Freedman: 'No one has attempted to rebut how 3 independent centers, JMA, NASA, NOAA all came to same conclusion on surface temps… giant conspiracy!'
Meteorologist Anthony Watts rebuts: 'Andrew, they all use the same base surface data. The Global Historical Climate Network (GHCN) from NOAA’s NCDC...They all agree because they only have one data source. Therefore, they are NOT independent as you claim.'
Climatologist Dr. Roger Pielke Sr. weighs in: 'The raw surface temperature data from which all of the different global surface temperature trend analyses are derived are essentially the same. The best estimate that has been reported is that 90 – 95% of the raw data in each of the analyses is the same (P. Jones, personal communication, 2003). That the analyses produce similar trends should therefore come as no surprise. Indeed, this overlapping of raw data between different analyses of multidecadal surface temperature trends is an issue which has not received adequate scrutiny with respect to the value added of more than one analysis.'