wait a minute, slow down, the debate is not about whether global warming is real - the fact that global mean surface temperartures have been rising for a century is incontrovertable.
The debate is about what causes the rise in temp., and whether that cause is natural or man-made. So don't imply that the Northwest passage opens up each Spring - it doesn't. This is truly and astonishing development. Now that the fact of global warming is once again proven beyond any reasonable doubt, the question is do we need to do anything about it, or is this something we should learn to deal with because it is a completely natural phenomena.
"Incontrovertable", you say? Oh, reeeeeeeeeeeeeeeeeeeeeeeaaaaaaaaaaaaaaaaaaally?
Earth to clamboat: It's HUGELY "controvertable", my friend.
I suggest you keep up with current events and give up that ridiculous Sierra Club membership. They'll rot your brain with "pseudo-science".