For a falsifiable experiment, see Lindzen &#38; Choi.<p><a href="http://motls.blogspot.com/2009/11/spencer-on-lindzen-choi.html" rel="nofollow">http://motls.blogspot.com/2009/11/spencer-on-lindzen-choi.ht...</a><p>In essence, all the input to the IPCC climate models assume a negative relationship between outgoing radiation and temperature increases, while observational data indicates that the relationship is in fact opposite. This basically the opposite of what the greenhouse effect is believed to do.