Climate Change <!> Man-Made
So we've been here for what, seven seconds in a 24-hour "life of the Earth" anology, and producing significant amounts of carbon for much, much less than 5% of that (hell, it's only really been the last what, 150 years out of over three THOUSAND!) so unless dinosaurs had a much more advanced society than is currently believed, there should be little doubt that the climate goes in cycles.
Archeological evidence PROVES this by having semi-regular layers made from the remains of plants, animals etc - if you get rocks associated with glaciers every hundred thousand "layers", you can bet there's a fairly regular cycle there. If you can work out how old each layer is (carbon-14 dating etc) then you can get a pretty good idea of the cycle time too. This is "known" because lots of different groups have INDIVIDUALLY tested the evidence and reached the same conclusions - repeated testing and validation being the old "Scientific Method" I was taught at school.
The "Climate Change is all our fault and we should stop doing anything at all" brigade, on the other hand, seem to have gone back to the older religious version of Scientific Method where the truth is whatever they say it is, and woe betide anyone who dares to say different.
Remember the Cold Fusion controversy? One team claims to have produced cold fusion but then nobody else can replicate their results, so obviously they are wrong. But someone takes data NASA has admitted is possibly a little, um, flawed (as in "We don't have accurate data so we'll just make it up and hope nobody notices...") and then creatively interprets it using his own formulae, then manages to "lose" the data and the way he fiddled the figures, sorry, worked out his easily demonstratable method of taking raw data and getting "proof" that just happens to further his own ends, when told to do so by a court of law.
If humaniti were really the sole cause of climate change then there would be no real difference between the various strata from the first thin crust to the current layer of frozen magma we dwell on.
Yes, we can make a difference - but it's the sort of difference made by a bug to the speed of your car as it squashes itself on your windshield. A far better reason to save energy is that the resources we have (comparatively) easy access to are going to run out eventually. Not only that, but the more energy you "save" means you don't need to waste money on, say heating your house or filling your car fueltank. (On a related topic, ever noticed how the more energy we save by, say, insulating our homes and buying more fuel-efficient cars, the more the energy compaines charge so they keep their profits??)
Yes, the climate is changing, but then we live on a planet that is one of the most complex system of interactions imaginable. IF the green meanies were right, then it would not matter how much we reduce our "carbon footprint" since the damage to the biosphere has already occurred and the change has started - there is no way to reverse it, no matter how hard you try. It's not like a conveyor belt - you can't turn turn the motor off and it stops running - "Climate Change" is happening and there is nothing you can do about it now.
A far better question is to ask who benefits most from the whole "man-made climate change" theory? The energy companies do as they can charge us more for each watt we use. The "environmental lobby" does since it gives them their fifteen muinutes of fame (would anyone still remember Al Gore if he'd just kept his mouth shut like most 'failed' US political candidates?) The scientific world does since it gives so many of them reasons to apply for funding. The media does since it gives them an endless stream of horror stories (exactly HOW did Climate Change cause the tsunami and earthquakes around the south Pacific last week?) to peddle to the masses. The State does because it gives a reason to limit where and when the public can travel, and who they are allowed to talk to when they get there...
We've reached the top of the first incline on the "Cool Earth" roller-coaster. The balance has shifted (maybe a few years earlier than if we hadn't started burning fossil fuels, maybe a few - like 50!- thousand years late on the Ice Age cycle) and we are now on the drop to the first corner.
Sit back and enjoy the ride. It's too damn late to get off.