Nature is a source of solutions to many of the pressing challenges of development, from food security to climate change. Illustrations of this claim are increasing around the world, and the figures supporting it are now beyond dispute; they demonstrate just how closely dependent our societies are on nature and natural resources. Development actors – both international development aid organizations and donor governments – and nature conservation bodies have, however, not yet managed to find the right common denominator to link environmental issues definitively and irreversibly with those of human development. These two communities must redouble their joint efforts in the immediate future, in order to save nature and mankind.