1. By scattering sulfur powder into the earth's atmosphere, the sun is blocked and the temperature is lowered.

2. Like seawater, a large amount of iron salt is dispersed, which dissolves and absorbs heat to cool down.

3. whimsy means thinking what you want, regardless of the actual effect. You can try to make a super refrigerator, driven by the sun, and then put the earth in it, haha.