Chocophiles, rejoice! You may now look forward to a day when scarfing down a Mars bar comes with slightly less guilt.

Earlier this year, the candy bar's eponymous manufacturer, which also produces M&Ms, Snickers, Milky Way, and other chocolate delights, inked a deal with the Rainforest Alliance, promising that all of its cocoa purchases would be certified as sustainably grown by the year 2020. Next year the company's Galaxy bar, a big hit across the pond, will be similarly certified by the alliance. This will allow the confectioner to keep pace with Cadbury, which has shifted to sustainable suppliers for its Dairy Milk bars.

"It's rocking Candyland," says Chris Wille, chief of sustainable agriculture for the alliance, who explains that this is no small endeavor. All of the world's cocoa is grown in the tropics, in places like Ghana, the Ivory Coast, and Ecuador, where poor farmers raze rainforest to plant cocoa trees. Without the shade of the forest canopy, the temperature and erosion rate rise while water becomes scarce. Sustainable cocoa farms leave forests intact, improving growing conditions and preserving habitat and biodiversity.