Look, I have the greatest respect for Freeman Dyson.
But just because you know very much about a certain thing does not mean that you know very much about certain other things. Just because you are fairly certain about the things you know very much about doesn't mean your certainty is automatically transferred to things of which you know very little.
To put it simply: You know about as much as I do about climate science. You even admit your lack of knowledge.
But then you rationalize your bullshit contrary opinion with the notion of climate scientists who never go outside, never take real measurements, and somehow work only with computer models. Climate science is not wholly done by simulation-only shut-ins. Even fucking weathermen look out the window and use barometers and thermometers and all kinds of real world science.
Climate scientists correlate much more data on a much larger scale. This isn't rocket science or advanced physics. It's basic knowledge about a very general field of scientists studying our actual physical world using actual physical data. They don't sit around and say, "Hey, it's warm out, must be global warming."
That kind of sloppy thinking is pretty much confined to mush-headed corporate apologists and disingenuous fundamentalists: "If there's global warming then how come it's so cold outside right now?"
In other words, Freeman Dyson is very intelligent, but that doesn't mean he isn't acting like a moron.