Tracing TRACE #1: How Effective Are Climate Policies? It Depends.
Picture: OECD (2025), The effects of climate policies on emissions – evidence from a comprehensive and systematic review of the ex-post empirical literature, Inclusive Forum on Carbon Mitigation Approaches Papers, OECD Publishing, Paris. Licensed under CC BY 4.0. https://creativecommons.org/licenses/by/4.0/
We are currently developing a self-reflection tool for students at TRACE. On the one hand, this tool is intended to give us more insight into where young people see themselves in the context of climate agency, in other words, how they perceive their ability to contribute to climate action individually and collectively. On the other hand, it is intended for use in the classroom. Students will be able to access the tool through our website, complete the questionnaire online, see their results displayed immediately, can compare them with aggregated results from all other participants, and discuss the questions and ideas raised about climate agency in class together.
One aspect we wanted to include in the tool seemed straightforward at first: asking young people to estimate the greenhouse gas emission potential of various policy measures. But it’s not that simple, as a closer look at the available data shows. The calculations from various studies for different policy measures appear to vary widely (see Figures 8–11 in OECD, 2025). These wide variations make it difficult to identify clear differences between policy measures. For example, carbon tax is in the transport and power sectors, on average, the most effective measure. Yet, the variation across studies vary so widely (e.g., due to the variety of power plants considered or differences between countries and policy contexts examined) that no clear distinction can currently be determined between carbon taxes and other instruments such as emissions trading systems. In contrast, evidence for private-sphere mitigation measures appears to be more consistent. A meta-analysis by Diana Ivanova et al. (2020), for example, shows comparatively clear differences between actions, such as the greater mitigation potential of avoiding fossil fuel cars compared to adopting a seasonal diet (see Figure 7 in Ivanova et al., 2020).
Of course, policy measures remain indispensable for effective climate mitigation. But our work on the tool reminded us that the effectiveness of climate action is often context-dependent, methodologically complex, and not always easy to communicate in simplified ways.
For climate education, this raises an important challenge: How can we support young people in understanding the importance of structural and policy measures, even when their mitigation potential is complex, context-dependent, and difficult to compare directly?
These questions are currently informing the further development of the TRACE reflection tool. In the upcoming pilot phase, we aim to explore how young people engage with different forms of climate agency and how complex evidence about mitigation effectiveness can be meaningfully discussed in educational settings.
If you know of any relevant studies or data sources that could support this work, we would be very happy to hear from you: contact@trace-climate-education.eu.
References:
- OECD (2025). The effects of climate policies on emissions – evidence from a comprehensive and systematic review of the ex-post empirical literature. Inclusive Forum on Carbon Mitigation Approaches Papers, OECD Publishing, Paris.
- Ivanova, D., Barrett, J., Wiedenhofer, D., Macura, B., Callaghan, M., & Creutzig, F. (2020). Quantifying the potential for climate change mitigation of consumption options. Environmental Research Letters, 15(9), 093001.