How am I supposed to know?

[Mr Khan]

Immortal said:

@Mr Khan, while you're offering me the answer - scientists are trustworthy (for hard sciences) - on a silver platter, I'm not sure why I should trust you on this. What if my local churchman says that he's trustworthy and that he's not biased? What to do then?

I mean, we could get up into some ol' post-positivist shit here, but largely empirical facts are empirical facts. You can look up the experiments, you can (if you have the means) replicate them. It requires you to get informed about things, certainly, but as far as some of the more controversial parts of science goes, that isn't too hard. Learn what has impacted, say, earth's temperature in the past to learn whether you think the arguments for anthropocentric global warming seem to pass muster, or look into theories on natural selection and genetics.

Especially in the modern days of the internet, it's easy to find these things and see them explained in relatively easy ways to follow.