Skeptical Science is a good source for understanding the common arguments you see.
If you're more interested in the actual science, the IPCC reports are a bit dry and a bit conservative, but might be worth a glance. Read the summaries first.
The paper that convinced me is 18 years old, but if you're interested in the science might be the keystone. It is External Control of 20th
Century Temperature by
Natural and Anthropogenic
Forcings.
More seriously you could look at some coursera courses.
A for-instance is changes in the arctic that you can get on for free: but there's a metric shitload of related courses there.