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arXiv · 1710.08297

Coastal flood implications of 1.5 {\deg}C, 2.0 {\deg}C, and 2.5 {\deg}C temperature stabilization targets in the 21st and 22nd century

Abstract

Sea-level rise (SLR) is magnifying the frequency and severity of coastal flooding. The rate and amount of global mean sea-level (GMSL) rise is a function of the trajectory of global mean surface temperature (GMST). Therefore, temperature stabilization targets (e.g., 1.5 {\deg}C and 2.0 {\deg}C of warming above pre-industrial levels, as from the Paris Agreement) have important implications for coastal flood risk. Here, we assess differences in the return periods of coastal floods at a global network of tide gauges between scenarios that stabilize GMST warming at 1.5 {\deg}C, 2.0 {\deg}C, and 2.5 {\deg}C above pre-industrial levels. We employ probabilistic, localized SLR projections and long-term hourly tide gauge records to construct estimates of the return levels of current and future flood heights for the 21st and 22nd centuries. By 2100, under 1.5 {\deg}C, 2.0 {\deg}C, and 2.5 {\deg}C GMST stabilization, median GMSL is projected to rise 47 cm with a very likely range of 28-82 cm (90% probability), 55 cm (very likely 30-94 cm), and 58 cm (very likely 36-93 cm), respectively. As an independent comparison, a semi-empirical sea level model calibrated to temperature and GMSL over the past two millennia estimates median GMSL will rise within < 13% of these projections. By 2150, relative to the 2.0 {\deg}C scenario, GMST stabilization of 1.5 {\deg}C inundates roughly 5 million fewer inhabitants that currently occupy lands, including 40,000 fewer individuals currently residing in Small Island Developing States. Relative to a 2.0 {\deg}C scenario, the reduction in the amplification of the frequency of the 100-yr flood arising from a 1.5 {\deg}C GMST stabilization is greatest in the eastern United States and in Europe, with flood frequency amplification being reduced by about half.

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BibTeXRIS

D. J. Rasmussen, Klaus Bittermann, Maya K. Buchanan, Scott Kulp, Benjamin H. Strauss, Robert E. Kopp, Michael Oppenheimer. 2017-10-23. Coastal flood implications of 1.5 {\deg}C, 2.0 {\deg}C, and 2.5 {\deg}C temperature stabilization targets in the 21st and 22nd century. https://doi.org/10.1088/1748-9326%2Faaac87

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