In this chapter, we provide with a brief historical overview of the encounter between design and the global environment in the Anthropocene, investigating the moment when the traditional figures of conception (namely the engineer and the architect) merged under the single term "design". We then offer a philosophical inquiry into the meaning of design today, and the crucial role of designers next to engineers. We more particularly look at the issue of scales (space scale and time scale) in the context of the ecological crisis, and at the significance and the usefulness of an approach in terms of the "milieu" rather than of the environment. We show that the articulation of global and local is possible, as is possible a transition both digital and ecological, and that the important distinction is not between global and local design, but between two ideas of eco-design.