According to a new study, coastal cities in the United States may experience flooding incidents even on a daily basis if sea-level rise is not mitigated.
Researchers from the University of Illinois at Chicago, the University of Hawaii at Mānoa and the U.S. Geological Survey (USGS) collaborated to produce a study that assesses the U.S. coastal flooding patterns in the forthcoming years by quantifying the extreme water-level incidents associated to sea-level rise. The study was published in the Journal Scientific Reports.
In comparison to pre-industrial times, the average global temperature has risen by 1°C as a result of the greenhouse effect. Moreover, current estimates predict twice that rise by 2100. Temperature increase leads to ice melting in the north and south poles, which, in turn, results in seawater level rises.
Currently, the sea level has elevated by 20 centimeters on average compared to the 19th century. However, the rise is not evenly distributed globally and some regions experience more significant changes. According to the Intergovernmental Panel on Climate Change, oceans could rise by 1,1 meters by 2100, if the greenhouse effect is not mitigated.
Scientists utilized prediction models of sea-level rise along with data from 202 tide gauges installed in the coastal regions of the United States to derive the rate of future flooding in those areas. The quantification of sea-level rise was performed by modeling probable emission scenarios.
The results of the study are alarming. It was shown that if sea-level rise is not mitigated, floods that were considered to occur "once in a lifetime" will take place almost every day in 90% of the coastal regions evaluated. These regions include major cities such as Miami, Honolulu or New Orleans. "...the present-day 50-year extreme water level will be exceeded almost every day during peak tide before the end of the 21st century for 90% of the U.S. coast," the study mentions.
Practically, if these predictions are accurate, the viability of coastal regions will be threatened. Future public policy makers will have to provide radical protection projects to address the flooding incidents. Otherwise, the impact on infrastructure and people will be devastating.
Moreover, according to the scientific team, the problems will arise well before the 21st century. Even small changes in the seawater level will result in significant alterations in flooding potential. The eventuality of extreme flooding will double every 5 years, therefore, coastal regions will soon be affected. "Miami, Honolulu, Charleston, Atlantic City, and many other US cities currently experience minor flood levels during tides exacerbated by any storm conditions. If sea-level projections hold, and in the absence of adaptation by 2050, this flooding will become much more widespread, frequent, and severe," Sean Vitousek, a Research Oceanographer at USGS and co-author of the study, warned.