This “history” was never peer reviewed. It was sent around via e‐mail by NCDC, which explained, “Our methodology was not documented in the open refereed literature. This [memorandum] is an attempt to provide that documentation.”
Sending an e‐mail to everyone is not quite the same as peer review.
Nor was this history a record of global temperature after all. Instead, according to NCDC, it is an “index” that combines three different measures, kind of like putting fruit salad in a blender.
The three measures were land surface temperatures, which by definition are hardly global; sea surface temperatures taken from ships; and data from a network of buoys whose deployment was begun in the mid‐1980s. The last two measurements are very different from the first, and in order to create the desired fruit salad, NCDC adjusted the sea surface temperature data up by 25 percent after 1982. That certainly might make things appear to be a bit warmer in recent years!
In point of fact, the sea surface temperature data are increasingly at odds with air temperatures taken over the ocean. No one knows the reason for this, but the air temperatures just happen to match up perfectly with those recorded by NASA’s satellites, which happen to match up perfectly with the Weather Bureau’s (what it was called before it became a “service”) weather balloons. None of those records shows a lick of global warming in the last 20 years.
Parenthetically, we might note that recent reports about the satellite data being in error are themselves in error. Annual temperature averages taken by weather balloons look exactly like those measured by the satellites. So the satellite cannot be wrong unless, somehow, thermometers in the 1,125,000 weather balloons launched over the last 20 years have been making exactly the same mistakes in temperature measurement as the satellites.
In order to reassure all the recipients of their e‐mail that their new blended‐index approach was a good idea, NCDC observed that the three records jammed together looked an awful lot like NASA scientist James Hansen’s global temperature history. “The match is very good,” they wrote. But the Hansen history does not remove the effect of urban warming, which is known to bias global temperatures by about 0.2 degree. No wonder it’s so hot.
So NCDC had a choice: Either use sea surface temperature data that disagree with marine air temperatures and data from satellites and weather balloons, or use one of those three mutually agreeable records that all show no warming. Guess which choice they made for “busy elected officials”?
This isn’t temperature measurement, it’s hot air.