If you want to be intelligent and scientific about it, you don't have to "believe" anything. You go find the data that actual investigators and scientists have collected. Then you sit down and look at the data, and you SEE what's going on.
When you do this with climate data, you SEE that Earth's climate is changing, in the direction of warmer, more and faster than it ever has before.
When you LOOK at the actual measurements, you SEE what's happening. You don't have to believe anything. You don't have to stand there and listen to anybody who tries to tell you it's fake. You don't have to put up with anybody telling you you're being indoctrinated, or somebody is lying to you. You see the actual measured numbers, and you SEE what's going on.