NOAA Tampering Exposed

By Paul Homewood

Last month, NOAA caused a lot of controversy by adjusting historic global temperature data to show that the pause had never happened. This has been well covered by WUWT and others, but what is less well known is that NOAA have been making similar but subtle adjustments year by year for a while now.

When they do this, the old versions are never archived, and they do not publically announce what they have done. Instead, the new figures simply replace the old version.

Fortunately, however, Walter Dnes has been archiving the old data each month since January 2010. His results were published at WUWT last week.

I have used his data to show in a simple fashion what the total effect of these changes since 2009 has been.

First, we can look at the changes that have been made to annual data back to 1880. Figure 1 shows, for instance, that the temperature anomaly for 1938 published currently is 0.13C lower than was published in January 2010. In contrast the anomaly for recent years has been increased, for instance 2009 has increased from 0.56C to 0.64C.

Figure 1

The overall effect of these changes has been to cool the 1930’s and 40’s, and increase warming in recent years.

Note as well though the way that the changes have steadily added to temperature anomalies since 1999, thus conveniently removing the pause.

The effect of these recent changes can be seen in more detail in Figure 2. Temperatures have been progressively increased as each year has gone by.

Figure 2

For instance, in their State of the Climate Report for 2010, NOAA showed 2010 and 2005 tying as the warmest years, 0.02C higher than 1998.

http://www.ncdc.noaa.gov/sotc/global/201013

Figure 3

However, the latest version shows that 2010 as being 0.04C warmer than 2005, and 0.06C warmer than 1998.

http://www.ncdc.noaa.gov/cag/time-series/global

Figure 4

But the tampering is even worse than this, as changes were being made prior to Walter Dnes beginning his archiving in 2010. It is difficult to get a handle on the full extent, since NOAA do not archive these things.

We can though see how things changed between 2004 and 2010.

Take another look at the 2010 version in Figure 3. The anomaly for 1998 was 0.60C, 0.06C higher than the figure for 2004.

But when we look at the State of the Climate Report for 2004, we find that 1998 was 0.09C warmer than 2004. In other words, between 2004 and 2010, the temperature for 1998 has been reduced relative to 2004 by 0.03C.

Add that to the 0.06C already identified, and by magic 1998 is now demoted to only the fifth warmest year!

http://www.ncdc.noaa.gov/sotc/global/200413

It is little wonder that, with tampering on this scale, the NOAA dataset has been diverging so drastically from the satellite numbers since 1998.