Not quite. And that's because the GCM's don't properly account for natural variations in climate. What we do know that for every doubling of CO2 levels we will see about 1C of warming, other things being equal. Problem is - other things don't remain equal. Solar activity, oceans, cosmic rays, tectonic shifts, volcanoes, earth's axial tilt, cloud cover, albedo. They all play a factor in short and long term climate fluctuations. And they are not modelled because we don't know enough about their behavior.