Nothing New on IPCC Claim to Devastating Climate Change

A forthcoming UN report will warn.that climate change will displace hundreds of millions of people by the end of this century, increasing the risk of violent conflict and wiping trillions of dollars off the global economy.
So what's new? The UN’s Intergovernmental Panel on Climate Change has been saying this for years without any logical basis for their predictions. It's in the same category as fortune-telling.
As an analogy, I can predict that the moon will move out of its orbit and collide with the earth with the complete devastation of mankind, but I have no justification for that prediction. Neither does the IPCC in their prediction of climate change devastation.
We know from archaeological data that there have been climate extremes during the history of the earth, but mankind has been able to live through it. Climate change will continue to exist, and an increase in global warming may occur. This is basically no different than what occurs in short-term weather changes, and the need for preparation to minimize disastrous effects. However, a little common sense is also necessary in deciding the likelihood of disastrous effects coming to pass and how much preparation might be justified. Up to now, the IPCC has ignored those considerations. It merely says something equivalent to we better get ready for the collision of the moon with the earth.