Read here. Not only has the IPCC flagrantly reported false science in its reports, it has also been the purveyor of incredibly, wrong-way predictions about the climate. Why are the IPCC's climate models so awfully bad at climate predictions?
Well, the real scientists keep doing the needed grunt research, which includes the discovery that the ocean current conveyor system is entirely different than what the IPCC climate models assumed.
When a mistake of this magnitude is made, it is safe to conclude that any previous IPCC climate report predictions had no basis in reality. Indeed, garbage input definitely ends up producing garbage output; a truism that the IPCC constantly lives up to.
"That seems all well and good, except the MOC [Meridional Overturning Circulation] is not following the IPCC script. As the paper by Dr. Willis shows, there has been no slowdown over the past 7 years and probably none over the past 20 years, years during which global temperatures are purported to have risen significantly...The conveyor belt doesn't work as scientists thought and that has implications for global heat transfer, and hence climate, over time. Now it would appear that discrepancy was only the beginning and climate science has once again gotten the conveyor belt currents wrong...This shows the weakness of the science behind climate change. The predictions of future climate change are based on current understanding of how climate works—the theory. And the theory is based on observations of climate behavior in the past—the data. Except that the data regarding fluctuations in the MOC were spotty and incomplete. Now, with better data it looks like the theory is wrong. This in turn, means that all existing models are based on incorrect assumptions and may also have been calibrated using erroneous historical data. Yet predictions of future disaster generated by these models form the heart of the climate change alarmists' case for radical socioeconomic change."