On 12 May 2025, we welcomed a particularly exciting lecture by Guillaume Delafosse from the Centre d'Economie de Paris-Saclay (ENS Paris-Saclay) as part of our PARSEC BrownBags. Under the title "Growth or Degrowth? An Inquiry into a Directed Technical Change and the Environment Model", the lecture was dedicated to a highly topical and controversially discussed question of ecological economics: Is sustainable growth even possible under the given environmental limits - or is there no way around targeted shrinkage ("degrowth")?
The presentation centred on a critical examination of the "Directed Technical Change and the Environment" model by Acemoglu et al. (2012), which often serves as the theoretical basis for green growth. Delafosse presented two extensions of this model, in which he took into account the influence of finite resources and the lack of so-called "backstop" technologies (i.e. indefinitely available alternatives such as CO₂ storage or fusion energy), among other things.
The question of whether technological innovation alone is sufficient to enable sustainable growth or whether there are structural limits that make a rethink towards degrowth necessary was discussed in particular. In a scenario, it was shown that with realistic assumptions about resource utilisation and substitution possibilities, a permanent economic decline can be a necessary component of climate policy strategies.
The presentation was rounded off with an exciting discussion.
