NCDC updates database for Dec08 – NCDC's own graphic shows decadal cooling trend

One of the best things about WUWT is the number of eyes and minds at work, multiplying the efforts. This is interesting. Now that the 1998 El Nino is disappearing off the 10 year scale, things are looking a bit different

From “crosspatch” in comments:

NCDC now has December 2008 in the database. Annual North American temperature since 1998 (11 years of data) is falling over the period at a rate of 0.78(F)/decade or 7.8(F)per century. At this rate we will be in an ice age within 5 decades. If you can get the graphic, the heavy black like is the average over the century 1901 to 2000.

Here is the graphic from their automated graphics generator linked to their database:

Source: National Climatic Data Center

While the link he provided is only a result, I’m sure he’ll share the method in comments to this post.

UPDATE: He has indeed, see below. Try your own hand at it. The trend will likely flatten a bit with the removal of 1998 from the 10 year set. Of course you could pick any number of scales/periods and get different results. The point being made here is that the last 10 years hasn’t met with some model expectations.

Also I have corrected in the text the reference to Centigrade when it was actually Fahrenheit, note the (F). NCDC being an arm of the US government operates on the English unit system whereas most other organizations use metric, and thus Centigrade. I’ve made the mistake myself, so has NASA, who famously lost a Mars probe when they botched orbit entry calculations by use of Metric and English units on different science teams.

UPDATE2: Some folks are erroneously thinking that this graph above represents a global trend, it does not. Read on.

It represents US data from NCDC. Also there has been the usual complaint that “10 years isn’t long enough to determine any useful trend”. Perhaps, but when NASA’s James Hansen went before congress in 1988 to declare a “crisis in the making”, there had only been about 10 years of positive trend data since the PDO flip in 1978. It seemed adequate then:

In the graph above, note that the GISS station data does follow the Hansen C scenario, but that we are currently well below it.

Yes we really do need longer data periods to determine climate trends, 30 years is the climatic standard,  but you can also learn useful information from examining shorter trends and regional trends.