Long-term sea-level rise implied by 1.5 degree and 2 degree Celsius warming levels

A new study led by Michiel Schaeffer of Climate Analytics explores the effect of various potential emission pathways on future sea-level rise, using a model based on data on sea levels over the last millennium.

Date20 August 2012

Some further sea-level rise is already inevitable, with the best possible case being a rise of 59 cm above 2000 levels over the twenty-first century following a hypothetical reduction of emissions to zero by 2016. However, the study underlines the significant impact that different mitigation scenarios will have in determining the extent and rate of sea-level rise by 2100, but even stronger by 2300.

A scenario in which global mean temperature is allowed to increase to 3 degrees Celsius above pre-industrial levels, for example, would involve sea-level rise of between 2 and 4 m over the coming three centuries, while ambitious mitigation targets which limit warming to 1.5 degrees could substantially slow down the rate at which it occurs, resulting in a rise of 1.5 m by 2300, and possibly less than that.

A number of uncertainties are associated with these projections, particularly given the difficulty of predicting the behaviour of the Greenland and Antarctic ice sheets, precise models of which are still being developed. What is clear is that a commitment to multi-meter sea level rise after 2100 can be avoided by immediate action to cut greenhouse-gas emissions.

Authors: Michiel Schaeffer (Climate Analytics, Germany, and Wageningen University and Research Centre, The Netherlands), Bill Hare (Climate Analytics, Germany), Stefan Rahmstorf (Potsdam Institute for Climate Impact Research, Germany), and Martin Vermeer (Department of Real Estate, Planning and Geoinformatics, Aalto University School of Engineering, Finland)

The findings of the paper have been reported in a number of articles in the international media. Below are links to a selection:

Think Progress: New studies on sea level rise make clear we must act now

Der Spiegel: Meeresspiegel legt trotz Klimaschutz stark zu

Climate Central: Three new studies on sea-level rise bring new concerns

Grist: Rising Sea Levels: It’s worse than you think

Phys.org: Significant sea-level rise in a 2-degree warming world

Zeenews India: Global warming can lead to significant sea-level rise