People often don't realize how old the science behind climate change is. There's an excellent discussion at https://history.aip.org/climate/20ctrend.htm#M_35_

People often don't realize how old the science behind climate change is. There's an excellent discussion at https://history.aip.org/climate/20ctrend.htm#M_35_ https://history.aip.org/climate/20ctrend.htm#M_35_ ; quoting from that paragraph: "Returning to old records, in 1986 the group produced the first truly solid and comprehensive global analysis of average surface temperatures, including the vast ocean regions, which most earlier studies had neglected. They confirmed that there had been considerable warming from the late 19th century up to 1940, followed by some regional cooling in the Northern Hemisphere. Global conditions had been roughly level until the mid 1970s. Then the warming had resumed with a vengeance. The warmest three years in the entire 134-year record had all occurred in the 1980s."