Assessing feasibility concerns in climate mitigation scenarios

What drives the feasibility of climate scenarios commonly reviewed by organizations like the Intergovernmental Panel on Climate Change (IPCC)? And can they actually be extrapolated to the real world? A new systematic framework can help understand what to improve in the next generation of scenarios and explore how to make ambitious emission reductions possible by strengthening enabling conditions. 

While the IPCC is in the midst of the drafting cycle of the Sixth Assessment Report, whose publication will start in the second half of 2021 –  one of the most relevant events for the global climate change community, there is an ongoing debate on how to assess the feasibility of ambitious climate mitigation scenarios developed through integrated assessment models and to which extent they are actually achievable in the real world. In their new study published in Environmental Research Letters, researchers from the RFF-CMCC European Institute on Economics and the Environment (EIEE) and IIASA developed a systematic framework that allows identifying the type, timing, and location of feasibility concerns raised by climate mitigation scenarios.

Feasibility is a complex concept that is currently getting significant academic attention. The authors build on the past advancements in theoretical discussions and propose to operationalize feasibility in terms of timing, disruptiveness and scale of transformation across geophysical, technological, economic, institutional and socio-cultural feasibility dimensions. A feasibility evaluation of each indicator in each decade is developed, and a flexible aggregation procedure allows assessing feasibility concerns across dimensions and time. This flexible approach allows looking at the “big picture”, to assess for instance which dimension raises major feasibility concerns, but also analyzing more detailed questions such as intertemporal trade-offs within and across different dimensions.

This systematic framework is extremely useful to understand what to improve in the next generation of scenarios but also to analyze more systematically what type of enabling factors might bring us closer to more ambitious mitigation paths.

The paper just published applies the framework to the publicly available scenario set from the IPCC Special Report on Global Warming of 1.5°C. “One of our major findings is that currently many scenarios assume relatively fast overall decarbonization rate in regions which have a relatively low mitigation capacity”, says Elina Brutschin, a Research Scholar at IIASA within the Transformative Institutional and Social Solutions Research Group, and first author of the study. “This suggests that many feasibility concerns are related to institutional constraints such as government effectiveness”. While improving the quality of governance in many regions might be complicated, targeted capacity building and investments can significantly contribute to overcoming this challenge.

“Currently, to assess socio-cultural feasibility concerns, we focus on the transformation that is manifested through behavioral changes in diets and energy consumption. It is a research branch that shows great potential and opens up a lot of critical work to achieve more and more detailed results. In the future we plan to improve our evaluation of socio-cultural feasibility concerns by including more indicators and incorporating insights on attitudes and behavioral changes from the social sciences”, says Silvia Pianta, a Postdoctoral Researcher EIEE and PhD Fellow at Bocconi University. “Here we find that the current generation of scenarios does not explore demand-side mitigation to its full potential and that more research is necessary in this area”, adds Bas van Ruijven, who is the leader of the Sustainable Service Systems (S3) group in the Energy, Climate, and Environment (ECE) program at IIASA.

Massimo Tavoni, Director of EIEE and Professor of Climate Change Economics at Politecnico di Milano, highlights that the framework allows tracing important intertemporal trade-offs. “As argued in past studies focusing on mitigation costs, we now clearly show that delaying global climate action increases feasibility risks, because delayed action requires an overall larger system to be transformed much faster and by relying on new technologies”. Valentina Bosetti, Senior Scientist at EIEE and Professor at the Economics Department of Bocconi University, adds that “a better understanding of inter-temporal and inter-dimensional trade-offs, incorporating insights from experts and policymakers, is essential to take the feasibility concepts to the next level”.

As part of this framework, an interactive visual tool was developed with the key contribution of Giacomo Marangoni, Researcher at EIEE and Assistant Professor at Politecnico di Milano,  who points out that “a new data visualization method is extremely valuable when looking at multidimensional concepts such as feasibility. We developed a tool that allows visualizing our feasibility evaluations for different scenarios and assessing the sensitivity of our results to the definition of different feasibility concern thresholds”.

Finally, Keywan Riahi, who is the Director of the Energy, Climate, and Environment Program at IIASA, summarizes that  “a new versatile framework was developed that can be applied to any set of scenarios and constantly improved by incorporating new insights from the empirical literature on what is feasible in the real world”. He also adds that “while currently the framework was developed to evaluate global scenarios, it can be adjusted to have a more systematic evaluation of regional or national feasibility concerns”.

Reference:
Brutschin, E., Pianta, S., Tavoni, M., Riahi, K.,  Bosetti, V., Marangoni, G., and van Ruijven, B. (2021) A multidimensional feasibility evaluation of low-carbon scenarios. Environmental Research Letters.
https://doi.org/10.1088/1748-9326/abf0ce