These bars are the joint venture of Bloomsberry & Co., a chocolate producer in Salem, Mass., and TerraPass, a foundation that works for greenhouse-gas reduction. When you buy a bar, you not only treat yourself to a nice dessert, but TerraPass will match your purchase with one of their own — they buy 133 pounds of carbon emissions credits for every bar sold. That’s a pretty sweet trade, no matter how you slice it. The wrappers also contain 15 easy tips for reducing your carbon footprint in other enjoyable ways — a nice reminder that doing the right thing doesn’t have to hurt. About $5.50 a bar at Whole Foods. Learn more at www.bloomsberry.com or www.terrapass.com.