Of Minimal Interest
Monday, October 19th, 2009NASA GISS keeps a table of monthly average global temperatures at this address:
http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt
The way to read a particular monthly number is to interpret the value as hundredths of a degree above or below the absolute global mean for 1951-1980. The unit of measure is degrees celcius.
So when we look at the table and see that the anomaly for September 2009 was 86, that is 86/100 of a degree. What it means is that this past September was nearly a degree warmer, world-wide, than the 1951-1980 average temperature for September.
What I find useful about this table is that I can look at long term trends. Each row has a column with the heading J-D. This column represents the average annual anomaly for all months of that year. You have to go back to 1976 to see a negative number. Every year since then has been above the mean. That’s a trend.
The 2009 anomaly is currently 70. With September being even warmer than that, there is at least the possibility that the average will go higher than 70. If it stays at 70, 2009 will be tied with 1998 as the second warmest year on record. When the average anomaly of 70 happened in 1998, it was an immense leap from the previous record of 48 in 1987.
Since then it has been eclipsed by the 2005 anomaly of 76, and approached by every other year since 2002. In other words, that shocking new record anomaly has quietly become the norm.
We are now headed into an El Nino, but we are also in a prolonged solar minimum. Thus, another 1998-like leap is unlikely any time soon, but certainly it will happen when the elements of these events line up again as they did in 1998.
And there is no denying that this solar minimum is significantly warmer than the Daulton Minimum and the Maunder Minimum. 2008 was a cool year, with an anomaly of “only” 54, low by recent standards.
It was the 9th warmest year on record.
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