Hmm it sure does (make sense), or are you suggesting that we cannot possibly know anything about the world prior to 1970 if there were no measurements for it then? because that's not the case at all. It's the same way that the Police can prove someone committed a crime even tho no-one else was present, thru evidence (forensics, DNA, etc). The page I linked calls it "Scientific evidence" but it's still evidence. They have been doing weather-related measurements since 1970, but the measurements can go back thousands of years (thru Geology, Archeology, and other fields). It's mentioned on the page. , "Ancient evidence can also be found in tree rings, ocean sediments, coral reefs, and layers of sedimentary rocks" You don't have to have been alive when the tree was young to know things about that time. "Trees contain some of nature's most accurate evidence of the past. Their growth layers, appearing as rings in the cross section of the tree trunk, record evidence of disastrous floods, insect attacks, lightning strikes, and even earthquakes that occurred during the lifespan of the tree. They also hold excellent records of climate." https://scied.ucar.edu/learning-zone/how-climate-works/tree-rings-and-climate