This paper reviews the current status of the debate about concept of environmental sustainability, and mentions its related aspects of growth, limits, scale and substitutability. The paper suggests that ES is a clear concept and that it is universal and rigorous. While the many paths leading to ES in each country or sector will differ, the goal remains constant. ES is contrasted from social and economic sustainability, because the three types of sustainability follow different laws and require different means by (...) different disciplines to achieve each of them. ES is fundamental for survival of humanity; but ES without some measure of social sustainability will not be very attractive. The three now need to be integrated.This conceptualisation is far from an academic exercise. The monumental challenge of ensuring that possibly ten billion people are decently fed and housed within less than two human generations—without damaging the environment on which we all depend—means that the goal of environmental sustainability must be reached as soon as humanly possible. (shrink)