If you're curious to learn more about this, I really strongly recommend reading the latest IPCC Assessment Report Summary for Policymakers[1]. It's a pretty easy read, will take an hour or two, and you'll come out the other side with a really good understanding of the fundamentals.
[1] Here's the latest, from AR5 in 2014. It's a little out of date, but it holds up fine as an introduction (mostly what's new since then is "we've done nothing, so things are now even worse"). AR6 is due out in 2022. https://www.ipcc.ch/site/assets/uploads/2018/02/AR5_SYR_FINA... (3.5 MB)
[1] Here's the latest, from AR5 in 2014. It's a little out of date, but it holds up fine as an introduction (mostly what's new since then is "we've done nothing, so things are now even worse"). AR6 is due out in 2022. https://www.ipcc.ch/site/assets/uploads/2018/02/AR5_SYR_FINA... (3.5 MB)