Mitigation, Adaptation and the Lag

Carbon dioxide already emitted remains airborne for centuries, and the oceans take decades to finish warming in response to what is already there, so a degree of further change is committed whatever happens to emissions now. Mitigation acts on the far end of that lag by cutting future emissions; adaptation acts on the near end by reducing harm from change already under way. Treating them as alternatives misreads the timescales — the real question is how to split a budget across two different decades.