The relationship between greenhouse-gas forcing, global mean temperature change and sea-level rise due to thermal expansion of the oceans is investigated using upwelling–diffusion and pure diffusion models. The sensitivities of sea-level to short-timescale forcing and deep-water formation rate changes are examined. The greenhouse-gas-induced thermal expansion contribution to sea-level rise between 1880 and 1985 is estimated at 2–5 cm. Projections are made to the year 2025 for different forcing scenarios. For the period 1985–2025 the estimate of greenhouse-gas-induced warming is 0.6–1.0 °C. The concomitant oceanic thermal expansion would raise sea level by 4–8 cm.