Wasn't the Nasa data shown to be a little less than reliable recently?
I can find the thread if you like, but I'm sure you know the one I mean - the one where NASA themselves admitted that their data was a little inaccurate.
< < diplomatic mode...


A panel of statisticians chaired by Edward J. Wegman, of George Mason University, found significant problems with the methods of statistical analysis used by the researchers and with the IPCC's peer review process. For example, the researchers who created the hockey stick used the wrong time scale to establish the mean temperature to compare with recorded temperatures of the last century. Because the mean temperature was low, the recent temperature rise seemed unusual and dramatic. This error was not discovered in part because statisticians were never consulted.
The IPCC published its Fourth Assessment Report in 2007 predicting global warming will lead to widespread catastrophe if not mitigated, yet failed to provide the most basic requirement for effective climate policy: accurate temperature statistics. A number of weaknesses in the measurements include the fact temperatures aren't recorded from large areas of the Earth's surface and many weather stations once in undeveloped areas are now surrounded by buildings, parking lots and other heat-trapping structures resulting in an urban-heat-island effect.
Even using accurate temperature data, sound forecasting methods are required to predict climate change. Over time, forecasting researchers have compiled 140 principles that can be applied to a broad range of disciplines, including science, sociology, economics and politics.
In a recent NCPA study, Kesten Green and J. Scott Armstrong used these principles to audit the climate forecasts in the Fourth Assessment Report. Messrs. Green and Armstrong found the IPCC clearly violated 60 of the 127 principles relevant in assessing the IPCC predictions. Indeed, it could only be clearly established that the IPCC followed 17 of the more than 127 forecasting principles critical to making sound predictions.
A good example of a principle clearly violated is "Make sure forecasts are independent of politics." Politics shapes the IPCC from beginning to end. Legislators, policymakers and/or diplomatic appointees select (or approve) the scientists — at least the lead scientists — who make up the IPCC. In addition, the summary and the final draft of the IPCC's Fourth Assessment Report was written in collaboration with political appointees and subject to their approval.