Policy dialogues in integrated assessment modelling (IAM) to strengthen climate change mitigation and adaptation

The authors critique current integrated assessment modelling (IAM), specifically as used in the IPCC Special Report on Global Warming of 1.5°C (SR15), for being biased toward market-based policies and global cost-optimization while ignoring local priorities and institutional barriers. They propose a 'fit-for-purpose' paradigm where models are selected based on stakeholder-defined questions and indicators, rather than fitting questions to existing models. This bottom-up approach is presented as essential for creating inclusive, voluntary low-carbon transitions, particularly in complex environments like cities and coastal areas. The brief suggests that this shift in process—not necessarily in the models themselves—is required for future IPCC reports and the Paris Agreement's Global Stocktake.

• Current integrated assessment modelling (IAM) results are skewed toward market-based mechanisms and mitigation efforts in developing and emerging economies because 'optimal' is typically defined as global least-cost or maximum utility.
• The pathways presented in the IPCC Special Report on Global Warming of 1.5°C (SR15) do not reflect the actual preferences or policies of NGOs, industry groups, or national governments, nor do they mirror how climate policy decisions are made in reality.
• Low-carbon transition policies are frequently driven by factors other than climate change, such as public health improvements and job creation, and are heavily dependent on local context.
• A 'fit-for-purpose' IAM approach requires selecting models based on the specific questions stakeholders need answered and using indicators relevant to the target audience, such as local employment figures rather than national GDP.
• Engaging stakeholders in the scoping of policy assessments can increase the identification of negative outcomes and implementation barriers by approximately 75% compared to relying solely on experts.
• Stakeholder-driven modelling is especially critical for cities and coastal areas due to high population densities and the complex competition between various human and natural systems.
• The authors suggest that IAMs should be used to explicitly investigate politically sensitive issues, such as the inertia caused by fossil fuel companies or dictatorships and the removal of counterproductive market-based structures.

APA

van Vliet, O., & Takama, T. (2018). Policy dialogues in integrated assessment modelling (IAM) to strengthen climate change mitigation and adaptation. Climate Strategies. https://climatestrategies.org/wp-content/uploads/2018/10/P2933_CS_Vliet_Takama_PRINT.pdf

Chicago

van Vliet, Oscar, and Takeshi Takama. Policy dialogues in integrated assessment modelling (IAM) to strengthen climate change mitigation and adaptation. Climate Strategies, 2018. https://climatestrategies.org/wp-content/uploads/2018/10/P2933_CS_Vliet_Takama_PRINT.pdf.

Wikipedia

{{cite report |last1=van Vliet |first1=Oscar |last2=Takama |first2=Takeshi |title=Policy dialogues in integrated assessment modelling (IAM) to strengthen climate change mitigation and adaptation |publisher=Climate Strategies |date=2018 |url=https://climatestrategies.org/wp-content/uploads/2018/10/P2933_CS_Vliet_Takama_PRINT.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{vanvliet2018policy, author = {van Vliet, Oscar and Takama, Takeshi}, title = {{Policy dialogues in integrated assessment modelling (IAM) to strengthen climate change mitigation and adaptation}}, institution = {Climate Strategies}, year = {2018}, url = {https://climatestrategies.org/wp-content/uploads/2018/10/P2933_CS_Vliet_Takama_PRINT.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }