The Boston Globe: Speech codes are rare in the industrialized, Western democracies. In Germany and Austria, for instance, it is forbidden to proselytize Nazi ideology or trivialize the Holocaust. Given those countries’ recent histories, that is a restraint on free expression we can live with.More curious are our own taboos on the subject of global warming. I sat in a roomful of journalists 10 years ago while Stanford climatologist Stephen Schneider lectured us on a big problem in our profession: soliciting opposing points of view. In the debate over climate change, Schneider said, there simply was no legitimate opposing view to the scientific consensus that man - made carbon emissions drive global warming. To suggest or report otherwise, he said, was irresponsible.