Publication Abstracts

Sweet et al. 2017

Sweet, W.V., R. Horton, R.E. Kopp, A.N. LeGrande, and A. Romanou, 2017: Sea level rise. In Climate Science Special Report: Fourth National Climate Assessment, Volume I. D.J. Wuebbles, D.W. Fahey, K.A. Hibbard, D.J. Dokken, B.C. Stewart, and T.K. Maycock, Eds. U.S. Global Change Research Program, pp. 333-363, doi:10.7930/J0VM49F2.

Global mean sea level (GMSL) has risen by about 7-8 inches (about 16-21 cm) since 1900, with about 3 of those inches (about 7 cm) occurring since 1993 (very high confidence). Human-caused climate change has made a substantial contribution to GMSL rise since 1900 (high confidence), contributing to a rate of rise that is greater than during any preceding century in at least 2,800 years (medium confidence).

Relative to the year 2000, GMSL is very likely to rise by 0.3-0.6 feet (9-18 cm) by 2030, 0.5-1.2 feet (15-38 cm) by 2050, and 1.0-4.3 feet (30-130 cm) by 2100 (very high confidence in lower bounds; medium confidence in upper bounds for 2030 and 2050; low confidence in upper bounds for 2100). Future pathways have little effect on projected GMSL rise in the first half of the century, but significantly affect projections for the second half of the century (high confidence). Emerging science regarding Antarctic ice sheet stability suggests that, for high emission scenarios, a GMSL rise exceeding 8 feet (2.4 m) by 2100 is physically possible, although the probability of such an extreme outcome cannot currently be assessed. Regardless of pathway, it is extremely likely that GMSL rise will continue beyond 2100 (high confidence).

Relative sea level (RSL) rise in this century will vary along U.S. coastlines due, in part, to changes in Earth's gravitational field and rotation from melting of land ice, changes in ocean circulation, and vertical land motion (very high confidence). For almost all future GMSL rise scenarios, RSL rise is likely to be greater than the global average in the U.S. Northeast and the western Gulf of Mexico. In intermediate and low GMSL rise scenarios, RSL rise is likely to be less than the global average in much of the Pacific Northwest and Alaska. For high GMSL rise scenarios, RSL rise is likely to be higher than the global average along all U.S. coastlines outside Alaska. Almost all U.S. coastlines experience more than global mean sea level rise in response to Antarctic ice loss, and thus would be particularly affected under extreme GMSL rise scenarios involving substantial Antarctic mass loss (high confidence).

As sea levels have risen, the number of tidal floods each year that cause minor impacts (also called "nuisance floods") have increased 5- to 10-fold since the 1960s in several U.S. coastal cities (very high confidence). Rates of increase are accelerating in over 25 Atlantic and Gulf Coast cities (very high confidence). Tidal flooding will continue increasing in depth, frequency, and extent this century (very high confidence).

Assuming storm characteristics do not change, sea level rise will increase the frequency and extent of extreme flooding associated with coastal storms, such as hurricanes and nor'easters (very high confidence). A projected increase in the intensity of hurricanes in the North Atlantic (medium confidence) could increase the probability of extreme flooding along most of the U.S. Atlantic and Gulf Coast states beyond what would be projected based solely on RSL rise. However, there is low confidence in the projected increase in frequency of intense Atlantic hurricanes, and the associated flood risk amplification and flood effects could be offset or amplified by such factors as changes in overall storm frequency or tracks

Export citation: [ BibTeX ] [ RIS ]

BibTeX Citation

@inbook{sw03000d,
  author={Sweet, W. V. and Horton, R. and Kopp, R. E. and LeGrande, A. N. and Romanou, A.},
  editor={Wuebbles, D. J. and Fahey, D. W. and Hibbard, K. A. and Dokken, D. J. and Stewart, B. C. and Maycock, T. K.},
  title={Sea level rise},
  booktitle={Climate Science Special Report: Fourth National Climate Assessment, Volume I},
  year={2017},
  pages={333--363},
  publisher={U.S. Global Change Research Program},
  address={Washington, D.C.},
  doi={10.7930/J0VM49F2},
}

[ Close ]

RIS Citation

TY  - CHAP
ID  - sw03000d
AU  - Sweet, W. V.
AU  - Horton, R.
AU  - Kopp, R. E.
AU  - LeGrande, A. N.
AU  - Romanou, A.
ED  - Wuebbles, D. J.
ED  - Fahey, D. W.
ED  - Hibbard, K. A.
ED  - Dokken, D. J.
ED  - Stewart, B. C.
ED  - Maycock, T. K.
PY  - 2017
TI  - Sea level rise
BT  - Climate Science Special Report: Fourth National Climate Assessment, Volume I
SP  - 333
EP  - 363
DO  - 10.7930/J0VM49F2
PB  - U.S. Global Change Research Program
CY  - Washington, D.C.
ER  -

[ Close ]

• Return to 2017 Publications

• Return to Publications Homepage