There is no real debate. The people who actually know the science are largely in agreement about the conclusions. The "debate" being spoke of is faux debate stirred up by people from think tanks funded by oil companies. It's about as meaningful as fundy wackos going on about how there is large debate over the legitimacy over the theory of evolution.
I've known this was bullshit for 20+ years, back when I read an article that predicted sea level rises up to 2 feet, +/- 2 feet. In other words, it may be sooooo bad, the we wouldn't even be able to tell that it's happening! The real problem is anthropogenic continental drift, anyways.
In any formula, constants (especially those obtained from handbooks) are to be treated as variables.