Uncertainty is a common challenge to any long-term planning. This working paper takes stock of how long-term low-emission development strategies submitted to UNFCCC perceive and handle uncertainties, and how scenarios are used to illustrate different pathways that countries may take under uncertainty. Based on the stock-take and literature review, the paper suggests application of a model-assisted quantitative approach to systematically exploring uncertainty and identifying policy-relevant scenarios to improve the practice. To experiment with the applicability and usefulness of the approach, the paper demonstrates a model-assisted scenario analysis. The results illustrate the benefits and applicability of the approach along with some limitations. This publication is intended for researchers and policy analysts who are tasked with or interested in analyses for developing long-term climate strategies.