6.2.12 (HL)—Climate model scenarios

A climate scenario is a conditional ‘if–then’ pathway based on stated emissions, technology, policy and socioeconomic assumptions—not a guaranteed forecast.

Compare scenarios by holding the question and model framework constant, then state which emissions, technology, policy and socioeconomic assumptions differ. Read output ranges for sea-level rise, local temperature and precipitation over the same time horizon.

A lower-emissions pathway may project less warming and sea-level rise, but local precipitation can still vary by region and model; the result is conditional on the scenario assumptions.

Report assumptions, time horizon, location, variable, model range and uncertainty before comparing impacts.

Scenario labels are not predictions of what must happen; they describe consequences of choices and conditions.