Observation-based selection of climate models projects Arctic ice-free summers around 2035

Abstract Arctic sea ice has been retreating at an accelerating pace over the past decades. Model projections show that Ocean could be almost free in summer by middle of this century. However, uncertainties related to these are relatively large. Here we use 33 global climate models from Coupled Intercomparison Project 6 (CMIP6) and select best capture observed sea-ice area volume northward ocean heat transport refine model ice. This selection leads lower relative multi-model mean without ice-free conditions occur as early around 2035. These results highlight a potential underestimation future loss when including all CMIP6 models.