Science Ph.D. to a sociological post-doc? I am finishing up my phd, with a heavy climate change/plant physiology/molecular focus. Would it be possible to now enter a more sociological post-doc (e.g. connection between economic models and climate change, or gender vs. climate change, etc.)? How disparate can your phd and postdoc be when your phd is in a hard science?

My goal after my postdoc is a teaching position at a liberal arts college focusing both on hard science, and sociology if at all possible. 

Any advice is greatly appreciated!
The only issue is finding a post doc that will accept you. That is up to them, of course. You will need to sell yourself and whatever skills you have. Some department that is happy about cross-disciplinary studies would be a good place to look. 

Another possibility is to use a more science-y post doc and use the time and contacts to develop more of the skills used in sociology, though I'd guess that you are pretty familiar with statistical based research already. 

The next issue would be to find a liberal arts college that wants those skills. Again, one that values cross disciplinary studies would be good. Many top places will put value on that. Again, you could start heavily committed to one of your skill areas and gradually move to a wider base through your research and taking advantage of teaching opportunities. 

In general, though, I'd say it is do-able, but will take both a wide search for positions and a good way to present yourself to advantage in each case. 

Finally, develop a wide circle of collaborators who can help you meld and move between the areas.