Over the past two decades, climate change provoked the risk of flooding of coastal territories by one and a half times. According to the conclusions of the International Group of Scientists, published in the journal Nature Communications, this increase is caused mainly by increasing the level of sea and the strength of storm engines. In the future, the duration of the exit of the sea outside the coastal strip, including in the Far East, will increase several tens of times. Briefly about the study reported in a press release on phys.org.
Researchers used a digital model of the Alos WORLD 3D surface with a resolution of 30 meters (AW3D30). The AW3D30 was obtained in the period 2006-2011 using optical stereophotogrammetry, when two satellite surface images taken from different positions are compared. The analysis was limited to the coating of the surface model from 60 degrees of northern latitude up to 60 degrees of southern latitude. Scientists also used additional databases to identify two key coastal topography parameters: the tilt of the beach and the maximum ground (subaeral) coast height.
Scientists also used data on sea level anomalies near the coast, wave height and atmospheric states published by various land monitoring services. This made it possible to assess how much the number of cases of overflows through the coastal strip between 1993 and 2015 along the global coastline and predict the further situation.
It turned out that the probability of overflow is the highest in the Gulf of Mexico, southern Mediterranean, West Africa, Madagascar and the Baltic Sea. Over the past two decades, the risk of selling the sea outside the coastline rose by 50 percent. As for the future situation, the number of hours during which the coast of sea water occurs 50 times during the XXI century in the worst scenarios of global warming caused by a high level of anthropogenic emissions.
The number of overflow hours increases in geometric progression, that is, a faster pace than the average speed of sea level increase. According to scientists, it will be noticeably already for 2050, no matter how serious the climate of the Earth will change. By the end of the century, the acceleration will depend on the future scenario of greenhouse gas emissions and, therefore, from raising sea level.
Global warming will make events such as Hurricane Catherine in 2005, Cyclone XINTY 2010 and Typhoon Hayang 2013, more frequent and strong. As the authors of the study predict, countries in tropical regions, North-West USA, Scandinavia and the Far East of Russia are most seriously affected.