Global Warming Questions

Given the quantity and quality of scientists who say global warming is happening, and the shrinking voices of those who say it is not, I tend to believe that global warming is in fact happening. There is some contention, however, as to whether it is caused by human activity. There is a strong correlation between the rise in the levels of man-made CO2, and the rise in temperatures which heavily implicates human activity, but a correlation is not proof. This is where the global warming deniers step in. they say that the increase in solar radiation over the past few years is responsible for the warming, and that the rise in temperature is causing the rise in CO2 in the atmosphere rather than the other way around, or that there is some other reason for the correlation. I personally find this to be far fetched, because if the rise in CO2 is a result of higher temperatures, then you have to have to believe that the majority of the rise in CO2 in the atmosphere is not the result of human activity. If that's the case what else could have caused this? The deniers like to point out that more CO2 comes from volcano explosions than from industry, but have there really been that many more volcanic activity in the last 150 years that would explain why the levels of CO2 are so much higher than they were over the previous centuries?

We know that more greenhouse gases theoretically causes an increase in temperature. We know that human being have been producing a lot of greenhouse gases.

Is it really all that far fetched to believe that humans are causing this increase in temperature?

That being said, I think some of the things that environmentalists are saying are a little far fetched. Some would like you to think that this spells the end of life on Earth, or for the more restrained ones, the end of civilization. Now, come on. Sure, with all of the areas that would be flooded it would create a huge refuge problem that would cause severe worldwide economic problems, but would that really result in the collapse of civilization? And would the effects of global warming accumulate so quickly that we couldn't adjust to the changes in time?