Things are as they are because they were as they were.

I don’t know who first said that but it is an astoundingly accurate expression of a deep philosophical idea in child like English. (Misner, Thorne & Wheeler ascribes this to Thomas Gold.)

Newtonian physics was implicitly founded upon that idea and that new physics illustrated the idea so well that it was adapted to many other realms, often with less success.

Before Newton, Kepler had found his marvelous rules for predicting where the planets would be, but that was taken by most as a God given set of rules and set out especially for the planets. Before Newton

Things were as they were because God fore ordained them so.
There is often confusion between prediction of climate and of weather. Today’s weather is largely due to yesterday’s weather. Our climate 10 years hence depends on many things, but not today’s climate which depends on where the mountains are, which will be as they are now, and it depends on the CO2, which won’t be as it is now.

If we have a model to predict climate from these things we should by all means test the model on today’s climate!