As global warming raises sea levels worldwide, scientists have long warned that many low-lying coastal areas will be permanently submerged.
But a new study published on Thursday has found that rising sea levels are likely to pose an additional threat of economic loss in this century, which will move faster: as the oceans rise, powerful coastal storms, Accidental waves and extremely high tides will be able to transport tens of millions of property worldwide and trillions of dollars to millions of dollars at risk of flooding from time to time.
This study, published in Scientific Reports, calculates that 171 million people living today face at least some risk of coastal flooding from extremely high tides or hurricanes when strong winds from hurricanes or other storms cover ocean waters. Are and push. It is onshore. While many are currently protected by sea walls or other defenses, such as not everyone in the Netherlands.
If the nations of the world continue to emit greenhouse gases, and the sea level rises by just 1 to 2 feet, the risk of flooding will increase by about a third of coastal land. In 2050, 204 million people currently living on the coasts will face flood risks. By 2100, it reaches 253 million people under a medium emission scenario called RCP4.5. (The actual number of people at risk may vary, as researchers did not try to predict future coastal population changes.)
Ibru Kierzi, a doctoral candidate at the University of Melbourne in Australia, said, “Even though the average sea level rises relatively slowly, we found that these other flood hazards such as high tides, storms and waves breaking will greatly increase . ” And lead author of the study. “It is important to consider them.”
Areas with particular risk include North Carolina, Virginia, and Maryland in the United States, northern France and northern Germany, the southeastern coast of China, Bangladesh, and the Indian states of West Bengal and Gujarat.
This flood can cause severe economic damage. The study found that people currently living in areas at risk from a 3-foot rise in sea level owned $ 14 trillion in assets in 2011, an amount equal to 20 percent of global GDP that year.
The authors acknowledge that they are highly incomplete estimates of the potential cost of sea-level rise. For one, they do not factor in the possibility that communities will take action to protect themselves, such as raising their homes, building sea walls or withdrawing inland.
The study did not account for any valuable infrastructure, such as roads or factories, which sit in harm’s way. A full economic accounting would require more research, Ms. Kirsky said.
There are already indications that from time to time floods are wreaking havoc in coastal areas. A July analysis by the National Oceanic and Atmospheric Administration found that high-tide flooding in cities along the Atlantic and Gulf Coast has increased five-fold since 2000, a change that is damaging homes, including drinking water. Is supplying and flooding the streets.
The new study improves future coastal flood risk estimates by combining existing models of sea level rise, tides, waves, storms and coastal topography while examining those models against data collected from tidal gauges around the world An attempt has been made to make. In previous research, Ms. Kirszie said, waves were not looked at in such detail on breaking factors that could temporarily raise local sea levels.
Michael Oppenheimer, a climate scientist at Princeton University, said not to be involved in the study, “Trying to increase extreme sea levels and hurricanes is a very complex problem and there are still a lot of uncertainties.” But, he said, it was important for scientists to develop good projections, because if cities like Boston or New York hope to build expensive new storm surge blockers or other defenses, they should plan for decades before higher sea levels arrive Will need to make.
The new study found that only a third of future coastal floods came from rising sea levels that would permanently submerge the lowlands. Two-thirds of the risk came from extreme high tides, storm waves, and potential increases in breaking waves. In many coastal areas, the type of historically rare flood that occurs once every 100 years, on average, may subside every 10 years or by the end of the century.
Scientists say that countries in the world can greatly reduce future flood hazards by cutting emissions faster, especially while Antarctica may reduce the likelihood of rapid ice sheets collapsing later in the century. Will also raise sea level compared to forecast.
But, Dr. The world has become so hot now, said Oppenheimer, that a significant rise in sea level is assured by 2050, no matter what happens to emissions. “This means that we too need to start preparing to adapt now,” he said.