Gore is doing his power point, which anyone who has seen his movie will know very well. It appears that most Senators are actually staying to watch: which has to be a surprise.
The problem with Gore is that he is too alarmist. He cherry-picks the scientific evidence from the worst-case scenarios. It almost makes it sound like such a huge problem, and that there's nothing we can do about it.
Personally, for public-relations issues, I would prefer we look at the (very real) short-term problems (migration, drought, famine, etc.) instead of the truly apocalyptic view that Gore puts forward.