"The fact is that we can't account for the lack of warming at the moment and it is a travesty that we can't," said Kevin Trenberth, one of the world's preeminent climate scientists and lead author of the 2001 and 2007 IPCC reports.
Trenberth's statement is compelling on its own, but the subsequent discussion is even more illuminating. Later in the same e-mail thread, fellow climate scientist Tom Wigley replies that he does not agree with Trenberth's assertion. Trenberth then responds to Wigley, clarifying and expounding upon his earlier claims: "How come you do not agree with a statement that says we are no where close to knowing where energy is going or whether clouds are changing to make the planet brighter. We are not close to balancing the energy budget. The fact that we can not account for what is happening in the climate system makes any consideration of geoengineering quite hopeless as we will never be able to tell if it is successful or not! It is a travesty!"Read more at the link above