The problem with climate science is that it's so difficult.
No, it is actually VERY VERY SIMPLE.
1. To show that CO2 has an effect on heat, get two glass jars. One filled with CO2, and one filled with air. Shine an infared lamp (or even just sunlight) on both jars. You can measure that the CO2 jar absorbs more heat, because it's hotter than the air jar. This principle has been known and well-understood for over 100 years, and you can demonstrate this in an elementary-school classroom.
2. To show that human industrial activity releases a shitton (ie. enough to affect the whole world's climate) is also relatively simple. Get in a plane, and fly over the Los Angeles basin. Just look at the carpet of constantly running automobiles, as far as the eye can see across many hundreds and hundreds of square miles. Wrap your brain around this happening 24x7, week after week, month after month
These two simple observations are obvious and plain enough that it affected me on a gut-level. No math required. It's plain and obvious. Not at all subtle.
Now: to observe the actual effects on the world, is not so easy. One way is to look at photos, over decades, of glaciers that have receded. If you've been alive for 30+ years (or longer), you know damn well that even though we've had a couple of harsh winters, it's certainly not like it was when we were kids. If you ask older people, they can tell you that things have definitely changed. But this effect is subtle enough that even the very old people who remember Minnesota winters 70 years ago, don't seem to be able to grasp how very different the climate there is now.