I think the argument, and it is a valid one, is the example of "the chicken or the egg". Are CO2 levels rising because the world is getting hotter, or is the world getting hotter because CO2 levels are rising. No one can answer that definitively. I do know that I have been hearing for years that Earth isn't the only planet in the solar system that is warming.
http://www.space.news/2015-10-06-en...eating-up-scientists-blame-solar-warming.html
The question is are we doing damage ourselves, and if so, how bad is it. No one knows. Everyone guesses, even informed ones, but they are still guesses. I remember in college all my Profs (mostly progressives) were convinced that by 2013 the icecaps were going to be gone!
This guy made a fortune of climate change.
Next question is how can we fix it. Well if we can't answer the first question how can we answer the second. My POV is that we should be good stewards of the world we live in and should strive to limit our impact on nature. But I don't think we should up end our economy or handicap ourselves so that we can't compete on a global economy with other countries who could care less and just keep pumping out CO2 while laughing all the way to the bank. I think there are solutions that would limit our output, but honestly America alone will have little to no impact, even if you believe the hard liners.