Part of the dramatic rise occurring after the 1970s is a direct response to the clean air / pollution legislation that started getting passed in western countri

Part of the dramatic rise occurring after the 1970s is a direct response to the clean air / pollution legislation that started getting passed in western countries. Pollution seeds the air with potent cloud condensation nuclei, creating a higher average cloud cover, and reflecting more shortwave solar radiation. We've got cleaner healthier air, but less cloudy. I believe there was also a noticeable effect from the pollution decrease when global shipping dropped during covid, you had less cloud cover from ship trails, and more solar radiation reaching the surface. https://www.nature.com/articles/s41586-022-05122-0 https://www.nature.com/articles/s41586-022-05122-0 2022 Nature article on the phenomena.