The Climate Research Unit at East Anglia University is responsible for gathering data from weather stations around the world. They collect, correlate and “adjust” it, ostensibly to account for different measurement methods. The scientists there also play the largest role in issuing the IPCC reports, including the infamous and ultimately discredited “hockey stick.” Part of the reason you may have difficulty finding an authoritative source for temperature information is that the CRU just admitted that they destroyed all of their raw (unadjusted) data. http://www.timesonline.co.uk/tol/news/environment/article6936328.ece
Some of the internal correspondence between these “scientists” at the East Anglia Climate Research Unit was just released and it was revealed that there was widespread destruction of information subject to freedom of information requests along with evidence of everything from tax fraud to attempts to stack peer review journals with friendly faces and control the outcome of the debate. They couldn’t even reproduce their own results, using their own adjusted data run through their own computer programs. So in short… we have no way to know one way or the other which years are warmest and it is doubtful such a measure would have an agreed upon meaning anyway. Which measuring stations will you use? Do you use satellite, thermometer or proxy data? Do you use sea temperatures, or atmospheric, or land measurements and how do you combine the different types etc… The hockey stick for instance was the result of cherry picking from amongst a set of proxy data (tree rings). Not only was the data cherry picked from this subset but it was then arbitrarily combined with an entirely different set of measurements to generate the uptick at the end we are so familiar with.
BTW, the notes from the programmer in charge of trying to reproduce what has been published in peer review journals are quite funny. The guy was literally pulling out his hair and eventually had to give up the effort.
Not to overstate the case but when you have putative scientists who refuse to release their data and describe their methods so that their results can be reproduced and on top of that you have widespread destruction of the original readings you aren’t really dealing with science. That is not to take sides in any debate just to state the facts as currently known. If warming is occurring it would be nice to know but it is hard to find a reliable source on which to make any claims at all. This problem is not contained to just the CRU. Similar problems exist with researchers in New Zealand and elsewhere for instance. They apparently adjusted their data upwards as well and have yet to release a full explanation as to why. Then this data was sent to the CRU and adjusted yet again.
Phil Jones, one of the alleged conspirators at the CRU sums up his view when responding to a fellow scientist’s request for data in one of the e-mails thusly;
Such a response is the very essence of the scientific method is it not?