Quite right. Geologist here - I know a lot of folks who study climate and paleoclimate, they know what they're doing. If anything I'd say the evidence is even more solid than most well-informed people realize.

edit: if anyone wants comprehensive data, a good place to start is with the IPCC reports, particularly the "physical science basis" section: http://ipcc.ch/report/ar5/wg1/

This is a few years old now (they're currently working on the "sixth report") but the data was already clear and uncontroversial.