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Title: Can paleoclimate evidence rule out climate sensitivity above 5 K?
Plain: Several recent climate models warm by more than 5 degrees for doubled CO2. Past climates such as the last ice age may show this is too much.
Precise: Determine whether combined constraints from the Last Glacial Maximum, the mid-Pliocene, the early Eocene and the historical record exclude $\mathrm{ECS} > 5\ \mathrm{K}$ at the 95 percent level, accounting for state dependence of feedbacks and forcing uncertainties. An answer is a posterior probability for $\mathrm{ECS} > 5\ \mathrm{K}$ with stated assumptions.
Settled by: Bayesian synthesis of paleoclimate proxies and model emergent constraints with explicit state-dependence and structural uncertainty.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: partially-resolved
Status note: (empty)
Posed since: (empty)