J-PAL North America, the MIT Abdul Latif Jameel Poverty Action Lab regional office, convened the second cohort of the Climate Action Learning Lab this spring, bringing together 17 climate leaders from four U.S. government agencies and nonprofit groups. Over four months participants sharpened their ability to generate and use evidence, translate research insights into program designs, and pinpoint policy interventions that can be rigorously evaluated. The Lab was launched in 2025 to meet the urgent need for solid evaluation of programs that boost climate resilience and accelerate low‑carbon transitions. By helping participants define interventions and draft evaluation plans, the Lab aims to produce evidence on which approaches work best and for whom. Scientific advisor Peter Christensen notes that embedding rigorous evaluation allows precise measurement of emissions‑reduction impacts, reveals behavioral mechanisms and cost‑effectiveness, and builds a knowledge base for better policymaking. The second cohort represented Boston’s Sustainability Office, the Hawaii Climate Change Mitigation and Adaptation Commission, the Oregon Department of Environmental Quality, and the Electrification Coalition. From May to August they received training on impact evaluation, research‑question formulation, and assessing the external validity of existing evidence. Participants also explored J-PAL’s newly released Climate Action Evidence Review, which synthesizes current findings and highlights critical research gaps. Boston’s team examined a potential evaluation of its Boston Energy Saver program to gauge effects on small‑business energy cost savings and incentive uptake. Hawaii evaluated three candidate programs and selected a rebate‑finder tool that connects residents with climate initiatives, focusing on uptake among vulnerable communities. Throughout the Lab, J-PAL researchers held personalized strategy sessions to advise on feasibility and evidence gaps. In August J-PAL North America hosted a virtual summit where cohort members presented priority research questions and evaluation plans, receiving feedback that clarified next steps. Ashley Blackwell of the Electrification Coalition said the Lab gave her team a strong foundation for grant applications, new project design, and early‑stage impact assessment. Although formal programming has ended, J-PAL North America will continue to support randomized evaluations through researcher partnerships and funding opportunities, and will integrate this cohort into the Climate Action Community of Practice alongside the inaugural members to keep exchanging ideas and advancing evidence‑informed mitigation and adaptation strategies. Review