Long-term sea-level rise implied by 1.5 °C and 2 °C warming levels
Author: ["Michiel Schaeffer","William Hare","Stefan Rahmstorf","Martin Vermeer"]
Publication: Nature Climate Change
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Abstract
Sea-level rise is one of the key consequences of climate change. Its impact is long-term owing to the multi-century response timescales involved. This study addresses how much sea-level rise will result in coming centuries from climate-policy decisions taken today. Sea-level rise (SLR) is a critical and uncertain climate change risk, involving timescales of centuries1. Here we use a semi-empirical model, calibrated with sea-level data of the past millennium2, to estimate the SLR implications of holding warming below 2 °C or 1.5 °C above pre-industrial temperature, as mentioned in the Cancún Agreements3. Limiting warming to these levels with a probability larger than 50% produces 75–80 cm SLR above the year 2000 by 2100. This is 25 cm below a scenario with unmitigated emissions, but 15 cm above a hypothetical scenario reducing global emissions to zero by 2016. The long-term SLR implications of the two warming goals diverge substantially on a multi-century timescale owing to inertia in the climate system and the differences in rates of SLR by 2100 between the scenarios. By 2300 a 1.5 °C scenario could peak sea level at a median estimate of 1.5 m above 2000. The 50% probability scenario for 2 °C warming would see sea level reaching 2.7 m above 2000 and still rising at about double the present-day rate. Halting SLR within a few centuries is likely to be achieved only with the large-scale deployment of CO2 removal efforts, for example, combining large-scale bioenergy systems with carbon capture and storage4.
Cite this article
Schaeffer, M., Hare, W., Rahmstorf, S. et al. Long-term sea-level rise implied by 1.5 °C and 2 °C warming levels. Nature Clim Change 2, 867–870 (2012). https://doi.org/10.1038/nclimate1584
