Are these solar terms relative to the northern hemisphere, China or the world?

This is for the whole world! Hehe, I used to have this question in junior high school! But now I am engaged in geography! These will all be solved! I can tell you very responsibly! Because summer solstice and winter solstice solar terms are named by people in the northern hemisphere! It will become a rule in the future! It will be used around the world! Hope to adopt and give favorable comments!