Full question: "chance that an AI system exists that can meaningfully improve the ability of non-expert humans to perform sophisticated cyber attacks, develop biological or nuclear weapons, or otherwise cause severe harm"

improve the ability of non-expert humans to perform these tasks. Acting like a somewhat better search engine and surfacing text books isn't enough. The model must be able to take a non-expert human, and make them significantly better at these dangerous tasks. Most frontier labs test for the ability of their models to improve these risks; I will go by their reporting, or if it believed to be untrustworthy, independent third-party reporting.

Current models today are not "smart" enough to actually be useful at allowing non-experts to cause harm. But many people worry this will change, and this is one of the primary reasons why people are worried about the future AI and believe we should not be developing it further. This question tries to understand if we should be worried about this as a concern for future models.