Science: Are humans to blame for Global Warming?

Is it just bad science that compels astronauts and some fringe scientists to conclude that humanity causes global warming?

Onboard the space station, the canadian astronaut said that "the polar ice caps have melted, and some of the snow is gone." He attributed this to human caused global warming. But, is he just blowing smoke, or do we, as the residents of the planet, have to take some of the blame?

Evidence shows that the Earth is coming out of a global ice age, and sunspot activity is the highest it's ever been, and the volcanos around the Ring of Fire, are pouring billions of tons of Carbon into the air.

Is it folly to imagine that we two legged masters of the Earth can be the cause of the ozone layer depleting, or is it just bad science?

I seem to remember these same scientists as those who were on the Global Freezing bandwagon thirty years ago.

I suppose the next question is, "What do we do about it?" Somehow, I don't think that just taxing a person for driving a car, or breathing, (yes, I can see where this is going,) will fix anything. All it's going to do is a) rake in big bucks for someone to sell pieces of paper with "Carbon Tax Credit" written on it, b) make people feel better about themselves, and c) destroy a vibrant economy that's already reeling on the ground.

If the government was really serious about fixing the problems, they'd mandate that the auto manufacturers have to make cars that run on 80% electricity, 20% something else, or simply say, "You have to make electric cars that travel 800 miles on a charge and can be recharged while moving down the road." If government were really serious about cutting down on smog combustible vehicles, they'd tell BNSF (The railroad through Texas, Oklahoma, etc,) to make some room in it's schedule for passenger trains between the bigger cities. I know I'd ride it between Lubbock, Dallas, Amarillo, etc. I'd rather read a book than drive.

But, the government won't, because they'd rather steal your money and make speeches, than fix the problem.

Or at least, that's how it seems to me.