I've heard that the production and import of chocolate has some consequences including deforestation, excessive use of pesticides and CO2 emissions. There are also concerns about exploitation of workers. And that's all before even considering milk chocolate, where animal agriculture (especially dairy cows) is known to have its own environmental impact.
If I am going to be purchasing chocolate, how can I choose the most sustainable? Ideally I'm looking for advice on picking the best ingredient composition and understanding the relative value of different labels. My priorities (in order) are forest-effects (land use change), fair labour practices, and CO2 emissions.