We present a unified framework for calculating country-specific climate damages resulting from past or future greenhouse gas emissions from any known emitter.  We then demonstrate four applications of this method: calculation of ``carbon debt" owed by individual emitters (e.g. individual people or firms) based on past emissions, calculation of country-level ``loss and damage" payments owed by large historical emitters to developing countries, correction of official GDP time series to reflect climate externalities, and construction of a damage function that maps different levels of future warming to global aggregate economic damages.