Institute for Governance & Sustainable Development

Sea-Level Rise Accelerating from Human-Caused Warming

Parallel cuts to carbon dioxide and super pollutants can stop half of future rise this century

25 February 2016 – Sea-levels are rising faster than anytime in nearly 3,000 years, according to an analysis published this week in the Proceedings of the National Academy of Sciences, and are expected to rise even faster in the future due to continued climate warming.  A related analysis by Climate Central this week calculated that 67% of coastal floods since 1950 were driven by climate change.

Sea-level rise could be slowed up to 50% by a dual strategy reducing of short-lived super pollutants along with carbon dioxide, according to calculations in an earlier paper. [IGSD’s press release on the Nature Climate Change paper is here.] Short-lived super pollutants (which include black carbon, tropospheric ozone, hydrofluorocarbons (HFCs), and methane) remain in the atmosphere for just days to a few decades, allowing their warming reductions to be felt quickly after mitigation.

Sea-level rise is caused by the melting of land-based glaciers and the expansion of the oceans as they absorb more of heat from continuing climate warming.  There is further evidence that the Greenland Ice Sheet and the West Antarctic Ice Sheet are most likely becoming unstable. These ice sheets hold a vast amount of water that would devastate coastal communities. The National Snow & Ice Data Center notes that “if the Greenland Ice Sheet melted, scientists estimate that sea-level would rise about 6 meters (20 feet). If the Antarctic Ice Sheet melted, sea-level would rise by about 60 meters (200 feet).” Even without total collapse of either ice sheet, business-as-usual emissions scenarios project over four feet of sea-level rise possible by the end of the century.

“The question of just how much disintegration of the polar ice sheets will contribute to sea-level during the 21st century…is ultimately the most important unknown, both with regard to sea-level and potentially with respect to the whole field of climate change,” Princeton climate scientist, Michael Oppenheimer, told The Washington Post.

“Unless we slam on the breaks with fast cuts to the super pollutants along with carbon dioxide, sea-levels will keep rising for many centuries, with the potential for deadly surprises if ice sheet dynamics are more fragile than we previously suspected,” said Durwood Zaelke, President of the Institute for Governance & Sustainable Development.

IGSD’s Primer on HFCs is here.

IGSD’s Primer on Super-Pollutants is here.