Why do you get angry at me, when all I do is post what the US National Academy of Sciences say? They say it's a "settled scientific fact".
Is there uncertainty in the science of climate change? Of course there is. Science can never give you a 100%, rock solid guarantee. I've stated that like ten billion times on your board, with respect to climate science. We've studied gravity for 400 years, and nobody has a rock solid, 100%, unimpeachable guarantee for what exactly the causes and mechanisms are of the gravitational force.
Are there alternative theories that explain the current warming trend? Nope. There are no plausible alternative theories. As the US National Science Academy states, the evidence and data are overwhelming. The earth is warming, and it is highly likely that it is due mostly to human activities. It is so well established at this point, that it has moved from a theory, to a settled scientific fact in the eye of the Academy.
Are there guesses, speculation, and hypotheses about other causes of global warming? Without a doubt. Cyber space, rightwing blogs, and editorial columns are replete with guesses and speculations about cooling trends, and how natural variation is causing all this. Is all this guesswork and speculation actual scientific theories? Nope. There hasn't been any plausible, credible, and peer reivewed scientific research that has even come remotely close to explaining the current warming trend, better than the current accepted scientific fact: that humans are very likely, most responsible for the warming