The evidence is in how rapidly glaciers and ice sheets are melting, all over the world. Of course, I can't PROVE any of that - as they say, you can take a horse to water..... Anyone can see that weather patterns have become rather strange lately, especially rainfall.
Actually I don't think it matters whatever anyone believes, because I (and many scientists) believe there's nothing we can do about it that will have any significant effect. Just be careful that as you stand there like the proverbial ostrich with your head in the sand the tide doesn't come in and drown you.