I think you hit the nail on the head Grz. A problem this huge can never be attributed to a single cause. Is it possible that part of the warming is just a natural cycle? Yes - unfortunately we can't have a control with a second earth with no humans on it to compare our present situation to, but to close your eyes to the worsening state of our globe is not the course people should be taking. Even if global warming is completely part of a natural cycle, the remedies that are being proposed will only be a positive thing for our earth and it's inhabitants.