The interpretation of science-based targets for cities - Validating Deadline 2020, One Planet City Challenge, and Tyndall Local Carbon Budget Tool

Abstract

Abstract We scrutinize widely-used, distinct methods to set city-level climate goals: Deadline 2020, One Planet City Challenge, and Tyndall Local Carbon Budget Tool. Through meticulous verification and validation of data input, calculation processes, and documentation, the exercise assesses whether the methods are fit-for-purpose. Our results establish confidence in all methods but given limitations and high uncertainties involved around emission target setting, we conclude that reduction goals should be understood as reference points for targeting the highest level of ambitious action on the ground. We stress the precautionary principle, particularly in cities of the Global South, so that climate actions remain well-grounded, considering each city's capacity and influence. This overdue exercise emphasizes the need for transparent and multi-faceted methods, adaptable to different city contexts, to ensure continued effectiveness in guiding city-level climate action around the globe. We propose recommendations that emphasize multi-level governance and prioritize action through a more nuanced approach to evaluating and enhancing city climate targets.