I understand that the people who hand out the Nobel Peace Prize don't necessarily place a great deal of value on the truth. They did give one to Rigoberta Menchu. But, in that case, no one really knew that she had lied in order to serve the truth until after she won the prize.
Al Gore's most prominent contribution to the issue of global warming was to put out a feature length power point called An Inconvenient Truth. Even if you believe that human contribution to climate change is a serious problem that requires a response, it is hard to deny that most inconvenient thing about his movie is that it contains an awful lot of stuff that's not true. An English court recently held that it could not be shown to school children without the correction of multiple inaccuracies. In one of the tastier ironies of contemporary politics, Gore's film which (unscientifically)urges us to shut up about the fact or extent of global warming because of "scientific consensus" departs from that consensus when necessary to make the threat of global warming appear to be more dire than most scientists believe it to be. Gore himself may have admitted this when he said it was appropriate to have an "overrepresentation of factual presentations on how dangerous" global warming is. (Although, in fairness, who know that that means?)
I have a hard time taking people who gave Yassir Arafat a peace prize seriously, but there is still some value in the Nobel brand. Is the committee endorsing truthiness? Is it telling us that exaggeration in a "good cause" is to be commended? Is it saying that, yes, Virginia there really is a ManBearPig.