08 October 2015

Past and Future Sea-Level Rise Along the Coast of North Carolina

Summary

We evaluate relative sea level (RSL) trajectories for North Carolina, USA, in the context of tide-gauge measurements and geological sea-level reconstructions spanning the last ∼11,000 years. RSL rise was fastest (∼7 mm/yr) during the early Holocene and slowed over time with the end of the deglaciation. During the pre-Industrial Common Era (i.e., 0–1800 CE), RSL rise (∼0.7 to 1.1 mm/yr) was driven primarily by glacio-isostatic adjustment, though dampened by tectonic uplift along the Cape Fear Arch. Ocean/atmosphere dynamics caused centennial variability of up to ∼0.6 mm/yr around the long-term rate. It is extremely likely (probability P = 0.95) that 20th century RSL rise at Sand Point, NC, (2.8 ± 0.5 mm/yr) was faster than during any other century in at least 2,900 years. Projections based on a fusion of process models, statistical models, expert elicitation, and expert assessment indicate that RSL at Wilmington, NC, is very likely (P = 0.90) to rise by 42–132 cm between 2000 and 2100 under the high-emissions RCP 8.5 pathway. Under all emission pathways, 21st century RSL rise is very likely (P > 0.90) to be faster than during the 20th century. Due to RSL rise, under RCP 8.5, the current ‘1-in-100 year’ flood is expected at Wilmington in ∼30 of the 50 years between 2050-2100.

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