How effective are climate solutions aimed at “using less stuff and using it better”? New research, led by CMCC, evaluates the future impacts of circular economy strategies holistically, accounting for systemic interactions and other factors that vary by culture and income but are often overlooked. “Without proper evaluation tools, we risk implementing well-intentioned policies that deliver disappointing results – or worse, that accidentally undermine our climate goals,” says lead author of the study and CMCC researcher Leticia Magalar. 

Integrated Assessment Models (IAMs) are a critical tool to generate insights into energy system transformations vital for achieving net-zero emissions. With rising interest for circular economy policies – spanning recycling, repair, reuse, and consumption reduction – models need to evolve to model the climate benefits of circularity with greater detail and accuracy.

A new study published in Resources, Conservation and Recycling identifies important opportunities to enhance IAMs by better incorporating the climate impacts of circular economy policies. The research, led by CMCC’s Leticia Magalar, presents a comprehensive framework to guide improvements across IAMs used worldwide to inform climate policy.

“For years, climate models have told us we need to transform our energy systems – and they’re right. But they’ve been largely silent on another powerful climate solution: using less stuff and using it better,” explains Magalar. “Our research shows this silence isn’t because circular economy doesn’t matter – it’s because our models aren’t yet equipped to evaluate it properly. The good news is that we now have a clear path forward.”

The study analyzes 15 IAMs, finding that current model coverage is concentrated on material use reduction (50%) and recycling (28%) but less so on repair, reuse, and product lifespan extension (together around 19%). Additionally, supply chain representations are incomplete, often focusing on manufacturing and consumption stages, while largely missing resource extraction and waste management phases.

“We can’t plan what we can’t measure,” says Magalar. “The stakes are high because circular economy strategies aren’t guaranteed climate wins. Recycling can be energy-intensive. Keeping old appliances longer extends the lifetime of less efficient models. Savings from buying refurbished goods might get spent on carbon-heavy activities. Without proper evaluation tools, we risk implementing well-intentioned policies that deliver disappointing results – or worse, that accidentally undermine our climate goals.”

The research reveals that 70% of present studies assume circular policies will meet predetermined outcomes instead of rigorously modeling how specific policies perform in practice. This points to an important research and policy evaluation gap.

Furthermore, none of the models analyzed capture how circular economy policies need to work at a systems level. “A recycling policy doesn’t succeed in isolation – it requires proper waste sorting by households, collection infrastructure, factories equipped to use recycled materials, and products designed to be recyclable in the first place. All these points are influenced by cultural differences and income levels that are not accounted for,” says Magalar.

In contrast, the framework developed in the study offers practical solutions to integrate circular economy policies holistically, accounting for systemic interactions like the dependence of recycling programs on waste sorting infrastructure, industrial capacity, and product design – factors that vary by culture and income but are often overlooked in current models

The goal is to make sure that policymakers have accurate and case specific information so that they can ensure that circular economy investments are aligned with climate goals and that they can adjust strategies to make them more effective where they may fall short.

“Policymakers are already implementing circular economy measures – the EU alone has dozens of such policies in place. But without proper modeling tools, we’re essentially flying blind on their climate benefits,” explains Magalar. “Our framework gives the modeling community a clear blueprint for improvement.”

This study represents a major step toward enabling IAMs to provide more complete, nuanced guidance on the circular economy’s role in the transition to a sustainable, net-zero emissions future.

“The bottom line is that policymakers can now have a clearer understanding of how circular economy strategies are currently addressed in climate models – and what gaps must be closed to support smarter, more effective mitigation planning,” concludes Magalar.

CMCC led this research, bringing together expertise in policy science, integrated assessment modeling, and energy planning. The research was conducted as part of a collaboration between CMCC and the Federal University of Rio de Janeiro.

For more information:

Magalar, L., Verdolini, E., Szklo, A., (2026). Unlocking circular economy policies in integrated assessment models. Resources, Conservation and Recycling, 214, 108094. https://doi.org/10.1016/j.resconrec.2025.108614