http://pajamasmedia.com/blog/climate...inglepage=true

New emails from James Hansen and Reto Ruedy (download PDF here) show that NASA's temperature data
was doubted within NASA itself, and was not independent of CRU's embattled data, as has been
claimed.


March 10, 2010 - by Charlie Martin

Email messages obtained by the Competitive Enterprise Institute via a Freedom of Information Act
request reveal that the climate dataset of NASA's Goddard Institute for Space Studies (GISS) was
considered - by the top climate scientists within NASA itself - to be inferior to the data
maintained by the University of East Anglia Climate Research Unit (CRU).

The NASA scientists also felt that NASA GISS data was inferior to the National Climate Data Center
Global Historical Climate Network (NCDC GHCN) database.

These emails, obtained by Christopher Horner, also show that the NASA GISS dataset was not
independent of CRU data.

Further, all of this information regarding the accuracy and independence of NASA GISS data was
directly communicated to a reporter from USA Today in August 2007.

The reporter never published it.

-------------

There are only four climate datasets available. All global warming study, such as the reports from
the UN Intergovernmental Panel on Climate Change (IPCC), must be based on these four.

They a the NASA GISS dataset, the NCDC GHCN dataset, the CRU dataset, and the Japan
Meteorological Agency dataset.

Following Climategate, when it became known that raw temperature data for CRU's "HADCRU3? climate
dataset had been destroyed, Phil Jones, CRU's former director, said the data loss was not
important - because there were other independent climate datasets available.

But the emails reveal that at least three of the four datasets were not independent, that NASA GISS
was not considered to be accurate, and that these quality issues were known to both top climate
scientists and to the mainstream press.

In a response to reporter Doyle Rice of USA Today, Dr. Reto Ruedy - a senior scientist at NASA -
recommended the following:

Continue using NCDC's data for the U.S. means and Phil Jones' [HADCRU3] data for the global
means. .

We are basically a modeling group and were forced into rudimentary analysis of global observed
data in the 70s and early 80s. .

Now we happily combine NCDC's and Hadley Center data to . evaluate our model results.

This response was extended later the same day by Dr. James Hansen - the head of NASA GISS:

[For] example, we extrapolate station measurements as much as 1200 km. This allows us to include
results for the full Arctic. In 2005 this turned out to be important, as the Arctic had a large
positive temperature anomaly. We thus found 2005 to be the warmest year in the record, while the
British did not and initially NOAA also did not. .

It should be noted that the different groups have cooperated in a very friendly way to try to
understand different conclusions when they arise.

Two implications of these emails: The data to which Phil Jones referred to as "independent" was
not - it was being "corrected" and reused among various climate science groups, and the
independence of the results was no longer assured; and the NASA GISS data was of lower quality than
Jones' embattled CRU data.

The NCDC GHCN dataset mentioned in the Ruedy email has also been called into question by Joe D'Aleo
and Anthony Watts. D'Aleo and Watts showed in a January 2010 report that changes in available
measurement sites and the selection criteria involved in "homogenizing" the GHCN climate data
raised serious questions about the usefulness of that dataset as well.

These three datasets - from NASA GISS, NCDC GHCN, and CRU - are the basis of essentially all
climate study supporting anthropogenic global warming.

Charlie Martin is a Colorado computer scientist and freelance writer. He holds an MS in Computer
Science from Duke University, where he spent six years with the National Biomedical Simulation
Resource, Duke University Medical Center. Find him at http://chasrmartin.com, and on his blog at
http://explorations.chasrmartin.com.