Nicolas Alaux (2025): Identification of Future Trajectories for Carbon Budget Compliant Buildings: An Austrian Perspective, 1st reviewer: Alexander Passer, 2nd reviewer: Bernhard Steubing, 3rd reviewer: Guillaume Habert
In order to fight climate change, a rapid and sustained reduction in greenhouse gas emissions is imperative, particularly carbon dioxide (CO2). As global warming depends directly on the cumulative sum of emissions released, it is possible to calculate the maximum amount of CO2 that can still be emitted worldwide in order to keep the increase in temperature within the limited range of 1.5–2 °C. The building sector plays a central role in this, accounting for around 37 percent of global CO2 emissions. This dissertation examines how Austria’s building stock can reduce its emissions in line with these figures between 2023 and 2050.
To this end, a model has been developed that maps the building stock throughout its entire life cycle—from construction and use to dismantling—combining a dynamic material flow analysis with a prospective life cycle assessment. A review of pertinent publications informed the identification of strategies and influencing factors, after which their interactions were analyzed and integrated into scenarios. In 2023, building stock generated around 30 million tons of CO2 equivalents, 73 percent of which was attributable to their operation. Of the ten strategies identified for reducing emissions, particular importance is assigned to those relating to the development of living space and population size, on the one hand, and to the use of renewable energies, on the other. Four scenarios illustrate possible paths for reducing cumulative emissions by 28 to 47 percent, in line with the 2 °C target—provided that ambitious technical and social changes are implemented.
