If greenhouse gas emissions remain at current levels, global sea-level rise will by 70 to 120 centimeters by 2100, according to the results of a new survey of 90 of the world’s most active ocean and climate scientists.

The survey was conducted by researchers from the United States and Germany, and published in the recent Quaternary Science Reviews. It is the largest survey of scientists on sea-level rise ever, with over 90 scientists from 18 countries participating.





The survey focused on two scenarios: one, in which current greenhouse gas emissions remain at current levels. This scenario, according to Stefan Rahmstorf from the Potsdam Institute for Climate Impact Research, “would threaten the survival of some coastal cities and low-lying islands.” The other scenario in the survey studied significant reductions in greenhouse gas emissions; in this scenario, sea-level rise would be slightly lower, at 40–60 centimeters by 2100.

The report acknowledged the uncertainties in predicting sea-level rise due to the diverse and complex influences which affect the rise. The authors acknowledge that most high-profile, recent predictions of sea-level rise have turned up too conservative. Observed sea-level rise as measured by satellites over the past two decades, say the authors, has exceeded earlier expectations. Similarly, current predictions of sea-rise by the Intergovernmental Panel on Climate Change (IPCC) have now been revised upwards by about 60% from predictions that were published as recent as 2007. The pattern is clear: actual sea-level rise has been more severe than many scientists have predicted.

Aware both of governmental largesse in greenhouse gas mitigation efforts (manifested by the anemic results of the Warsaw climate conference this week) and the fossil-fuel industry’s insatiable hunger for digging up ever-increasing sources of fossil fuels sources — despite the clear warnings about continued emissions (manifested by Shell’s new plan for Arctic drilling) — the scientists involved in this survey indeed predict the higher-end scenario for greenhouse gas emissions, and resulting catastrophic sea-level rise.