July 2008 Update on Global Temperature – HadCrut
Posted by The Diatribe Guy on July 14, 2008
In the strange world of temperature anomalies, we have the HadCrut data, that can be found here. Column 2 (right next to the date) is the global temperature anomaly. The most recent anomaly is 0.314 (or 31.4 in GISS-equivalent-speak). I still have not yet put a spreadsheet together to fully track this, but it is in progress and I should have it completed for next month. I may even get some predicted anomalies out before then.
Since it’s difficult to compare this directly to other measures due to differences in baseline averages that define the anomalies, it is best to take a look at the data (at this point anyway) against itself.
The June measure of 31.4 is the coolest June since 2000. Similar to GISS, though, it is still warm on an overall historical basis, yielding the 10th highest June anomaly in the data set (159 points). On an overall anomaly basis, it is in the top 7% of all anomalies over the course of the measured period, 1850-current. The 12-month average of 29.7 is the lowest since the period ending April 2001.
One of the interesting things about the HadCrut data is that, unlike GISS and NCDC, the methodology is not publicly available. We get a number, and we’re expected to believe it. I have no particular reason to suggest they are doing one thing or another with their numbers, but this lack of transparency doesn’t lend itself to a high level of trust.
The overall average anomaly over the time period is -17.4. I only mention that to show that the anomaly we see is not representative of the level above or below average, but simply relates to a baseline.
One of the interesting things to me is that the RSS, UAH, and HadCrut anomalies all went up from the previous month. The outlier is once again GISS, except that in this instance, the GISS went down from the previous month. NCDC has yet to be released.
HadCrut is also more consistent with the satellite measures in how long the cooling trend extends back. The furthest back we can fit a negative trend line is the May 1997 – over 11 years.