Wikipedia has been uniformly denounced as a non-reputable source for discussions on science of any kind, let alone discussions in this Earth sciences forum. Here is a nice little graph from Wikipedia showing an apparent strong correlation between global temperature and atmospheric CO2 concentration: So if Wikipedia is a disreputable source, why did I use it as a source in this post? The reason: The United Nations Environment Programme used this very image in its "Climate Change Science Compendium 2009" report. See figure 1.3 on page 5 of the report, with attribution "Hanno 2009". McMullen, C.P. and Jabbour, J. (2009). Climate Change Science Compendium 2009. United Nations Environment Programme, Nairobi, EarthPrint. http://www.unep.org/compendium2009/PDF/compendium2009.pdf [Broken] At least the authors of this compendium could have been honest and cited the source as Wikipedia. http://commons.wikimedia.org/wiki/File:CO2-Temp.png Source: graph drawn by Hanno using data from different sources With junk like this, is it any surprise that people question the science behind AGW?