Furthermore the vast majority of IR in the susceptible band is produced by re-radiation of energy that was visible light hitting an object on earths surface being absorbed and re-radiated in the IR spectrum..... the albedo of the earths surface is a major player in this. Land use changes driven by population change albedo both locally and globally hence influencing how much susceptible IR is produced plus global cloud cover during daylight hours is not really tracked until very recently
We have no idea what earth albedo was doing from 1850 until albedo measurement started to be a thing around 2010
Climate science is still like an infant crawling certainly not mature or "settled" ...
For a time NASA looked at the brightness of the lunar surface in the new moon period which gave a tiny bit of data when the moon was actually visible in that phase. See earthshine project.
