This paper builds on four qualitative backcasting scenarios that illustrate sustainable futures in a Swedish setting. The paper complements the originally qualitative scenarios by developing an eight‐step modified and expanded IPAT model—originally describing environmental impact as a product of population, affluence, and technology—that also enables quantitative descriptions of the scenarios. The modified and expanded IPAT model is used to show how the scenarios can stay within the climate aspect of sustainability. The result is quantified descriptions of the development paths of energyrelated carbon dioxide emissions, working hours, man‐made capital stocks, recycled and nonrecycled materials used, and different types of energy used in the four scenarios. The four main findings are (a) the back‐bone instrument in making the energy system fossilfree will, in all scenarios, substitute fossil energy with renewable energy; (b) however, to succeed with that it is necessary to use different mixes of many complementary climate policy instruments; (c) IPAT models can be modified and expanded in many different ways to act as quantitative descriptions of different technological developments and social changes in scenario exercises; (d) by disregarding gross domestic product as a proxy for affluence, and replacing it with labor and capital, behavioral concepts like sharing and prolonged product lifetimes can more easily be introduced as climate policy options in a modified and expanded IPAT model.