Sebastian Schuster

The study investigates if causal claims based on a theory-of-change approach for impact reporting are credible. The authors use their most recent impact report for a Social Bond to show how theory-based logic models can be used to map the sustainability claims of issuers to quantifiable indicators. A single project family (homeownership loans) is then used as a case study to test the underlying hypotheses of the sustainability claims. By applying Bayes Theorem, evidence for and against the claims is weighted to calculate the degree to which the belief in the claims is warranted. The authors found that only one out of three claims describe a probable cause–effect chain for social benefits from the loans. The other two claims either require more primary data to be corroborated or should be re-defined to link the intervention more closely and robustly with the overarching societal goals. However, all previous reported indicators are below the thresholds of the most conservative estimates for fractions of beneficiaries in the paper at hand. We conclude that the combination of a Theory-of-Change with a Bayesian Analysis is an effective way to test the plausibility of sustainability claims and to mitigate biases. Nevertheless, the method is—in the presented form—also too elaborate and time-consuming for impact reporting in the sustainable finance market.

Recent research on the natural resource use of private consumption suggests a sustainable Material Footprint of 8 tons per capita by 2050 in industrialised countries. We analyse the Material Footprint in Germany from 2015 to 2020 in order to test whether the Material Footprint decreases accordingly. We studied the Material Footprint of 113,559 users of an online footprint calculator and predicted the Material Footprint by seasonally decomposed autoregressive (STL-ARIMA) and exponential smoothing (STL-ETS) algorithms. We find a relatively stable Material Footprint for private consumption. The overall Material Footprint decreased by 0.4% per year between 2015 and 2020 on average. The predictions do not suggest that the Material Footprint of private consumption follows the reduction path of 3.3% per year that will lead to the sustainable consumption of natural resources.

Every diet has an impact on an individual’s health status, the environment, as well as on social concerns. A growing number of meals are consumed in the out-of-home catering sector, in which a systematic sustainability assessment is not part of common practice. In order to close this gap, an instrument was developed as part of the NAHGAST project. After more than one year of using the NAHGAST online tool, it needs to be assessed what positive environmental influences can be realized by using the tool. For this reason, this article deals with the question of whether an online tool can enable stakeholders from the out-of-home consumption sector to revise their meals with regard to aspects of a sustainable diet. In addition, it will be answered how precise recipe revisions of the most popular lunchtime meals influence the material footprint as well as the carbon footprint. In conclusion, an online tool can illustrate individual sustainability paths for stakeholders in the out-of-home consumption sector and enables an independent recipe revision for already existing meals. The results show that even slight changes in recipes could lead to savings of up to a third in carbon footprint as well as in material footprint. In relation to the out-of-home consumption sector, this results in the potential for substantial multiplication effects that will pave the way for the dissemination of sustainable nutrition.