatribe Guy on July 25, 2008

Sorry it took me a while to get to this, but life has been busy, and this ain’t my day job…

But I have finally gotten around to updating my spreadsheets and charts with the release of the NCDC (NOAA) temperature anomalies. The June anomaly was 0.4732 in June. This represented a slight increase over the May anomaly of 0.4374. So, four of the five measures showed a slight increase over May, with one temperature measure moving in the other direction: GISS. One must be fair to point that out, since GISS is usually looked at as the outlier in the other direction. I’m not saying it helps build confidence in the measure, it just is what it is.

NCDC anomalies, though, deviate from the satellite results even more starkly than the other surface measures. The satellite data tells us that June was actually relatively cool by historical standards. NCDC is telling us a different story. The June 2008 anomaly is the coolest since 2004, and cooler than 6 of the past 7 years, continuing the short-term trend downward. But from there the past anomalies drop off considerably. There are no monthly anomalies prior to 1997 that are higher than the 2008 reading. That just seems odd to me, especially given the disparity from the satellite data. But it’s what the data we have says. Accordingly, 2008 is the 9th warmest June in the history of the data.

I remember making the argument at some point about how you can spin the data a couple different ways. One way is to point out that it’s the 9th warmest June on record. Sounds impressive… However, there’s also the mountain climbing analogy, where after you reach the summit, your first steps down will still be close to the summit. The fact that you are near the summit does not indicate a continuing trend upward, even though each step you take actually increases your average elevation per step until some point lower down on the mountain. Could it be that this is what we are witnessing with temperatures? All the temperature measures show a short-term cooling trend. The fact that we are still near historical highs may indicate continued warming, or it just may be that we are in the initial phases of cooling. As always, only time will tell.

As for the run of year-over-year decreases in anomalies, 11 of the last 12 months show a decline. The exception is March 2008 versus March 2007.

As kind of an aside, I wanted to share the following news article I came across today: Anchorage, Alaska is on pace to have it’s coldest summer on record. They are, of course, quick to explain that this can’t be looked upon as a trend. Of course, they’re right. But it seems like that is mentioned in every story I see that indicates it is cooling on our planet. At some point, the totality and cumulative affect of all these circumstantial evidences would seem to indicate a larger trend. If the data were saying a different thing, that would be one thing – but it’s not. I personally think we’re in store for more cooling ahead. But we’ll see.

That said, you can’t really argue the long-term trend, other than to say it is by no means a catastrophic warming trend. But it is, in fact, warming over the long haul, at least over the last 130 years.

As always, I look at the cooling trend, as well. This month, the initial month remained January 2001, but we did gain the additional June data point. So, the current trend is 7.5 years, just like the GISS data shows.

Here is an update to the changes in the 60-month slope values over the data set:

I will now discuss the upcoming predicted anomalies from the ncdc data. After that, click on the “read more” link to see a series of other charts that may interest you: 60, 180, and 360 month trend lines; graphs of the change in slope values for 60, 180, and 360 month trend lines; 15 year and 30 year changes in slope values over the life of the data set. I don’t want to clog your browser with all these with a full post.

It is now time to brag a little bit. See this post on anomalies predicted for June on the NCDC data and you will find an average predicted anomaly of 47.8. The average excuding high and low was 47.8, and the median prediction was 48.1. The lowest value predicted was 42.0 using the 240-month model, and the highest vlaue predicted was 53.6 using the 300-month model. The actual result, as previously shared, was 47.3! This means that, for one glorious month, anyway, my model accurately projected the global temperature to within 0.005 degrees, using the average values. Not bad, if I say so myself.

Last month, the July prediction using the averages had a bit higher range, from 48.3 to 49.2. Updating the analysis for the new data, the range of predictions has tightened. Should the model hold, we can expect to see an anomaly of 48.3 to 48.8. The lowest predicted anomaly is the value using the 120-month trend lines, at 42.7. The highest predicted anomaly is the value derived from the 180-month trend lines: 54.1.

I won’t put the next year’s predictive values in grid form. In general, the predicted anomalies look to increase slightly if past data trends hold, and then the winter/spring is expected to be warmer before falling back down to anomalies at today’s levels by next August.

For a look at those historical charts, click…

It is interesting to note that the 30-year slope was negative from the start of the data set until 1926. Due to data limitations, we don’t know how long back this extended. It dipped slightly negative starting in 1959 and remained negative until 1973. It was a very slight negative. The overall 30-year warming slopes are more positive than the decreases are negative. Since 1973, there have been no stretches of 30-year anomalies where the slope has been negative. The chart easily shows that a historical high was reached a few years ago, but since then things have flattened, and the curve is actually sloping downward.

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