The above graph shows the revision of the RSS-MSU temperature history. Blue shades signify upward corrections and dark yellow shades signify downward corrections, resulting in an overall decrease of global warming from 0.169 to 0.159° per decade.

 Temperature graphs of various metrics draw closer together. Until 2003 they were “all over the place” (see “reasononline”). After correction in 2003, John Christy” stated in an e-mail to “reasononline” dryly: “The previous linear extrapolation indicated a temperature of +0.9 C +/- 0.5 C in 2100, the new data indicate a temperature of +1.2 +/- 0.5 C.” This was consistent with 0.12 C warming per decade at that time. At the same time, RSS made upward corrections on their own. But “reasononline” continued: “However, the Remote Sensing Systems team has made some additional adjustments, such that their global trend is 0.193 degrees per decade. Christy and Spencer disagree with those additional RSS adjustments, but acknowledge that it’s an open scientific question which team is correct.”

This open scientific question led Mears et al., 2003 to publicly rebuke the Spencer and Christy version and performed trends for a seperate “channel” (in 4000 – 7000 m altitude) which they claimed to reconfirm their earlier findings.

Five years later, the two satellite units seemed to continue to work at cross purposes. But now it was the turn for Carl Mears and Frank Wentz at Remote Sensing Systems to take a step back and to adjust their exaggerated RSS warming history downward. Below listed are the new curve fits per decade for the temperature records as of October 2008:

Satellites:
UAH + 0.127/decade (unchanged)
RSS + 0.159/decade (old + 0.169)

Surfaces:
Giss + 0.161/dec.
HadCrut3 + 0.16/dec.
NCDC + 1.627/dec.

New averaged 100-year extrapolation October 2008: + 1.54°C after 100 years, if warming remains akin to the last 30 years. Please find below the newly adjusted, superimposed temperature graph. I included the major volcanos for reference. According to the new curve fits, the two satellite records tend to be more in line with each other and less in line with surface stations.

The above graph is updated November 17 and thus includes the outcome of the recent brouhaha around the release of flawed October data by Giss (5th-warmest, not the warmest October).